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At least 973 records · Page 54Linked to original sources

Keeping pace: Migrating sea lampreys adjust swim speed in response to shifting water velocity to maintain a constant ground speed

Upstream migrating fish must balance energetic costs with environmental and ecological constraints. Theoretical models predict that fish can conserve energy by adjusting swim speed in response to changing water velocity, but detailed field tests of these predictions remain rare. We used fine-scale acoustic telemetry and hydrodynamic modeling to track adult sea lamprey (Petromyzon marinus) migrating through a river and evaluated how movement speeds varied with environmental conditions and individual traits. Swim speed increased with faster water velocities, while ground speed remained constant, supporting the hypothesis that lampreys regulate swim effort to maintain a fixed migration pace. The average ground speed aligned with a predicted optimum of ∼1 body length per second. Both swim and ground speeds declined slightly in deeper water, suggesting a trade-off between movement efficiency and predator avoidance. These findings provide field-based support for a theoretical model of energy optimization and underscore how migratory fish adaptively adjust behavior to local hydrodynamic conditions. Our results highlight the value of using high-resolution tracking and environmental modeling to reveal behavioral tactics that underlie efficient migration strategies.

Michigan↗

3D semantic mapping of surface geological features

Semantic mapping in 3D is fundamental to a wide range of geoscientific studies and applications, including geomorphology, hazard assessment, and environmental monitoring. However, automatically segmenting geological features from large-scale photogrammetric datasets remains a significant challenge. We present a methodology to address this gap. Using overlapping images collected over environments of interest, Structure-from-Motion (SfM) produces georeferenced point clouds and estimates camera poses. Existing large vision models, such as Segment Anything Model, segment objects in the images, generating pixel-segmentation associations. To produce pixel-point associations, we project the points back onto the camera image planes. As objects are independently segmented across multiple images with different perspectives, we develop a segmentation mosaicking algorithm to build probabilistic point-segmentation associations that combines the pixel-segmentation associations and pixel-point associations. Our methodology is validated using both synthetic data generated by Kubric and real-world UAV-SfM data. The implementation is designed to be compatible with existing SfM software, including Agisoft and OpenDroneMap, for photogrammetry mapping in geoscience studies. As a case study, we apply our method to the semantic mapping of precariously balanced rocks (PBRs), which provide upper-bound constraints on historical ground motion shaking intensity. To support object-level identification of PBRs, we additionally integrated Grounding DINO, enabling text-prompted segmentation of features of interest within UAV imagery. This case study demonstrates the effectiveness of our method in generating a 3D semantic map of PBRs, enabling spatial distribution of PBR fragility for earthquake hazard analysis.

Computers & Geosciences↗

Case report: Observations on expulsions from 20 years of radiotransmitter implantation in adult Burmese pythons

Background Radiotelemetry as a research tool has advanced our understanding of snake behavior and ecology. However, surgical transmitter implantation can lead to health complications for study animals, including expulsion, which may also interfere with research objectives. Two implantation methods include intramuscular and coelomic placements, and we evaluate expulsion rates of transmitters using these methods in Burmese pythons ( Python bivittatus ) in southern Florida. Results From 2005 to 2024, we implanted 305 transmitters in 142 adult Burmese pythons, primarily using intramuscular implantation ( n = 221), then transitioning to include coelomic placement ( n = 84). There were no observations of transmitter-related mortality. Overall, 98.7% of transmitters were retained, with a 1.3% expulsion rate ( n = 4 transmitters). Expelled transmitters were only observed in intramuscularly implanted transmitters from 4 of 13 gravid females. Conclusions We observed no mortality related to transmitter implantation and few instances of transmitter expulsion, indicating that both intramuscular and coelomic implantation techniques are effective for monitoring adult pythons in the wild. However, there is some risk that females may expel transmitters when gravid, and this risk may be reduced when implanting transmitters intracoelomically. Our findings may be useful for studies of other large-bodied snake populations worldwide where radiotransmitter implantation is appropriate and logistically feasible.

