USGS Science⌕ Search

SEARCH · USGS Science

Results for “Environmental International”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources
USGS2013

The Borderlands - A region of physical and cultural diversity: Chapter 2 in United States-Mexican Borderlands: Facing tomorrow's challenges through USGS science

The area surrounding the United States–Mexican border is very physically and culturally diverse and cannot be generalized by any single description. To assist in an accurate appraisal and understanding of this remarkable region, the Borderlands team has divided it into eight subareas based on the watershed subareas of the U.S. Geological Survey Border Environmental Health Initiative (http://borderhealth.cr.usgs.gov) (fig. 2–1), the boundaries of which are defined primarily by surface-water drainage basins. The drainage basins directly adjacent to or crossing the international boundary were automatically included in the defined border region, as were those basins that contain unconsolidated aquifers that extend to or cross the international boundary. Also, “protected areas” adjacent to included basins were selectively added to the defined border region. Though some geographic features are entirely within the Borderlands, many features—deserts, mountain ranges, rivers, etc.— extend beyond the region boundaries but are still influential to Borderlands environments (fig. 2–2). In some cases, the authors of the following chapters have made fine adjustments to the Borderlands boundaries, and they have described those alterations where necessary. By describing and studying these subareas individually and comparing them to one another, we can emphasize the physical and cultural diversity that makes the Borderlands such an important geographic area.

United States-Mexico Borderlands↗
USGS2000

Interagency field manual for the collection of water-quality data

The Interagency Field Manual for the Collection of Water-Quality Data was initiated by the U.S. Environmental Protection Agency (USEPA), Region VI, to compile field water-sample-collection methods (water column only) commonly used by various "participating" agencies for assessing the water quality of international and transboundary rivers. These agencies include the USEPA-Regions VI and IX, International Boundary and Water Commission (IBWC), U.S. Geological Survey (USGS), Bureau of Reclamation (BOR), and State regulatory agencies. The manual is intended to provide an objective assessment of the benefits and limitations associated with each sampling method to enable the collector to select the field procedure that is most appropriate for the respective agency’s needs or individual project’s data quality objectives (DQO).

Open-File Report↗
USGS2026

Status of round goby invasion fronts in New York and Quebec: Implications for Lake Champlain

Invasive round goby Neogobius melanostomus have advanced eastward through the state of New York and provinces of Ontario and Quebec over the past two decades and are approaching Lake Champlain, one of the largest lakes in North America. This manuscript describes international efforts to monitor round goby populations during 2021–2025 on (a) the southern approach to Lake Champlain via the Hudson River and Champlain Canal, and (b) the northern approach to Lake Champlain via the Saint Lawrence River and Richelieu River. Monitoring utilized environmental DNA (eDNA), backpack electrofishing, beach seining, benthic trawling, and viral hemorrhagic septicemia virus (VHSV) testing. In the Champlain Canal, round goby were captured as far north as the downstream side of the C1 dam (97 kilometers [km] from Lake Champlain) while eDNA detections occurred as far north as the upstream side of the C2 dam (90 km from Lake Champlain). In the Richelieu River, round goby were captured as far south as Saint-Marc-sur-Richelieu (82 km from Lake Champlain) while the southern-most eDNA detections occurred near the Canadian side of the international border (4 km from Lake Champlain). Water temperature influenced habitat usage of round goby in the Champlain Canal, with catch rates in near-shore areas declining at < 10 °C. All VHSV test results were non-detections at the mouth of the Richelieu River, while one positive and two inconclusive results occurred along the Champlain Canal. Together, these data have informed multiple mitigation measures and have implications for management of aquatic invasive species across North America.

