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At least 91 records · Page 5Linked to original sources
USGS2020

Threats posed by the Fungal Kingdom to humans, wildlife, and agriculture

The Fungal Kingdom includes at least six million eukaryotic species and is remarkable with respect to its profound impact on global health, biodiversity, ecology, agriculture, manufacturing, and biomedical research. Approximately 625 fungal species have been reported to infect vertebrates, 200 of which can be human-associated, either as commensals and members of our microbiome or as pathogens that cause infectious diseases. These organisms pose a growing threat to human health with the global increase in the incidence of invasive fungal infections, prevalence of fungal allergy, and the evolution of fungal pathogens resistant to some or all current classes of antifungals. More broadly, there has been an unprecedented and worldwide emergence of fungal pathogens impacting animal and plant biodiversity. Approximately 8,000 species of fungi and Oomycetes are associated with plant disease. Indeed, across agriculture, such fungal diseases of plants include new devastating epidemics of trees and jeopardize food security worldwide by causing epidemics in staple and commodity crops that feed billions. Further, ingestion of mycotoxins contributes to ill health and causes cancer. Coordinated international research efforts, enhanced technology translation, and greater policy outreach by scientists are needed to more fully understand the biology and drivers that underlie the emergence of fungal diseases and to mitigate against their impacts. Here, we focus on poignant examples of emerging fungal threats in each of three areas: human health, wildlife biodiversity, and food security.

mBio↗
USGS1996

The Fox River PCB transport study: Stepping stone to a healthy Great Lakes ecosystem

Polychlorinated Biphenyls (PCBs) in the Great Lakes Despite being banned since the 1970's, polychlorinated biphenyls (PCBs) continue to pose a threat to the environment because of their persistence and toxicity to organisms ranging from minute algae to fish, waterfowl, and human beings. PCBs, a set of 209 related chlorinated organic compounds, had various industrial uses such as in hydraulic fluids, cutting oils, sealants, and pesticides. Despite the manufacturing ban in the mid-1970's, PCBs remain ubiquitous in the environment. In the Laurentian Great Lakes of the Midwest. PCBs and other toxic compounds contaminate bottom sediments at almost all designated "areas of concern" (AOC)(figure 1, upper left inset). The International Joint Commission, a binational group from Canada and the United States, has identified these AOCs in their efforts to restore and protect Great Lakes ecosystems. One such area, the Fox River which flows into Green Bay, has been the focus of much scientific study in an effort to improve not only that river but to apply lessons learned to other AOCs. The final goal is a healthy Great Lakes food chain with fish and waterfowl that are safe to consume.

Fox River, Great Lakes, Lake Winnebago↗
USGS2003

Survival, transport, and sources of fecal bacteria in streams and survival in land-applied poultry litter in the upper Shoal Creek basin, southwestern Missouri, 2001–2002

Densities of fecal coliform bacteria along a 5.7-mi (mile) reach of Shoal Creek extending upstream from State Highway 97 (site 3) to State Highway W (site 2) and in two tributaries along this reach exceeded the Missouri Department of Natural Resources (MDNR) standard of 200 col/100 mL (colonies per 100 milliliters) for whole-body contact recreation. A combination of techniques was used in this report to provide information on the source, transport, and survival of fecal bacteria along this reach of Shoal Creek. Results of water-quality samples collected during dye-trace and seepage studies indicated that at summer low base-flow conditions, pastured cattle likely were a substantial source of fecal bacteria in Shoal Creek at the MDNR monitoring site (site 3) at State Highway 97. Using repeat element Polymerase Chain Reaction (rep-PCR), cattle were the presumptive source of about 50 percent of the Escherichia coli ( E. coli ) isolates in water samples from site 3. Cattle, horses, and humans were the most common presumptive source of E. coli isolates at sites further upstream. Poultry was identified by rep-PCR as a major source of E. coli in Pogue Creek, a tributary in the upper part of the study area. Results of the rep-PCR were in general agreement with the detection and distribution of trace concentrations of organic compounds commonly associated with human wastewater, such as caffeine, the antimicrobial agent triclosan, and the pharmaceutical compounds acetaminophen and thiabendazole (a common cattle anthelmintic). Significant inputs of fecal bacteria to Shoal Creek occurred along a 1.6-mi reach of Shoal Creek immediately upstream from site 3. During a 36-hour period in July 2001, average densities of fecal coliform and E. coli bacteria increased from less than or equal to 500 col/100 mL upstream from this stream reach (sample site 2c) to 2,100 and 1,400 col/100 mL, respectively, at the MDNR sampling site. Fecal bacteria densities exhibited diurnal variability at all five sampling sites along the 5.7-mi study reach of Shoal Creek, but the trends at successive downstream sites were out of phase and could not be explained by simple advection and dispersion. At base-flow conditions, the travel time of bacteria in Shoal Creek along the 5.7-mi reach between State Highway W (site 2) and the MDNR sampling site (site 3) was about 26 hours. Substantial dispersion and dilution occurs along the upper 4.1 mi of this reach because of inflows from a number of springs and tributaries and the presence of several long pools and channel meanders. Minimal dispersion and dilution occurs along the 1.6-mi reach immediately upstream from the MDNR sampling site. Measurements of fecal bacteria decay in Shoal Creek during July 2001 indicated that about 8 percent of fecal coliform and E. coli bacteria decay each hour with an average first-order decay constant of 0.084 h -1 (per hour). Results of field test plots indicated that substantial numbers of fecal bacteria present in poul try litter can survive in fields for as much as 8 weeks after the application of the litter to the land surface. Median densities of fecal coliform and E. coli in slurry-water samples collected from fields increased from less than 60 col/100 mL before the application of turkey and broiler litter, to as large as 420,000 and 290,000 col/100 mL after the application of litter. Bacteria densities in the test plots generally decreased in a exponential manner over time with decay rates ranging from 0.085 to 0.185 d -1 (per day) for fecal coliform to between 0.100 and 0.250 d -1 for E. coli . The apparent survival of significant numbers of fecal bacteria on fields where poultry litter has been applied indicates that runoff from these fields is a potential source of fecal bacteria to vicinity streams for many weeks following litter application.

