Released July 18, 2025 13:39 EST

2025, Scientific Investigations Report 2025-5054

Chloe Codner, Nicole C. Gammill, Isaac A. Dale, Amy S. Morris, Ethan A. Kirby, Grant M. Graves, Evin J. Fetkovich, Derrick L. Wagner, Jon E. Sanford, Colin A. Baciocco

The 1973 Oklahoma Groundwater Law (Oklahoma Statutes §82-1020.5) requires that the Oklahoma Water Resources Board conduct hydrologic investigations of the State’s groundwater basins to support a determination of the maximum annual yield for each groundwater basin. At present (2025), the Oklahoma Water Resources Board has not established a maximum annual yield for the Red River alluvial aquifer east of Lake Texoma. To support the evaluation and determination of a maximum annual yield, a hydrogeologic framework and conceptual groundwater-flow model were developed to assess groundwater availability in the Red River alluvial aquifer east of Lake Texoma.

The scope of this hydrologic investigation is the alluvium and terrace containing the Red River alluvial aquifer in Oklahoma between Lake Texoma, the Texas State line, and the Arkansas State line, an extent referred to in this report as “the eastern part of the Red River alluvial aquifer.” Parts of the alluvium and terrace extent in Arkansas and Texas are included in some analyses to address hydrologic influences from outside the aquifer’s boundaries in Oklahoma.

The eastern part of the Red River alluvial aquifer in southeastern Oklahoma consists of approximately 401,280 acres of Quaternary alluvium and terrace deposits associated with the Red River and its major tributaries. Mean annual recharge to the aquifer for the 1980–2022 study period was estimated to be 8.62 inches per year, or 17.98 percent of the mean annual precipitation over the same period (47.94 inches). This mean annual recharge rate is equivalent to an inflow of approximately 288,250 acre-feet per year for the eastern part of the Red River alluvial aquifer. Recharge estimated using the Soil-Water-Balance code accounts for 98.7 percent of the conceptual-model inflows to the eastern part of the Red River alluvial aquifer. Saturated-zone evapotranspiration accounts for 11.9 percent and net streambed seepage accounts for 87.4 percent of the outflows in the conceptual model.

Released July 17, 2025 14:22 EST

2025, Scientific Investigations Report 2025-5056

Janet H. Curran

The U.S. Geological Survey, in cooperation with the Alaska Department of Transportation and Public Facilities, inventoried selected special conditions for annual peak flows and identified extreme floods at streamgages in Alaska through water year 2022 to facilitate hydrologic analysis. Special conditions identified from U.S. Geological Survey gaging records and basin characteristics included regulation and diversion, urbanization, indeterminate drainage areas, drainage areas less than the minimum used in regional analyses, glacial lake outburst floods, other outburst floods, and snowmelt floods. For peak flows that occurred during calendar years 1980–2019, an atmospheric river dataset was used to identify atmospheric river presence or absence on the dates peak flows occurred. Extreme floods (defined as peak flows exceeding the 1-percent annual exceedance probability flood magnitude or an empirical measure of relative magnitude using Creager’s coefficient C) were identified and associated with flood-generating mechanisms using the other inventoried special conditions and other information.

The gaging record contained glacial lake outburst floods at 15 streamgages and other types of outburst floods at 10 streamgages. Non-outburst peak flows in Alaska resulted from a mixture of rainfall and melt-based flood-generating mechanisms in all but the most rain-dominated seasonal flow regime. Melt-based flood-generating mechanisms included snowmelt, high-elevation snow and ice melt, or rain-on-snow events. Atmospheric rivers were common in Alaska and conterminous basins in Canada, occurring in that region on 67 percent of the days in the calendar year 1980–2019 period. Atmospheric rivers were more common on the days of peak flows and even more common on the days of non-outburst extreme floods. The percentage of days when an atmospheric river was present increased to 78 percent for the days of peak flows in that period and to 83 percent for the days of non-outburst extreme floods in that period. Of 149 extreme floods in the gaging record, 38 were generated by outburst floods. Of the non-outburst extreme floods, 72 percent were generated by rainfall and 26 percent were generated by melt-based processes or a combination of rainfall and melt-based processes. Flood-generating mechanisms could not be determined for the final 2 percent of the non-outburst extreme floods because the month and day of the peak flows were unknown and no other information was available. Secondary factors strongly associated with extreme floods included antecedent rain and streamflow conditions and warm storm conditions that produced rain instead of snow or generated snowmelt.

Released July 17, 2025 09:08 EST

2025, BioScience

Marissa Weiss, Addie Rose Holland, Anthony W. D'Amato, Linda A. Deegan, William H. Farmer, Christopher Hoving, Ambarish Karmalkar, Alexander W. Latzka, Madeline Magee, Peter B. McIntyre, Toni Lyn Morelli, Michael Notaro, Nancy Olmstead, Richard Palmer, Nancy Pau, Rosalind B. Renfrew, Christine A. Ribic, John Sheppard, Michelle D. Staudinger, Benjamin Zuckerberg, Bethany A. Bradley

The rapid pace of climate change demands changes in management practices. Despite abundant climate adaptation research, the implementation of climate adaptation can lag in the management space. In the present article, we argue that relationship-centered engagement—establishing and maintaining relationships among researchers and natural resource managers—is critical for bridging the research–management gap. We evaluated researcher–manager partnerships within the US Northeast Climate Adaptation Science Center and identified three cultural shifts that institutions, funders, researchers, and managers could adopt to boost the odds of translating findings into action: acknowledging and supporting the central role of relationships in creating and implementing actionable science, lengthening funding timelines to better support establishing and maintaining relationships, and aligning institutional rewards to support relationship building. A renewed focus on relationships can lead to more diverse and effective partnerships that bridge knowledge to practice and hasten adaptation to climate change.

Released July 16, 2025 09:26 EST

2025, Ecological Solutions and Evidence (6)

Bea Combs-Hintze, Jeffrey A. Hostetler, C.S. Calleson, B. Basset, C. Ainsworth, Julien Martin

1. Boat collisions are a known and increasing threat to many marine wildlife populations. The Florida manatee Trichechus manatus latirostris is a key example of a species with high boat-related mortality, whose long-term viability and population are limited by human activities in shared habitats. The goal of this work was to quantify the probability of lethal injury to Florida manatees using community-reported data on collisions with boats. We test the hypothesis that higher boat speeds increase the probability of lethal injury to manatees. Empirical data to test this hypothesis are collected opportunistically, with low sample sizes and uncertainty in reported boat speed.
2. We fit a logistic regression model using Bayesian inference with Markov Chain Monte Carlo to community-reported collision data. We also present results for two errors-in-variables modelling approaches that account for uncertainty in boat speeds reported as qualitative values. The first uses a multiple imputation approach, whereas the second uses Bayesian estimation with informed priors. We evaluated issues related to quasi-separation, sample size, and measurement errors using simulated data.
3. The models predicted that the probability of lethal injury increased at greater strike speed. However, the small number of records with low boat speed or where the injury was considered non-lethal contributed to uncertainty around this functional relationship. Although the relationships were consistent among models, the uncertainty was greater for the errors-in-variables models.
4. Practical implication. When combined with information on manatee and boat abundance and behaviour, the results of this analysis can be used to predict the number of deadly collisions, test alternative management scenarios and inform speed zone regulations. We also identify ways to improve data reporting to reduce uncertainty in the effect of boat speed on lethal injury to marine wildlife. This type of analysis can be applied to any marine animal where records of collisions with boats are kept.

Released July 15, 2025 10:35 EST

2025, Scientific Investigations Report 2025-5045

Scott M. Carpenter, Martin C. Holdrege, Daniel R. Schlaepfer, Jessica Phillips, Paul Griffin, William K. Lauenroth, John B. Bradford

This report synthesizes current (2024) science-based knowledge related to the impacts of climate change on big sagebrush vegetation in Western North America. This effort was conducted through the U.S. Geological Survey working with the Bureau of Land Management as part of multiple science syntheses to aid management agencies developing environmental impacts assessments in response to human-related or caused events. This report reviews the potential impacts climate change may have on sagebrush vegetation and related management decisions. The body of the synthesis introduces the diverse impacts of climate change across the region by first focusing directly on what climate change may entail in terms of altered temperature and precipitation patterns. The report then discusses how these changes could likely affect individual plant species based on experimental results and scale the impacts to species distributions and community composition. The synthesis section ends by surveying efforts to model potential future changes in habitat. The report goes on to link the synthesis conclusions to individual land uses or land management decisions, such as forage resources, restoration or fuel treatment. Finally, the report provides a section that discusses the pros and cons of available datasets that model the potential future of vegetation in the sagebrush region.

Released July 15, 2025 09:18 EST

2025, Environmental DNA (7)

Melisa E. Kozaczek, Stephen Frank Spear, Tyler J. Untiedt, Paul Albosta, Caden Jungbluth, Jared J. Homola, Elliott Barnhart, Christopher M. Merkes

Recent developments in molecular testing have created the opportunity for biologists and managers to detect environmental DNA (eDNA) of target species rapidly and without the requirement of a laboratory. These point-of-use protocols may be especially useful for early detection and rapid response for invasive species or surveillance for at-risk native species, where timely management decisions are critical. Point-of-use eDNA protocols also facilitate wider and less expensive implementation of eDNA methods. One of the key components to an effective point-of-use protocol is a rapid DNA extraction method. Several rapid extraction protocols are suitable for implementation in the field, but information regarding their relative effectiveness is lacking. We evaluated extraction efficiency of four DNA rapid extraction protocols using filters spiked with primary cultured grass carp (Ctenopharyngodon idella) gill cells. The extraction methods included two syringe-based column extractions, a lysis and extraction solution, and a divalent cation chelation resin (Chelex) extraction protocol alongside a laboratory-based control kit. We estimated DNA yield using a newly designed quantitative polymerase chain reaction (qPCR) assay targeting the grass carp nuclear genome. We evaluated two additional factors, filter type (mixed cellulose ester [MCE] and polyethersulfone [PES]) and background eDNA source (aquaculture or river). The lysis and extraction solution and Chelex extraction both had the highest overall yield, with MCE filters further increasing Chelex yield while the enzyme extraction yield was dependent on interaction with both filter and eDNA source. Our results indicate that rapid extraction protocols, such as solutions with short heating steps, are effective for DNA isolation and help to increase the overall accessibility of eDNA analyses.

Released July 15, 2025 07:45 EST

2025, Fact Sheet 2025-3033

Dan Walters

Introduction

The geographic information system (GIS) community in Vermont has a long history of interdisciplinary and cooperative projects that have facilitated the leveraging of geospatial technology on myriad data acquisitions across the State. High-resolution elevation data are proving to be a resource of great economic value in dealing with many important issues in Vermont. Vermont attained statewide coverage of quality level 2 coverage of topographic light detection and ranging (lidar) data in 2019. Having access to elevation data that are exponentially more accurate than what was previously available is enabling GIS professionals to better support and empower decision makers in economically important efforts such as environmental protection, public safety, watershed management and water quality, geology, transportation planning, forest and wildlife management, local planning, and flood plain management. In addition, developing a consistent and seamless statewide topographic framework supplants the traditionally time consuming and costly approach of extensive field data collection by requiring less time and money, therefore adding economic benefits. Critical applications that meet the State’s management needs depend on lidar data that provide a highly detailed three-dimensional (3D) model of the Earth’s surface and aboveground features.

The 3D Elevation Program (3DEP) is managed by the U.S. Geological Survey (USGS) in partnership with Federal, State, Tribal, U.S. territorial, and local agencies to acquire consistent lidar coverage at quality level 2 or better to meet the many needs of the Nation and Vermont. The status of available and in-progress 3DEP baseline lidar data in Vermont is shown in figure 1. 3DEP baseline lidar data include quality level 2 or better, 1-meter or better digital elevation models, and lidar point clouds, and must meet the Lidar Base Specification version 1.2 (https://www.usgs.gov/3dep/lidarspec) or newer requirements. The National Enhanced Elevation Assessment identified user requirements and conservatively estimated that availability of lidar data would result in at least $1.64 million in new benefits annually to the State. The top eight Vermont business uses for 3D elevation data, which are based on the estimated annual conservative benefits of 3DEP, are shown in table 2.

Released July 11, 2025 09:00 EST

2025, Journal of Hydrology (662)

Kul Bikram Khand, Gabriel B. Senay, MacKenzie Friedrichs, Koong Yi, Joshua Fisher, Lixin Wang, Kosana Suvočarev, Arman Ahmadi, Housen Chu, Stephen P. Good, Kanishka Mallick, Justine E.C. Missik, Jacob A. Nelson, David E. Reed, Tianxin Wang, Xiangming Xiao

Remote sensing-derived evapotranspiration (RSET) products capture the spatiotemporal variations of evapotranspiration (ET) from field to basin scales with unprecedented details. However, their accuracy varies across RSET estimation methods and diverse hydroclimate regions. While ET modeling efforts to account for biophysical processes and controlling parameters have made good progress in recent years, a parallel approach of integrating in-situ ET with RSET could reduce biases in RSET products. Basin water balance ET (WBET) and flux tower ET are widely applied to evaluate RSET accuracy, yet such ET measurements are rarely used for RSET bias corrections, especially for large area applications. To address this issue, we propose a novel approach: the water balance equivalence (WABE) method, which generates spatially continuous WBET for correcting biases in RSET products. The WABE method computes synthetic WBET by integrating observed WBET and flux tower-derived FLUXCOM ET, which fills the spatial gaps of observed WBET and generates a spatially continuous WBET dataset. Synthetic WBET (2002–2015 annual average) of eight-digit hydrologic unit code (HUC8) basins across the conterminous United States (CONUS), constituting 44 % (887 out of 2035 basins) of CONUS basins, was determined within 2.0 % (RMSE = 12 %) of observed WBET at CONUS and between 1–12 % (RMSE = 3–33 %) across 18 regions in CONUS. With WABE-based bias corrections, the overall annual bias of RSET decreased from 10 % (RMSE = 34 %) to 6 % (RMSE = 26 %) across 37 flux tower sites. The WABE method offers a new approach for RSET accuracy improvement and shows great promise for large area implementations with a potential to yield substantial benefits for building accurate basin water budgets and water management decisions.

Released July 11, 2025 08:46 EST

2025, NeoBiota (99) 363-370

Gretchen E. Anderson, McKayla M. Spencer, Ray W. Snow, Andrea Currylow, Frank N. Ridgley, Bryan G. Falk, Amy A. Yackel Adams

Burmese pythons (Python molurus bivittatus) and African rock pythons (Python sebae) have established invasive populations in southern Florida, severely disrupting local ecosystems. We analysed necropsy data from 2,179 pythons captured between 2006 and 2022, revealing nine cases of coelomic foreign bodies, primarily consisting of bird beaks, which presumably entered the coelom following gastrointestinal perforations during prey consumption. Despite the presence of foreign bodies, most examined pythons exhibited no obvious health issues. These findings indicate that the consumption of prey with sharp morphological features, such as wading birds, may not impede the pythons’ survival or health significantly, thereby underscoring their adaptability as apex predators in the Greater Everglades Ecosystem.

Released July 11, 2025 08:36 EST

2025, Book chapter, Evapotranspiration in agro-ecosystems and forestry

Gabriel B. Senay, Stefanie Kagone, Kul Bikram Khand, Gabriel Edwin Lee Parrish, Claudia Young, Michael Budde

AActual evapotranspiration (ETa) is an essential climate variable that can be used for drought monitoring and water availability assessment because of its close connection with vegetation, soil moisture, and the water cycle. An operational ETa using the Visible Infrared Imaging Radiometer Suite (VIIRS) and global weather datasets was developed through the Simplified Surface Energy Balance Model (SSEBop) model. An operational framework is established with the Famine Early Warning System Network (https://earlywarning.usgs.gov/fews) to generate and update global 1 km ETa at dekadal (∼10 day), monthly, and yearly time scales since February 2012. Modeled ETa at monthly and annual time scales was evaluated using 67 eddy covariance (EC) flux tower stations around the world and water balance-based ETa based on 810 United States eight-digit Hydrologic Unit Code (HUC8) and 18 Global Runoff Data Center (GRDC) basins. The correlation coefficient (r=0.68–0.94) shows relatively strong and consistent performance across the three datasets, capturing the spatiotemporal variability in HUC8 and GRDC basins and EC tower sites reliably. The bias (3%–15%) and root mean square error (RMSE: 13%–34%) showed relatively large errors and high variability among the three datasets. The evaluation results indicate the usefulness of the VIIRS ETa for drought monitoring and early warning applications without further adjustments, while bias-correction and calibration procedures may be required before using the VIIRS ETa data for localized water budget assessments. Availability of gridded actual ETa data from a combination of flux towers and basin-scale ETa is desired to establish bias-correction procedures to improve the absolute accuracy of remote-sensing ETa such as the SSEBop VIIRS operational products.

Released July 10, 2025 09:42 EST

2025, Philosophical Transactions of the Royal Society B: Biological Sciences (380)

Loren McClenachan, Bruce T. Anderson, Jason A. Addison, Steven J. Barbeaux, Karoline Moore, Kai Muir, Katherine L. Reedy, Ingrid B. Spies, Catherine F. West

n the Gulf of Alaska, a series of marine heat waves depleted Pacific cod (Gadus macrocephalus) biomass to the lowest abundance ever recorded and led to the fishery’s closure in 2020. Although the fishery has been productive for decades, this collapse may have historical precedents. Traditional knowledge holders refer to cod as ‘the fish that stop’, and there is a suggested period of decline in the 1930s. Here we conduct a catch reconstruction of the early commercial fishery (1864–1950), confirming a rapid catch decline in the 1920s and 1930s. Next, we evaluate evidence for possible drivers. We document changes to demand and technology that contributed to declining catch. However, we also find both qualitative and quantitative evidence of depletion, suggesting catch declines were not driven entirely by social factors. Overfishing may have contributed to localized catch declines as evidenced by declining catch rates in heavily fished localities. We also find evidence for climate as a driver of regional decline, with the period of catch decline characterized by up to 2°C higher temperatures as compared to the earlier period of high fisheries production. Our analysis underscores the importance of understanding long-term drivers of fisheries productivity and the value of linking fisheries and climate histories.