BioRxiv↗
USGS2006

Response to comment on “Persistence of pharmaceutical compounds and other organic wastewater contaminants in a conventional drinking-water-treatment plant”

The U.S. Geological Survey (USGS) and the Centers for Disease Control thank Dr. Till for her comments concerning our research ( Till, 2005 ) and welcome the opportunity to respond. The primary objective of our study was to evaluate the potential for organic wastewater-related contaminants (OWCs), including pharmaceuticals, to survive a conventional drinking-water-treatment process and persist in potable-water supplies ( Stackelberg et al., 2004 ). Our study was supported by two USGS laboratories: the National Water Quality Laboratory (NWQL), which provided the HPLC/ESI-MS and CLLE GC/MS data and the Ocala Water Quality and Research Laboratory (OWQRL), which provided the LC/MS data ( Stackelberg et al., 2004 ). Although discussed as distinct techniques by Dr. Till and indicated by differing acronyms to distinguish the laboratories producing the data, as described in our paper, the two LC/MS methods are very similar; they consist of a solid-phase extraction method with analysis of the extract produced using high-performance liquid chromatography coupled to an electrospray ionization mass spectrometer operated in the positive mode. The NWQL and OWQRL report ‘trace’ and ‘ultratrace’ determinations of analytes that provide significant benefit for describing the presence and fate of low-level contaminants. For mass spectral methods, an analyte is qualitatively identified by its retention time on the chromatographic column as well as the presence of two or more confirming ions with area ratios that match that of the reference standard compounds. Because of a recognized increased risk of false positives, these qualitative identification criteria are used in conjunction with abundant quality-control samples (detailed below) to confirm detection prior to making an estimate of the concentration. These qualitative identification criteria must be met before a compound is considered present (or detected) in a sample ( Oblinger Childress et al., 1999 ). When a compound has been qualitatively identified in an environmental sample (whether above or below its reporting level [RL]), it is assessed in context with associated field and laboratory blanks, field and laboratory replicates, and other data, such as appropriate laboratory reagent spikes. An environmental concentration is calculated only after determining that field and laboratory procedures did not contaminate the samples. The concentrations are then calculated from 5- to 8-point calibration curves using internal standard quantitation. Our lowest calibration standard is intentionally much lower than the RL, typically 10 times lower. The most abundant molecular or fragment ion is used for quantitation, and, for the two LC/MS methods, at least one, and where possible two, qualifier ions are used for confirmation. For the GC/MS method, with its greater degree of fragmentation, one quantitation and two qualifier ions are used. When any of the abovementioned qualitative identification criteria are not met, the analyte is considered not present and is reported as “less than” the RL.

Science of the Total Environment↗
USGS2012

USGS Environmental health science strategy: providing environmental health science for a changing world: Public review release