Water-Resources Investigations Report↗
USGS2019

Precision mapping of snail habitat provides a powerful indicator of human schistosomiasis transmission

Recently, the World Health Organization recognized that efforts to interrupt schistosomiasis transmission through mass drug administration have been ineffective in some regions; one of their new recommended strategies for global schistosomiasis control emphasizes targeting the freshwater snails that transmit schistosome parasites. We sought to identify robust indicators that would enable precision targeting of these snails. At the site of the world’s largest recorded schistosomiasis epidemic—the Lower Senegal River Basin in Senegal—intensive sampling revealed positive relationships between intermediate host snails (abundance, density, and prevalence) and human urogenital schistosomiasis reinfection (prevalence and intensity in schoolchildren after drug administration). However, we also found that snail distributions were so patchy in space and time that obtaining useful data required effort that exceeds what is feasible in standard monitoring and control campaigns. Instead, we identified several environmental proxies that were more effective than snail variables for predicting human infection: the area covered by suitable snail habitat (i.e., floating, nonemergent vegetation), the percent cover by suitable snail habitat, and size of the water contact area. Unlike snail surveys, which require hundreds of person-hours per site to conduct, habitat coverage and site area can be quickly estimated with drone or satellite imagery. This, in turn, makes possible large-scale, high-resolution estimation of human urogenital schistosomiasis risk to support targeting of both mass drug administration and snail control efforts.

PNAS↗
USGS2015

Human activities and climate variability drive fast-paced change across the world's estuarine-coastal ecosystems

Time series of environmental measurements are essential for detecting, measuring and understanding changes in the Earth system and its biological communities. Observational series have accumulated over the past 2–5 decades from measurements across the world's estuaries, bays, lagoons, inland seas and shelf waters influenced by runoff. We synthesize information contained in these time series to develop a global view of changes occurring in marine systems influenced by connectivity to land. Our review is organized around four themes: (i) human activities as drivers of change; (ii) variability of the climate system as a driver of change; (iii) successes, disappointments and challenges of managing change at the sea-land interface; and (iv) discoveries made from observations over time. Multidecadal time series reveal that many of the world's estuarine–coastal ecosystems are in a continuing state of change, and the pace of change is faster than we could have imagined a decade ago. Some have been transformed into novel ecosystems with habitats, biogeochemistry and biological communities outside the natural range of variability. Change takes many forms including linear and nonlinear trends, abrupt state changes and oscillations. The challenge of managing change is daunting in the coastal zone where diverse human pressures are concentrated and intersect with different responses to climate variability over land and over ocean basins. The pace of change in estuarine–coastal ecosystems will likely accelerate as the human population and economies continue to grow and as global climate change accelerates. Wise stewardship of the resources upon which we depend is critically dependent upon a continuing flow of information from observations to measure, understand and anticipate future changes along the world's coastlines.

Global Change Biology↗
USGS2024

Microplastic-mediated new mechanism of liver damage: From the perspective of the gut-liver axis

Microplastics (MPs) are environmental contaminants that are present in all environments and can enter the human body, accumulate in various organs, and cause harm through the ingestion of food, inhalation, and dermal contact. The connection between bowel and liver disease and the interplay between gut, liver, and flora has been conceptualized as the “gut-liver axis”. Microplastics can alter the structure of microbial communities in the gut and the liver can also be a target for microplastic invasion. Numerous studies have found that when MPs impair human health, they not only promote dysbiosis of the gut microbiota and disruption of the gut barrier but also cause liver damage. For this reason, the gut-liver axis provides a new perspective in understanding this toxic response. The cross-talk between MPs and the gut-liver axis has attracted the attention of the scientific community, but knowledge about whether MPs cause gut-liver interactions through the gut-liver axis is still very limited, and the effect of MPs on liver injury is not well understood. MPs can directly induce microbiota disorders and gut barrier dysfunction. As a result, harmful bacteria and metabolites in the gut enter the blood through the weak intestinal barrier (portal vein channel along the gut-liver axis) and reach the liver, causing liver damage (inflammatory damage, metabolic disorders, oxidative stress, etc.). This review provides an integrated perspective of the gut-liver axis to help conceptualize the mechanisms by which MP exposure induces gut microbiota dysbiosis and hepatic injury and highlights the connection between MPs and the gut-liver axis. Therefore, from the perspective of the gut-liver axis, targeting intestinal flora is an important way to eliminate microplastic liver damage.

Science of the Total Environment↗
USGS2011

Status and understanding of groundwater quality in the Santa Clara River Valley, 2007-California GAMA Priority Basin Project