Released July 10, 2025 09:35 EST

2025, Ecosphere (16)

M.A. Pastore, S.J. Nelson, E.A. Burakowski, A.R. Contosta, A.W. D’Amato, S. Garlick, E. O. Lindsey, D.A. Lutz, Toni Lyn Morelli, A.P.K. Siren, Grace A. Smith, A. Weiskittel

Climate change is reducing snowpack across temperate regions with negative consequences for human and natural systems. Because forest canopies create microclimates that preserve snowpack, managing forests to support snow refugia—defined here as areas that remain relatively buffered from contemporary climate change over time that sustain snow quality, quantity, and/or timing appropriate to the landscape—could reduce climate change impacts on snow cover, sustaining the benefits of snow. We review the current understanding of how forest canopies affect snow, finding that while closed-conifer forests and snow interactions have been extensively studied in western North America, there are knowledge gaps for deciduous and mixed forests with dormant season leaf loss. We propose that there is an optimal, intermediate zone along a gradient of dormant season canopy cover (DSCC; the proportion of the ground area covered by the canopy during the dormant season), where peak snowpack depth and the potential for snow refugia will be greatest because the canopy-mediated effects of snowpack sheltering (which can preserve snowpack) outweigh those of snowfall interception (which can limit snowpack). As an initial test of our hypothesis, we leveraged snowpack measurements in the northeastern United States spanning the DSCC gradient (low, <25% DSCC; medium, 25%–50% DSCC; and high, >50% DSCC), including from 2 sites in Old Town, Maine; 12 sites in Acadia National Park, Maine; and 30 sites in the northern White Mountains of New Hampshire. Medium DSCC forests (typically mature mixed coniferous–deciduous forests) exhibited the deepest peak snowpacks, likely due to reduced snowfall interception compared to high DSCC forests and reduced snowpack loss compared to low DSCC forests. Many snow accumulation or snowpack studies focus on the contrast between coniferous and open sites, but our results indicate a need for enhanced focus on mixed canopy sites that could serve as snow refugia. Measurements of snowpack depth and timing across a wider range of forest canopies would advance understanding of canopy–snow interactions, expand the monitoring of changing winters, and support management of forests and snow-dependent species in the face of climate change.

Released July 09, 2025 17:20 EST

2025, Techniques and Methods 5-B13

James L. Gray, Leslie K. Kanagy, Christopher J. Kanagy, Cyrissa A. Anderson

A direct-injection liquid chromatography/tandem mass spectrometry method was developed to determine 34 per- and polyfluoroalkyl substances (PFAS), including selected branched isomers, in centrifuge supernatant of matrix-modified (amended with approximately 50 percent methanol) water samples. The method has been validated in reagent water, surface water, groundwater, and wastewater effluent. Other water types (for example, drinking water, untreated wastewater, and landfill leachate) have been analyzed by the method but not systematically validated. Recovery of isotope-dilution standards, added to each sample, may be used to assess method performance in nonvalidated matrices on a sample-by-sample basis.

Using this method, PFAS concentrations were determined in the range of 2–2,000 nanograms per liter in water samples. This range can be extended by diluting concentrated samples. At circumneutral pH, most compounds are present in the environment in their ionized form, and data are reported as such (for example, perfluorooctanoic acid is referred to as “perfluorooctanoate” [PFOA], perfluorooctane sulfonic acid is referred to as “perfluorooctane sulfonate” [PFOS]).

Sample preparation procedures were designed without the use of filtration and with minimum sample handling steps to mitigate procedural losses of target compounds due to sorption to surfaces. Further, isotope-dilution quantification allowed for the correction of bias that may result from procedural losses, matrix-induced signal suppression or enhancement, and other factors.

Validation experiments to characterize bias and variability, method detection level, and holding time were done in four distinct water matrices—reagent water, surface water, treated wastewater effluent, and groundwater—at multiple concentration levels. Mean PFAS recoveries met data quality objectives of bias and variability studies in all four validation matrices except for two compounds with low and variable recovery in the reagent water matrix only. Isotope-dilution standards, treated as surrogate compounds, were analyzed in more than 1,500 customer-submitted environmental samples with aggregate recovery of 102.5±6.5 percent (mean±standard deviation). Maximum holding times for all target compounds in the four validation matrices were 28 days for refrigerated samples and 90 days for frozen samples.

Released July 09, 2025 16:30 EST

2025, Data Report 1213

Donald S. Sweetkind

Structure contours and other geologic information from numerous published geologic maps were digitized and compiled into a digital dataset showing the configuration of a single stratigraphic datum, the base of the Dakota Sandstone and its equivalents across the Colorado Plateau. The principal maps compiled in digital form are a series of 1:250,000-scale 1 degree (°) × 2° quadrangle maps published by the U.S. Geological Survey, augmented by other geologic maps published at various map scales. The compiled digital dataset contains geologic map polygons of the Dakota Sandstone and regional stratigraphic equivalents, the location of faults and fold axes, structure contour lines that define the altitude of the base of the unit and bedding orientation data computed from the structure contour lines. This report provides the scientific rationale for compilation of these data and describes the compilation methodology for each of the data elements. This report provides an extended description of the data compilation in a companion U.S. Geological Survey digital data release of spatial data and attributes associated with the contoured surface and associated geologic data layers.

Released July 09, 2025 12:45 EST

2025, Fact Sheet 2025-3034

Chris Cretini

Introduction 

Recent and ongoing collections of high-resolution elevation data in Louisiana are providing information that supports improved critical public safety modeling and enables the State to strengthen its efforts to fight the effects of land subsidence and sea-level rise. The availability of current and accurate three-dimensional (3D) elevation data supports numerous business activities, including flood risk management, infrastructure and construction management, coastal zone management, wildlife and habitat management, recreation, agriculture and precision farming, urban and regional planning, water supply and quality assessment, and natural resources conservation. Critical applications that meet the State’s management needs depend on light detection and ranging (lidar) data that provide a highly detailed 3D model of the Earth’s surface and aboveground features.

The 3D Elevation Program (3DEP) is managed by the U.S. Geological Survey (USGS) in partnership with Federal, State, Tribal, U.S. territorial, and local agencies to acquire consistent lidar coverage at quality level 2 or better to meet the many needs of the Nation and Louisiana. The status of available and in-progress 3DEP baseline lidar data in Louisiana is shown in figure 1. 3DEP baseline lidar data include quality level 2 or better, 1-meter or better digital elevation models, and lidar point clouds, and must meet the Lidar Base Specification version 1.2 (https://www.usgs.gov/3dep/lidarspec) or newer requirements. The National Enhanced Elevation Assessment identified user requirements and conservatively estimated that availability of lidar data would result in at least $6.96 million in new benefits annually to the State. The top 10 Louisiana business uses for 3D elevation data, which are based on the estimated annual conservative benefits of 3DEP, are shown in table 2.

Released July 09, 2025 11:50 EST

2025, Fact Sheet 2025-3016

Christopher J. Schenk, Tracey J. Mercier, Cheryl A. Woodall, Phuong A. Le, Andrea D. Cicero, Ronald M. Drake II, Geoffrey S. Ellis, Michael H. Gardner, Sarah E. Gelman, Jane S. Hearon, Benjamin G. Johnson, Jenny H. Lagesse, Heidi M. Leathers-Miller, Kristen R. Marra, Kira K. Timm, Scott S. Young

Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean conventional resources of 7.8 billion barrels of oil and 91.9 trillion cubic feet of gas in the West Greenland-East Canada Province.

Released July 09, 2025 09:04 EST

2025, Water Environment Research (97)

Kimberly R. Beisner

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment, but sources that contribute to temporal and spatial variability in surface waters are not well defined. Many states are assessing PFAS in water resources, and insight from these statewide assessments can help guide future sampling efforts. A statewide assessment of 28 PFAS was conducted in New Mexico starting in 2020, and subsequent follow-up sampling has improved understanding of PFAS occurrence and sources throughout the state. PFAS were present in all major rivers of New Mexico (Rio Grande, Pecos River, San Juan River, Animas River, Canadian River, Gila River, Rio Chama, and Rio Puerco) with 13 of 28 analyzed PFAS (PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFBs, PFPeS, PFHxS, PFOS, PFOSA, 6:2 FTS) detected from at least one sample for samples collected between 2020 and 2024. This study found high temporal and spatial variability—PFAS concentrations ranged from below the laboratory detection level to 156 ng/L, with concentrations generally increasing downstream on the major rivers. PFBS was the most frequently detected and highest concentration PFAS in this study, ranging from 1 to 93 ng/L, followed by PFBA and PFPeA, ranging from 0.9 to 32 ng/L. The average of the sum of PFAS detected increased by an order of magnitude from 4 to 46 ng/L in the Rio Grande as it flows through Albuquerque, the largest urban area in New Mexico. PFAS concentration increased by 58% after a stormflow pulse flushed over Albuquerque and contributed water to the Rio Grande. The contribution of wastewater to surface water resources varied diurnally as well as seasonally. Sampling multiple locations on major rivers across multiple seasons, taking into account known anthropogenic inputs, would enhance characterization of temporal and spatial variability of PFAS concentrations. Increased sampling frequency at sites with wastewater contribution and focused investigations in areas with higher than expected PFAS could increase understanding of potential sources and variability of source contributions.

Released July 09, 2025 08:56 EST

2025, Ecosphere (16)

Brian Scott Dugovich, Emily M. Tomaszewski, Eric K. Cole, Sarah Dewey, Daniel MacNulty, Brandon Scurlock, Daniel Stahler, Paul C. Cross

The widespread practice of supplemental feeding, a bottom-up forcing of resource availability, is intended to improve wildlife population health and survival. However, supplemental feeding could trigger indirect effects by altering predation rates and disease dynamics. We investigated the effects of feeding on three key elk (Cervus canadensis) population productivity metrics (calf:cow ratios, annual change in elk density, and harvestable surplus) across 13 regions in the Greater Yellowstone Ecosystem (GYE) over 26 years. Incorporating previous population size, climate, predator, and harvest data in a Bayesian regression framework revealed new insights about elk productivity metrics in the GYE. Supplemental feeding was associated with increased calf:cow ratios (4.9%) but was not substantially related to changes in elk density and harvestable surplus, which are both management targets. Notably, the feeding effect on calf:cow ratios appeared to be offset by increased wolf (Canis lupus) and grizzly bear (Ursus arctos horribilis) predation. We hypothesize that increased elk productivity resulting from supplemental feeding is primarily transferred to predator and pathogen trophic levels in this system with limited observed effects on elk abundance and harvestable surplus. Anthropogenic food resources may have unintended indirect consequences on other trophic levels that potentially limit the direct impacts of feeding.

Released July 08, 2025 12:33 EST

2025, Open-File Report 2025-1034

Travis S. Schmidt, Ashley M. Bussell, Molly A. Moloney, James L. Dunnigan, Trevor M. Selch, Jessica E. Brandt, Craig A. Stricker, A. Robin Stewart, Veronika A. Kocen, Danielle Cleveland, Vicki S. Blazer, Sarah E. Janssen, Jacob M. Ogorek, Meghan Dunn, Theresa L. McBride, Katie B. Adams, Benjamin P. Colman, Matt Young, Jennie Christensen

Lake Koocanusa, a reservoir, receives mine wastes from metallurgical coal mines in the Elk River Valley of British Columbia, Canada. Selenium and other elements discharged by the mines into the waters of the United States can pose unknown risks to aquatic life. The U.S. Geological Survey Wyoming-Montana Water Science Center can collaborate with Montana Fish, Wildlife and Parks and other State and Federal agencies to design studies and to collect fish tissues to help fill this knowledge gap. This report describes the processes, techniques, and methods used to collect and analyze fish tissue collected from Lake Koocanusa; and procedures used to review and manage data, including quality assurance and quality control procedures used by the U.S. Geological Survey Wyoming-Montana Water Science Center and supporting analytical laboratories. These fish tissue collections began in 2021.

Released July 08, 2025 10:21 EST

2025, Open-File Report 2025-1026

Stacie A. Hathaway, James C. Molden, Robert Peck, Kristen R. Rex, Cheryl S. Brehme, Theo Black, Robert N. Fisher

Executive Summary

The purpose of this Wake Atoll Vessel Movement Biosecurity Program Efficacy document is to provide the United States Air Force (USAF) with an unbiased review of the current (2015; hereafter referred to as the 2015 Biosecurity Plan) biosecurity plan for the military base Wake Island Airfield (WIA) on Wake Atoll (hereafter Wake). Periodic reviews are an integral step for evaluating plan efficacy and updating plans with new information for improving plan effectiveness. The U.S. Geological Survey (USGS) acted as an external expert to provide the first unbiased assessment of the program and observe how it was being implemented. The USAF 2015 Wake Island Biosecurity Management Plan goes beyond sea vessel and container biosecurity; however, those aspects were not included in this evaluation.

We used several methods for a quality assurance evaluation of the 2015 sea vessel and shipping container biosecurity program specified in the Biosecurity Plan. Our evaluation included real-time observations in Hawai`i and at Wake. We surveyed cargo staging areas and empty shipping containers before supply shipment and the containers, barge, and marina at Wake after shipment. We used various detection tools and techniques (for example, visual encounter surveys, glue boards, chew cards, camera traps, and so on). We carried out an insect mortality experiment trial using one of the required shipping container biosecurity tools (dichlorvos impregnated pest strips). We also included a table-top review of documentation (largely the 2015 Biosecurity Plan) with respect to our observations to provide an assessment of how well the Biosecurity Plan protocols were carried out and how well they serve their intended purpose.

We observed biosecurity concerns in each focal area and stage of cargo handling (before and after barge movement) across all surveys of containers, flat racks, break bulk, warehouses, and dock areas. Using visual inspections, we recorded biosecurity concerns for every empty container we inspected before it was to be stuffed with cargo. Most containers had structural integrity issues (such as holes and damaged floorboards) and sanitation concerns, including live animals and plant matter or seeds. About one third of the containers had mold and a few had wet floorboards or standing water. We detected live animals on the break bulk, and flat racks were in poor condition. Next, we inspected cargo staging areas and noted extensive permeability of the building where cargo was staged for the 2018 resupply shipment and the building that had typically been used. We included the adjacent dock area used for staging break bulk, shipping containers and mooring the barge. We detected more than 5,000 individuals of 105 species. We also detected seeds in each location and scattered vegetation in the dock area, including growing in from the area outside separated by a chain link fence.

During surveys at Wake, we observed that 100 percent of the shipping containers, including all containers sent with required biosecurity tools, had live animals. The barge had only one unsecured snap trap for intercepting rodents aboard, we saw areas with fairly deep layers of dirt (or soil; we did not examine it to determine its properties), and there was plant matter with seed heads on the barge gangway that could easily be transported onto the barge. There was also only one snap trap station that was improperly placed on the dock. We also observed piled wood and vegetation nearby that could provide refuge to potential stowaway animals escaping.

Combined, surveys of the containers, staging areas, barges, and receiving area in Hawai`i and at Wake resulted in detection of more than 9,000 individuals of 131 animal species; nearly 4,000 individuals of 62 species were detected in surveys of containers once they had arrived at Wake. None of the species identified are known to be native to Wake. Our preliminary risk analysis of all species detected included eight species that we scored as high risk of potentially negative effects to biodiversity, infrastructure, or human health should they arrive at Wake and become established. Six of these species were only recorded using tools not clearly required by the Biosecurity Plan or being used to implement the plan.

We observed that the required biosecurity tools intended to intercept animals in the cargo staging area did not target the suite nor number of species present. Our analysis also indicated the required biosecurity tools intended to intercept animals in shipping containers were inadequate to handle the volume of organisms that were in the containers. The insect mortality trial experiment showed the pest strips were highly effective for only one of the three species tested, leaving uncertainty about how effective they are across the suite of potential species stowing away in cargo and containers.

Base Operating Support (BOS) did not carry out all Biosecurity Plan actions, but we also noted the document uses terminology such as “recommendation” as opposed to “requirement” which may lead contractors to consider those actions as optional. However, USAF provided evidence of BOS training and follow up; this included detailed identification of specific requirements for some of the biosecurity actions that we did not observe being carried out.

The 2015 Biosecurity Plan contains critical and useful components that seem to be well carried out. However, we also saw discrepancies, weaknesses, or both across methods and protocols currently used for Wake Atoll biosecurity. We observed shortcomings at each stage of our survey as well as in the plan as written, and we suggest general modifications to the Biosecurity Plan for consideration to potentially strengthen biosecurity overall.

Prevention is the most efficient and cost-effective biosecurity measure. Based on our findings, we see possible solutions to improve existing preventative biosecurity efforts and reduce potential incursion at Wake. These potential solutions include creating and implementing the following:

• Minimum cargo staging area sanitation and permeability standards,
• Minimum shipping container integrity and sanitation standards,
• Stand-alone inspection protocols,
• Inspection checklists,
• Monitoring protocols,
• Accountability reporting,
• Horizon scanning for prioritizing and targeting species of highest concern,
• Expansion of educational materials and outreach,
• Schedules for biosecurity plan reviews and updates

Management of invasive species enhances capability to protect human health and the environment as well as to advance mission accomplishment. Biosecurity plans are an integral component for addressing invasive species. Periodic evaluation of the efficacy of these plans is useful for identifying elements that are working well and for illuminating those that can be improved. Evaluations encourage consideration of new tools and adaptation of processes to achieve better outcomes and accommodate potential future threats more efficiently and more cost effectively.

Released July 08, 2025 10:10 EST

2025, Biological Invasions (27)

Valentina Alvarez, Robert N. Fisher, Stacie A. Hathaway, Robert C. Thomson

The spread of human commensal species is intricately tied to human movements and historical events. Through waves of human migrations, colonization, trade routes, commercial activities, and war, humans have redistributed species from their native ranges to widely scattered areas across the Pacific. Deciphering the invasion history of recent human-mediated introductions is challenging due to similar genetic signatures arising from these factors, which complicates the identification of specific pathways or sources. The extensive timeline of human events in the Pacific further compounds this challenge, potentially leading to numerous introductions from various regions over an extended period. The house gecko (Hemidactylus frenatus), a human commensal native to Southeast Asia, is now widespread in the Pacific region. While its current range is often attributed to activities during and following World War II (WWII), its invasion history necessitates a finer-scale dissection given the dynamic and extensive history of human-mediated introductions in the Pacific. We combine population genetics, phylogenetics, and approximate Bayesian computation to infer the invasion history of the house gecko from its native to its introduced range in the Pacific. Patterns of differentiation across native and introduced populations align with the extent of each region’s wartime involvement and the invasion history reconstruction supports the predicted chronology of introductions given a war-induced spread. This marks the first comprehensive genetic assessment of the house gecko’s invasion history in the Pacific and provides evidence in support of an initial spread across the Pacific consistent with WWII activities.

Released July 08, 2025 09:09 EST

2025, General Information Product 254

Jason M. Fine, Rodney R. Caldwell

As of October 2024, the U.S. Geological Survey (USGS) operated 588 sites across the United States and its territories as part of the Groundwater Climate Response Network (CRN). The CRN is comprised of wells selected to monitor the effects of climate variability, such as droughts, on groundwater levels nationwide. The CRN includes nearly 500 locations with real-time data and more than 100 sites with non-real-time data available to the public on the CRN web mapper and the USGS National Water Dashboard.