America has an abundance of natural resources. We have bountiful clean water, fertile soil, and unrivaled national parks, wildlife refuges, and public lands. These resources enrich our lives and preserve our health and wellbeing. These resources have been maintained because of our history of respect for their value and an enduring commitment to their vigilant protection. Awareness of the social, economic, and personal value of the health of our environment is increasing. The emergence of environmentally driven diseases caused by environmental exposure to contaminants and pathogens is a growing concern worldwide. New health threats and patterns of established threats are affected by both natural and anthropogenic changes to the environment. Human activities are key drivers of emerging (new and re-emerging) health threats. Societal demands for land and natural resources, a better quality of life, improved economic prosperity, and the environmental impacts associated with these demands will continue to increase. Natural earth processes, climate trends, and related climatic events will add to the environmental impact of human activities. These environmental drivers will influence exposure to disease agents, including viral, bacterial, prion, and fungal pathogens, parasites, natural earth materials, toxins and other biogenic compounds, and synthetic chemicals and substances. The U.S. Geological Survey (USGS) defines environmental health science broadly as the interdisciplinary study of relations among the quality of the physical environment, the health of the living environment, and human health. The interactions among these three spheres are driven by human activities, ecological processes, and natural earth processes; the interactions affect exposure to contaminants and pathogens and the severity of environmentally driven diseases in animals and people. This definition provides USGS with a framework for synthesizing natural science information from across the Bureau and providing it to environmental, natural resource, agricultural, and public-health managers. The USGS is a Federal science agency with a broad range of natural science expertise relevant to environmental health. USGS provides scientific information and tools as a scientific basis for management and policy decision making. USGS specializes in science at the environment-health interface, by characterizing the processes that affect the interaction among the physical environment, the living environment, and people, and the resulting factors that affect ecological and human exposure to disease agents. This report describes a 10-year strategy that encompasses the portfolio of USGS environmental health science. It summarizes national environmental health priorities that USGS is best suited to address, and will serve as a strategic framework for USGS environmental health science goals, actions, and outcomes for the next decade. Implementation of this strategy is intended to aid coordination of USGS environmental health activities and to provide a focal point for disseminating information to stakeholders. The "One Health" paradigm advocated by the World Health Organization (WHO, 2011), and the American Veterinary Medicine Association (AVMA, 2008), among others, is based on a general recognition that the health of humans, animals, and the environment are inextricably linked. Thus, successful efforts to protect that health will require increased interdisciplinary research and increased communication and collaboration among the broader scientific and health community. This strategy is built upon that paradigm. The vision, mission, and five cornerstone goals of the USGS Environmental Health Science Strategy were developed with significant input from a wide range of stakeholders. Vision - The USGS is a premier source of the environmental health science needed to safeguard the health of the environment, fish, wildlife, and people. Mission - The mission of USGS in environmental health science is to contribute scientific information to environmental, natural resource, agricultural, and public-health managers, who use that science to support sound decision making. USGS provides the science to: - Goal 1: Identify, prioritize, and detect contaminants and pathogens of emerging environmental concern. - Goal 2: Reduce the impact of contaminants on the environment, fish, wildlife, and people. - Goal 3: Reduce the impact of pathogens on the environment, fish, wildlife, and people. - Goal 4: Discover the complex interactions and combined effects of exposure to contaminants and pathogens. - Goal 5: Prepare for and respond to environmental impacts and related health threats of natural and anthropogenic disasters. Goals 1 through 4 are intended to provide science to address environmental health threats in a logical order, from informing prevention and preparedness, to supporting systematic management response to environmental health issues. Goal 4 addresses the interaction among contaminants and pathogens, an issue of emerging concern in environmental health science. Goal 5 acknowledges the fact that natural and anthropogenic disasters can cause immediate and prolonged adverse environmental health threats. This strategy proposes that USGS take the following strategic science actions to achieve each of the five goals of this strategy: Goal 1: Identify, prioritize, and detect contaminants and pathogens of emerging environmental concern. - Strategic Science Action 1. - Prioritize contaminants and pathogens of emerging concern to guide research, detection, and management activities. - Strategic Science Action 2. - Conduct surveillance and monitoring to provide early warning of emerging health threats. - Strategic Science Action 3. - Develop approaches and tools that identify vulnerable environmental settings, ecosystems, and species. Goal 2: Reduce the impact of contaminants on the environment, fish, wildlife, and people. - Strategic Science Action 1. - Systematically characterize the sources, occurrence, transport and fate of environmental contaminants to guide efforts to manage and mitigate contamination. - Strategic Science Action 2. - Evaluate the threats of contamination on the health of the environment, fish, wildlife, and people, and inform the associated management and protection efforts. - Strategic Science Action 3. - Characterize potential human exposure to support establishment of health-based standards or guidelines and contamination-reduction efforts. Goal 3: Reduce the impact of pathogens on the environment, fish, wildlife, and people. - Strategic Science Action 1. - Determine the biotic and abiotic factors that control the ecology of infectious diseases affecting natural populations of aquatic and terrestrial species and potential transmission to other animals and humans. - Strategic Science Action 2. - Establish how natural and anthropogenic environmental changes affect the distribution and severity of infectious diseases in natural populations of aquatic and terrestrial species and potential transmission to other animals and humans. - Strategic Science Action 3. - Develop surveillance systems to identify changing patterns of disease activity in priority geographic areas. Goal 4: Discover the complex interactions and combined effects of exposure to contaminants and pathogens. - Strategic Science Action 1. - Identify how exposure to one class of disease agents (contaminants or pathogens) can make an organism more susceptible to effects from exposure to the other class of disease agents. - Strategic Science Action 2. - Implement interdisciplinary studies that characterize the effects of combined exposure to pathogens and contaminants. Goal 5: Prepare for and respond to the environmental impacts and related health threats of natural and anthropogenic disasters. - Strategic Science Action 1. - Establish a formal interdisciplinary science capability to rapidly assess the environmental health risks associated with disasters. - Strategic Science Action 2. - Enhance methods to anticipate, prepare for, and identify environmental, ecological, and related health impacts of future disasters. This strategy is one of seven USGS science strategies developed concurrently: - Climate and Land Use Change - Core Science Systems - Ecosystems - Energy and Mineral Resources - Environmental Health - Natural Hazards - Water. This strategy describes how USGS will address the highest priority environmental health issues facing the Nation. The ultimate intended outcome of this science strategy is prevention and reduction of adverse impacts to the quality of the environment, the health of our living resources, and human health. Communication with, and receiving input from, partners and stakeholders regarding their science needs is essential for successful implementation of this strategy. It is incumbent on USGS to reach out to all stakeholders to ensure that USGS efforts are focused on the highest priority environmental health issues and that products are provided in the most timely and usable form to all those who can use them. USGS must reach out to the scientific community, internally and externally, to ensure that our efforts are integrated with and take full advantage of the activities of others.