Groundwater quality in the approximately 460-square-mile Santa Clara River Valley study unit was investigated from April through June 2007 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project is conducted by the U.S. Geological Survey (USGS) in collaboration with the California State Water Resources Control Board and the Lawrence Livermore National Laboratory. The Santa Clara River Valley study unit contains eight groundwater basins located in Ventura and Los Angeles Counties and is within the Transverse and Selected Peninsular Ranges hydrogeologic province. The Santa Clara River Valley study unit was designed to provide a spatially unbiased assessment of the quality of untreated (raw) groundwater in the primary aquifer system. The assessment is based on water-quality and ancillary data collected in 2007 by the USGS from 42 wells on a spatially distributed grid, and on water-quality data from the California Department of Public Health (CDPH) database. The primary aquifer system was defined as that part of the aquifer system corresponding to the perforation intervals of wells listed in the CDPH database for the Santa Clara River Valley study unit. The quality of groundwater in the primary aquifer system may differ from that in shallow or deep water-bearing zones; for example, shallow groundwater may be more vulnerable to surficial contamination. Eleven additional wells were sampled by the USGS to improve understanding of factors affecting water quality.The status assessment of the quality of the groundwater used data from samples analyzed for anthropogenic constituents, such as volatile organic compounds (VOCs) and pesticides, as well as naturally occurring inorganic constituents, such as major ions and trace elements. The status assessment is intended to characterize the quality of untreated groundwater resources in the primary aquifers of the Santa Clara River Valley study unit, not the quality of treated drinking water delivered to consumers. Relative-concentrations (sample concentration divided by health- or aesthetic-based benchmark concentration) were used for evaluating groundwater quality for those constituents that have Federal and (or) California benchmarks. A relative-concentration greater than 1.0 indicates a concentration greater than a benchmark. For organic and special interest constituents, relative-concentrations were classified as high (greater than 1.0); moderate (greater than 0.1 and less than or equal to 1.0); and low (less than or equal to 0.1). For inorganic constituents, relative-concentrations were classified as high (greater than 1.0); moderate (greater than 0.5 and less than or equal to 1.0); and low (less than or equal to 0.5). Aquifer-scale proportion was used as the primary metric in the status assessment for evaluating regional-scale groundwater quality. High aquifer-scale proportion is defined as the areal percentage of the primary aquifer system with relative-concentrations greater than 1.0. Moderate and low aquifer-scale proportions are defined as the areal percentage of the primary aquifer system with moderate and low relative-concentrations, respectively. Two statistical approaches, grid-based and spatially weighted, were used to evaluate aquifer-scale proportions for individual constituents and classes of constituents. Grid-based and spatially weighted estimates were comparable in the Santa Clara River Valley study unit (within 90 percent confidence intervals). The status assessment showed that inorganic constituents were more prevalent and relative-concentrations were higher than for organic constituents. For inorganic constituents with human-health benchmarks, relative-concentrations (of one or more constituents) were high in 21 percent of the primary aquifer system areally, moderate in 30 percent, and low or not detected in 49 percent. Inorganic constituents with human-health benchmarks with high aquifer-scale proportions were nitrate (15 percent of the primary aquifer system), gross alpha radioactivity (14 percent), vanadium (3.4 percent), boron (3.2 percent), and arsenic (2.3 percent). For inorganic constituents with aesthetic benchmarks, relative-concentrations (of one or more constituents) were high in 54 percent of the primary aquifer system, moderate in 41 percent, and low or not detected in 4 percent. The inorganic constituents with aesthetic benchmarks with high aquifer-scale proportions were total dissolved solids (35 percent), sulfate (22 percent), manganese (38 percent), and iron (22 percent). In contrast, the results of the status assessment for organic constituents with human-health benchmarks showed that relative-concentrations were high in 0 percent (not detected above benchmarks) of the primary aquifer system, moderate in 2.4 percent, and low or not detected in 97 percent. Relative-concentrations of the special interest constituent, perchlorate, were moderate in 12 percent of the primary aquifer system and low or not detected in 88 percent. Relative-concentrations of two VOCs-carbon tetrachloride and trichloroethene (TCE)-were moderate in 2.4 percent of the primary aquifer system. One VOC-chloroform (water disinfection byproduct)-was detected in more than 10 percent of the primary aquifer system but at low relative-concentrations. Of the 88 VOCs and gasoline oxygenates analyzed, 71 were not detected. Pesticides were low or not detected in 100 percent of the primary aquifer system. Of the 118 pesticides and pesticide degradates analyzed, 13 were detected and 5 of those had human-health benchmarks. Two of these five pesticides-simazine and atrazine-were detected in more than 10 percent of the primary aquifer system. The second component of this study, the understanding assessment, was to identify the natural and human factors that affect groundwater quality on the basis of the evaluation of land use, physical characteristics of the wells, and geochemical conditions of the aquifer. Results from these analyses are used to explain the occurrence and distribution of selected constituents in the primary aquifer system of the Santa Clara River Valley study unit. The understanding assessment indicated that water quality varied spatially primarily in relation to depth, groundwater age, reduction-oxidation conditions, pH, and location in the regional groundwater flow system. High and moderate relative-concentrations of nitrate and low relative-concentrations of pesticides were correlated with shallow depths to top-of-perforation, and with high dissolved oxygen. Groundwater of modern and mixed ages had higher nitrate than pre-modern-age groundwater. Decreases in concentrations of total dissolved solids (TDS) and sulfate were correlated with increases in pH. This relationship probably indicates relations of these constituents with increasing depth across most of the Santa Clara River Valley study unit. Previous studies have indicated multiple sources of high concentrations of TDS and sulfate and multiple geochemical processes affecting these constituents in the Santa Clara River Valley study unit. Manganese and iron concentrations were highest in pre-modern-age groundwater at depth and in the downgradient area of the Santa Clara River Valley study unit (closest to the coastline), indicating the prevalence of reducing groundwater conditions in these aquifer zones.

Scientific Investigations Report↗
USGS2012

Status and understanding of groundwater quality in the two southern San Joaquin Valley study units, 2005-2006 - California GAMA Priority Basin Project