Florida↗

Cumulative effects of multiple stressors on marine mammals: Elephant seals as a model system

Noise exposure is a potential stressor for free-ranging marine mammals and is often studied in the absence of other environmental factors. Here, a multi-investigator, interdisciplinary effort was undertaken to examine the response of elephant seals to multiple stressors. An integrated physiological and ecological approach was taken, including immunology, stress physiology, toxicology, animal behavior, population biology, and life history theory, to examine the cumulative effects of exposure to multiple stressors in elephant seals. While we measured the response of individual animals, a population response can be predicted by incorporating these results into the long-term data on elephant seal demographics.

Book chapter↗

Population structure and genetic stock identification in southeastern United States loggerhead sea turtles (Caretta caretta) using genome-wide SNPs

Characterizing the genetic structure and connectivity between populations of endangered species can be used to inform management actions. In vagile species with high gene flow or recently established populations, such characterizations can be difficult to undertake using traditional genetic markers, and genetic stock identification (GSI) may be confounded by allele-sharing between populations. Loggerhead sea turtles ( Caretta caretta ) in the southeastern United States comprise seven management units (MUs) based on female philopatry inferred via mitochondrial DNA sequences, yet nuclear microsatellite data do not reflect divergence. Further, loci for accurate GSI are not currently known. To address this, we generated genome-wide single nucleotide polymorphism (SNP) data from 146 females nesting at individual sites representative of each southeastern United States MU. We found weak (F ST =0.001–0.003) but significant divergence among all MUs, with more notable divergence between the Gulf Coast and Atlantic Ocean MUs, and amongst the Atlantic Ocean MUs. We then used an iterative leave-one-out approach to identify candidate loci for GSI. This approach identified loci that could assign individuals to natal ocean basins (i.e., to the Gulf Coast or to the Atlantic Ocean), and to individual MUs within the Atlantic Ocean, with high (≥90%) success and accuracy. Analyses of genome-wide SNPs refined our understanding of the magnitude and scale of population connectivity in loggerhead turtles in the southeastern United States, and provided a foundation for the development of SNP panels for accurate, fine-scale GSI in sea turtles.

Alabama, Florida, Georgia↗

Spatial and temporal drivers of variability in abundance of two stream fishes

An understanding of how and why animal populations vary in space and time informs effective conservation and management. We used spatial and temporal flow metrics to explore flow-ecology relationships for two fish species, Mountain Sucker Pantosteus platyrhynchus (Cope, 1874) and Mottled Sculpin Cottus bairdii Girard, 1850, across 64 sites and 8 years in Wyoming, U.S.A. We found variation in Mottled Sculpin and Mountain Sucker abundance was driven to a greater extent by spatial flow metrics (e.g., drainage area, median summer flow) with differing direction of response between species. The opposing responses to spatial variation in median summer flow could reflect the ability of Mountain Sucker to persist in non-perennial habitats, likely due to their relatively high mobility and recolonization capacity. Responses to temporal flow metrics (e.g., previous year spring flow, previous year autumn flow) were weaker but consistent across species likely due to similar reproductive strategies and timing. The lack of stronger flow effects on population variability in both species likely corresponds to high variability in local habitat characteristics that are mediating population response. These findings underscore how considering spatial context informs conservation planning and suggest that flow-ecology relationships may be mediated by species-specific traits and local habitat conditions.

Wyoming↗

Spatially referenced watershed models for the binational Red–Assiniboine River Basin: Bayesian vs frequentist comparison

Excess nutrient loading remains a leading cause of declining water quality in lakes, estuaries, and coastal waters worldwide, with global economic costs of US$200 billion – US$2 trillion annually from impacts on fisheries, tourism, freshwater resources, and water treatment. Our study focuses on total phosphorus (TP) in Lake Winnipeg and its binational Red-Assiniboine River Basin, where nutrient inputs have degraded water quality and increased cyanobacterial blooms. These changes pose ecological, public health, and economic risks. We applied a spatially referenced watershed model with a hybrid statistical-mechanistic structure partitioning annual nutrient loads into land-use export, land-to-water delivery, and in-reservoir decay. Bayesian and traditional frequentist model calibrations were compared. In the frequentist model, coefficients for agricultural inputs, forests /wetlands, stream channels, precipitation, and reservoir losses were statistically significant, whereas coefficient for wastewater was not. In contrast, all variables were successfully calibrated using the Bayesian approach. Model results delineate TP-export hotspots across the basin, showing that 54–62% of TP originates from the U.S., with agricultural sources ranging 62–72%—highlighting the importance of agriculture-focused Best Management Practices. Given the global relevance of nutrient-driven water-quality challenges, our results highlight Bayesian calibration for robust risk assessment and adaptive nutrient management.