Released July 08, 2025 07:55 EST

2025, PeerJ (13)

Robert S. Cornman

Background

Proteins encoded by the canonical transient receptor potential (Trpc) gene family form transmembrane channels involved in diverse signal-transduction pathways. Trpc4 has been shown necessary for the induction of nonshivering thermogenesis (NST) in mice, a key component of which is thermogenic brown adipose tissue (BAT). In bats, Trpc4 exhibited diversifying selection within exons encoding regulatory binding sites of TRPC4.

Methods

To assess whether diversification of these regulatory sequences mirrors the diversification of mammalian thermoregulatory strategies, the ratio of nonsynonymous to synonymous substitutions (ω) was estimated for multiple tetrapod outgroups and eutherian orders. Four questions were addressed: (1) Did the ancestral eutherian Trpc4 diverge under positive selection from nonplacental mammals that lack BAT? (2) Did Trpc4 subsequently become more constrained in descendant eutherian clades? (3) In eutherian clades that subsequently lost BAT by inactivation of the thermogenin gene Ucp1, did Trpc4 become less constrained? (4) Does the evolutionary rate of Trpc4 differ between quantitatively more heterothermic mammal orders (bats and rodents) relative to quantitatively less heterothermic outgroups (carnivores, artiodactylids, and primates)?

Results

Coincident with the advent of BAT, Trpc4 evolutionary rate increased significantly in ancestral eutheria after their divergence from nonplacental mammals but a branch-site model did not support a rate class ω > 1 along that branch. In descendant eutherian mammals, Trpc4 became far more constrained, with an evolutionary rate less than half that of tetrapod clades lacking NST, a pattern was not seen in other Trp channel genes. Intensifying selection in descendent eutherian mammals was further supported with the RELAX program, which also indicated reduced constraint on Trpc4 in clades that have secondarily lost BAT. However, no consistent pattern was identified within mammalian orders with strong variation in heterothermy: evidence of increased evolutionary rate was again found in bats for Trpc4 as well as homologs it directly binds in heteromeric membrane channels (Trpc5 and Trpc1), yet all rodent Trpc genes had low evolutionary rates. Evolutionary rates of Trpc4 and Trpc1 in bats were consistent with relaxed constraint whereas bat Trpc5 experienced diversifying selection. Most variation among tetrapod TRPC4 sequences lies within an 85 amino-acid window that is functionally uncharacterized. Sequence alignments demonstrated that the TRPC4 β isoform, which lacks a portion of the C-terminal regulatory region, originated in basal eutherians but appears to be lost in many tip lineages. Collectively, the data indicate that the C-terminal region of TRPC4 has responded to selection on NST thermoregulation during the diversification of eutherian mammals. The drivers of increased diversification of Trpc4 and interacting genes in bats remain to be determined.

Released July 07, 2025 10:14 EST

2025, PNAS (122)

James E. Cloern, Alan Jassby

Nutrient (nitrogen and phosphorus) pollution is an environmental problem of global concern because overenrichment of water bodies increases phytoplankton biomass and ecosystem metabolism, depletes oxygen in bottom waters, and increases the frequency and intensity of harmful algal blooms. These responses to nutrient pollution have motivated policies to reduce anthropogenic nutrient inputs. However, these policies have not been universally implemented and their success at reducing phytoplankton biomass is confounded by other components of global change that regulate the conversion of nutrients into biomass. These regulating processes themselves are changing in the Anthropocene. Our study is an assessment of changing phytoplankton biomass over the period 2000–2019, using chlorophyll a trends measured in 191 lakes and 159 estuarine-coastal sites. Our results show that phytoplankton biomass has decreased in most lakes, increased in most coastal sites, and the largest trends have been predominantly negative for lakes and positive for coastal sites. These results provide evidence of opposing directions of phytoplankton biomass change between lakes and coastal sites in this recent period of unprecedented global change. Nutrient pollution is a knotty environmental problem, and our study indicates that it might be a particularly challenging problem for ecosystems situated in densely populated landscapes where freshwater and sea water meet. Success at overcoming this challenge will require deeper scientific understanding of changes in processes that regulate the conversion of nutrients into phytoplankton biomass, substantial investments of time and resources to reduce nutrient inputs, and a flexible strategy designed to anticipate and adapt to a changing world.

Released July 07, 2025 09:32 EST

2025, Ecosystems (28)

Juan Pinos, Keegan Hammond, Michael C. Duniway, John P. Anderson, Niall P. Hanan, Matthew D. Petrie

Soil moisture is a key link between hydrologic and ecologic processes in desert shrublands. Understanding how soil moisture is spatially distributed in desert shrublands provides valuable insights into how shrubs use and impact limiting water resources, and how shrublands may respond to future meteorological and climate change. Our goals were to determine how soil moisture is partitioned between soil volumes under canopies and in the bare soil interspaces across multiple desert shrublands, and to evaluate the roles of physical soil properties, shrub-type characteristics, meteorology, and measurement resolution in influencing and observing variation in soil moisture partitioning. Utilizing two long-term soil moisture datasets (monthly resolution, 30 years, whole soil profile measurements; and 30 min resolution, 10 years, 10–30 cm measurements), we compared soil moisture partitioning across nine northern Chihuahuan Desert shrubland sites (three sites dominated by creosotebush [Larrea tridentata], three by honey mesquite [Prosopis glandulosa], and three by tarbush [Flourensia cernua]) in the Jornada Basin, southern New Mexico, USA. Over 30 years, monthly, whole profile data showed that soil moisture in mesquite shrublands was consistently higher in bare soil interspaces compared to under canopies, whereas soil moisture under and between shrubs was more similar in creosotebush and tarbush shrublands. Physical soil properties were linked as explanatory variables of long-term soil moisture partitioning (monthly whole profile dataset), whereas 30-minute data showed that shorter-term periods of higher precipitation promoted greater near surface soil moisture (10–30 cm) in bare soil interspaces that was not captured at monthly time steps. Thus, although the long-term average partitioning of soil moisture in these shrublands is strongly controlled by soil physical properties, soil moisture partitioning varies at shorter timescales (daily to weekly) in response to precipitation events. Moreover, shrub-type characteristics influenced soil moisture partitioning, with dense and tall mesquite shrubs having lower under canopy soil moisture than tarbush, and root architecture potentially influencing partitioning across creosotebush sites. These results illustrate diversity in soil moisture partitioning both between and within shrublands of the northern Chihuahuan Desert, and elucidate how physical soil properties, shrub-type characteristics, and meteorological variation interact to shape their soil moisture dynamics.

Released July 07, 2025 08:17 EST

2025, Fishes (10)

Ji X. He, Charles P. Madenjian

Fish year-class strength (YCS) has been estimated via longitudinal analysis of catch-at-age data and via catch-curve regression, but no study has compared the two approaches. The objective of this study was to compare YCS estimates derived from both approaches applied to catch-at-age data for the lake trout (Salvelinus namaycush) population in the main basin of Lake Huron, one of the Laurentian Great Lakes of North America. YCS was reconstructed for both hatchery-stocked and wild lake trout. Akaike information criterion (AIC) and Bayesian information criterion (BIC) were used to compare 14 linear mixed-effects models for longitudinal analysis of catch-at-age data, and three linear mixed-effects models for catch-curve regression. From the best models based on AIC or BIC comparisons, YCS estimates with year-class as a fixed effect were consistent with those estimated with year-class as a random effect. Patterns and trends in the YCS estimates were also the same or similar between the longitudinal analysis of catch-at-age data approach and the catch-curve regression approach, suggesting that both modeling approaches are applicable to a variety of fish populations. indicating that both approaches provide robust measures of YCS. Potential bias in using the approach of catch-curve regression could be caused by abrupt changes in adult mortality. It is also critical to recognize multiple recruitment origins for using the approach of longitudinal analysis of catch-at-age data.

Released July 07, 2025 08:12 EST

2025, Geophysical Research Letters (52)

Mohammadreza Jamalreyhani, Ruijia Wang, Brandon Schmandt, Andres Felipe Peña Castro, Margaret Elizabeth Glasgow

Subsurface wastewater injection has increased the seismicity rate within the Raton Basin over more than two decades, with the basin-wide injection rate peaked between 2009-2015. To understand the evolution of injection-induced earthquakes, we systematically analyzed 2016-2024 broadband recordings with a machine-learning-based phase picker and constructed a catalog with 95,993 earthquakes (-1≤M_L≤4.3). We then inverted for full centroid moment tensors (CMT) for 90 M_L ≥ 2 events, with a special interest in constraining the non-double-couple components via probabilistic metrics. Both relocations and CMT solutions support basement-rooted normal faults, including graben and half-graben structures. Furthermore, we observe the non-double-couple components that imply elevated pore pressure in the fault zones. An earthquake cluster emerged in the north-central basin in 2023, preceded by ~1-yr of increased injection volume from wells within 15km. Despite a basin-wide decrease in the injection volume, we highlights the persistence of seismicity that remains to sensitive to injection rates within the Raton Basin.

Released July 05, 2025 10:18 EST

2025, Biodiversity and Conservation

Noah J. Hunt, Lisa H. Crampton, Tyler A Winter, Jack D Alexander, Roy Glib, Richard J. Camp

Hawaii hosts one of Earth’s most unique and threatened avifaunas. Upslope migration of mosquito-vectored avian malaria on Kauaʻi (maximum elevation 1,598 m) has likely caused its rapid loss of avifaunal diversity; only 8 of 13 historic forest bird species remain. We update the status and trends of Kauaʻi forest bird populations since the original (1981) surveys using the latest (2023) survey data and distance sampling. We fit detection functions to species-specific count data and stratified estimates across the Interior (since 1981) and Exterior (since 2000) survey areas, and between low (900–1,100 m), medium (1,100–1,300 m) and high (> 1,300 m) elevation bands (since 2000). Log-linear trends of ʻakekeʻe (Loxops caeruleirostris), ʻanianiau (Magumma parva), ʻiʻiwi (Drepanis coccinea), and Kauaʻi ʻamakihi (Chlorodrepanis stejnegeri) steeply declined across the timeseries, with extinction of ʻakekeʻe and ʻiʻiwi expected before 2050. Undetected in 2023, ʻakikiki (Oreomystis bairdi) were excluded from analysis. ʻApapane (Himatione sanguinea), Kauaʻi ʻelepaio (Chasiempis sclateri), Chinese hwamei (Garrulax canorus), and white-rumped shama (Copsychus malabaricus) were stable overall. Northern cardinal (Cardinalis cardinalis) steadily declined, whereas Japanese bush warbler (Horornis diphone) and warbling white-eye (Zosterops japonicus) exponentially increased. Taxonomic and functional diversity did not vary greatly across our timeseries, while the proportion of introduced species in the Exterior increased from 34 to 59%. However, introduced species do not replace the losses of ecological functions from native species, whose populations are likely declining from avian malaria. Future monitoring can be used to evaluate forest bird population responses to mosquito suppression using the Incompatible Insect Technique.

Released July 05, 2025 10:05 EST

2025, Global Change Biology (31)

Emma Reich, Jessica Guo, Drew Peltier, Emily C. Palmquist, Kimberly Samuels-Crow, Rohan Boone, Kiona Ogle

Ecosystem responses to precipitation pulses (“pulse responses”) exert a large control over global carbon, water, and energy cycles. However, it is unclear how the timing and magnitude of pulse responses will vary across ecosystems as precipitation regimes shift under accelerating climate change. To address this issue, this study evaluates how plants and ecosystems respond to precipitation pulses and explores potential implications of altered precipitation regimes for the carbon and water cycles. In particular, we conducted a global meta-analysis to quantify the magnitude and timing of plant and ecosystem carbon-related (A_net, NPP, GPP, R_eco, R_bg) and water-related (ET, T, Ψ, g_s) responses to 587 precipitation pulses. By analyzing pulse-response metrics published in the primary literature, we evaluated the characteristics of those pulse responses. We assessed whether precipitation pulses lead to a classic pulse response (i.e., a hump-shaped response as described by the pulse-reserve framework), a linear pulse response, a combination of classic and linear, or a lack of a pulse response. If a pulse response occurred, we explored the factors that drove its timing, magnitude, and speed. Our meta-analyses revealed that the classic, hump-shaped response is not ubiquitous, as it only accounted for 52% of the pulse responses. However, when a pulse response did occur, carbon-related responses to precipitation pulses were larger in magnitude (e.g., larger peak) than water-related pulse responses at relatively arid sites. However, at relatively mesic sites, this relationship reversed (i.e., water-related responses to precipitation pulses were larger than carbon-related responses). Additionally, larger precipitation pulse amounts increased water-related response magnitudes more than carbon-related response magnitudes across both arid and mesic sites. Therefore, under future precipitation intensification, carbon-related responses to precipitation pulses may become more decoupled from water-related pulse responses in wetter biomes but more coupled to water-related pulse responses in drier biomes.

Released July 05, 2025 08:49 EST

2025, Hydrobiologia

Joseph V. Brown, William E. Kelso, Diaz Rodrigo, Wesley Daniel, Haley M. Brassard, Michael D. Kaller

Although the aquarium trade is an important pathway for direct and indirect non-native species introductions into freshwater systems, knowledge and attitudes of participants in the trade regarding alien species issues is largely undocumented. Therefore, we administered a survey to investigate attitudes and behaviors of aquarists and non-aquarists regarding the aquarium trade as a pathway for invasive species introductions. We hypothesized aquarists would be better educated on potential introductions than non-aquarists. Due to their engagement with organisms and replication of natural habitats, we also expected aquarists would exhibit more positive attitudes and behaviors toward the environment than non-aquarists. Most respondents seemingly understood the severity of invasive species problems, regardless of status as an aquarist. Aquarists thought the aquarium trade was less responsible for species introductions than non-aquarists and also felt more aware of laws regarding invasive species. However, over half of aquarists disposed of aquarium water down a drain in their house or directly into a nearby water body, which is a known mode of invasion. This information can inform further efforts to provide educational opportunities for participants in the non-native pet/aquarium trade, with the goal of enhancing protection efforts for native biodiversity.

Released July 05, 2025 08:35 EST

2025, Journal of Great Lakes Research

Muruleedhara Byappanahalli, Noel B. Pavlovic, Cindy H Nakatsu

The microbial role in dune succession along the Great Lakes freshwater sand dunes remains poorly understood. A chronosequence study was conducted to understand the relationships among soil bacterial communities, soil chemistry, and prescribed burning at the Indiana Dunes National Park. Soil bacterial communities and chemistry, as well as groundlayer vegetation were sampled during 2015 and 2017 from seven successional stages from the beach (contemporary) to the 14,000-year-old oak forest. Bacterial communities from unburned and burned sites among stages were determined by 16S rRNA gene amplicon sequencing. Soil pH and cations decreased from early (beach, foredune, secondary dune, and woodland transition) to late (oak savanna, woodland, and oak forest) successional stages, while organic matter and organic carbon concentrations increased in the late successional stages. Bacterial alpha diversity showed no significant differences among stages, but a significant interaction was found between stage and prescribed burning (H = 39.7, p < 0.001). Bacterial communities separated mainly along stage by all four beta diversity metrics used (Bray Curtis, Jaccard, and Weighted and Unweighted UniFrac), with the main difference observed along the primary axis (weighted UniFrac, 48 %). Bacterial phyla were differentially abundant in older soil stages compared to beach (ANCOM-BC, q < 0.05); likewise, differential abundances in genera were evident when burned and unburned sites were compared. A Mantel test indicated stronger congruency between the bacterial communities and soil chemistry than between bacterial communities and vegetation. Collectively, soil chemical and microbial parameters along with management practices contribute to dunal successional patterns in the Great Lakes.

Released July 05, 2025 08:01 EST

2025, Wetland Ecology & Management (33)

Melanie K. Vanderhoof, Peter Nieuwlandt, Heather E. Golden, Charles R. Lane, Jay Christensen, William Keenan, Wayana Dolan

The retention of surface water in wetlands and lakes can modify the timing, duration, and magnitude of river discharge. However, efforts to characterize the influence of surface water on discharge regimes have been generally limited to small, wetland-dense watersheds. We developed random forest models to explain spatial variability in six hydrologic signatures, reflecting flashiness, high, and low flow conditions, at 72 gaged watersheds with variable water storage capacity across the conterminous United States. In addition to variables representing meteorology and landscape characteristics, we also tested the inclusion of surface water dynamics, derived from Sentinel-1 and Sentinel-2. Models for all six signatures improved with the addition of catchment characteristics, including surface water dynamics, relative to models with only climate variables. Percent improvement in model adjusted R², mean square error, and Akaike information criterion ranged from 4.00 to 14.33%, 5.00 to 20.30%, and 2.75–8.14, respectively. Automated variable selection can be indicative of the relative importance of certain variables over others. Using a forward selection process, five of the six signature models selected remotely sensed inundation or wetland variables (p < 0.05). For example, the variable semi-permanent and permanent (SP + P) floodplain inundation (i.e., lakes along rivers) was associated with lower annual flashiness. Further, SP + P non-floodplain waters and geographically isolated wetlands significantly contributed to explaining variability in the low flow signatures. Our findings underscore the capacity of wetlands to stabilize and maintain flows during dry periods. Improved understanding of how surface water dynamics influence hydrologic signatures can inform wetland restoration efforts and facilitate improved resilience to extreme flow conditions.

Released July 04, 2025 10:24 EST

2025, Movement Ecology (13)

Erik Andersen, Justin Clapp, Milan Vinks, Todd C. Atwood, Daniel D. Bjornlie, Cecily M. Costello, David Gustine, Mark A. Haroldson, Lori L. Roberts, Karyn D. Rode, Frank T. van Manen, Ryan H. Wilson

Background

Information on reproductive success is crucial to understanding population dynamics but can be difficult to obtain, particularly for species that birth while denning. For grizzly (Ursus arctos) and polar bears (U. maritimus), den visits are impractical because of safety and logistical considerations. Reproduction is typically documented through direct observation, which can be difficult, costly, and often occurs long after den departure. Reproduction could be documented remotely, however, from post-denning movement data if discernable differences exist between females with and without cubs.

Methods

We trained support vector machines (SVMs) with eight variables derived from telemetry data of female grizzly (2000–2022) and polar bears (1985–2016) with or without cubs during seven periods with lengths ranging from 5 to 60 days starting at den departure. We assessed SVM classification accuracy by withholding two samples (one cub-present, one cub-absent), training SVMs with the remaining data, predicting classification of the withheld samples, and repeating this process for each sample combination. Additionally, we evaluated how classification accuracy for grizzly bears was influenced by sample size, length of the post-departure period, and frequency of standardized location estimates.