Groundwater quality in the southern San Joaquin Valley was investigated from October 2005 through March 2006 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project is conducted by the U.S. Geological Survey (USGS) in collaboration with the California State Water Resources Control Board and the Lawrence Livermore National Laboratory. There are two study units located in the southern San Joaquin Valley: the Southeast San Joaquin Valley (SESJ) study unit and the Kern County Subbasin (KERN) study unit. The GAMA Priority Basin Project in the SESJ and KERN study units was designed to provide a statistically unbiased, spatially distributed assessment of untreated groundwater quality within the primary aquifers. The status assessment is based on water-quality and ancillary data collected in 2005 and 2006 by the USGS from 130 wells on a spatially distributed grid, and water-quality data from the California Department of Public Health (CDPH) database. Data was collected from an additional 19 wells for the understanding assessment. The aquifer systems (hereinafter referred to as primary aquifers) were defined as that part of the aquifer corresponding to the perforation interval of wells listed in the CDPH database for the SESJ and KERN study units. The status assessment of groundwater quality used data from samples analyzed for anthropogenic constituents such as volatile organic compounds (VOCs) and pesticides, as well as naturally occurring inorganic constituents such as major ions and trace elements. The status assessment is intended to characterize the quality of untreated groundwater resources within the primary aquifers in the SESJ and KERN study units, not the quality of drinking water delivered to consumers. Although the status assessment applies to untreated groundwater, Federal and California regulatory and non-regulatory water-quality benchmarks that apply to drinking water are used to provide context for the results. Relative-concentrations (sample concentration divided by benchmark concentration) were used for evaluating groundwater. A relative-concentration greater than 1.0 indicates a concentration greater than the benchmark and is classified as high. The relative-concentration threshold for classifying inorganic constituents as moderate or low was 0.5; for organic constituents the threshold between moderate and low was 0.1. Aquifer-scale proportion was used as the primary metric for assessing the quality of untreated groundwater for the study units. High aquifer-scale proportion is defined as the areal percentage of the primary aquifers with a high relative-concentration for a particular constituent or class of constituents. Moderate and low aquifer-scale proportions were defined as the areal percentage of the primary aquifers with moderate and low relative-concentrations, respectively. Two statistical approaches—grid-based and spatially weighted—were used to evaluate aquifer-scale proportions for individual constituents and classes of constituents. Grid-based and spatially weighted estimates were comparable for the two study units in the southern San Joaquin Valley (within 90 percent confidence intervals). The status assessment showed that inorganic constituents were more prevalent than organic constituents and that relative-concentrations were higher for inorganic constituents than for organic constituents. For inorganic constituents with human-health benchmarks, the relative-concentration of at least one constituent in the SESJ study unit was high in 30 percent of the primary aquifers. In the KERN study unit, the relative-concentration of at least one constituent was high in 23 percent of the primary aquifers. In the SESJ and KERN study units, the inorganic constituents with human-health benchmarks detected at high relative-concentrations in more than 2 percent of the primary aquifers were arsenic, boron, vanadium, nitrate, uranium, and gross alpha radioactivity. Additional constituents with human-health benchmarks—antimony, radium, and fluoride—were detected at high relative-concentrations in the KERN study unit. For inorganic constituents with aesthetic benchmarks (secondary maximum contaminant levels, SMCLs), the relative-concentration of at least one constituent in the SESJ study unit was high in 6.6 percent of the primary aquifers. In the KERN study unit, the relative-concentration of at least one constituent was high in 22 percent of the primary aquifers. Inorganic constituents with aesthetic benchmarks detected at high relative-concentrations in the primary aquifers in the SESJ and KERN study units were iron and manganese. Additional constituents with aesthetic benchmarks—total dissolved solids (TDS), sulfate, and chloride—were detected at high relative-concentrations in the KERN study unit. In contrast, the status assessment for organic constituents with human-health benchmarks showed that relative-concentrations were high in 4.8 percent and 2.1 percent of the primary aquifers in the SESJ and KERN study units, respectively. The special-interest constituent, perchlorate, was detected at high relative-concentrations in 1.2 percent of the primary aquifers in the SESJ study unit. Twenty-eight of the 78 VOCs (not including fumigants) analyzed were detected. Of these 28 VOCs, benzene had high relative-concentrations in the SESJ study unit, and relative-concentrations for the other 27 VOCs were moderate and low. Five of the 10 fumigants were detected; 1,2-dibromo-3-chloropropane (DBCP) was the only fumigant with high relative-concentrations in the SESJ and KERN study units. Of the 136 pesticides and pesticide degradates analyzed, 33 were detected. Human-health benchmarks were established for eighteen of the detected pesticides. Dieldrin was detected at moderate relative-concentrations in the SESJ and KERN study units. All other pesticides detected with human-health benchmarks were present at low relative-concentrations. The detection frequencies for two of these pesticides—simazine and atrazine—were greater than or equal to 10 percent in the SESJ and KERN study units. The understanding assessment of groundwater quality included an analysis of correlations of selected water-quality constituents or classes of constituents with potential explanatory factors. The understanding assessment indicated that the concentrations of many trace elements and major ions were correlated to well depth, groundwater age, and/or geochemical conditions. Many trace elements were positively correlated with depth. Arsenic, boron, vanadium, fluoride, manganese, and iron concentrations increased with well depth or depth to top-of-perforations. The concentrations for these trace elements also were higher in older (pre-modern) groundwater. In contrast, uranium concentrations decreased with increasing depth and groundwater age. Most trace elements were correlated to geochemical conditions. Arsenic, antimony, boron, fluoride, manganese, and iron concentrations generally were higher wherever the pH of the groundwater was greater than 7.6. Concentrations for these constituents generally were higher at low concentrations of dissolved oxygen (DO). Uranium was the exception; uranium concentrations generally were lower at high pH and at high concentrations of DO. Nitrate concentrations generally were lower in deeper wells. Nitrate concentrations also were higher in groundwater with higher DO. Total dissolved solids, sulfate, and chloride concentrations were higher in the KERN study unit than in the SESJ study unit. Total dissolved solids were negatively correlated with pH in the KERN study unit. Total dissolved solids and sulfate were higher in areas with more agricultural land use. Chloride concentrations increased with depth to top-of-perforations in the KERN study unit. Organic constituents and constituents of special interest, like many inorganic constituents, were correlated with well depth, groundwater age, and DO. Unlike most trace elements, however, solvent and pesticide detections, and total trihalomethanes (THM), DBCP, and perchlorate concentrations decreased with increasing well depth. Volatile organic compound, solvent, and pesticide detections, and THM concentrations also were lower in older (pre-modern) groundwater than in modern-age groundwater. Solvent detections and total THM, DBCP, and perchlorate concentrations increased with increasing DO concentrations.

California↗
USGS2018

Human Bacteroides and total coliforms as indicators of recent combined sewer overflows and rain events in urban creeks

Combined sewer overflows (CSOs) are a known source of human fecal pollution and human pathogens in urban water bodies, which may present a significant public health threat. To monitor human fecal contamination in water, bacterial fecal indicator organisms (FIOs) are traditionally used. However, because FIOs are not specific to human sources and do not correlate with human pathogens, alternative fecal indicators detected using qPCR are becoming of interest to policymakers. For this reason, this study measured correlations between the number and duration of CSOs and mm of rainfall, concentrations of traditional FIOs and alternative indicators, and the presence of human pathogens in two urban creeks. Samples were collected May–July 2016 and analyzed for concentrations of FIOs (total coliforms and E . coli ) using membrane filtration as well as for three alternative fecal indicators (human Bacteroides HF183 marker, human polyomavirus (HPoV), pepper mild mottle virus (PMMoV)) and nine human pathogens using qPCR. Four of the nine pathogens analyzed were detected at these sites including adenovirus, Enterohemorrhagic E . coli , norovirus, and Salmonella . Among all indicators studied, human Bacteroides and total coliforms were significantly correlated with recent CSO and rainfall events, while E . coli, PMMoV, and HPoV did not show consistent significant correlations. Further, human Bacteroides were a more specific indicator, while total coliforms were a more sensitive indicator of CSO and rainfall events. Results may have implications for the use and interpretation of these indicators in future policy or monitoring programs.