Red–Assiniboine River Basin↗

Improving the use of expert opinion in disease risk analysis for conservation translocations

Conservation translocations are subject to considerable uncertainty and risk, of which disease is one of the most recognized. To address disease risks, several protocols for qualitative disease risk analysis (qDRA) exist and are used for responsible conservation translocation planning. Existing qDRA protocols usually rely on expert judgment, but they lack quantitative aggregation of elicited estimates, transparent treatment of uncertainty, and explicit comparison of alternative disease risk management pathways. We added these factors to a qDRA for translocation of a charismatic species that is extinct in the wild, the sihek (Guam kingfisher) ( Todiramphus cinnamominus ). We asked a panel of seven independent experts to quantify their judgment of risks of pathogen release, exposure, and consequences for seven pathogen hazards under three translocation management scenarios. Experts suggested that implementing a full biosecurity protocol would reduce risk for several pathogen hazards but would have variable effectiveness (11–65% depending on the hazard). There was substantial uncertainty associated with individual experts and noise among different experts, showing the potential for error if decisions are based on single-point judgments (i.e., providing judgment of a central tendency without accounting for uncertainty) from one expert or on collaborative consensus of multiple experts, as is current practice.

Conservation Biology↗

Peak-, mean-, and low-streamflow regional-regression equations for natural streamflow in central and western Colorado, 2019

The U.S. Geological Survey (USGS), in cooperation with the Colorado Department of Transportation, developed peak-, mean-, and low-streamflow regional-regression equations for estimating various statistics for natural streamflow in hydrologic regions of central and western Colorado. The peak-streamflow regression equations were developed using data from 418 streamgages, consisting of 15,202 years of record and a mean of approximately 36 years of record per streamgage. The mean- and low-streamflow regional-regression equations were developed using data from 323 streamgages where daily streamflow data were collected year-round. The annual exceedance-probability discharges for each streamgage were computed using the USGS software program PeakFQ. Mean monthly and 7-day minimum and maximum streamflows were computed using the USGS software program SWToolbox. Streamflow-duration values were computed using an R script. The regional-regression equations were determined using data for the period of record for a given streamgage through water year 2019. Geographic information systems datasets were used to develop 55 basin and 42 climatic characteristics, which were evaluated as candidate explanatory variables in the regression analysis. For the peak-streamflow regional-regression equations, the study area was divided into four hydrologic regions based on mean basin elevation, including the Plateau (less than 8,014 feet), Mid-Elevation (8,015 feet to 9,492 feet), Sub-Alpine (9,493 feet to 10,490 feet), and Alpine (greater than 10,490 feet) regions. For the peak-streamflow equations, the selection of basin and climatic characteristics was based on the 1-percent annual exceedance-probability discharge for each hydrologic region. For the mean streamflow, streamflow-duration values, and 7-day minimum and maximum streamflows, the study area was divided into four hydrologic regions based on river basin, including the (1) Colorado-East Slope Headwaters, (2) Green River, (3) Rio Grande, and (4) San Juan-Dolores. For mean streamflows, basin and climatic characteristics were evaluated separately for the annual period and each month for each hydrologic region. Regional regression equations published in this report are available for use in the USGS web-based program StreamStats.