Results

Accuracy of predicting cub presence or absence was 87% for grizzly bears with only 5 days of post-departure data and increased to a maximum of 92% with 20 days of data. For polar bears, accuracy was 86% at 5 days post-departure and increased to a maximum of 93% at 50 days. Classification accuracy for grizzly bears increased from 76 to 90% when sample size increased from 10 to 30 bears while holding period length constant (30 days) but did not increase at larger sample sizes. When sample size was held constant, increasing the length of the post-departure period did not affect classification accuracy markedly.

Conclusion

Presence or absence of grizzly and polar bear cubs can be identified with high accuracy even when SVM models are trained with limited data. Detecting cub presence or absence remotely could improve estimates of reproductive success and litter survival, enhancing our understanding of factors affecting cub recruitment.

Released July 04, 2025 09:58 EST

2025, Journal of Environmental Management (391)

Emily J. Wilkins, Sarah Lynn Rappaport Keener, Wylie Carr, Samantha G. Winder, Julianne Reas, Daniela B. Daniele, Spencer A. Wood

Research shows that climate change is already affecting both resources and visitors in U.S. National Parks. We sought to better understand if and how park staff across the National Park Service are adapting to climatic changes that affect visitor use, as well as barriers and challenges to adaptation and information needs. We conducted semi-structured qualitative interviews with 63 staff from 31 representative national park units across the United States. We qualitatively coded interviews for themes using deductive and inductive coding approaches. Results indicate that park staff are already taking action to adapt to changes that are affecting visitor use, including efforts to increase resiliency of infrastructure and to support the health and safety of visitors (e.g., increased communication, preventative search and rescue, changes to programming). Common barriers and challenges include institutional factors (such as funding, staffing capacity, and shifting priorities), uncertainty about future conditions, and difficulties with prioritizing climate adaptation. Data, tool, and information needs varied, but commonly included social science data such as visitor surveys, and tools to help synthesize and standardize information and help translate science into action. These results provide insights into current actions park staff are taking to adapt to climate change and what resources may be helpful in the future to lower the challenges and barriers to adaptation.

Released July 04, 2025 09:01 EST

2025, Aquatic Toxicology (286)

Cunlong Wang, Jason Tyler Magnuson, Chunmiao Zheng, Wenhui Qiu

Per- and polyfluoroalkyl substances (PFAS) are persistently accumulated in both environmental media and biological systems, leading to significant toxicological effects. Although research on PFAS has expanded in recent years, systematic reviews on its concentration distribution in aquatic environments and biota, as well as its toxicological effects, remain scarce. Moreover, existing literature lacks systematic analyses of diverse aquatic environments and organisms. This review investigates the contamination levels of PFAS in aquatic environments. It also provides a systematic analysis of bioaccumulation in planktonic, swimming, and benthic organisms, including bioaccumulation factors (BAF), biomagnification factors (BMF), trophic magnification factors (TMF), and biota-sediment accumulation factors (BSAF), and evaluates the potential toxic effects on aquatic ecosystems. This study aims to provide theoretical support for the environmental regulation and management of PFAS. Additionally, it seeks to offer data references and potential research directions for future studies, thereby promoting the advancement of PFAS-related research and policy development.

Released July 04, 2025 08:06 EST

2025, Ecological Applications (35)

Antti Piironen, Jeffrey M. Knetter, Kyle A. Spragens, Joshua Dooley, Vijay P. Patil, Eric T. Reed, Megan V. Ross, Daniel Gibson, Adam C. Behney, Mark J. Petrie, Todd Sanders, Mitch D. Weegman

Joint estimation of demographic rates and population size has become an essential tool in ecology because it enables evaluating mechanisms for population change and testing hypotheses about drivers of demography in a single modeling framework. This approach provides a comprehensive perspective on population dynamics and how animal populations will respond to global pressures in future years. However, long-term data for such analyses are often limited in quantity and quality. We developed an integrated population model combining data on demography and population size from nine different sources to understand the population ecology of the lesser snow goose (Anser caerulescens caerulescens) in the Pacific Flyway in North America from 1970 to 2022. We divided the flyway population into Wrangel Island and Western Arctic subpopulations and assessed demographic mechanisms for population change and environmental and anthropogenic drivers that influenced demography. During 1970–2022, the estimated spring population of snow geese in the Pacific Flyway increased from ~300,000 to ~2,300,000. Short-term changes in population growth rate were primarily driven by changes in productivity in the Western Arctic and productivity and immigration in Wrangel Island. Changes in hunting and natural mortality had less influence on short-term but likely contributed to the pronounced long-term population growth. Early snowmelt positively influenced per capita productivity in both regions, and warm, rainy weather during the non-breeding season was associated with high per capita productivity in the Western Arctic. In the Western Arctic, per capita productivity was negatively associated with population size, and adult natural mortality was positively associated with population size, indicating density-dependent regulation in this subpopulation. In Wrangel Island, warm weather in early fall decreased juvenile natural mortality. Our results demonstrate that per capita productivity and immigration, rather than adult survival, were the primary mechanisms of short-term population change in this long-lived species. Our results also indicate that environmental conditions and density-dependent effects can impact population dynamics more than harvest, even for a long-lived, commonly harvested species. We demonstrate that a warming climate can have multiple effects on demography, emphasizing the importance of assessing a variety of spatial and temporal factors when predicting how populations might respond to large-scale environmental changes. This emphasizes the importance of conservation plans that consider these environmental drivers, although this may complicate direct management of such populations.

Released July 04, 2025 07:48 EST

2025, Geochemistry, Geophysics, Geosystems (26)

Shaul Hurwitz, R. Blaine McCleskey, Bryant Jurgens, Jacob B. Lowenstern, Laura E. Clor, Andrew Hunt

To improve our understanding of hydrothermal activity on the Yellowstone Plateau volcanic field, we collected and analyzed a large data set of δ²H, δ¹⁸O, and the ³H concentrations of circum-neutral and alkaline waters. We find that (a) hot springs are fed by recharge throughout the volcanic plateau, likely focused through fractured, permeable tuff units. Previous work had stressed the need for light δ²H water recharge restricted to the northern part of the plateau or recharge during past cold periods. However, new data from the Y-7 drill hole suggests that recharge is not restricted to a certain area or a cold period. (b) δ¹⁸O values of thermal waters in the geyser basins are shifted from the global meteoric water line by temperature-dependent water-rock reactions with higher subsurface temperatures resulting in a greater shift. (c) Large temporal variations in the isotopic composition of meteoric water recharge and small temporal variability in the isotopic composition of hot spring discharge implies that the volume of groundwater in, and around the Yellowstone caldera is substantially larger than the volume of annual water recharge. (d) Hot springs discharged through different rhyolitic units correlate with identifiable differences in δ²H and δ¹⁸O compositions, ³H concentrations, and water chemistry that imply equilibration at different temperatures and travel along different flow paths. (e) Based on measured ³H concentrations, we calculate that hot spring waters in the central part of the geyser basins mostly contain <2% post-1950 meteoric water, whereas waters discharged at the basin margins contain larger fractions of post-1950s meteoric water.

Released July 03, 2025 11:22 EST

2025, Scientific Investigations Report 2025-5038

Casey J.R. Jones

The Coconino aquifer was investigated as a potential groundwater resource for the Hopi Tribe and Navajo Nation in northeastern Arizona. Basic groundwater chemistry, including major ions, total dissolved solids, and selected trace metal concentrations, are presented and analyzed to characterize the Coconino aquifer. The geochemical compositions of groundwater are associated with changes in geology and groundwater movement and are compared to drinking-water standards to determine suitable areas for potential groundwater resource development. Dissolved-solids concentrations in much of the Coconino aquifer water were higher than the U.S. Environmental Protection Agency’s secondary drinking-water standard of 500 milligrams per liter (mg/L) due to a buried halite body in the southeastern part of the study area. However, trace metal concentrations were generally low. Groundwater may need to be treated for high dissolved-solids concentrations before it is suitable for use as a resource for the Hopi Tribe and Navajo Nation.

Released July 03, 2025 07:22 EST

2025, Scientific Investigations Report 2025-5049

Brian V. Twining, Kerri C. Treinen, Jeffrey A. Zingre

The U.S. Geological Survey (USGS)—in cooperation with the U.S. Department of Energy (DOE) for the Naval Reactors Laboratory Field Office that supports operations for the Naval Reactors Facility (NRF) located at the Idaho National Laboratory (INL)—drilled and constructed well NRF-17 (formerly borehole USGS 151) and well NRF-18 (formerly borehole USGS 152) for stratigraphic framework analyses and water-quality monitoring at the Idaho National Laboratory (INL) near the NRF, in southeastern Idaho. Borehole USGS 151 was continuously cored from about 48 to 1,070 feet (ft) below land surface (BLS); rotary drilled from approximately 1,070 to 1,720 ft BLS; and re-drilled to complete construction as a monitor well NRF-17, completed to 461 ft BLS. Borehole USGS 152 was continuously cored from approximately 19 to 1,259 ft BLS; rotary drilled from approximately 1,259 to 1,630 ft BLS; and re-drilled to complete construction as a monitor well NRF-18, completed to 450 ft BLS.

Geophysical data were examined with photographed core material to record lithologic descriptions and to suggest zones where groundwater flow was anticipated. Basalt flows varied from highly fractured to dense, with high-to-low vesiculation. Well NRF-17 generally was constructed in mostly dense basalt (greater than 75 percent), and well NRF-18 was constructed in primarily fractured and (or) vesicular basalt. In well NRF-17, the well capacity is directly affected by the limited amount of fractured basalt, which serves as the primary pathway for groundwater. This effect was observed during the pumping test conducted after the well's final construction.

Single-well aquifer tests were done at wells NRF-17 and NRF-18 to provide estimates of transmissivity and hydraulic conductivity after final well construction and initial well development. Estimated values of transmissivity and hydraulic conductivity for well NRF-17 were 8.81 feet squared per day (ft2/d) and 1.04×10-2 feet per day (ft/d), respectively. Estimated values of transmissivity and hydraulic conductivity for well NRF-18 were 4.77×103 ft²/d and 5.61 ft/d, respectively. The NRF-17 pump test resulted in 19.41 ft of measured drawdown at a sustained average pumping rate of 3.3 gallons per minute (gal/min). The NRF-18 pump test resulted in 0.55 ft of measured drawdown at a sustained average pumping rate of 31.0 gal/min.

Water-quality samples collected from the two wells were analyzed for cations, anions, metals, nutrients, volatile organic compounds, stable isotopes, and radionuclides. Water samples for select inorganic constituents showed concentrations consistent with signatures from tributary valley groundwater with influences from ephemeral surface-water recharge from the Big Lost River. Water-quality samples analyzed for stable isotopes of oxygen and hydrogen are consistent with signatures from tributary valley groundwater and surface-water recharge inputs to the aquifer. No measured water-quality results were greater than their respective maximum contaminant levels for public drinking-water supplies. Inorganic and nutrient water-quality results for well NRF-17 and well NRF-18 suggest the groundwater in this area is potentially affected by industrial wastewater disposal.

Released July 02, 2025 14:30 EST

2025, General Information Product 252

Brian E. McCallum, Melissa L. Riskin

The U.S. Geological Survey (USGS) operated 12,165 continuous surface-water monitoring locations (streamgages) across the United States in 2024. The streamgages provide information on river height and streamflow, typically at 15-minute intervals. This information is then made available to everyone, most of it delivered nearly in realtime on the USGS National Water Dashboard.

Released July 02, 2025 10:14 EST

2025, Seismological Research Letters

William L. Yeck, Robert B. Herrmann, John Patton, William D. Barnhart, Harley M. Benz

The U.S. Geologic Survey National Earthquake Information Center (NEIC) monitors global seismicity, producing a catalog of earthquake source parameters in near-real-time to provide information that can help mitigate the societal impact of earthquakes. The NEIC commonly relies on teleseismic observations to constrain earthquake source parameters (e.g., location, depth, magnitude, and mechanism) due to a lack of local and regional observations. For these ‘teleseismic’ events, depth phase (i.e., pP, sP) arrival time observations provide the best estimate on source depth. However, depth phases are often difficult to accurately identify and/or pick. Therefore, NEIC relies on waveform modeling, such as those determined from W-phase (M_ww), body wave (M_wb), and regional (M_wr) moment tensor estimations, to provide constraints on source depth. While depth estimates from these approaches are informative, higher frequency observations provide more precise estimates because depth phases are more prominently observed at higher frequencies. Here, we present NEIC’s relatively high-frequency (~0.04 to 1 Hz) teleseismic waveform modeling approach, termed Synthetic Depth Phase Modeling (SynDepth), for determining source depth. SynDepth was developed to provide NEIC with a tool that enables rapid, accurate, and quantifiable estimates of earthquake source depth in cases where locator depths are not reliable. This relatively simple and fast procedure searches over 1 km-incremented source depths and an expanding triangular source-time function to find the best-fitting solution. We compare automatic SynDepth solutions for a dataset of 1,216 earthquakes (M5.5-M7.6) between 2017 and 2021 to NEIC-derived depth estimates from other methods. Our approach provides a robust depth estimate for earthquakes lacking local arrival time data, and it minimizes the need for analyst review of depth-phase picks (pP, sP) or using predefined ‘fixed’ depths.

Released July 02, 2025 09:12 EST

2025, Geophysical Research Letters (52)

Ezgi Karasözen, Michael E. West, Katherine R. Barnhart, John J. Lyons, Terry Nichols, Lauren N. Schaefer, Bohyun Bahng, Summer Ohlendorf, Dennis M. Staley, Gabriel J. Wolken

Alaska's coastal communities face growing landslide hazards owing to glacier retreat and extreme weather intensified by the warming climate, yet hazard monitoring remains challenging. As part of ongoing experimental monitoring in Prince William Sound, we detected three large landslides (0.5–2.3 M m³) at Surprise Inlet on 20 September 2024, within the span of an hour. These events were identified in near real-time through seismic data and later confirmed using satellite imagery, tidal records, and infrasound. The landslides generated a modest tsunami, and a 4 cm wave was recorded by a tide gauge 18 km away, marking the first recorded landslide to reach water since monitoring began in this region in 2021. Here, we examine the detection and interpretation of these landslides using multiple data sources and modeling. We demonstrate the effectiveness of this regional seismic monitoring system and show how complementary instrumentation, where available, can enhance detection capabilities.

Released July 02, 2025 07:37 EST

2025, Scientific Investigations Report 2023-5101

Aaron L. Pugh

During the spring and summer of 2020, the U.S. Geological Survey conducted single-well slug tests on selected observation wells within the Mississippi Alluvial Plain in Arkansas and Mississippi to estimate hydraulic conductivity and transmissivity values for the Mississippi River Valley alluvial and middle Claiborne aquifers. Well and aquifer data were collected from field measurements, well-construction reports, and published aquifer-thickness information. A total of 324 slug-in and slug-out tests were conducted on 48 wells by using mechanical slugs to displace the water column and submersible pressure transducers to record changes in water levels in the wells. Hydraulic conductivity of the aquifers in which the wells are screened was estimated by curve fitting the water-level-change data using aquifer test analysis software. Estimates of aquifer transmissivity were made by multiplying the estimated hydraulic conductivity value by the aquifer thickness at well locations. Mean hydraulic conductivity estimates for 44 observation wells screened in the Mississippi River Valley alluvial aquifer range from 3 to 401 feet per day, and mean transmissivity estimates range from 285 to 80,559 feet squared per day. Mean hydraulic conductivity estimates for four observation wells screened in units of the middle Claiborne aquifer range from 0.14 to 183 feet per day, and mean transmissivity estimates range from 55 to 67,913 feet squared per day. The results from these tests can be used to improve the understanding of water availability and groundwater migration, to refine groundwater models, and to ultimately provide stakeholders and decisionmakers better information for management of the groundwater resources within the Mississippi Alluvial Plain.

Released July 02, 2025 07:35 EST

2025, Open-File Report 2025-1036

Md Obaidul Haque, Md Nahid Hasan, Ashish Shrestha, Rajagopalan Rengarajan, Mark Lubke, Daniel Steinwand, Paul Bresnahan, Jerad L. Shaw, Kathryn Ruslander, Esad Micijevic, Michael J. Choate, Cody Anderson, Jeff Clauson, Kurt Thome, Ed Kaita, Raviv Levy, Jeff Miller, Leibo Ding, Cibele Teixeira Pinto

Executive Summary 

The U.S. Geological Survey Earth Resources Observation and Science Calibration and Validation (Cal/Val) Center of Excellence focuses on improving the accuracy, precision, calibration, and product quality of remote-sensing data, leveraging years of multiscale optical system geometric and radiometric calibration and characterization experience. The Earth Resources Observation and Science Cal/Val Center of Excellence Landsat Cal/Val Team continually monitors the geometric and radiometric performance of active Landsat missions and makes calibration adjustments, as needed, to maintain data quality at the highest level.

This report provides observed geometric and radiometric analysis results for Landsats 8 and 9 for quarter 4 (October–December) of 2024. All data used to compile the Cal/Val analysis results presented in this report are freely available from the U.S. Geological Survey EarthExplorer website: https://earthexplorer.usgs.gov.

Released July 02, 2025 07:24 EST

2025, Scientific Investigations Report 2025-5035

Emily Richardson, Tamara Kraus, Katy O'Donnell, Jeniffer Soto-Perez, Crystal Sturgeon, Elizabeth Stumpner, Brian Bergamaschi

Executive Summary

This report summarizes results from boat-based, high-resolution water-quality mapping surveys completed before, during, and after upgrades to the EchoWater Resource Recovery Facility (EchoWater Facility), the regional wastewater facility for the City of Sacramento and surrounding areas, near Elk Grove, California. Surveys were completed in the tidal aquatic environments of the Sacramento–San Joaquin Delta (Delta) in spring (May or June) 2018, 2020, 2021, and 2022. In each survey, a suite of in situ sensors were used to continuously (one measurement per second) measure water-quality conditions, nutrients, phytoplankton abundance, and species composition. In addition to in situ data collection, discrete water samples were collected about every 2 miles while underway for determination of phosphate, ammonium, and nitrate concentration. The boat stopped at about 30 locations to collect discrete samples for a suite of additional analytes, including phytoplankton enumeration. The four surveys represent snapshots in time across different phases of the EchoWater Facility Biological Nutrient Reduction (BNR) upgrade. The May 2018 survey represents conditions before the upgrade. The second survey (June 2020) represents conditions after implementation of the Nitrifying Sidestream Treatment. The third survey (May 2021) was completed immediately after the completion of the BNR upgrade and represents a transitional period, and the final survey (May 2022) represents post-upgrade conditions.