Pennsylvania↗
USGS2023

Modeling, mapping, and measuring the risk of freshwater invasive species across Alaska

Freshwater ecosystems of the Alaskan Arctic and Subarctic provide resources that are culturally, ecologically, and economically invaluable. Presently, these regions are relatively free of the impacts from invasive species compared to southern latitudes. To date, there have been relatively few verified introductions of aquatic invasive species (AIS) to freshwater ecosystems in Alaska. The expanding list and distribution of AIS has led to significant negative ecological and economic impacts (e.g., waterweed Elodea nuttalli ; E. canadensis and northern pike Esox Lucius introduced outside its native range in Alaska). Escalating human activity across Alaskan lands and waters, coupled with rapidly shifting environmental conditions, increases the potential for new species introductions and subsequent establishment. Creating a proactive framework for well-informed decision-making and action can improve the effectiveness of prevention efforts and bolster decision support tools that help resource managers direct limited resources. Prioritizing AIS that may be introduced and become established, as well as the locations at highest risk of invasion, is foundational to building a proactive invasive species management framework in Alaska. This project sought to identify and prioritize AIS known to be invasive in the contiguous United States, evaluate current and future habitat suitability for AIS in Alaska, and assess potential for AIS to be transported to habitats across Alaska, utilizing similar assessment methods as implemented for Bering Sea marine invasive species and non-native plants in Alaska. To accomplish this goal, the objectives of the project were to: 1) develop a formal ranked list of potential AIS to freshwater systems of Alaska; 2) assess the level of establishment risk for potential AIS by developing habitat suitability models for waterbodies across Alaska; and 3), identify potential pathways and specific vectors for high-risk AIS to invade Alaska and develop a framework for how vector analysis will be completed to understand transport risk. Overall, our goal is horizon scanning which is defined by Roy et al. (2019) as “a systematic examination of potential threats and opportunities, within a given context, and likely future developments, which are at the margin of current thinking and planning.” The scans include pathway analyses and risk screening of species present at pathway origin points, with a focus on identifying species at high risk of being introduced, becoming established, spreading, and causing harm. We refined a list of 28 AIS from a list of hundreds based on characterizations of species’ invasiveness and species’ proximity to Alaska (USGS 2020; GBIF 2022). Next, we evaluated the relative invasiveness of individual species to create an initial AIS ranking. We sought to characterize habitat suitability of AIS by selecting variables that were continental in scale, covering North America to include Alaska as well as the lower 48 states comparing natural discharge, sub-basin average terrain slope (degrees), average silt fraction, average organic carbon, lithological class, and human footprint in sub-basin in 2009. We estimated AIS habitat suitability across the entire state of Alaska using the physiological tolerances of the AIS (Appendix 2). We also evaluated pathways and vectors for the introduction of AIS (Appendix 2). Many pathways and vectors considered did not meet the criteria for Alaska or freshwater systems. Of the 28 ranked species that we categorized as very high, high, and moderate levels of invasiveness; all three risk groups included fish and mollusks (Appendix 2). One commonality of the very high-invasiveness-ranked species was the availability of Ecological Risk Screening Summary documents (USFWS, 2022) produced by U.S. Fish and Wildlife Service (USFWS), except for the goldfish ( Carassius auratus ) and the New Zealand mudsnail ( Potamopyrgus antipodarum ). The Ecological Risk Screening Summary is now available for New Zealand mudsnails. In general, fish species often ranked very high or high in invasiveness and included sportfish and aquarium fish, suggesting the importance of pathways such as aquarium trade, fishing industry, intentional (but illegal) introductions of sportfishes and aquarium fishes for establishment. The technique we used for habitat suitability models necessitated aquatic environmental datasets that were continental in scale, which was often interpolated from very coarse resolution source data layers, particularly in Alaska. Better spatial data representing aquatic environments would likely improve this approach. While the lack of introductions in Alaska and nearby provinces and states is encouraging, the lack of occurrence data for the focal species also created complications for habitat suitability modeling. Despite the challenges, the habitat suitability models indicated limited suitability for warmwater species while some species, such as Brook trout (S alvelinus fontinalis ), have high habitat suitability across Alaska no matter what threshold approach is taken. Some environmental predictors were more important than others. Specifically, the most important predictor variable, ‘frost free days,’ was critical for 15 out of 28 species as expected due to harsh winter conditions in Arctic and Subarctic regions. The second most important predictor was ‘subbasin land surface runoff’, a variable that indicates the amount of discharge and runoff, while the third most important predictor was ‘snow cover’ another indication of winter conditions. Overall, the ability to understand the effect of future climate scenarios on the establishment of AIS was challenging. A detailed dataset of freshwater temperatures and water chemistry (e.g., pH, calcium) would greatly improve the ability to predict invasiveness of freshwater species to Alaska’s ecosystems on a regional basis. Future studies may benefit from a more focused geographic scope examining a group of subbasins or a regional basin rather than the entire state. These drainages could be selected based upon the mostly likely locations of introduction pathways. The two most prevalent pathway risks for AIS are in-state transfer and stowaways/contaminants. Although there are examples of introductions from other pathways, the risk is somewhat mitigated by Alaska’s climate and regulations. However, variable application of protocols for inspection and cleaning of fishing gear, watercraft, and other similar items while traveling into Alaska as well as transferring from waterbody to waterbody within the state creates a substantial risk in introducing invasive species. We plot cumulative invasive vulnerability for all subbasins and for the top 10% of subbasins (Appendix 3).

Alaska↗
USGS2018

Macrobenthic infaunal communities associated with deep‐sea hydrocarbon seeps in the northern Gulf of Mexico

There are thousands of seeps in the deep ocean worldwide; however, many questions remain about their contributions to global biodiversity and the surrounding deep‐sea environment. In addition to being globally distributed, seeps provide several benefits to humans such as unique habitats, organisms with novel genes, and carbon regulation. The purpose of this study is to determine whether there are unique seep macrobenthic assemblages, by comparing seep and nonseep environments, different seep habitats, and seeps at different depths and locations. Infaunal community composition, diversity, and abundance were examined between seep and nonseep background environments and among three seep habitats (i.e., microbial mats, tubeworms, and soft‐bottom seeps). Abundances were higher at seep sites compared to background areas. Abundance and diversity also differed among microbial mat, tubeworm, and soft‐bottom seep habitats. Although seeps contained different macrobenthic assemblages than nonseep areas, infaunal communities were also generally unique for each seep. Variability was 75% greater within communities near seeps compared to communities in background areas. Thus, high variability in community structure characterized seep communities rather than specific taxa. The lack of similarity among seep sites supports the idea that there are no specific infauna that can be used as indicators of seepage throughout the northern Gulf of Mexico, at least at higher taxonomic levels.