Colorado↗

The future for reptiles: Advances and challenges in the Anthropocene

The future for the Reptilia will be one of continued discovery of the extant diversity of species in every group and continued challenges for their conservation. Most species will persist, albeit in smaller and increasingly fragmented geographic ranges, and active conservation measures can help to ensure survival of highly vulnerable species. There are more than 12,440 documented species of reptiles, up from 10,500 only seven years ago. Transfer of laboratory techniques, computational resources, and access to literature to herpetologists throughout the world is fueling the increase in systematic studies of reptiles. The bulk of reptiles are the squamates, lizards and snakes, with impressive diversity on most continents. Habitat loss, landscape fragmentation, exploitation, invasive species, environmental contamination, and global warming are persistent challenges to all biodiversity, including reptiles. Endemism, ecological specialization, and restricted ranges generally make species more vulnerable to anthropogenic disturbances. Moreover, the natural history information that is so important for informing conservation aims is lacking for most newly described forms, whether they represent completely novel discoveries or result from taxonomic revisions. The major lineages of reptiles exhibit enormous variation in life history traits, ranging from extremely long-lived species with low fecundity to those with short generation times and high fecundity. Reptiles vary in their degree of ecological specialization, and many live in difficult-to-sample habitats. It is implausible, if not impossible, to gather detailed information on thousands of species of reptiles, many of which are secretive and difficult to study. However, evaluating where species are likely to fit along life history gradients of time to maturity, brood size, and frequency of reproduction reveals much about their abilities to persist in the face of anthropogenic disturbance. Combined with information on geographic distribution and the severity of anthropogenic pressures, consideration of life history strategies reveals important implications for conservation of reptile species. Modern approaches to conservation of reptiles, including conservation translocations, regulation of the international trade in reptiles, management of imperiled species in the context of landscapes, progress in confronting emerging diseases, and resolving human-wildlife conflict in all its forms can help ensure the persistence of the great diversity of the Reptilia in the Anthropocene.

Book chapter↗

Cyanobacterial bloom occurrence and emergency department visits for asthma or wheeze, Wisconsin, 2017–2019

Background: Cyanobacterial harmful algal blooms (cyanoHABs) pose risks to human and animal health. Methods: We investigated the relationship between cyanoHABs and asthma or wheeze-related emergency department (ED) visits near three Wisconsin cities (Green Bay, Madison, and Oshkosh) during 2017–2019. CyanoHAB exposure was approximated using the Cyanobacterial Assessment Network remotely sensed satellite indicator of cyanobacterial biomass, a chlorophyl algorithm (Chl BS ) aggregated by water-adjacent ZIP Code Tabulation Areas (ZCTA), and distance weighted from the nearest waterbody. Weekly counts of ED visits for asthma or wheeze were aggregated by ZCTA. Poisson generalized linear models estimated the association between the weekly number of ED visits and weekly Chl BS, adjusting for maximum temperature, dewpoint, fine particulate matter (PM 2.5 ), month, and correlation within ZCTA. Results: During 2017–2019, 7,057 ED visits for asthma or wheeze occurred in the study area (42 ZCTAs). Peaks in Chl BS occurred between June and October, with higher values in Lake Winnebago and Lake Mendota compared to Green Bay. Chl BS was not associated with ED visits for asthma or wheeze (adjusted rate ratio = 1.00, 95% confidence interval = 0.99, 1.00), and the presence of onshore winds did not change this result. Monthly aggregations of ED visits and Chl BS showed a monotonic trend between increasing Chl BS and ED visits during July–September. Conclusion: This study demonstrates the utility of remote sensing data in environmental health research. Future studies could explore individual-level exposure and outcomes to refine health risks associated with cyanoHABs.

Wisconsin↗

Effects of external water on volcanic column height and collapse

Volcanic plumes are important because they spread volcanic material, can impact climate, and pose hazards to aviation. Among eruption processes, column collapse is arguably the most consequential in terms of direct impacts, as it marks the onset of ground-hugging pyroclastic density currents that pose the greatest immediate threat to life and infrastructure. This study inves- tigates how external water, such as is incorporated during subaqueous eruptions, affects the critical condition (including mass eruption rate, temperature, and gas fraction) at which column collapse occurs in the atmosphere, referred to as “the column collapse condition”. We use the 1-D plume model, Plumeria , to explore how variations in external water (0–60 wt.%), vent exit velocity (75–125 m s −1 ), and initial magma temperature (700–1100 °C) affect the column collapse condition. We find that the occurrence of column collapse is highly sensitive to the amount of external water. Small amounts of external water (⪅ 25 wt.%) suppress column collapse, whereas higher amounts of water encourage collapse. Using more than 150,000 simulations, we map out the highly non-linear shape of the column collapse condition as a function of mass eruption rates and external water contents. The Richardson number, the ratio of buoyancy to shear forces, offers a useful framework for defining the column collapse condition for eruptions involving external water. This work enhances our understanding of how external water ingestion affects volcanic plume dynamics, including height and column collapse conditions. Recent shallow submarine eruptions that produced very tall atmospheric plumes and partial column collapse (e.g. the 2021 Fukutoku-Oka-no-Ba eruption in Japan and the 2022 Hunga eruption in Tonga) demonstrate the importance of understanding how external water influences the collapse of eruption columns.