Relevant hydrologic and climatic context such as water-year type, X₂ position (the distance from the Golden Gate Bridge to the point upstream where bottom salinity is 2 parts per thousand; Jassby and others, 1995), water export to import ratio, and management actions like the Delta Cross Channel gate operations are presented for each survey so they may be considered in comparisons among surveys. Differences in water-quality parameters, like turbidity, temperature, salinity, pH, and dissolved oxygen (DO) improve understanding of nutrient cycling and phytoplankton dynamics. Because the Delta is a complex system, we divided the study area into hydrologic zones to better examine general trends and obtain a broadscale view of differences among the 4 study years. Results are presented for each survey and parameter using box plots to compare the different hydrologic zones. We also present each parameter using contour maps by survey to display gradients across the system.

The most evident change to water quality in the Delta across surveys is related to the EchoWater Facility BNR upgrade, which included nitrification and denitrification processes. Through this upgrade, effluent ammonium (NH₄⁺) concentrations were reduced by more than 95 percent (from about 2,000 micromolars [μM] to below the reporting limit of 35 μM), and nitrate (NO₃⁻) concentrations increased from near zero to about 500 μM; therefore, the concentration of dissolved inorganic nitrogen (DIN; the sum of NH₄⁺ and NO₃⁻) in the effluent was reduced by about 75 percent between May 2018 and May 2022. The BNR upgrade resulted in a reduction in NH₄⁺ concentrations in aquatic habitats immediately below the facility, designated as the “north Delta tidal transition zone” (Bergamaschi and others, 2024), from about 30 μM pre-upgrade to near zero during the 2022 spring survey, whereas effluent NO₃⁻ increased from median concentrations of about 7 μM to about 15 μM. Because of the reduced effluent nitrogen loads and variability in Sacramento River nitrogen loads from upstream sources, DIN concentrations in the north Delta tidal transition zone decreased from a median of 53.3 μM in 2018 to 35.3 μM in 2020, 20.7 μM in 2021, and 11.3 μM in 2022 during the spring surveys.

The changes in DIN concentration and form observed in the north Delta tidal transition zone after the EchoWater Facility upgrade extended downstream but were rapidly altered by hydrologic mixing, biogeochemical processes, and other nutrient source inputs. Most of the Delta indicated near-zero concentrations of NH₄⁺ 1 year after the completion of the EchoWater Facility upgrades represented by the 2022 survey. Exceptions to this finding were observed in the San Joaquin River near Stockton and in Suisun Bay, indicating there are NH₄⁺ inputs to these locations from other sources (for example, Stockton Regional Wastewater Control Facility and Central Contra Costs Sanitary District wastewater treatment plants or agricultural and urban runoff).

Although there was an increase in NO₃⁻ concentrations in the north Delta tidal transition zone after the upgrade, increases in NO₃⁻ in other zones were not apparent, presumably because nitrification of effluent derived ammonium was no longer a source of NO₃⁻. Concentrations of DIN in many Delta zones were lower in 2022 compared to 2018 and 2020, with concentrations near or below what is considered potentially nitrogen limiting conditions for phytoplankton growth in the North Delta tidal transition zone and the Cache Slough complex channel system. Unrelated to the EchoWater Facility upgrade, NO₃⁻ and therefore DIN concentrations increased in the San Joaquin River near Stockton and in adjacent water bodies by survey date (likely associated with increasing drought conditions). The Mokelumne River had low DIN concentrations, except in 2018 when the Delta Cross Channel was open, which allowed nutrient-rich Sacramento River water to flow into this section of the river. Data from these surveys also support the hypothesis that nutrient drawdown during phytoplankton blooms may create localized nitrogen limiting conditions.

The BNR upgrade resulted in lower effluent phosphate (PO₄³⁻) concentrations, which lowered PO₄³⁻ concentrations in some zones of the Delta during the four spring surveys; however, PO₄³⁻ concentrations throughout the Delta remained above 0.3 μM, indicating that primary productivity was not limited by phosphorous availability. DIN and PO₄³⁻ decreased after the upgrade in many areas of the Delta, and the DIN to dissolved inorganic phosphorus (DIN:DIP) ratio remained similar to pre-upgrade conditions and was often below the Redfield Ratio of 16, indicating nitrogen is more likely to limit phytoplankton growth than phosphorous. Inputs of dissolved organic carbon (DOC) from the EchoWater Facility are a minor source of this constituent to the Delta, so the upgrade had little to no effect on DOC concentrations across the Delta.

Because phytoplankton abundance and species composition in the Delta are shaped by multiple factors other than nutrients (for example, light availability, temperature, salinity, and predation), it is important to consider these factors (as well as long-term monitoring) in addition to the EchoWater Facility upgrade. Although phytoplankton populations were low across much of the Delta during the spring surveys, several localized phytoplankton blooms (defined here as greater than 15 micrograms per liter [μg/L] of chlorophyll) provide insight into conditions that may favor the growth of beneficial and harmful species.

Released July 01, 2025 10:46 EST

2025, Nature Communications (16)

Anton Vaks, Andrew Mason, Sebastian F.M. Breitenbach, Alena Maria Giesche, Alexander Osinzev, Irina Adrian, Aleksandr Kononov, Stuart Umbo, Franziska A. Lechleitner, Marcelo Rosensaft, Gideon M. Henderson

Arctic warming is happening at nearly four times the global average rate. Long-term trends of permafrost dynamics cannot be estimated directly from monitoring of present-day thaw processes, requiring paleoclimate-proxy information. Here we use cave carbonates (speleothems) from a northern Siberian cave to determine when the Northern Hemisphere was mostly permafrost-free. At present, thick continuous permafrost in this region prevents speleothem growth. In a series of partially eroded caves, speleothems grew during the late Tortonian stage (8.68 ± 0.09 Ma), a time when the geographic position of this site was already similar to today. Paleotemperatures reconstructed from speleothems show that mean annual air temperatures (MAAT) in the region were + 6.6°C to + 11.1°C, when contemporary global MAAT were ~ 4.5 °C higher than modern. Our findings provide direct evidence that warming to Tortonian-like temperatures would leave most of the Northern Hemisphere permafrost-free. This may release up to ~ 130 petagrams of carbon, enhancing further warming.

Released July 01, 2025 09:53 EST

2025, Scientific Reports (15)

N.J. Daigle, Shannon L. White, Barbara A. Lubinski, Robin L. Johnson, David C. Kazyak, C.E. Verhille, C.A. Gillis, C.F.D. Sacobie

The Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) is an important species in eastern North America due to its conservation status and cultural significance. Local Mi'gmaw fishers have reported an increase in sturgeon sightings over the last decade in the Restigouche River and estuary. Mi’gmaw Knowledge, oral history, and archaeological finds attest to their historical presence in the region; however, the river is not a documented habitat for Atlantic sturgeon in Western literature. Based on community interest and concern, the Gespe’gewa’gi Institute of Natural Understanding co-developed a Two-Eyed Seeing collaboration to learn more about these sturgeon. Here, we investigate their genetic origin via microsatellite analyses and hypothesized that they would originate from the closest spawning habitat, the St. Lawrence River. We found that, overall, the largest contributor to our Atlantic sturgeon sampled from the Restigouche River system was the St. Lawrence River (85.7% of samples), followed by the Wolastoq (3.6%), then a mixture of the St. Lawrence, the Wolastoq, the Kennebec, and/or the Hudson River populations (10.7%). Improving our understanding of the distribution of Atlantic sturgeon through microsatellite analyses and leveraging range-wide genetic baselines directly assesses the genetic origin of unknown stock compositions and can support the future co-management of the species.

Released July 01, 2025 09:39 EST

2025, Landscape Ecology

Raymond LeBeau, Miguel L. Villarreal, Jerry D. Davis

Context

Montane meadows play an important hydrologic role in headwater catchments, but past land use has largely degraded their condition. Low-tech restoration methods, such as beaver dam analogs (BDAs), are increasingly used to support recovery of incised streams by promoting key geomorphic processes. However, there remains a need for studies that leverage UAS for monitoring low-tech restoration treatments in incised meadow systems.

Objectives

This study maps and characterizes geomorphic changes in two incised meadow stream channels in Red Clover Valley, CA with installed beaver dam analog structures. We used UAS-based photogrammetric surveys to track changes over a three-year period (2021–2023).

Methods

Geomorphic change was assessed using DEM differencing with error thresholding, repeat geomorphic unit (GU) classification, and Shannon Diversity Index (SHDI) to measure spatial shifts in geomorphic complexity.

Results

Geomorphic responses varied by site and survey period. The subchannel B (SCB) site exhibited net deposition, while the lower Dixie Creek (LDC) site showed net erosion. BDAs appeared to enhance geomorphic activity, particularly in LDC, where near BDA areas showed greater sediment deposition and localized erosion compared to reference sites. SHDI values were positively correlated with erosion at both sites, suggesting that erosional processes may have promoted geomorphic diversity by creating or reorganizing GU in the incised channels.

Conclusions

UAS-SfM surveys captured erosion and deposition patterns and revealed the influence of BDAs and local channel characteristics on geomorphic change and unit diversity. These findings highlight the utility of UAS methods for monitoring restoration impacts in incised montane meadow streams.

Released July 01, 2025 09:29 EST

2025, Journal of Hydrology: Regional Studies (60)

Fred D. Tillman, Melissa D. Masbruch, Jacob E. Knight, John A. Engott, Samuel Francisco Lopez, Casey J.R. Jones, Jesse E. Dickinson, Matthew P. Miller

Study region: Headwaters of the upper Colorado River basin (UCOL), USA

Study focus: Surface-water and groundwater numerical models incorporating water-use information were used to investigate changes in climate, water use, and simulated hydrologic responses of snow processes, evapotranspiration, groundwater, and streamflow during recent wet (1982–1999) and drought (2000–2022) periods in the headwater subregions of the upper Colorado River basin.

New hydrologic insights for the region: Decreases in average streamflow between wet and drought periods ranged from 20 % in the Colorado River headwaters subregion to 23 % in the Gunnison River headwaters subregion. Like streamflow, average surface runoff was statistically less during the drought than the wet period, with decreases from 24–31 % in the headwaters. On a volume basis, runoff decreases were greater than streamflow decreases in both the Colorado River and Gunnison River headwaters. Although the amount of water-year groundwater discharge to streams remained nearly the same between the wet and drought periods, groundwater as a percentage of streamflow increased between the wet and drought periods, highlighting the importance of groundwater in sustaining streamflow during drought conditions. Multiple linear regression analyses revealed that snowmelt-only models were better than the best precipitation and temperature models at explaining streamflow variability from all headwater subregions for both the wet and drought periods.

Released July 01, 2025 09:08 EST

2025, Scientific Reports (15)

Aubree Jones, Matthew J. O'Donnell, Amy M. Regish, Jacqueline Webb

Increases in water temperature due to global climate change are known to alter the course and timing of fish development. The mechanosensory lateral line (LL) system mediates flow-sensing behaviors vital for survival in fishes, but the effects of increased water temperatures resulting from climate change on its development have not been examined. Here LL development was documented in a cold-water salmonid (brook trout, Salvelinus fontinalis) reared at the thermograph of a long-term study stream (ambient) and two higher temperatures (+ 2 and + 4 °C) that reflect projected increases within their native range. At these two higher temperatures, fish reach crucial early life history transitions earlier (e.g., hatch, “swim-up” from gravel nests into the water column) and are larger in size through the parr (juvenile) stage. Early forming canal neuromast receptor organs are larger, and the process of canal morphogenesis is also accelerated suggesting potential consequences for neuromast function and presumably for LL-mediated behaviors. A potential mismatch between the timing of transitions in early life history stages, the ability to carry out LL-mediated behaviors (e.g., prey detection), and the timing of the seasonal emergence of their preferred prey, could have serious implications for cold-water salmonid ecology and survival.

Released June 30, 2025 13:30 EST

2025, Scientific Investigations Report 2025-5053

Sophie R. Bonner, Kurtis J. Nelson, Peter G. Rinkleff, Chad M. Hoffman, Paul F. Steblein

On September 19, 2024, the U.S. Geological Survey (USGS) held a virtual workshop titled “Potential for Evaluation of Fire Models with Remote Sensing Data Workshop” to assess the feasibility of using remotely sensed datasets to evaluate next-generation wildland fire behavior models. Remote sensing and fire modelling experts gathered to: (1) assess the suitability of a variety of classified, commercial, and publicly available remotely sensed datasets for advancing fire model evaluation; (2) develop ideas on how to integrate remotely sensed data products with fire model inputs and outputs; and (3) identify any barriers and limitations to performing an evaluation of next-generation fire models. The USGS National Civil Applications Center, USGS Earth Resources Observation and Science Center, and USGS Fort Collins Ecosystem Science Center presented information on remote sensing datasets for three Arizona wildfire case studies. The development teams of the Fire Dynamics Simulator and QUIC-Fire fire behavior models presented their models and current evaluation methodologies. Interspersed with these presentations were discussions regarding how to expand current wildfire remote sensing data collection efforts beyond operational needs to assist in future fire modeling.

Workshop participants agreed that several of the remote sensing datasets have potential for wildfire model evaluation. However, participants also identified several barriers and complications to performing a model evaluation including key gaps in wildfire datasets; uncertainties related to model fire-atmosphere reinitiation; lack of ground truthing and atmospheric correction of remotely sensed datasets; and differences in spatial, geolocation, radiometric, and temporal resolutions between the datasets and models. Further, the absence of standardized methodologies for image interpretation, poor understanding of sensor capabilities and limitations, and a lack of automation also hinder model evaluation efforts. Based on feedback from this workshop, USGS fire modelers are considering a project to address the uncertainties related to fire model reinitiation and encouraging fire practitioners to collaborate with remote sensing experts on wildland fires to improve data collection for a broader community of practice. Additionally, multiagency efforts are in development for a comprehensive cross-sensor validation and ground-truth campaign to test spatial, spectral, and geolocation sensor capabilities, determine limitations, and identify observational gaps for future sensor development and acquisition.

Released June 30, 2025 11:00 EST

2025, PLOS Water (4)

Aditi S. Bhaskar, Charles C. Stillwell, Matthew J. Burns, Kristina G. Hopkins, Christopher J. Walsh

The deleterious effects of directly-connected impervious surfaces on urban streams have been widely recognized. To deal with these effects, the use of stormwater control measures that aim to disconnect impervious surfaces and prevent stormwater from reaching the stream has surged. However, we lack widespread use of consistent metrics that describe how effective these stormwater control measures are for mitigating the effects of untreated stormwater. Using total impervious area neglects the effect of stormwater control measures whereas directly-connected impervious area assumes that stormwater control measures perform perfectly. Comparing the success of stormwater control measures across many watersheds and cities will require use of consistent metrics of effective imperviousness, describing actual performance of stormwater control measures in reducing impervious areas hydraulically connected to the stream. This work applies two published approaches to quantify effective imperviousness, one that measures the frequency of downstream flow disturbances and another that computes parameters from a paired rainfall-runoff regression analysis. We apply these approaches in two settings: 1) two watersheds with new low impact development in Clarksburg, Maryland, USA and 2) five watersheds with stormwater retrofits in Melbourne, Australia. These methods gave largely similar results, with differences in effective imperviousness ranging from 1%-9%. Using these approaches in Clarksburg, the effective imperviousness for the treatment watersheds was 6–12%, whereas the total imperviousness was 33–44% and the directly-connected imperviousness was 0%. In Clarksburg, effective imperviousness better described stream hydrologic and biotic outcomes compared to either total imperviousness or directly-connected imperviousness. In Melbourne, effective imperviousness was a better metric for hydrologic and water quality changes that are likely to provide ecological benefits. In both cases, new development and retrofits, we demonstrate the utility of effective imperviousness metrics for predicting stream outcomes and how these metrics may be used to understand the success of stormwater control measure using a consistent metric.

Released June 30, 2025 09:20 EST

2025, Open-File Report 2025-1032

Elena Safirova, Yelena Golovko, Nafisa Dulabova

Tungsten appears on the 2018 and 2022 U.S. Geological Survey critical mineral lists in part because of a very high global production concentration in China, which produces almost 83 percent of the world’s mined tungsten. Using known parameters and values from other tungsten mining operations, we created hypothetical scenarios in which three tungsten deposits in Uzbekistan are considered for development. Our results show that all three deposits are likely to be economically viable to develop under 2024 market conditions. If the three studied tungsten deposits were put into production, Uzbekistan could become the third-leading tungsten-producing country in the world and increase world output of tungsten by 2.7 percent. Putting these tungsten deposits in Uzbekistan into production could slightly reduce the tungsten global market concentration, therefore reducing the supply disruption potential for tungsten.

Released June 28, 2025 11:04 EST

2025, Environmental Toxicology and Chemistry

Staci Cibotti, Michelle Hladik, Emily May, Emma Pelton, Timothy Bargar, Natalie Johnston, Aimee Code

Since the 1980s, monarch butterfly (Danaus plexippus plexippus) populations across North America have declined by 80–95%. Although several studies have implicated pesticides as a contributing factor to their population declines, our understanding of monarch exposure levels in nature remains limited. In January 2024, a mass mortality event near an overwintering site in Pacific Grove, California, USA, provided an opportunity to analyze dead overwintering monarch butterflies for pesticide residues. Ten recently deceased butterflies were collected and analyzed using liquid and gas chromatography with tandem mass spectrometry (LC-MS/MS and GC-MS/MS). We identified a total of 15 pesticides and associated metabolites in the butterflies, including 8 insecticides (plus 1 associated metabolite), 2 herbicides (plus 2 associated metabolites), and 2 fungicides. On average, each monarch butterfly contained 7 pesticides, excluding transformation products if the parent compound was also detected. Notably, three pyrethroid insecticides—bifenthrin, cypermethrin, and permethrin—were consistently detected at or near each chemical’s lethal dose (LD₅₀). Bifenthrin and cypermethrin were found in every sample, while permethrin was present in all but two samples. The average concentrations of these insecticides were 451.9 ng/g dry weight (dw) for bifenthrin, 646.9 ng/g dw for cypermethrin, and 337.1 ng/g dw for permethrin. These findings demonstrate pesticide contamination in monarch butterflies, including within urban areas, and highlight the risks pesticides, especially insecticides, pose to monarch populations. Additional measures may be required to safeguard this species from pesticide exposure, particularly near aggregation locations, such as overwintering sites in coastal California.