Open-File Report↗
USGS2014

Digital database of microfossil localities in Alameda and Contra Costa Counties, California

The eastern San Francisco Bay region (Contra Costa and Alameda Counties, California) is a geologically complex area divided by faults into a suite of tectonic blocks. Each block contains a unique stratigraphic sequence of Tertiary sediments that in most blocks unconformably overlie Mesozoic sediments. Age and environmental interpretations based on analysis of microfossil assemblages are key factors in interpreting geologic history, structure, and correlation of each block. Much of this data, however, is distributed in unpublished internal reports and memos, and is generally unavailable to the geologic community. In this report the U.S. Geological Survey microfossil data from the Tertiary sediments of Alameda and Contra Costa counties are analyzed and presented in a digital database, which provides a user-friendly summary of the micropaleontologic data, locality information, and biostratigraphic and ecologic interpretations.

California↗
USGS2003

Handbook of ecotoxicology, second edition

Handbook of Ecotoxicology, Second Edition focuses on toxic substances and how they affect ecosystems worldwide. It presents methods for quantifying and measuring ecotoxicological effects in the field and in the lab, as well as methods for estimating, predicting, and modeling in ecotoxicology studies. Completely revised and updated with 18 new chapters, this second edition includes contributions from over 75 international experts. Also, a Technical Review Board reviewed all manuscripts for accuracy and currency. This authoritative work is the definitive reference for students, researchers, consultants, and other professionals in the environmental sciences, toxicology, chemistry, biology, and ecology - in academia, industry, and government.

Book↗
USGS2025

What is eDNA method standardization and why do we need it?

The rapid advancement of environmental DNA ( eDNA ) science in the past two decades has inspired a concomitant growth in the development of eDNA sampling and analytical methods. However, these methods are often developed by individual laboratories or institutions, which can isolate protocols within programmes, agencies or regions and prevent the beneficial exchange of data and ideas. Recent efforts to advance national and international coordination have resulted in a groundswell of standardisation efforts, but there is still considerable confusion around the role of formal standards for regulatory or research applications. With this commentary, we hope to provide clarity on the terminology used in standardisation discussions, including the differences between formal standards and best practice guidelines. Additionally, we discuss how eDNA method choice may be informed by environmental management scenarios and review examples of formal eDNA method standards being used to inform management action. The eDNA community now has an opportunity to develop a roadmap for method development to help close standardisation gaps, advance eDNA method adoption and accelerate our ability to monitor biological life at the scales our current environmental challenges demand.