Volcanica↗

Uranium—Deposits, production and resources, market dynamics, and supply chain risks

Introduction Interest in nuclear power for the generation of electricity has risen with the increase in the need for more diverse baseload power, enhanced energy security, and the development of new technologies, such as small modular reactors (SMRs), which could provide power for remote areas, industrial applications, and artificial intelligence (AI) data centers. In 2024, the U.S. Department of Energy received $2.7 billion in congressional funding to bolster the domestic uranium production and nuclear fuel supply chain and address reliance on imports from foreign suppliers. In 2025, the U.S. Government issued several Executive and Secretary’s orders aimed at revitalizing the U.S. nuclear sector. If SMRs are to be as widely deployed in the United States and worldwide as envisioned, demand for uranium (nuclear reactor fuel) will likely increase. After the Fukushima nuclear accident in 2011, the market spot price of uranium began a decline, followed by a decrease in U.S. and global uranium exploration and mine development expenditures that led to a uranium supply deficit until 2020, when prices started to recover, prompting a resurgence in uranium exploration and development. In January of 2024, the uranium spot price rose to a 17-year high $106 (U.S. dollars) per pound of U3O8 (triuranium oxide, commonly known as “yellowcake”), which is expected to increase uranium exploration, mine development, and uranium production domestically and worldwide.

Fact Sheet↗

Metallurgical coal—Deposits, production, resources, market dynamics, and supply chain risks

Plain Language Summary Metallurgical coal (met coal; consumed to produce coke for steelmaking) must meet specific chemical and physical specifications. In 2023, the conterminous United States produced 66 million short tons (mst) of met coal, consumed 15.85 mst domestically, exported 51.1 mst, and imported 0.7 mst. Most met coal was produced in the Appalachian Basin, but there are also resources that meet the specifications for met coal in the Western United States.

conterminous United States↗

Matagorda Formation—A new Holocene coastal stratigraphic unit, Texas

We propose and describe the Matagorda Formation, a new stratigraphic unit comprising Holocene coastal (sea-level influenced) deposits on the Texas coastal plain. This formation consists of sediments deposited in fluvial-deltaic, bay and bay-margin, and gulf-margin paralic environments since the last glacial maximum (marine oxygen isotope stage 2, or MIS 2) within and at the margins of stream valleys incised into the coastal plain since the last Pleistocene sea-level highstand during MIS 5. The Matagorda Formation includes informal coastal facies that are influenced by sea level and grouped into fluvial-deltaic deposits (Lavaca Member), bay and bay-margin deposits (Carancahua Member), and paralic gulf-margin deposits (Saluria Member). Other coastal facies, such as eolian sand or silt sheets and clay dunes, are included in the Matagorda Formation but are not included within the members. The type area is herein defined as the Matagorda Bay system on the central Texas coast, where many examples of facies within the proposed formation are exposed along and near the shoreline. The upper boundary of the Matagorda Formation is the active depositional or erosional surface either on land or at the water bottom beneath coastal streams, tidal channels, and bays. The lower boundary is a composite unconformity that may be marked by (1) a mature soil or erosional surface at the top of the Pleistocene Beaumont Formation (a sharp boundary with or without soil development below the unconformity), (2) the top of alluvial terrace deposits above the Beaumont Formation (Deweyville Formation or broad equivalent) within the incised valley (sharp boundary with or without soil development below the unconformity), or (3) fluvial deposits above the Beaumont Formation at the base of the incised valley that predate the Holocene transgression (possibly a gradational boundary where active deposition was occurring as sea level rose and base level reached the incised valley).