Released June 27, 2025 10:36 EST

2025, Water Resources Research (61)

Ashley Helton, James Dennedy-Frank, Ryan Emanuel, Scott C Neubauer, Kyra Adams, Marcelo Ardon, Lawrence Band, Kevin A. Befus, Hanne Borstlap, Jamie Duberstein, Adam Gold, Kominoski John, Alex Manda, Holly A. Michael, Stephen Moysey, Allison Myers-Pigg, Justine Annaliese Neville, Gregory Noe, Jeeban Panthi, Elnaz Pezeshki, Matthew Sirianni, Ward.Nicolas

Seawater intrusion (SWI) affects coastal landscapes worldwide. Here we describe the hydrologic pathways through which SWI occurs - over land via storm surge or tidal flooding, under land via groundwater transport, and through watersheds via natural and artificial surface water channels—and how human modifications to those pathways alter patterns of SWI. We present an approach to advance understanding of spatiotemporal patterns of salinization that integrates these hydrologic pathways, their interactions, and how humans modify them. We use examples across the East Coast of the United States that exemplify mechanisms of salinization that have been reported around the planet to illustrate how hydrologic connectivity and human modifications alter patterns of SWI. Finally, we suggest a path for advancing SWI science that includes (a) deploying standardized and well-distributed sensor networks at local to global scales that intentionally track SWI fronts, (b) employing remote sensing and geospatial imaging techniques targeted at integrating above and belowground patterns of SWI, and (c) continuing to develop data analysis and model-data fusion techniques to measure the extent, understand the effects, and predict the future of coastal salinization.

Released June 27, 2025 10:29 EST

2025, The Cryosphere (19) 2315-2320

Edward Bair, Dar Roberts, David R. Thompson, Philip Brodrick, Brent Wilder, Niklas Bohn, Christopher J. Crawford, Nimrod Carmon, Carrie Vuyovich, Jeff Dozier

Key to the success of spaceborne missions is understanding snowmelt in our warming climate, as this has implications for nearly 2 billion people. An obstacle is that surface reflectance products over snow show an erroneous hook with decreases in the visible wavelengths, causing per-band and broadband reflectance errors of up to 33 % and 11 %, respectively. This hook is sometimes mistaken for soot or dust but can result from three artifacts: (1) background reflectance that is too dark, (2) an assumption of level terrain, or (3) differences in optical constants of ice. Sensor calibration and directional effects may also contribute. Solutions are being implemented.

Released June 27, 2025 08:12 EST

2025, Sustainability Science

Sana Okayasu, Jan J. Kuiper, Halouani Ghassen, Kim Hyejin, Brian W. Miller, America Paz Duran, Vermeer Angelique, Machteld Schoolenberg, Shizuka Hashimoto, Carolyn J. Lundquist

The Nature Futures Framework (NFF), developed under the Intergovernmental Science–Policy Platform on Biodiversity and Ecosystem Services (IPBES), serves as a catalyst for advancing new scenarios and models focused on biodiversity and ecosystem services within the broader research community. In particular, the framework facilitates the development of scenarios and models that can help guide change processes toward desirable futures for nature and people. This paper assesses 31 studies that have engaged with the NFF since its introduction in 2020, aiming to identify which research areas have been addressed, and where development needs remain. The applications exhibit a large diversity in terms of locations, spatial scales, methods, outputs, and stakeholder involvement. The most common use of the framework has been in developing visions and scenarios. Nearly all studies engaged with diverse values of nature through the framework’s fundamental value perspectives: ‘Nature for Society’, ‘Nature for Nature’, and ‘Nature as Culture/One with Nature’. While the framework is generally perceived as useful, challenges remain in integrating the NFF across multiple scales and fully incorporating plural values, particularly in measuring relational aspects and avoiding Western-centric biases. Future research priorities include developing integrated, quantitative studies and exploring transformative pathways to enhance the framework's effectiveness in driving sustainable outcomes. Overall, the growing body of work using the NFF provides a strong foundation for distilling best practices, facilitating large-scale applications, and achieving the framework's objectives.

Released June 27, 2025 08:03 EST

2025, PLoS ONE (20)

Mathew Denton, Michael Cherkiss, Frank J. Mazzotti, Laura A. Brandt, Sidney T. Godfrey, Darren Johnson, Kristen Hart

Hydrologic alterations within the Everglades have degraded American alligator (Alligator mississippiensis) habitat, reduced prey base, and increased physiological stress. Alligator body condition declined across many management areas from 2000 through 2014, prompting us to investigate the relationship between their intraspecific isotopic niche dynamics and body condition. Alligators within the estuary had a larger niche driven by a wider range in stable carbon isotope ratios than those sampled in freshwater habitats. Spatially, model predictability was higher at the smaller scale, reflecting the variability in basal sources and biochemistry among capture sites. Male niches were often larger than those of females, driven by wider ranges of δ¹³C values, suggesting that they differ in their proportional use of habitats and or resources. However, the similar ranges of δ¹⁵N values indicated both sexes foraged within the same trophic level. Furthermore, while not significantly different, large alligators often had a larger niche with elevated δ¹⁵N values compared to medium-sized alligators. Although alligators utilize similar stable carbon and nitrogen isotope pools through time, there was considerable temporal variability. These temporal variations in alligators’ isotopic niche were likely influenced by seasonal hydrologic fluctuations within each site, with their niches often being larger in the spring captures than the fall captures. Alligators’ body condition estimates were correlated with intraspecific niche characteristics, including the mean centroid distance between sexes and the interaction between male and female niche size and overlap, within a site, capture period, and year. The variability in intraspecific niche dynamics, landscape heterogeneity, and dynamic hydrology are considerations for designing sustainable management strategies to conserve and enhance alligator populations within the Everglades landscape.

Released June 26, 2025 13:45 EST

2025, Scientific Investigations Report 2024-5134

David E. Ladd, John K. Carmichael

Closed depressions and sinking streams in karst landscapes pose difficulties for water-resources management, in the construction of roads and other public works, and in hydrologic and hydrogeomorphic analyses. Digital elevation models (DEMs) can be used to identify the location and determine the size and shape of closed depressions, but separating artificial depressions due to error from real depressions in DEMs can be difficult. Artificial depressions in the DEMs can result from errors that were inherited from limitations in the source data, the interpolation of the elevation data into a grid of values, or horizontal and vertical accuracy of the elevation data. Because the source dataset used to derive DEMs is only a model of the true landscape, field verification is necessary to separate artificial depressions from real ones in DEMs. DEM analysis alone can only be used to determine whether a depression is likely or unlikely to exist in the landscape.

The U.S. Geological Survey has applied methods to delineate depressions, sinking streams, and their watersheds by using DEMs derived from two sources of elevation data within karst areas of Tennessee and parts of surrounding States. Preliminary depressions, which include all depressions before separating the likely depressions from the unlikely depressions, were delineated from the DEMs with 30- by 30-foot cells derived from each elevation data source. The characteristics of these preliminary depressions were compared to occurrence probabilities for depressions derived from numerical error propagation tests in 10 test areas across the study area and to topographic-contour source data within a 17,739-square-mile test area in middle Tennessee and northern Alabama. The comparison was conducted to determine depression characteristics that, when combined with depression-proximity filters, could be used to separate unlikely from likely depressions. Preliminary depressions were examined in the field at 91 sites in Tennessee, and field observations were compared to digital determinations of unlikely and likely depressions.

The density and size of depressions derived from each elevation dataset were compared within eight karst regions in the study area. Depressions and their watersheds were compiled from each elevation dataset. Sinking streams derived from the National Hydrography Dataset and their watersheds also were compiled for the study area.

Released June 26, 2025 10:21 EST

2025, Frontiers in Water (7)

Kimberly Slinski, Gabriel B. Senay, Alkhalil Adoum, Shraddhanand Shukla, Amy McNally, James Rowland, Erwan Fillol, Soni Yatheendradas, Chris Funk, Andrew Hoell, Michael Jasinski

Introduction: Rangeland ponds are vital to the livelihoods of pastoral and agropastoral communities in Africa, providing an important source of water for livestock. However, sparse instrumentation across much of Africa makes it extremely challenging to monitor surface water availability in these areas. Model estimates of surface water, for example, as used by the Famine Early Warning Systems Network (FEWS NET) Water Point Viewer, are one of the few operational tools available to monitor surface water stress across pastoral areas of the Sahel and East Africa.

Methods: Water availability data from these models are difficult to validate. New methods using satellite data to classify surface water provide an opportunity to assess the performance of these tools. This study compares water availability estimates derived from Landsat and Sentinel 1 satellite imagery to in situ observations and model simulations of water availability in 22 ephemeral ponds located in the Ferlo region of Senegal.

Results and discussion: The Active-Passive Water Classification (APWC) algorithm detected surface water at each location. Over 2022 and 2023, water was detected in pond locations annually at a frequency of 68.2% for all ponds and at a frequency of 43.8% for ponds with a surface area <10,000 square meters (m²). The APWC results outperform global and continental surface water datasets in the Ferlo region. Seasonal water availability was captured in 12 ponds over the 2022 and 2023 seasons. The 12 locations can function as sentinel ponds to monitor local water availability. Study results demonstrate the viability of satellite methods to assess water availability in the region, as well as the challenges to using satellite-based methods to estimate water availability in small ponds.

Released June 26, 2025 09:50 EST

2025, Scientific Investigations Report 2025-5037

Emily J. Wilkins, Sarah M. Lindley, Karla Rogers, Rudy Schuster, Mark T. Hannon, Parker T. Rowland, Michael J. Runnels

Many people ascribe a variety of values to public lands and waters, but some values are more difficult to assess and quantify than others. Public participatory geographic information systems (PPGIS) are tools that have been used to help quantify and map the public’s diverse values for a landscape. This work describes the first known Office of Management and Budget–approved use of PPGIS by a Department of the Interior bureau. The U.S. Geological Survey developed an internet-based application to aid in gathering PPGIS data, called Values Mapping for Planning in Regional Ecosystems (VaMPIRE). Further, this work describes the first pilot of the VaMPIRE application in coordination with the Bureau of Land Management to collect spatial data and other survey data regarding the public’s uses of and values for locations within Mojave Trails National Monument. We emailed the link to the VaMPIRE application to an interested party email list in 2024 with 207 valid emails and received 74 responses; we also received 47 responses from members of an off-roading social media group. Of the list of 16 value options, recreation was the most popular value for the monument, followed by wilderness and inspirational. Over 1,000 points were placed throughout the monument, indicating locations people use or value, with the locations spread throughout the entire monument. Additionally, most survey respondents stated their ability to receive benefits in locations they mapped would not change in response to a hypothetical scenario related to recreational facility development. This report describes exploratory results from the first use of the VaMPIRE tool in Mojave Trails National Monument and includes reflections on how the process went and considerations for future use of VaMPIRE.

Released June 26, 2025 09:28 EST

2025, Scientific Investigations Report 2025-5042

Andrew P. Teeple, Zulimar Lucena, Christopher L. Braun, Evin J. Fetkovich, Isaac A. Dale, Shana L. Mashburn

The Wilcox Oil Company Superfund site (hereinafter referred to as “the site”) was formerly an oil refinery northeast of Bristow in Creek County, Oklahoma. Historical refinery operations contaminated the soil, surface water, streambed sediments, alluvium, and groundwater with refined and stored products at the site. The Wilcox and Lorraine process areas are where the highest concentrations of volatile organic compounds, semivolatile organic compounds, polycyclic aromatic hydrocarbons, and trace elements (including metals) (collectively hereinafter referred to as “contaminants”) were measured in a local shallow perched groundwater system within the alluvium (hereinafter referred to as the “alluvial aquifer”) at the site during previous site assessments. In order to understand the potential migration of contaminants through the soil and groundwater in these areas, the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, investigated aquifer characteristics of the alluvial aquifer in the Wilcox and Lorraine process areas of the site to (1) document hydraulic conductivity and other aquifer characteristics of the alluvial aquifer that govern contaminant fate and transport, (2) describe the geospatial extent and concentration of the contaminants in the alluvial aquifer in the Wilcox and Lorraine process areas, and (3) describe the geochemical controls pertaining to oxidation and reduction governing the fate and transport and the degradation potential of contaminants in the groundwater. Various data were compiled and collected to evaluate the aquifer characteristics at the site including the hydrogeologic framework, groundwater-flow system, geochemistry, and hydraulic properties of the aquifer. A total of 20 new (2022) groundwater monitoring wells were installed at the site to collect data used to supplement groundwater-level altitude and groundwater-quality data collected from older, existing groundwater monitoring wells and piezometers. Data compiled and collected for the study were used to evaluate the characteristics of the alluvial aquifer at the site. These aquifer characteristics are defined by the hydrogeologic framework, groundwater-flow system, geochemistry, and hydraulic properties of the aquifer.

Released June 26, 2025 09:22 EST

2025, Earth System Science Data 2887-2909

Anna Talucci, Michael M. Loranty, Jean E. Holloway, Brendan M. Rogers, Heather D. Alexander, Natalie Baillargeon, Jennifer L. Baltzer, Logan T. Berner, Amy Breen, Leya Brodt, Brian Buma, Jacqueline Dean, Clement J.F. Delcourt, Lucas R. Diaz, Catherine M. Dieleman, Thomas A. Douglas, Gerald Frost, Benjamin V. Gaglioti, Rebecca E. Hewitt, Teresa N. Hollingsworth, M. Torre Jorenson, Mark J. Lara, Rachel A. Loehman, Michelle C. Mack, Kristen L. Manies, Christina Minions, Susan M. Natali, Jonathan A. O'Donnell, David Olefeldt, Alison K. Paulson, Adrian V. Rocha, Lisa B. Saperstein, T.A. Shestakova, Seeta Sistla, Oleg Sizov, Andrey Soromotin, Merritt R. Turetksy, Sander Veraverbeke, Michelle A. Walvoord

As the northern high-latitude permafrost zone experiences accelerated warming, permafrost has become vulnerable to widespread thaw. Simultaneously, wildfire activity across northern boreal forest and Arctic/subarctic tundra regions impacts permafrost stability through the combustion of insulating organic matter, vegetation, and post-fire changes in albedo. Efforts to synthesis the impacts of wildfire on permafrost are limited and are typically reliant on antecedent pre-fire conditions. To address this, we created the FireALT dataset by soliciting data contributions that included thaw depth measurements, site conditions, and fire event details with paired measurements at environmentally comparable burned and unburned sites. The solicitation resulted in 52 466 thaw depth measurements from 18 contributors across North America and Russia. Because thaw depths were taken at various times throughout the thawing season, we also estimated end-of-season active layer thickness (ALT) for each measurement using a modified version of the Stefan equation. Here, we describe our methods for collecting and quality-checking the data, estimating ALT, the data structure, strengths and limitations, and future research opportunities. The final dataset includes 48 669 ALT estimates with 32 attributes across 9446 plots and 157 burned–unburned pairs spanning Canada, Russia, and the United States. The data span fire events from 1900 to 2022 with measurements collected from 2001 to 2023. The time since fire ranges from 0 to 114 years. The FireALT dataset addresses a key challenge: the ability to assess impacts of wildfire on ALT when measurements are taken at various times throughout the thaw season depending on the time of field campaigns (typically June through August) by estimating ALT at the end-of-season maximum. This dataset can be used to address understudied research areas, particularly algorithm development, calibration, and validation for evolving process-based models as well as extrapolating across space and time, which could elucidate permafrost–wildfire interactions under accelerated warming across the high-northern-latitude permafrost zone. The FireALT dataset is available through the Arctic Data Center (https://doi.org/10.18739/A2RN3092P, Talucci et al., 2024).

Released June 26, 2025 08:41 EST

2025, Report

K. Runyon, S. Buxner, K. Crane, C. Crow, A. Douglas, Lauren A. Edgar, D. Eppler, J.M. Hurtado, K. Rubins, M. Wagner

We report on six Findings related to the benefit of Artemis Base Camp (ABC) to lunar geoscience (Figure 1). These Findings are on the topics of 1) Repeat field site visits; 2) Geological experiments; 3) Satellite ABC campus(es); 4) Advanced lab equipment; 5) Frequent and resource-intensive EVAs; and 6) Geoscience STEM engagement. Lastly, we consider certain issues and caveats meriting further study in any base camp architecture.

Released June 26, 2025 08:33 EST

2025, North American Journal of Fisheries Management

Sophia Marie Bonjour, Keith B. Gido, Peter J. Pfaff, Abigail Rick, Aiden Masek

Released June 26, 2025 08:24 EST

2025, Environmental Science & Technology

Jiazhen Wang, Jason Tyler Magnuson, Yanqiu Feng, Wenjing Zhao, Chuanzi Gao, Chunmiao Zheng, Wenhui Qiu

The increasing use of plastic additives, particularly bisphenols (BPs), has raised significant concerns about their potential risks to human health, especially during critical developmental stages. In this study, we developed a novel high-throughput toxicity screening platform using zebrafish (Danio rerio) to identify and prioritize chemicals with cardiotoxic potential, which is based on multidimensional exposure pathways ranging from environmental to human levels. The platform quantitatively assesses heart rate changes based on multilevel exposure pathways (environmental, ecological, and human), effectively prioritizing the most relevant cardiotoxic compounds with potential health risks. Using this platform, we identified bisphenol P (BPP), a widely used substitute for bisphenol A, as a potent cardiotoxic compound. BPP exposure significantly inhibited heart development and function in zebrafish, inducing abnormal heart morphology, reduced heart rate, cardiac output, and hemodynamic disturbances. Additionally, NF-κB signaling pathway analysis, including morpholino knock-down and inhibitor experiments, confirmed that BPP mediates cardiac toxicity by inducing cardiomyocyte apoptosis. Our findings underscore the toxicity that BP substitutes can have, while highlighting the potential of this multidimensional screening platform in evaluating cardiovascular toxicity and guiding future toxicological assessments during critical developmental windows.

Released June 26, 2025 08:14 EST

2025, Science (388)

Brian J. Yanites, Marin Clark, Joshua J. Roering, A. Joshua West, Dimitrios Zekkos, Jane W. Baldwin, Corina Cerovski-Darriau, Sean F. Gallen, Daniel E. Horton, Eric Kirby, Ben Leshchinksy, H. Benjamin Mason, Seulgi Moon, Katherine R. Barnhart, Adam M. Booth, Jonathan A. Czuba, Scott W. McCoy, Luke A. McGuire, Allison M. Pfeiffer, Jennifer L. Pierce

Earth’s surface is sculpted by numerous processes that move sediment, ranging from gradual and benign to abrupt and catastrophic. Although infrequent, high-magnitude sediment mobilization events can be hazardous to people and infrastructure, leaving topographic imprints on the landscape and remarkable narratives in the historical record. Hazardous events such as fires, storms, and earthquakes accelerate erosion and sediment transport, increasing landscape sensitivity to subsequent perturbations, thus forming a cascading hazard. Although the redistribution of sediment across Earth’s landscape can result in higher risks to vulnerable populations, cascading processes are commonly unaccounted for in hazard assessments. Cascading hazards can occur almost immediately after triggering events, such as coseismic landslides, or over months, years, or even decades after an initial perturbation, such as debris flows after wildfires or flooding in channels alluviated by volcanic debris. Sediment cascades span Earth’s surface, from mountaintops to river valleys, where erosion, deposition, and aggradation can lead to a myriad of hazardous processes, including decreased river conveyance capacity, which increases the likelihood of downstream flooding. An improved understanding of the magnitude, frequency, and persistence of cascading hazards is critical given the rapid changes in the frequency and severity of storms, fires, sea-level change, and cryospheric melting, as well as the expansion of high-population-density urban footprints in regions susceptible to solid Earth hazards. Understanding the full consequences and underlying physics of Earth’s cascading land surface hazards can help minimize future human and economic losses.