Metabarcoding and Metagenomics↗
USGS2010

Development of a global land cover characteristics database and IGBP DISCover from 1 km AVHRR data

Researchers from the U.S. Geological Survey, University of Nebraska-Lincoln and the European Commission's Joint Research Centre, Ispra, Italy produced a 1 km resolution global land cover characteristics database for use in a wide range of continental-to global-scale environmental studies. This database provides a unique view of the broad patterns of the biogeographical and ecoclimatic diversity of the global land surface, and presents a detailed interpretation of the extent of human development. The project was carried out as an International Geosphere-Biosphere Programme, Data and Information Systems (IGBP-DIS) initiative. The IGBP DISCover global land cover product is an integral component of the global land cover database. DISCover includes 17 general land cover classes defined to meet the needs of IGBP core science projects. A formal accuracy assessment of the DISCover data layer will be completed in 1998. The 1 km global land cover database was developed through a continent-by-continent unsupervised classification of 1 km monthly Advanced Very High Resolution Radiometer (AVHRR) Normalized Difference Vegetation Index (NDVI) composites covering 1992-1993. Extensive post-classification stratification was necessary to resolve spectral/temporal confusion between disparate land cover types. The complete global database consists of 961 seasonal land cover regions that capture patterns of land cover, seasonality and relative primary productivity. The seasonal land cover regions were aggregated to produce seven separate land cover data sets used for global environmental modelling and assessment. The data sets include IGBP DISCover, U.S. Geological Survey Anderson System, Simple Biosphere Model, Simple Biosphere Model 2, Biosphere-Atmosphere Transfer Scheme, Olson Ecosystems and Running Global Remote Sensing Land Cover. The database also includes all digital sources that were used in the classification. The complete database can be sourced from the website: http://edcwww.cr.usgs.gov/landdaac/glcc/glcc.html.

International Journal of Remote Sensing↗
USGS2020

Managing native and non-native sea lamprey ( Petromyzon marinus ) through anthropogenic change: A prospective assessment of key threats and uncertainties

Sea lamprey ( Petromyzon marinus ) is a species of conservation concern in their native range of the Atlantic coasts of Europe (Near Threatened to Critically Endangered) and North America (Secure to Critically Imperiled), and an invasive species of great economic and ecological concern in the Laurentian Great Lakes. Despite differences in life history strategy (anadromous natives vs adfluvial non-natives), the biology of sea lamprey is sufficiently similar to expect comparable responses to large-scale environmental change. We take a prospective look at the future (50 to 100 years) of sea lamprey management in an era of considerable environmental disturbance, and consider biological responses, management actions, and the future status of populations across the native and non-native ranges. Based on facilitated discussion by a diverse group of international experts, two major but poorly characterized classes of threats to sea lamprey were identified: climate change and socio-political issues. We discuss how climate induced changes affect growth, bioenergetics, and phenology of sea lamprey, and associated effects on control tactics (pesticides and barriers) and conservation. We consider tensions surrounding improving connectivity in the Great Lakes while controlling invasive sea lamprey, and discuss supplements and alternatives to pesticides and their wider effect, as well as the effects of new invasive species. To prevent the extirpation of native sea lamprey populations, or the re-expansion of non-native populations, we conclude with a call for new and ongoing dialogue and collaboration among all sea lamprey biologists and managers across the native and non-native range.

Journal of Great Lakes Research↗
USGS1999

Internal surface water flows

Introduction The South Florida Ecosystem Restoration Program is an intergovernmental effort to reestablish and maintain the ecosystem of south Florida. One element of the restoration effort is the development of a firm scientific basis for resource decision making.The U.S. Geological Survey (USGS) provides scientitic information as part of the South Florida Ecosystem Restoration Program. The USGS began its own project, called the South Florida Ecosystem Project in fiscal year 1995 for the purpose of gathering hydrologic, cartographic, and geologic data that relate to the mainland of south Florida, Florida Bay, and the Florida Keys and Reef ecosystems. Historical changes in water-management practices to accommodate a large and rapidly growing urban population along the Atlantic coast, as well as intensive agricultural activities, have resulted in a highly managed hydrologic system with canals, levees, and pumping stations. These structures have altered the hydology of the Everglades ecosystem on both coastal and interior lands. Surface-water flows in a direction south of Lake Okeechobee have been regulated by an extensive canal network, begun in the 1940's, to provide for drainage, flood control, saltwater intrusion control, agricultural requirements, and various environmental needs. Much of the development and subsequent monitoring of canal and river discharge south of Lake Okeechobee has traditionally emphasized the eastern coastal areas of Florida. Recently, more emphasis has been placed on providing a more accurate water budget for internal canal flows.