Marine Ecology↗
USGS2020

Source-tracking approach for detecting and identifying sources of wastewater in waters of Hawaiʻi

Elevated concentrations of nutrients and the fecal-indicator bacteria enterococci are occasionally detected in Hawai‘i’s surface waters by the State of Hawai‘i Department of Health Clean Water Branch. Management efforts to improve the water quality of surface waters are complicated by the fact that nutrients and enterococci can originate from several sources, including wastewater, animal waste, and soils. Wastewater often is the suspected source of nutrients and bacteria, but the source may not always be unequivocally identifiable from the Clean Water Branch’s routine monitoring efforts. This report—prepared in cooperation with the State of Hawai‘i Department of Health Clean Water Branch—describes a source-tracking approach for Hawai‘i that is meant to help investigators determine whether wastewater is present in the environment and where wastewater might be originating, if it is present. Wastewater sources include domestic wastewater entering the environment through on-site disposal systems and municipal wastewater entering the environment through leaky sewer systems or injection-well disposal systems. The source-tracking approach relies on the use of field-measured water properties and multiple chemical tracers of wastewater, including optical brighteners, nutrients, hydrogen and oxygen isotopes in water, nitrogen and oxygen isotopes in nitrate, organic waste compounds, and human-use pharmaceutical compounds. The source-tracking approach proposes the following sequence of steps for investigators to execute: (1) gather background information on the study area, (2) conduct trolling-instrument surveys of physical properties of surface water and identify groundwater-discharge locations, (3) collect water samples at reconnaissance sites and analyze the samples for detergent optical brighteners and specific conductance, (4) collect water samples at targeted sites and have appropriate laboratories analyze the samples for chemical tracers of wastewater, and (5) evaluate analytical results for chemical tracers of wastewater and conclude whether wastewater is present in sampled waters. The conclusions can guide management and stakeholder efforts to protect and improve the quality of Hawai‘i’s water resources.

Hawaii↗
USGS2023

Creek and quarry water quality at Pipestone National Monument and pilot study of pathogen detection methods in waterfall mist at Winnewissa Falls, Pipestone, Minnesota, 2018–19

Pipestone National Monument is a 301-acre site sacred to many Native American Tribes, providing cultural exhibits and walking trails to Pipestone Creek, Winnewissa Falls, and historical pipestone quarries for numerous visitors each year. However, the Minnesota Pollution Control Agency has determined turbidity and fecal coliform bacteria occur in Pipestone Creek in high enough numbers to be a potential health hazard. Concerns also were raised about exposure risk from waterfall mist to visitors and staff. The U.S. Geological Survey and the National Park Service collaborated on a study to collect 21 water-quality samples from 8 creek sites and 3 quarries in 2018 and analyzed them for over 250 water-quality parameters and contaminants. Additional samples were collected in August 2019 to assess the waterfall mists from Winnewissa Falls. Nutrient concentrations in the creek and quarries were elevated in 2018, indicating they are affected by agricultural inputs. All sample concentrations for nitrate and total nitrogen in Pipestone Creek exceeded Minnesota standards and U.S. Environmental Protection Agency nutrient criteria. Minnesota standards and U.S. Environmental Protection Agency nutrient criteria for total phosphorus also were exceeded in some of the quarry samples. Twenty of 210 micropollutants had measurable concentrations: 13 pesticides, 5 pharmaceuticals, and 2 other types of micropollutants. Atrazine, deethylatrazine, and metolachlor ethanesulfonic acid were detected in all 21 samples collected during the study. The five pharmaceuticals detected were acetaminophen, gabapentin, gemfibrozil, metformin, and oxycodone. Gabapentin (10 of 21 samples) and metformin (8 of 21 samples) were the most commonly detected pharmaceuticals. None of the detected micropollutant concentrations exceeded any Minnesota standards or U.S. Environmental Protection Agency aquatic life benchmarks, except the acute toxicity benchmark for nonvascular plants for atrazine. Two cyanotoxins, anatoxin-a and microcystin, were detected, but concentrations were below U.S. Environmental Protection Agency guidelines for swimming or recreation. Notably, total coliform, fecal coliform, and Escherichia coli were detected in all creek samples, and concentrations generally decreased downstream, suggesting contamination potentially occurred upstream from the monument. Mycobacterium avium ssp. paratuberculosis was not detected in any creek sediment samples but was detected in three water samples from the creek. Three organisms were detected in the 2019 water and mist sampling from Winnewissa Falls. Two of these organisms can cause illness in humans ( Cryptosporidium and Legionella ), and a third (ruminant Bacteroides ) is an indicator of manure contamination. Despite few samples, pathogen-positive water samples and air sampling demonstrated the feasibility and utility of the mist sampling approach outlined in this report.

Minnesota↗
USGS2013

U.S. Geological Survey ecosystems science strategy—Advancing discovery and application through collaboration