Professional Paper↗

Population dynamics of Northern Pearl Dace Margariscus nachtriebi in anthropogenically altered headwater streams of the Nebraska Sandhills Ecoregion

Empirical evidence of population demographic responses to environmental perturbations is a major knowledge gap for aquatic vertebrate populations. Extensive habitat alteration including channelization of headwater streams influences the habitat template on which small-bodied fish are dependent to carry out distinct life stages and maintain or increase population growth. The objectives of this study were to (1) determine differences in geomorphic characteristics, and instream habitat (i.e., mesohabitat availability, water depth, and macrophyte coverage) in channelized and unchannelized stream sites, and (2) estimate survival of Northern Pearl Dace Margariscus nachtriebi in channelized and unchannelized stream sites. A capture-mark-recapture robust design study was conducted where a total of 1994 Northern Pearl Dace were double tagged and 853 were recaptured over the 374-day field study. Geomorphic characteristics and instream habitat in channelized and unchannelized stream sites differed (Pillai's Trace = 0.950, F (8, 6) = 14.228, p = 0.002). Specifically, mean sinuosity index ( F (1, 13) = 20.723, p = 0.0005) and the percentage of pool mesohabitat ( F (1, 13) = 4.929, p = 0.045) were both reduced in channelized versus unchannelized stream sites. Northern Pearl Dace seasonal survival was lower in channelized sites (Ŝ Spring to Summer = 0.34; SE = 0.06) compared to unchannelized sites (Ŝ Spring to Summer = 0.93; SE = 0.03) during spring to summer. Annual survival differed between channelized sites (Ŝ = 0.001; SE = 0.009) and unchannelized sites (Ŝ = 0.047; SE = 0.024). Channelization in headwater streams influenced population demographic parameters of stream fish. Northern Pearl Dace exhibited reduced survival in channelized sections of headwater streams flowing through the largest intact grassland ecosystem in North America. Mitigating channelization in streams may benefit persistence of native prairie fishes by increasing survival and subsequently aid in the restoration of headwater streams that flow through grassland ecosystems in North America.

Nebraska↗

Fish body midline segmentation using binary search

Body and caudal fin locomotion is ubiquitous in aquatic vertebrates, and kinematic models describing it are used in robotics, biomechanics and fisheries research. This paper presents a new algorithm to translate continuous body midlines of fish into a series of interconnected segments by identifying favorable joint positions along the body. The algorithm employs binary search to generate parsimonious kinematic models, aiming at minimizing the number of segments yet keeping approximation error below a user-defined threshold. To achieve this, the algorithm maximizes the length of each segment by determining the most distal joint position through repetitive shrinking of the search space. Theoretical and empirical analysis using two different datasets show that the binary search algorithm is substantially faster when compared to segment growing algorithm, which employs linear search to generate its models. There is four-fold improvement in computation time when generating models with less than 10 segments, which are typically sufficient to describe fish and fish-inspired robot movements. Furthermore, the multi-segment models generated by the binary search algorithm matched the ground truth models obtained through dynamic programming in over 97% of cases, and on average, contained one fewer segment than those produced by the Ramer–Douglas–Peucker algorithm, which is widely used in curvature simplification tasks. Our findings suggest that the binary search algorithm provides a computationally efficient approach for generating compact kinematic models and may facilitate the analysis of large datasets with high temporal and spatial resolution.

Computers and Electronics in Agriculture↗

Dynamic drainage reorganization in Eastern Tibet: Insights from the Yangtze River first bend

The modern drainage network of eastern Tibet is widely believed to have developed through a series of river capture and flow reversal events; however, the timing and mechanisms driving this reorganization remain contentious. Among these events, the river capture that formed the First Bend of the Yangtze River (YFB) stands out as both iconic and particularly debated. Here we present sedimentary provenance data from the Late Miocene–Quaternary Dali Basin, located south of the YFB, which indicate that a southward-flowing Jinsha River (i.e., the present-day upper Yangtze River) sourced sediment to the Dali basin at ∼7.4–6.4 Ma in a drainage configuration different from that of today. Because this interval postdates the initial establishment of a near-modern Jinsha River system prior to the Miocene, our results imply at least two discrete fluvial reorganizations occurred at the YFB—one preceding ∼7.4 Ma and another following ∼6.4 Ma. By integrating these findings with landscape evolution modeling, we infer that the initiation of rapid uplift of the Yulong-Haba Mountains and the Diancang Shan may have been responsible for these drainage reorganizations. These results underscore that Cenozoic drainage systems on the eastern Tibetan Plateau have evolved dynamically on a short timescale of ∼10 5 –10 6 -year, rather than remaining in a long-term stationary configuration on ∼10 7 -year timescales.

eastern Tibetan Plateau, first bend of the Yangtze↗