Florida↗
USGS2018

A comparison of the chemical sensitivities between in vitro and in vivo propagated juvenile freshwater mussels: Implications for standard toxicity testing

Unionid mussels are ecologically important and are globally imperiled. Toxicants contribute to mussel declines, and toxicity tests using juvenile mussels—a sensitive life stage—are valuable in determining thresholds used to set water quality criteria. In vitro culture methods provide an efficient way to propagate juveniles for toxicity testing, but their relative chemical sensitivity compared with in vivo propagated juveniles is unknown. Current testing guidelines caution against using in vitro cultured juveniles until this sensitivity is described. Our objective was to evaluate the relative sensitivity of juvenile mussels produced from both in vitro and in vivo propagation methods to selected chemicals. We conducted 96-h acute toxicity tests according to ASTM International guidelines with 3 mussel species and 6 toxicants: chloride, nickel, ammonia, and 3 copper-based compounds. Statistically significant differences between in vitro and in vivo juvenile 96-h median effect concentrations were observed in 8 of 17 tests, and in vitro juveniles were more sensitive in 6 of the 8 significant differences. At 96 h, 4 of the 8 statistically different tests for a given chemical were within a factor of 2, which is the intralaboratory variation demonstrated in a recent evaluation of mussel toxicity tests. We found that although differences in chemical sensitivity exist between in vitro and in vivo propagated juvenile mussels, they are within normal toxicity test variation. Therefore, in vitro propagated juvenile mussels may be appropriate for use in ASTM International-based toxicity testing.

Environmental Toxicology and Chemistry↗
USGS2013

The distribution of uranium over Europe: Geological and environmental significance

The variation of baseline levels of uranium in soil and stream sediments over Europe is described, based on new data prepared by the Forum of European Geological Surveys (FOREGS). The samples have been collected and analysed according to the protocols established for the International Union of Geological Sciences/International Association of Geochemistry and Cosmochemistry (IUGS/IAGC) Working Group on Global Geochemical Baselines. The baseline levels of U vary between 0??21 to 53 mg kg-1 in topsoils, 0??19 to 30 mg kg-1 in subsoils and < 1 to 59 mg kg-1 in stream sediments. There is generally good agreement between the levels of U in the three sample types, and the median concentration in all three media is approximately 2 mg kg-1. The most anomalous baseline levels occur over the Variscan orogen, especially areas into which late post-orogenic radiothermal high heat production (HHP) granites were emplaced. Spiderdiagrams based on trace element levels and rare earth element (REE) plots, confirm the association between the highest U anomalies and evolved radiothermal granites. High values are also associated with parts of the Alpine terrain especially in Slovenia, where there are historical U workings, and Southern Italy, where high values of U reflect contemporary volcanism. In contrast, much of the Caledonides of North West Europe and the Precambrian of the Baltic Shield and East European craton and its overlying sedimentary cover have very low values, generally < 4 mg kg-1. The results suggest that the main concern for the environment and human health from U, and the Th and K with which it is generally associated, is the naturally occurring total gamma radiation and radon potential associated with radiothermal granites. This is likely to be especially important where the granites are mineralised and have been worked historically, for example in the North West of the Iberian Peninsula where U and its decay products are likely to be more dispersed in the surface environment. The study also indicates the value of multi-element data in distinguishing between anthropogenic and naturally occurring anomalies.