Released June 26, 2025 07:51 EST

2025, Methods in Ecology and Evolution

Matthew J. Weldy, Damon B. Lesmeister, Tom Denton, Adam Duarte, Ben J. Vernasco, Amandine Gasc, Jennifer Rowe, Michael J. Adams, Matthew G. Betts

1. The biodiversity crisis necessitates spatially extensive methods to monitor multiple taxonomic groups for evidence of change in response to evolving environmental conditions. Programs that combine passive acoustic monitoring and machine learning are increasingly used to meet this need. These methods require large, annotated datasets, which are time-consuming and expensive to produce, creating potential barriers to adoption in data- and funding-poor regions. Recently released pre-trained avian acoustic classification models provide opportunities to reduce the need for manual labelling and accelerate the development of new acoustic classification algorithms through transfer learning. Transfer learning is a strategy for developing algorithms under data scarcity that uses pre-trained models from related tasks to adapt to new tasks.

2. Our primary objective was to develop a transfer learning strategy using the feature embeddings of a pre-trained avian classification model to train custom acoustic classification models in data-scarce contexts. We used three annotated avian acoustic datasets to test whether transfer learning and soundscape simulation-based data augmentation could substantially reduce the annotated training data necessary to develop performant custom acoustic classifiers. We also conducted a sensitivity analysis for hyperparameter choice and model architecture. We then assessed the generalizability of our strategy to increasingly novel non-avian classification tasks.

3. With as few as two training examples per class, our soundscape simulation data augmentation approach consistently yielded new classifiers with improved performance relative to the pre-trained classification model and transfer learning classifiers trained with other augmentation approaches. Performance increases were evident for three avian test datasets, including single-class and multi-label contexts. We observed that the relative performance among our data augmentation approaches varied for the avian datasets and nearly converged for one dataset when we included more training examples.

4. We demonstrate an efficient approach to developing new acoustic classifiers leveraging open-source sound repositories and pre-trained networks to reduce manual labelling. With very few examples, our soundscape simulation approach to data augmentation yielded classifiers with performance equivalent to those trained with many more examples, showing it is possible to reduce manual label-ling while still achieving high-performance classifiers and, in turn, expanding the potential for passive acoustic monitoring to address rising biodiversity monitoring needs.

Released June 25, 2025 12:32 EST

2025, Scientific Investigations Report 2025-5043

Nicole C. Gammill, S. Jerrod Smith

The 1973 Oklahoma Groundwater Law (Oklahoma Statute §82–1020.5) requires that the Oklahoma Water Resources Board conduct hydrologic investigations of the State’s aquifers to determine the maximum annual yield for each groundwater basin. The U.S. Geological Survey, in cooperation with the Oklahoma Water Resources Board, conducted an updated hydrologic investigation of the Salt Fork Arkansas River and Chikaskia River alluvial aquifers in northern Oklahoma for the study period spanning 1980–2020 and evaluated the simulated effects of potential groundwater withdrawals on groundwater flow and availability in the Salt Fork Arkansas River alluvial aquifer. A hydrogeologic framework and conceptual model were developed to guide the development of a numerical model.

Three groundwater-availability scenarios were evaluated by using the calibrated numerical model, which was focused on the Salt Fork Arkansas River alluvial aquifer. These scenarios were used to (1) estimate equal-proportionate-share groundwater withdrawal rates, (2) quantify the potential effects of projected well withdrawals on groundwater storage over a 50-year period, and (3) simulate the potential effects of a hypothetical 10-year drought. The 20-, 40-, and 50-year equal-proportionate-share groundwater withdrawal rates for the Salt Fork Arkansas River alluvial aquifer under normal recharge conditions were about 0.63, 0.58, and 0.57 acre-foot per acre per year, respectively. Projected 50-year groundwater withdrawal scenarios were used to simulate the effects of modified well withdrawal rates. Because well withdrawals were less than 2 percent of the calibrated numerical-model water budget, changes to the well groundwater withdrawal rates had little effect on simulated Salt Fork Arkansas River base flows and groundwater storage in the Salt Fork Arkansas River alluvial aquifer. A hypothetical 10-year drought scenario was used to simulate the potential effects of a prolonged period of reduced recharge on groundwater storage. Groundwater storage at the end of the hypothetical drought period was 14.5 percent less than the groundwater storage of the calibrated numerical model without the simulated drought.

Released June 25, 2025 11:50 EST

2025, Fact Sheet 2025-3029

Christopher J. Schenk, Tracey J. Mercier, Phuong A. Le, Andrea D. Cicero, Ronald M. Drake II, Sarah E. Gelman, Jane S. Hearon, Benjamin G. Johnson, Jenny H. Lagesse, Heidi M. Leathers-Miller, Kira K. Timm

Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean conventional resources of 4,098 million barrels of oil and 13,268 billion cubic feet of gas in the North Cuba area.

Released June 25, 2025 09:50 EST

2025, Open-File Report 2025-1027

Joseph E. Thomas, Thomas M. Gushue, Erica Byerley, Paul Grams

The Grand Canyon River Alert System (GCRAS) provides government-issued emergency alerts to wilderness recreationalists in the Grand Canyon, who are often outside the bounds of cellular signal reception. GCRAS is a collaboration between the U.S. Geological Survey (Grand Canyon Monitoring and Research Center), National Weather Service, Coconino County Emergency Management, and National Park Service. Technological advances in satellite communications have improved satellite signal availability in remote areas and increased the reliability of satellite communications using personal devices such as commercially available satellite messaging devices. These advancements have presented an opportunity to create a novel emergency alert system designed primarily for backcountry visitors to provide improved communications for periods of increased risk and potentially dangerous situations in the backcountry. GCRAS is designed specifically for the distinctive needs of satellite messaging devices and features reduced character count messages, short-code signup capability, and the ability to unsubscribe at any time. After a positive test of the system in March 2024, the system went live to the public and has been used more than two dozen times in 2024 to inform boaters and hikers of hazards (such as debris flows and flash floods) in the Grand Canyon. Satellite signal availability and device response time varies based on location and service provider, but initial testing showed messages arriving within 2–10 minutes. Although GCRAS was developed specifically for the Grand Canyon, the GCRAS framework could be applied to other wilderness areas. It can be used by emergency management authorities, land-management agencies, search and rescue units, and those concerned with public safety to help increase communication with people visiting or living in areas that are outside the signal of more traditional emergency-notification methods, such as cellular, wireless emergency alerts, and sirens.

Released June 25, 2025 09:22 EST

2025, Molecular Ecology (34)

Kara Suzanne Jones, David Pilliod, Aaron Aunins

Limitations of traditional insect sampling methods have motivated the development and optimisation of new non-lethal methods capable of quantifying diverse arthropod communities. Environmental DNA (eDNA) metabarcoding using arthropod-specific primers has recently been investigated as a novel way to characterise arthropod communities from the DNA they deposit on the surface of plants. This sampling method has had demonstrated success, but pollinators—especially bees—are oddly underrepresented in these studies. To evaluate this inconsistency, we investigated the limitations of eDNA metabarcoding for bees and other pollinators. We compared pollinator diversity derived from eDNA extracted from flowers and DNA extracted from pulverised bulk samples of insects collected from vane traps deployed at the same sites using three metabarcoding primers, two of which target arthropods generally (COI-Jusino and 16S-Marquina) and one that targets bumblebees (Bombus spp., COI-Milam). Across methods, we detected 77 insect families from 9 orders. The COI-Jusino marker amplified the highest taxonomic diversity compared to 16S-Marquina and COI-Milam. More amplicon sequence variants (ASVs) were recovered from vane traps (blue: 1357, yellow: 1542) than flowers (245), but only 23% of families and 13% of genera were shared among methods, indicating that flowers and blue and yellow vane traps may each sample different parts of the available arthropod community. Of 29 flower samples with known bee visitations, only 10 samples had bee detections from eDNA, and incomplete reference databases hindered assignment to species. Although our study provides additional evidence for the usefulness of eDNA metabarcoding for characterising arthropod communities, significant challenges remain when using eDNA metabarcoding methods to identify and quantify pollinator communities, especially bees.

Released June 25, 2025 08:57 EST

2025, Geophysical Research Letters (52)

Brian Menounos, Matthias Huss, Shawn Marshall, Mark Ednie, Caitlyn Florentine, Lea Hartl

Over the period 2021–2024, glaciers in Western Canada and the conterminous US (WCAN-US), and Switzerland respectively lost mass at rates of 22.2 ± 9.0 and 1.5 ± 0.3 Gt yr⁻¹ representing a twofold increase in mass loss compared to the period 2010–2020. Since 2020, total ice volume was depleted by 12% (WCAN-US) and 13% (Switzerland). Meteorological conditions that favored high rates of mass loss included low winter snow accumulation, early-season heat waves, and prolonged warm, dry conditions. High transient snow lines, and impurity loading due to wildfires (WCAN-US) or Saharan dust (Switzerland) darkened glaciers and thereby increased mass loss via greater absorbed shortwave radiation available for melt. This ice-albedo feedback will lead to continued high rates of thinning unless recently exposed dark ice and firn at high elevations is buried by seasonal snowfall. Physical models that simulate impurity deposition and movement through firn and ice are needed to improve future projections of glacier mass change.

Released June 25, 2025 08:36 EST

2025, Scientific Investigations Report 2025-5040

Jeffrey R. Kennedy, Meghan T. Bell, William G. Seelig

To better understand changes in groundwater storage and groundwater elevations, the U.S. Geological Survey, in cooperation with the City of Rio Rancho, New Mexico, carried out a multiyear groundwater monitoring project. Groundwater-level data were collected at 27 locations, including sites having multiple wells screened at different depths and those having long-term records. A repeat microgravity network of 20 stations was established, and surveys were carried out three times per year. The microgravity method provides a direct, quantitative measurement of mass change caused by aquifer filling or draining. Data collected during the 2019–23 study period indicate generally stable groundwater conditions, with small fluctuations in groundwater levels (increasing at some wells, declining at others), and small declines in groundwater storage over the period of record at most gravity locations (average = −0.33 foot of water per year). The discrepancy between the water-level and microgravity data may have been caused by a loss of soil moisture in the unsaturated zone, which is as much as 1,000 feet thick in some areas. At the Rio Rancho Advanced Water Treatment Facility, where the city recharges water through direct injection, there may be seasonal correlations in storage related to injection but no longer-term accumulation of recharged water in the immediate vicinity of the facility, indicating water is moving efficiently into the aquifer.

Released June 25, 2025 08:34 EST

2025, Newsletter

Kyra Harvey

This Memo to All Banders (MTAB 112) was released in June 2025. Subjects in this this memo are 1. The Chief’s Chirp; 2. Message from the Director of Eastern Ecological Science Center; 3. Staff Updates – celebrating Craig “Tut” Tuthill’s remarkable career and retirement; 4. Alerts – New reportband.gov link and Highly Pathogenic Avian Influenza; 5. News – Foundational science in flight factsheet, Notes From the Field: What’s on a sparrow’s dinner menu?, bird collision prevention, and BBL featured in Ducks Unlimited Podcast; 6. A note from the permitting shelves – ethics and photography guideline reminders; 7. A note from the supply room – band orders and returns; 8. Frequently asked questions – I haven’t gotten my band order yet, where is it?, Why does my Northern Cardinal kickout for bad age/sex warning on the Bander Portal?, and Where can I get my banding supplies?; 9. Auxiliary marker corner – reminder to double-check authorizations; 10. Banding and encounter highlights; 11. Message to the Flyways – GameBirds and band orders; 12. Moments in history – a history of the BBL; 13. Recent literature; 14. Upcoming events; and 15. Request for information.

Released June 24, 2025 09:17 EST

2025, American Mineralogist

Kathryn E. Watts, Allen K. Andersen

Economic concentrations of rare earth element (REE) minerals are uncommon in the Earth’s crust, with most occurring in carbonatites. Unlike most igneous rocks composed of silicate minerals, carbonatites are dominated by carbonate minerals, some of which can incorporate significant light REEs (LREEs; La, Ce, Pr, Nd). Technological applications of REEs are numerous and they have been identified as some of the most critical mineral commodities to the global economy. The Mountain Pass carbonatite stock in the Mojave Desert of California is the most economically significant REE deposit in the USA and contains a few to tens of percent (by volume) of the carbonate REE ore mineral bastnäsite. Despite the economic significance of the Mountain Pass deposit, studies of its ore mineralogy are limited. Here we present new carbonate ore mineralogy data for a compositionally diverse suite of carbonatitic rocks from the Mountain Pass stock and related dikes. Whole-rock geochemical data are integrated with mineral-scale textural and chemical data obtained by scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and microRaman spectroscopy. Our results document a complex spectrum of REE-bearing carbonate minerals and intermediate mixed-layer structures. Mineral species include bastnäsite [REE(CO₃)F], hydroxylbastnäsite [REE(CO₃)OH], parisite [Ca(REE)₂(CO₃)₃F₂], synchysite [Ca(REE)(CO₃)₂F], röntgenite [Ca₂(Ce,La)₃(CO₃)₅F₃], and sahamalite [(Mg,Fe²⁺)(REE)₂(CO₃)₄]. Carbonate ore mineralogy is heterogeneous within and between samples, including at the intracrystal scale. Complexly zoned crystals exhibit as many as five to six different compositional domains and syntaxial intergrowths, commonly with the more Ca-rich varieties (parisite, synchysite) forming crystal rims that surround relict bastnäsite cores. We attribute the phenocryst variability to changes in the chemistry and temperature of primary carbonatite magmas and evolved/exsolved fluids. Cross-cutting vein textures of calcite, celestine and various REE carbonate minerals, interstitial bastnäsite crystallization, breccia blocks lined by fine-grained bastnäsite, and the presence of hydroxylbastnäsite and partially hydroxylated bastnäsite point to the role of secondary hydrothermal processes in REE mineralization. Fluorcarbonate mineral compositions demonstrate that La and Ce are more structurally abundant in bastnäsite, whereas the more Ca-rich species (parisite, synchysite) contain a greater proportion of REE heavier than Pr (Nd, Sm, Eu, Gd) and Y. Atomic ratios of Pr/(Nd + Pr) are likewise variable, with the highest average value for bastnäsite (0.25) compared to parisite (0.22) and sychysite (0.21). This finding has geometallurgical implications, given that current mining operations are focused on recovery of Nd and Pr for high field strength permanent magnets and the Nd/Pr ratios are a critical factor in ore processing and magnet manufacture.

Released June 24, 2025 09:10 EST

2025, Agricultural and Forest Meteorology (372)

David E. Reed, Housen Chu, Brad G. Peter, Jiquan Chen, Michael Abraha, Brian Amiro, Ray G. Anderson, M. Altaf Arain, Paulo Arruda, Greg A. Barron-Gafford, Carl Bernacchi, Daniel P. Beverly, Sebastien C. Biraud, T. Andrew Black, Peter D. Blanken, Gil Bohrer, Rebecca Bowler, David R. Bowling, M. Syndonia Bret-Harte, Mario Bretfeld, Nathaniel A. Brunsell, Stephen H. Bullock, Gerardo Celis, Xingyuan Chen, Aimee T. Classen, David R. Cook, Alejandro Cueva, Higo J. Dalmagro, Kenneth J. Davis, Ankur Desai, Alison J. Duff, Allison L. Dunn, David Durden, Colin W. Edgar, Eugenie Euskirchen, Rosvel Bracho, Brent E. Ewers, Lawrence B. Flanagan, Christopher R. Florian, Vanessa Foord, Inke Forbrich, Brandon R. Forsythe, John Frank, Jaime Garatuza-Payan, Sarah Goslee, Christopher M. Gough, Mark B. Green, Timothy Griffis, Manuel Helbig, Andrew C. Hill, Ross Hinkle, Jason Horne, Elyn Humphreys, Hiroki Ikawa, Go Iwahana, Rachhpal Jassal, Bruce K. Johnson, Mark Johnson, Steven A. Kannenberg, Eric Kelsey, John King, John F. Knowles, Sara Knox, Hideki Kobayashi, Thomas Kolb, Randy Kolka, Ken Krauss, Lars Kutzbach, Brian T. Lamb, Beverly E. Law, Sung-Ching Lee, Xuhui Lee, Heping Liu, Henry W. Loescher, Sparkle L. Malone, Roser Matamala, Marguerite Mauritz, Stefan Metzger, Gesa Meyer, Bhaskar Mitra, J. William Munger, Zoran Nesic, Asko Noormets, Thomas L. O'Halloran, Patrick T. O'Keeffe, Steven F. Oberbauer, Walter Oechel, Patty Oikawa, Paulo C. Olivas, Andrew Ouimette, Gilberto Pastorello, Jorge F. Perez-Quezada, Claire Phillips, Gabriela Posse, Bo Qu, William L. Quinton, Michele L. Reba, Andrew D. Richardson, Valentin Picasso, Adrian V. Rocha, Julio C. Rodriguez, Roel Ruzol, Scott Saleska, Russell L. Scott, Adam P. Schreiner-McGraw, Edward A.G. Schuur, Maria Silveira, Oliver Sonnentag, David L. Spittlehouse, Ralf Staebler, Gregory Starr, Christina Staudhammer, Chris Still, Cove Sturtevant, Ryan C. Sullivan, Andy Suyker, David Trejo, Masahito Ueyama, Rodrigo Vargas, Brian Viner, Enrique R. Vivoni, Dong Wang, Eric J. Ward, Susanne Wiesner, Lisamarie Windham-Myers, David Yannick, Enrico A. Yepez, Terenzio Zenone, Junbin Zhao, Donatella Zona

Environmental observation networks, such as AmeriFlux, are foundational for monitoring ecosystem response to climate change, management practices, and natural disturbances; however, their effectiveness depends on their representativeness for the regions or continents. We proposed an empirical, time series approach to quantify the similarity of ecosystem fluxes across AmeriFlux sites. We extracted the diel and seasonal characteristics (i.e., amplitudes, phases) from carbon dioxide, water vapor, energy, and momentum fluxes, which reflect the effects of climate, plant phenology, and ecophysiology on the observations, and explored the potential aggregations of AmeriFlux sites through hierarchical clustering. While net radiation and temperature showed latitudinal clustering as expected, flux variables revealed a more uneven clustering with many small (number of sites < 5), unique groups and a few large (> 100) to intermediate (15–70) groups, highlighting the significant ecological regulations of ecosystem fluxes. Many identified unique groups were from under-sampled ecoregions and biome types of the International Geosphere-Biosphere Programme (IGBP), with distinct flux dynamics compared to the rest of the network. At the finer spatial scale, local topography, disturbance, management, edaphic, and hydrological regimes further enlarge the difference in flux dynamics within the groups. Nonetheless, our clustering approach is a data-driven method to interpret the AmeriFlux network, informing future cross-site syntheses, upscaling, and model-data benchmarking research. Finally, we highlighted the unique and underrepresented sites in the AmeriFlux network, which were found mainly in Hawaii and Latin America, mountains, and at under-sampled IGBP types (e.g., urban, open water), motivating the incorporation of new/unregistered sites from these groups.