Executive Summary Ecosystem science is critical to making informed decisions about natural resources that can sustain our Nation’s economic and environmental well-being. Resource managers and policymakers are faced with countless decisions each year at local, regional, and national levels on issues as diverse as renewable and nonrenewable energy development, agriculture, forestry, water supply, and resource allocations at the urban-rural interface. The urgency for sound decisionmaking is increasing dramatically as the world is being transformed at an unprecedented pace and in uncertain directions. Environmental changes are associated with natural hazards, greenhouse gas emissions, and increasing demands for water, land, food, energy, mineral, and living resources. At risk is the Nation’s environmental capital, the goods and services provided by resilient ecosystems that are vital to the health and wellbeing of human societies. Ecosystem science—the study of systems of organisms interacting with their environment and the consequences of natural and human-induced change on these systems—is necessary to inform decisionmakers as they develop policies to adapt to these changes. This Ecosystems Science Strategy is built on a framework that includes basic and applied science. It highlights the critical roles that U.S. Geological Survey (USGS) scientists and partners can play in building scientific understanding and providing timely information to decisionmakers. The strategy underscores the connection between scientific discoveries and the application of new knowledge, and it integrates ecosystem science and decisionmaking, producing new scientific outcomes to assist resource managers and providing public benefits. We envision the USGS as a leader in integrating scientific information into decisionmaking processes that affect the Nation’s natural resources and human well-being. The USGS is uniquely positioned to play a pivotal role in ecosystem science. With its wide range of expertise, the Bureau can bring holistic, cross-scale, interdisciplinary capabilities to the design and conduct of monitoring, research, and modeling and to new technologies for data collection, management, and visualization. Collectively, these capabilities can be used to reveal ecological patterns and processes, explain how and why ecosystems change, and forecast change over different spatial and temporal scales. USGS science can provide managers with options and decision-support tools to use resources sustainably. The USGS has long-standing, collaborative relationships with the Department of the Interior (DOI) and other partners in the natural sciences, in both conducting science and applying the results. The USGS engages these partners in cooperative investigations that otherwise would lack the necessary support or be too expensive for a single bureau to conduct. The heart of this strategy is a framework for USGS ecosystems science that focuses on five long-term goals, which are seen as interconnected components that reinforce our vision of the USGS providing science that is at the forefront of decisionmaking: Improve understanding of ecosystem structure, function, and processes. The focus for this goal is an understanding of how ecosystems work, including the dynamics of species, their populations, interactions, and genetics, and how they change across spatial and temporal scales. Advance understanding of how drivers influence ecosystem change. The challenges here are explaining the drivers of ecosystem change, their spatio-temporal patterns, their uncertainties and interactions, and their influence on ecosystem processes and dynamics. Improve understanding of the services that ecosystems provide to society. Here the emphasis is on the measurement of environmental capital and ecosystem services, and the identification of sources and patterns of change in space and time. Develop tools, technologies, and capacities to inform decisionmaking about ecosystems. This includes developing new technologies and approaches for conducting applications-oriented ecosystem science. A principal challenge will be how to quantify uncertainty and incorporate it in decision analysis. Apply science to enhance strategies for management, conservation, and restoration of ecosystems. These challenges include development of novel approaches to monitoring, assessment, and restoration of ecosystems; new methods to address species of concern and communities at risk; and innovations in decision analysis and support to address imminent ecosystem changes or those that are underway. Closely integrated with the five goals are four strategic approaches that provide the path forward for the USGS Ecosystems Mission Area. These approaches cross-cut all of the goals and are seen as essential to the implementation of this strategy: Assess information needs for ecosystem science through enhanced partnerships. Work with the DOI and other agencies and institutions to identify, design, and implement priority decision-driven ecological research. Promote the use of interdisciplinary ecosystem science. Design and conduct interdisciplinary process-oriented research in ecosystem science. Enhance modeling and forecasting. Build models to forecast ecosystem change, assess future management scenarios, and reduce uncertainties through an adaptive learning process. Support decisionmaking. Use quantitative approaches to assess the vulnerabilities of ecosystems, habitats, and species, and evaluate strategies for adaptation, restoration, and sustainable management. Following the four strategic approaches are a set of proposed actions that represent a sampling of specific USGS activities that align with this strategy and that address the Nation’s most pressing environmental needs. The strategy emphasizes coordination of activities across the USGS mission areas pursuant to these goals. Ecosystem science is inherently interdisciplinary and requires a broad perspective that incorporates the biological and physical sciences, climate science, information technology, and scientific capacity in mission areas across the Bureau. With its emphasis on coordination, this strategy can provide a critical underpinning for integrated science efforts with scientists from multiple mission areas of the USGS working together. Of course, the USGS will continue to conduct discipline-specific and interdisciplinary investigations, and both will continue to be vital parts of the ecosystem science portfolio. Finally, the strategy stresses the importance of coordination with other Federal agencies and organizations in the natural resources community. The USGS collaborates with resource agencies in the DOI and other organizations throughout the world to meet societal needs for species and ecosystem management. Working with these agencies and organizations, the USGS will play a key role in guiding sound decisionmaking during the next decade by advancing the scientific foundation for sustaining the natural resources that diverse, productive, resilient ecosystems provide.

Circular↗
USGS2012

The U.S. Geological Survey Ecosystem Science Strategy, 2012-2022 - Advancing discovery and application through collaboration

Ecosystem science is critical to making informed decisions about natural resources that can sustain our Nation’s economic and environmental well-being. Resource managers and policy-makers are faced with countless decisions each year at local, state, tribal, territorial, and national levels on issues as diverse as renewable and non-renewable energy development, agriculture, forestry, water supply, and resource allocations at the urban-rural interface. The urgency for sound decision-making is increasing dramatically as the world is being transformed at an unprecedented pace and in uncertain directions. Environmental changes are associated with natural hazards, greenhouse gas emissions, and increasing demands for water, land, food, energy, mineral, and living resources. At risk is the Nation’s environmental capital, the goods and services provided by resilient ecosystems that are vital to the health and well-being of human societies. Ecosystem science—the study of systems of organisms interacting with their environment and the consequences of natural and human-induced change on these systems—is necessary to inform decision-makers as they develop policies to adapt to these changes. This Ecosystems Science Strategy is built on a framework that includes basic and applied science. It highlights the critical roles that USGS scientists and partners can play in building scientific understanding and providing timely information to decision-makers. The strategy underscores the connection between scientific discoveries and the application of new knowledge. The strategy integrates ecosystem science and decision-making, producing new scientific outcomes to assist resource managers and providing public benefits. The USGS is uniquely positioned to play an important role in ecosystem science. With its wide range of expertise, the agency can bring holistic, cross-scale, interdisciplinary capabilities to the design and conduct of monitoring, research, and modeling and to new technologies for data collection, management, and visualization. Collectively, these capabilities can be used to reveal ecological patterns and processes, explain how and why ecosystems change, and forecast change over different spatial and temporal scales. USGS science can provide managers with options and decision-support tools to use resources sustainably. The USGS has long-standing, collaborative relationships with the DOI and other partners in the natural sciences, in both conducting science and its application. The USGS engages these partners in cooperative investigations that otherwise would lack the necessary support or be too expensive for a single bureau to conduct. The heart of this strategy is a framework and vision for USGS ecosystems science that focuses on five long-term goals, which are seen as interconnected and reinforcing components: • Improve understanding of ecosystem structure, function, and processes. The focus for this goal is an understanding of how ecosystems work, including the dynamics of species, their populations, interactions, and genetics, and how they change across spatial and temporal scales. • Advance understanding of how drivers influence ecosystem change. The challenges here are explaining the drivers of ecosystem change, their spatio-temporal patterns, their uncertainties and interactions, and their influence on ecosystem processes and dynamics. • Improve understanding of the services that ecosystems provide to society. Here the emphasis is on the measurement of environmental capital and ecosystem services, and the identification of sources and patterns of change in space and time. • Develop tools, technologies, and capacities to inform decision-making about ecosystems. This includes developing new technologies and approaches for conducting applications-oriented ecosystem science. A principal challenge will be how to quantify uncertainty and incorporate it in decision analysis. • Apply science to enhance strategies for management, conservation, and restoration of ecosystems. These challenges include development of novel approaches to monitoring, assessment, and restoration of ecosystems; new methods to address species of concern and communities at risk; and innovations in decision analysis and support to address imminent ecosystem changes or those that are underway. Closely integrated with the five goals are four strategic approaches that provide the path forward for the USGS Ecosystems Mission Area. These approaches cross-cut all of the goals and are seen as essential to the implementation of this strategy: • Assess information needs for ecosystem science through enhanced partnerships. Work with the DOI and other agencies and institutions to identify, design, and implement priority decision-driven ecological research. • Promote the use of interdisciplinary ecosystem science. Design and conduct interdisciplinary process-oriented research in ecosystem science. • Enhance modeling and forecasting. Build models to forecast ecosystem change, assess future management scenarios, and reduce uncertainties through an adaptive learning process. • Support decision-making. Use quantitative approaches to assess the vulnerabilities of ecosystems, habitats, and species, and evaluate strategies for adaptation, restoration, and sustainable management. Following the strategic approaches are a set of proposed actions that represent a sampling of specific activities that align with this strategy and that address the Nation’s most pressing environmental needs. The strategy emphasizes coordination of activities across the USGS mission areas pursuant to these goals. Ecosystem science is inherently interdisciplinary and requires a broad perspective that incorporates the biological and physical sciences, climate science, information technology, and scientific capacity in mission areas across the Bureau. With its emphasis on coordination, this strategy can provide a critical underpinning for integrated science efforts with scientists from multiple mission areas of the USGS working together. Of course, the USGS will continue to conduct both discipline-specific and interdisciplinary investigations, and both will continue to be vital parts of the ecosystem science portfolio. Finally, the strategy stresses the importance of coordination with other Federal agencies and organizations in the natural resources community. The USGS collaborates with resource agencies in the DOI and other organizations throughout the world to meet societal needs for species and ecosystem management. Working with these agencies and organizations, the USGS will play a key role over the next decade in advancing the scientific foundation for sustaining the natural resources that diverse, productive, resilient ecosystems provide.