Transactions of the Institution of Mining and Meta↗
USGS2016

Migratory corridors of adult female Kemp’s ridley turtles in the Gulf of Mexico

For many marine species, locations of migratory pathways are not well defined. We used satellite telemetry and switching state-space modeling (SSM) to define the migratory corridor used by Kemp's ridley turtles (Lepidochelys kempii) in the Gulf of Mexico. The turtles were tagged after nesting at Padre Island National Seashore, Texas, USA from 1997 to 2014 (PAIS; n = 80); Rancho Nuevo, Tamaulipas, Mexico from 2010 to 2011 (RN; n = 14); Tecolutla, Veracruz, Mexico from 2012 to 2013 (VC; n = 13); and Gulf Shores, Alabama, USA during 2012 (GS; n = 1). The migratory corridor lies in nearshore Gulf of Mexico waters in the USA and Mexico with mean water depth of 26 m and a mean distance of 20 km from the nearest mainland coast. Migration from the nesting beach is a short phenomenon that occurs from late-May through August, with a peak in June. There was spatial similarity of post-nesting migratory pathways for different turtles over a 16 year period. Thus, our results indicate that these nearshore Gulf waters represent a critical migratory habitat for this species. However, there is a gap in our understanding of the migratory pathways used by this and other species to return from foraging grounds to nesting beaches. Therefore, our results highlight the need for tracking reproductive individuals from foraging grounds to nesting beaches. Continued tracking of adult females from PAIS, RN, and VC nesting beaches will allow further study of environmental and bathymetric components of migratory habitat and threats occurring within our defined corridor. Furthermore, the existence of this migratory corridor in nearshore waters of both the USA and Mexico demonstrates that international cooperation is necessary to protect essential migratory habitat for this imperiled species.

Gulf of Mexico↗
USGS2025

Cyanotoxin production in shallow subtropical lakes is driven by nutrient enrichment and primary producer abundance on the millennial scale

Increased cyanotoxin concentrations from harmful algal blooms (HABs) in lake systems pose a global challenge to water quality. Although progress has been made in monitoring cyanotoxins in modern environments over recent decades, identifying the triggers of cyanotoxin release by cyanobacteria has yielded mixed results from experimental and analytical studies. Paleolimnological reconstructions can reveal whole-lake long-term changes, but few studies have directly measured cyanotoxins alongside other water quality proxies. Here, we investigated the drivers of sedimentary total microcystin (MC) concentrations on millennial scales in hypereutrophic Lakes Dora and Marian in central Florida, USA. We analyzed dated sediment records using paleolimnological techniques to reconstruct nutrient deposition, cyanobacteria abundance (photosynthetic pigments), and cyanotoxins (total MCs). The objective was to investigate the linkage between MC concentrations in the sediments with both biotic (cyanobacteria and other primary producers) and abiotic factors (nutrients and climate). We found that MC production occurred throughout the ∼7000-year period, progressing from periods of moderate to low, and then to high concentrations in both lakes. Statistical analyses showed that historical MC concentrations were correlated with sedimentary measurements of total phosphorus (TP), cyanobacteria abundance, and other primary producer groups, such as cryptophytes. However, there was only a minimal correspondence with climate proxies, such as charcoal and pollen, suggesting that internal nutrient cycling and human pressures were the dominant drivers of MC deposition. Our study demonstrates that cyanotoxins have occurred for millennia in both lakes with maintained relationships to nutrients and other environmental factors that existed both in historic and modern limnological conditions.

Florida↗
USGS1998

Proactive responses to human impacts that balance development and Atlantic salmon (Salmo salar) conservation: An integrative model

Incorporating human impacts into conservation plans is critical to protect natural resources. Using a model that examines how anthropogenic changes might be proactively influenced to promote conservation, we argue that a denser human population does not spell inevitable doom for Atlantic salmon (Salmo salar). Humans affect the Atlantic salmon ecosystem deleteriously through landscape alteration, exploitation, external inputs, and resource competition. An intact ecosystem provides positive feedback to society by providing food, ecosystem services, and improving the quality of life. As Atlantic salmon and associated ecosystem benefits are increasingly valued by society, policies, laws, and regulations that protect salmon populations and habitats are codified into a 'control system' or institutional infrastructure. Via research that helps maintain wild salmon populations and in informing the public about the benefits of a healthy Atlantic salmon ecosystem, scientists can influence public attitudes and facilitate the implementation of environmental policies that moderate harmful anthropogenic changes. Because exchange among scientists is of paramount importance in increasing our understanding of important interrelationships between humans and fish, we recommend the establishment of an international salmon organizational for research.