Released June 24, 2025 09:00 EST

2025, The Seismic Record (5) 239-249

Jessie K. Saunders, David J. Wald

We examine responses to the U.S. Geological Survey’s “Did You Feel It?” (DYFI) survey and its companion earthquake early warning (EEW) questionnaire to assess the performance of the U.S. ShakeAlert EEW system directly from the alert recipients’ perspectives. ShakeAlert rapidly detects earthquakes and develops alert information, but as official alert delivery partners issue these alerts, it is thus difficult to determine how many people were alerted and when. We investigate DYFI reports for six California earthquakes that had EEW alerts and substantial responses to the DYFI EEW questionnaire. Comparisons of ShakeAlert predictions to reported intensities demonstrate that magnitude estimation accuracy is not necessarily indicative of ground-motion prediction accuracy. Perceived warning time distributions indicate that estimating maximum-expected warning times using the S-wave arrival is a reasonable assumption when discussing public EEW performance. However, we also find many reports of shorter warning times, late alerts, and missed alerts than expected based on ShakeAlert publication times, suggesting alert delivery latencies are substantial and highly variable. The novelty of our analysis is that we demonstrate that the DYFI EEW survey provides useful EEW efficacy information—independent of the specific alerting pathway—that can be used to inform our choices for conveying EEW performance.

Released June 24, 2025 08:15 EST

2025, Environmental Monitoring and Assessment (197)

Linnea A. Rock, William W. Fetzer, Lindsay S. Patterson, Samuel J. Sillen, Ron Steg, Annika W. Walters, Sarah M. Collins

Reservoirs serve critical roles providing drinking water, irrigation, flood control, hydropower, recreation, fisheries, and aquatic habitat. Yet their physical position, complex shape, and large watersheds make reservoirs especially susceptible to eutrophication and harmful algal bloom (HAB) production. Boysen Reservoir, WY, is a high priority for proactive nutrient management because it is an important source for drinking water and recreation, and has a history of toxic cyanobacterial blooms. We combined four years of comprehensive monitoring efforts by state and federal agencies to characterize the spatiotemporal patterns of nutrient inflow, internal water quality dynamics, and phytoplankton community shifts in Boysen Reservoir. We found nutrient inflow was hydrologically driven, with snowmelt runoff transporting high nutrient loads. Our findings suggest physicochemical and nutrient conditions of the reservoir were strongly different between the furthest reaches of the reservoir, but less variable among the intermediate sites. Space did not play a role in phytoplankton community dynamics, but time was an important factor. Cyanobacteria dominated phytoplankton communities by mid-summer across the reservoir and were driven mainly by temporal physicochemical conditions, like stratification and water temperature. The two most dominant phytoplankton taxa across the four years of sampling were N-fixing, toxin producing cyanobacteria. Extensive monitoring efforts and data analyses can illuminate strategies to safeguard water resources via understanding the drivers of water quality changes and HAB production.

Released June 23, 2025 14:10 EST

2025, Open-File Report 2025-1033

Mark C. Marvin-DiPasquale, R. Blaine McCleskey, Samantha L. Sullivan, Jonathan Casey Root, Serena M. Seawolf, Katherine M. Ransom, Susan A. Wherry, Evangelos Kakouros, Shaun Baesman

The report focuses on the screening of previously published concentration data associated with 12 elements of concern (aluminum, arsenic, cadmium, chromium, copper, iron, mercury, manganese, lead, selenium, uranium, and zinc) measured in stream surface waters of three hydrologic basins (Delaware River Basin, Illinois River Basin, and the Upper Colorado River Basin). The purpose of this analysis is to determine what subsets of the original dataset (containing more than 1,500,000 observations) may be most suitable for each of two types of modeling efforts. The first type of modeling envisions a machine learning approach to determine which geospatial attributes are most significant in describing the spatial distribution of elemental concentrations within a basin. The second type of modeling envisions a stepwise regression approach to develop multivariable models that can be used to determine high resolution time-series estimates of elemental concentrations or loads at discrete U.S. Geological Survey real-time stream surface water sites. These site-specific temporal models are based on continuous measurements of available discharge and (or) in situ sensor data (temperature, pH, turbidity, dissolved oxygen, specific conductance, and (or) fluorescent dissolved organic matter) as the explanatory variables. The data screening for both model types considered historical trends in analytical methods and detection quantitation limits, the extent of censored data, data density, and environmental relevance with respect to three U.S. Environmental Protection Agency water quality thresholds (drinking water guidelines, human health criteria, and aquatic life criteria). The result of this analysis was the production of a final list of potential models deemed suitable for further development based upon the data exclusion (or inclusion) scheme developed herein for each model type. In both cases, the final models included mostly the three crustal elements (iron, manganese, and aluminum) that are found at comparatively high concentrations in surface water, whereas most of the more pernicious elements were excluded from the final model lists owing to various data limitations. The one exception to this was arsenic, for which the existing data were sufficient at three U.S. Geological Survey real-time sites for potential further development of time-series models.

Released June 23, 2025 11:05 EST

2025, Proceedings of the National Academy of Sciences (122)

Nate Mantua, Heather M. Bell, Anne E. Todgham, Miles E. Daniels, Jacques Rinchard, Jarrod R. Ludwig, John Field, Steven T Lindley, Freya Elizabeth Rowland, Catherine A. Richter, David Walters, Bruce P. Finney, Anne R. Distajo Haskell, Donald Tillitt, Dale C. Honeyfield, Taylor N. Lipscomb, Kevin Kwak, Jason Kindopp, Dennis E. Cocherell, Abigail Ward, Thomas H. Williams, Jeff Harding, Nann A. Fangue, Carson Jeffres, Rocio Iliana Ruiz-Cooley, Steven Litvin, Scott Foott, Mark Adkison, Brett Kormos, Peggy Harte, Frederick S. Colwell, Christopher P. Suffridge, Kelly Shannon, Amanda Cranford, Charlotte Ambrose, Aimee N. Reed, Rachel C. Johnson

Thiamine (vitamin B₁) deficiency in marine systems is a globally significant threat to marine life. In 2020, newly hatched Chinook salmon (Oncorhynchus tshawytscha) fry in California’s Central Valley (CCV) hatcheries swam in corkscrew patterns and died at unusually high rates due to a lack of this essential vitamin. We subsequently investigated the impacts and causes of thiamine deficiency in California’s anadromous salmonids. Our laboratory studies defined the relationship between thiamine concentrations in Chinook salmon eggs and early life-stage survival in offspring; we used these data to develop a model that estimated 26 to 48% thiamine-dependent fry mortality across consecutive years (2020–2021) for winter-run Chinook salmon. We established an egg surveillance effort that found widespread thiamine deficiency in CCV Chinook salmon in 2020 and 2021, and emerging thiamine deficiency in Klamath River and Trinity River coho salmon (Oncorhynchus kisutch) in 2021. We determined that thiamine injections into adults raised egg thiamine concentrations above levels found to impact early life-stage survival and swimming behavior. Ocean surveys, prey nutrition, salmon gut contents, and stable isotope data link thiamine deficiency to an ocean diet dominated by a booming population of northern anchovy (Engraulis mordax). This forage fish had low thiamine, high lipid, and high thiaminase activity levels consistent with both a thiaminase and oxidative stress hypothesis for causing thiamine deficiency in California salmon. Our research suggests California’s already stressed anadromous salmonids will continue to be impacted by thiamine deficiency as long as their ocean forage base and diet are dominated by northern anchovy.

Released June 23, 2025 10:42 EST

2025, JGR Biogeosciences (130)

Wayana Dolan, Tamlin M. Pavelsky, Julianne Davis, Nathan LaFramboise, Catherine Polik, Rose Cory

Northern deltas receive chromophoric dissolved organic matter (CDOM) from their watersheds, which can be oxidized to carbon dioxide upon absorption of sunlight (i.e., photomineralized). These deltas also receive total suspended solids (TSS), which may shade sunlight absorption by CDOM, thus limiting photomineralization. To quantify this interaction for the first time, we measured photomineralization rates at 11sites in the Peace‐Athabasca Delta (PAD), Canada. We sampled waters during a July 2022 field campaign for TSS concentration, CDOM concentration (_^αCDOM,λ), total downwelling sunlight attenuation coefficients (K_d,_tot,_λ), and light attenuation coefficients due to CDOM (K_d,_CDOM,λ). TSS ranged from <1 to 112 mg/L with an average of 19 ± 34 mg/L (mean ± one standard deviation), an order of magnitude lower than TSS reported in rivers entering the PAD earlier in the open water season. ^α_CDOM,λ at 305 nm (^α_CDOM,₃₀₅) ranged from 23.3 to 65.2 m^-1, K_d,_CDOM,305 ranged from 26.3 to 74.1 m⁻¹, and K_d,_tot,305 ranged from 19.0 to 63.7 m⁻¹.  The ratio of sunlight absorbed by CDOM relative to total sunlight attenuation K_d,_{CDOM,λ/Kd,tot,λ} was inversely correlated with TSS concentration across all wavelengths measured (305–412 nm). TSS thus limited photomineralization rates by shading CDOM from ultraviolet A and visible wavelengths of sunlight, reducing photomineralization rates by up to 56% compared to rates in the absence of TSS or other non-CDOM particles that attenuate sunlight. Results suggest that shifts in delta hydrology that affect TSS concentration likely influence photomineralization rates within TSS-rich northern deltas.

Released June 23, 2025 10:32 EST

2025, Arboriculture and Urban Forestry (51)

Michael Alonzo, Peter Christian Ibsen, Dexter Locke

Urban trees mitigate extreme heat through shading and evapotranspiration, but cooling effectiveness varies with tree traits, spatial configurations, and climate. This systematic mapping review synthesizes findings from 115 studies (2018 to 2024) using RepOrting standards for Systematic Evidence Syntheses (ROSES) protocols. Studies were categorized based on geographic location, climate zone, and heat metric (e.g., land surface temperature or air temperature), highlighting a geographic skew toward North America and Asia and underrepresentation of arid and tropical zones. Findings show that urban trees consistently outperform other vegetation types in cooling, particularly in hotter, drier climates when water is available. Dense, tall canopies provide broad-scale cooling, while mixed plantings with shrubs or grass enhance local effects. However, conflicting conclusions arise from using land surface versus air temperature, as these metrics respond differently to tree canopy. Key knowledge gaps include the role of native versus non-native species in arid climates, the effect of urban morphology on cooling, and tree performance during extreme heat. Most studies remain small-scale and limited in generalizability, emphasizing the continued need for city-specific knowledge. This review highlights urban trees as vital for heat mitigation and the importance of harmonizing research objectives and methods to inform planning and practice effectively.

Released June 22, 2025 09:12 EST

2025, Ecosphere (16)

Kristen I. Shive, Clarke Alexandra Knight, Zachary L Steel, Charlotte K. Stanley, Kristen N. Wilson

Successive catastrophic wildfire seasons in western North America have escalated the urgency around reducing fire risk to communities and ecosystems. In historically frequent-fire forests, fuel buildup as a result of fire exclusion is contributing to increased fire severity. The probability of high-severity fire can be reduced by active forest management that reduces fuels, prompting federal and state agencies to commit significant resources to increase the pace and scale of fuel reduction treatments. However, lower severity areas of wildfires also have the potential to act as “treatments,” and even catastrophic fires with large areas of high severity can still have substantial areas of lower severity fire that may be improving forest conditions locally. We quantified active management and wildfire severity across yellow pine and mixed conifer (YPMC) forests in the Sierra Nevada of California over a 22-year period (2001–2022). We did not detect increases in the area treated through time, but the area of beneficial wildfire (low to moderate severity) increased substantially, exceeding active treatment area in 8 of 22 years. Overall, beneficial wildfire treated ~17% more area than all treatments combined, and roughly four times more area than fire-related treatments alone. We then used disturbance history to evaluate resistance to high-severity wildfire and forest loss across the YPMC range. Of the 2.3 million ha YPMC of forests in 2001, 20% lost mature forests due to high-severity fire by 2022, which is nearly half of all YPMC area burned. Most of the landscape (47%) remains at risk of high-severity fire because it had no restorative disturbances, but 33% of the study area has some level of resistance to high-severity wildfire. In these areas, resistance will need to be enhanced and maintained over time via active management or managed wildfire, but these treatment needs will likely outpace capacity even under optimistic implementation scenarios. Given limited resources for implementing active management and the likelihood of a more fiery future, incorporating beneficial wildfire into landscape-level treatment planning has the potential to amplify the impact of active management treatments.

Released June 22, 2025 07:49 EST

2025, Earth Surface Processes and Landforms (50)

Jonathan Warrick, Daniel Buscombe, Kilian Vos, Andrew C. Ritchie, Bob Battalio

Pocket beaches are short, headland-bound coastal landforms that may exhibit shoreline rotation in response to time-varying wave conditions. Here we examine the presence, location and style of pocket beach rotation along the 1700 km coast of California using a comprehensive 22-year satellite-derived shoreline dataset. These analyses identify 23 pocket beaches that exhibit annual cycles of rotation, and these beaches have two general types. In southern California, pocket beaches rotate clockwise, or towards the south, in the winter season (‘winter southward’ transport of sand). These beaches have symmetric rotation patterns and strong seasonality in wave direction (winter west swell and summer south swell), which is indicative of rotation from seasonal oscillations in longshore sediment transport. In northern California, pocket beaches rotate counterclockwise, or towards the north, in the winter (‘winter northward’ transport of sand), and they are characterized by strong asymmetry (winter beach is overall narrower than the summer beach) and strong seasonality in wave power. Rotation of these northern California beaches is related to both cross-shore and longshore sediment transport, caused by large west-to-northwest swell of the winter and smaller northwest wind waves of the summer. We acknowledge that many more rotating pocket beaches likely exist in California owing to the undersampling of the smallest beaches in the source data. In the end, we conclude that seasonally rotating pocket beaches are a fundamental coastal landform type of the California coast, owing to its wave seasonality and rocky and cliff-backed morphology.

Released June 21, 2025 09:42 EST

2025, Earth and Space Science (12)

Hayden L. Jacobson, Gabriel Walton, Katherine R. Barnhart, Francis K. Rengers

Constraining the grain size distribution of granular deposits with complex surfaces is difficult with existing approaches. Field and laboratory techniques are time consuming and limited by the maximum grain size that laboratories can accommodate. In this study, we present a new method to identify the coarse fraction of the grain size distribution at a debris-flow fan deposit surveyed with terrestrial laser scanning (TLS) in Glenwood Canyon, Colorado, USA. This method is a novel grain segmentation algorithm developed for application to point cloud data of deposits with complex surfaces and angular grains ranging in size from centimeters to a meter. This approach combines an existing random forest machine learning method with a novel iterative clustering algorithm. We compared the grain size distribution from our algorithm with a Wolman pebble count conducted in the field, and found a root mean squared error of less than 2 cm from the 5th to 95th percentile of the grain size distribution of grains ranging from cobble to boulder sized (6.3–78 cm in our application). Finally, we compared our new algorithm with an existing open-source grain segregation algorithm, and our method outperformed the selected alternative when applied to the debris-flow deposit point cloud.

Released June 20, 2025 10:20 EST

1976, Book chapter, Wildlife diseases

Milton Friend, John H. Abel Jr.

The effects of selected environmental pollutants on avian salt gland function were studied in the mallard duck, Anas pZatyrhynchos. DDE and several organophosphates were found to have an inhibitory effect on the ability of these glands to concentrate and secrete salt from the body. DDE significantly reduced secretion rates from the salt glands. More severe effects were observed following exposure to organophosphate insecticides; reduction in gland size, reduced ability of the birds to secrete Na+ via the salt glands, and reductions in cholinesterase activities in the salt gland and hypothalamus all contributed to elevated mortality levels in treatment birds over controls.

Released June 20, 2025 09:31 EST

2025, JGR Earth Surface (130)

John C. Warner, Christopher R. Sherwood, Christie A. Hegermiller, Zafer Defne, Joseph B. Zambon, Ruoying He, George Xue, Daoyang Bao, Dongxiao Yin, Melissa Moulton

Hurricane-induced morphological changes and associated community hazards along sandy, barrier-island coastlines have been studied primarily from the perspective of ocean-side attack by storm-driven ocean surge and large waves. Thus, our understanding of long-term barrier island morphological change focuses on beach erosion, overwash, and inlet formation. In contrast, outwash events with inundation from the sound side, such as one that occurred in Cape Lookout National Seashore, North Carolina, USA during Hurricane Dorian (September 2019), are understudied. Studying such events can improve understanding of barrier island response and stability for a broader range of conditions. Here, we model the hydrodynamics and morphological evolution of a barrier island using a coupled wave-current-sediment transport modeling system. Wind-driven surge in Pamlico Sound led to overtopping from the sound side, which eroded outwash channels and transported sediment seaward into the nearshore. Simulations reproduce the channel features observed with aerial imagery and provide information not available from the remote-sensing observations, including channel depths (>2 m) and the fate of the eroded sand. We found that >99% of the eroded sand was deposited in the nearshore, within 1,000 m of the shoreline in depths <10 m, suggesting that the deposited sediment remains available for littoral transport and beach recovery. Simulations with combinations of coarse or fine sediment and vegetated or unvegetated landcover indicate that channel position did not vary with grain size or vegetation, while volume of erosion and channel morphology were more responsive to variations in grain size and less responsive to presence of vegetation.

Released June 20, 2025 07:57 EST

2025, Eos, American Geophysical Union

Avi Strange, Oliwia Jasnos, Lauren Toth, Nancy G. Prouty, Thomas M. DeCarlo

No abstract available.