Open-File Report↗
USGS2025

Tapwater-contaminant mixtures and risk in a biofuel-facility impacted private-well community

We assessed private-well drinking water (DW) at the point of use ( i.e. , tapwater, TW) within a rural Nebraska community around a state-closed biofuel facility, which used pesticide-treated corn seed as feedstock for ethanol production. Organic (485), inorganic (34), and microbial (13) analytes were assessed at 15 locations in June 2022, to evaluate the relative contribution of facility-consistent pesticides (seed-treatment fungicides and insecticides) to overall TW-contaminant exposures and predicted human-health risks. Thirty-three organics (12 pesticides) and 28 inorganics were detected, the former including the fungicide sedaxane, insecticide chlorantraniliprole, and multiple neonicotinoid insecticides/degradates, all consistent with seed treatment and respective biofuel-facility waste. Assessment of pesticides only at extant point-of-use (POU) treatment taps at three sites demonstrated complete elimination of all TW-pesticide detections. Based on detection of maximum pesticide concentrations in a home located downstream along a creek capturing facility runoff, pesticides only were assessed in January 2023 again at this home and at three adjacent locations, confirming results at the former and documenting decreasing TW-pesticide concentrations, including neonicotinoids, with increasing distance from the creek. Human-health DW benchmarks are not available for many detected pesticides, including the detected fungicide and insecticides, but precautionary screening levels were exceeded frequently due to multiple inorganics. The results indicate that exposures to multiple (median: 4.5; range: 1–7) co-occurring TW contaminants of potential human-health concern are common, warranting consideration of point-of-entry or POU treatment(s) throughout the community to reduce or eliminate unrecognized exposures to TW contaminants, including facility-associated pesticides in down-gradient locations. More broadly, results emphasize the importance of continued characterization of private-TW exposures, employing a environmentally informative analytical scope, to identify and mitigate risks of unrecognized exposures in private-well-dependent rural communities.

Nebraska↗
USGS1994

Life-history organization of Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) in Yellowstone Lake

Life-history organization of the cutthroat trout (Oncorhynchus clarki) may be viewed at various levels, including species, subspecies, metapopulation, population, or individual. Each level varies in spatial scale and temporal persistence, and components at each level continually change with changes in environment. Cutthroat trout are widely distributed throughout the western United States, occurring in such diverse environments as coastal rivers of the Pacific Northwest and interior streams of the Great Basin. During its evolution the species has organized into 14 subspecies with many different life-history characteristics and habitat requirements. Within subspecies, organization is equally complex. For example, life-history traits, such as average size and age, migration strategy, and migration timing, vary among individual spawning populations of Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) in tributary streams of Yellowstone Lake. Understanding the effects of human perturbations on life-history organization is critical for management of the cutthroat trout and other polytypic salmonid species. Loss of diversity at any hierarchical level jeopardizes the long-term ability of the species to adapt to changing environments, and it may also lead to increased fluctuations in abundance and yield and increase the risk of extinction.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS2021

Preserving soil organic carbon in prairie wetlands of central North America

Wetlands of the Prairie Pothole Region (PPR) in the Great Plains of central North America are numerous, densely distributed, and have highly productive plant and animal communities (Photo 49). When in a natural, unaltered condition, these wetlands store relatively large amounts of organic carbon in their soils (Photo 50). Human alterations, such as extensive drainage and land-use conversion for agriculture (Figure 7), have been linked with the loss of soil organic carbon (SOC) and associated emission of carbon dioxide (CO 2 ), as well as impacts to other ecosystem services provided by these wetlands, such as wildlife and waterfowl habitat, plant biodiversity, flood mitigation, groundwater recharge, nutrient removal and retention, and recreation (Gleason et al., 2011). It has been estimated that more than half of the wetlands of the PPR have been lost due to drainage and other disturbances, with losses approaching 90 percent in some areas (Dahl, 2014; Serran et al., 2018). The goal of this case study was to identify land-management strategies that are consistent with maintaining and increasing SOC stocks of PPR wetlands. Two overarching strategies generally are promoted to preserve and enhance SOC stocks of PPR wetlands: avoided drainage and rewetting or restoration. Avoided drainage involves protecting natural, unaltered wetlands from impacts of human actives with the purpose of retaining wetland functions and services such as carbon storage. Rewetting or restoration involves reestablishing natural hydrology and land use with the purpose of enhancing wetland functions and services that were previously lost due to human activities. Avoided drainage provides immediate and long-lasting benefits, while replenishing SOC through rewetting and restoration requires many decades. Both strategies are associated with higher methane (CH 4 ) emissions but lower CO 2 and nitrous oxide (N 2 O) emissions.

Alberta, Iowa, Manitoba, Minnesota, Montana, North↗