Conference Paper↗
USGS2026

Guidelines for producing integrated 210Pb and 14C age-models

Accurate reconstructions of past environmental changes are crucial in paleoecological research and require reliable chronologies of sedimentary archives. Establishing robust age-models and obtaining the most appropriate proxies for analysis is a complex scientific endeavor, requiring extensive resources and collaboration among specialists, including radiochronologists. Radiometric dating methods, such as 210 Pb and radiocarbon ( 14 C), are frequently employed to establish chronologies in aquatic sedimentary deposits and peat bogs. In this study, we review key aspects of sampling, analysis, and the principles underlying 210 Pb and 14 C age-models, focusing on methods for developing robust joint chronologies for paleoenvironmental research. Drawing largely from the authors' experiences and group discussions during and after a scientific workshop in 2022, we discuss important considerations for site selection, sampling strategies, and radiometric dating to construct integrated 210 Pb and 14 C age-models. Using expert consensus, this group – called Paleostats – aims to provide a set of best practices for other geochronologists with this methods paper. Among our conclusions, we emphasize the importance of accounting for site-specific factors such as prior information on sedimentation rates to establish appropriate sampling and analytical strategies. The use of appropriate coring devices can minimize disturbance to sediments and ensure the core surface remains intact and preserved until sectioning. Where excess 210 Pb is expected, sectioning at intervals of ≤1 cm provides an adequate sampling resolution for 210 Pb dating. Exceptions are possible, allowing for ~2–3 cm sections in areas with confirmed high sedimentation rates (e.g., > 1 cm yr −1 ). Recovering deeper core sections for 14 C dating with sufficient overlap allows for accounting errors in depth estimates made in the field. Special attention is advised during time intervals where validation proxies, such as the human-made radionuclides 137 Cs or post-bomb 14 C, are expected, and to determine the depth of secular equilibrium between 210 Pb and 226 Ra. Radiocarbon analyses are commonly performed by accelerator mass spectrometry, and age models are constructed mainly using Bayesian statistics with Markov Chain Monte Carlo techniques (e.g., Bacon ). A Bayesian approach ( Plum ) is now available for producing 210 Pb age-models, which infers the 210 Pb ex flux, eliminates the need for selecting an equilibrium depth, and allows dating cores with incomplete 210 Pb ex inventory. Plum offers improved chronologies by integrating raw 210 Pb and 14 C data, and these age-models can be enriched with other dating methodologies, such as identifying tephras and other well-recorded historical events. Harmonized reporting would contribute to making radiometric age-models reproducible, which would benefit from an international effort. Using 210 Pb and 14 C to produce integrated age-models may yield better insights into the interplay between natural and recent anthropogenic forcings on ecosystems. This can enhance our understanding of environmental processes and their impacts on climate change, ultimately supporting science-based assessments and decisions.

Earth-Science Reviews↗
USGS2005

Why is metal bioaccumulation so variable? Biodynamics as a unifying concept

Ecological risks from metal contaminants are difficult to document because responses differ among species, threats differ among metals, and environmental influences are complex. Unifying concepts are needed to better tie together such complexities. Here we suggest that a biologically based conceptualization, the biodynamic model, provides the necessary unification for a key aspect in risk: metal bioaccumulation (internal exposure). The model is mechanistically based, but empirically considers geochemical influences, biological differences, and differences among metals. Forecasts from the model agree closely with observations from nature, validating its basic assumptions. The biodynamic metal bioaccumulation model combines targeted, high-quality geochemical analyses from a site of interest with parametrization of key physiological constants for a species from that site. The physiological parameters include metal influx rates from water, influx rates from food, rate constants of loss, and growth rates (when high). We compiled results from 15 publications that forecast species-specific bioaccumulation, and compare the forecasts to bioaccumulation data from the field. These data consider concentrations that cover 7 orders of magnitude. They include 7 metals and 14 species of animals from 3 phyla and 11 marine, estuarine, and freshwater environments. The coefficient of determination ( R 2 ) between forecasts and independently observed bioaccumulation from the field was 0.98. Most forecasts agreed with observations within 2-fold. The agreement suggests that the basic assumptions of the biodynamic model are tenable. A unified explanation of metal bioaccumulation sets the stage for a realistic understanding of toxicity and ecological effects of metals in nature.

Environmental Science & Technology↗