USGS Science⌕ Search

SEARCH · USGS Science

Results for “Environmental Monitoring and Assessment”

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 559 records · Page 31Linked to original sources
USGS2020

Understanding the relationship between stream metabolism and biological assemblages

Biological assemblages are commonly used for assessing stream health, but there is increased interest among the freshwater research community in incorporating measures of stream function, such as metabolism, to strengthen stream-health assessments. Presently, there is limited information about the relationships between stream metabolism and biological assemblages, along with the measurement period required to relate metabolism with stream biota. Our study assessed which environmental factors explained stream metabolism and to what degree stream metabolism and minimum dissolved oxygen (DOmin) were related to invertebrate and fish metrics in streams distributed across several regions of the United States. Furthermore, we evaluated the number of metabolism monitoring days required for maximizing the ability to detect relationships between stream metabolism and biological assemblage metrics. We sampled 17 sites distributed among reference, agricultural, and urban areas for stream metabolism, nutrients, habitat, and biological assemblages (invertebrates and fishes). Overall, sites were heterotrophic with gross primary production (GPP) and ecosystem respiration (ER) related primarily to days since last high flow, canopy cover, maximum water temperature, and total phosphorus. DOmin was related to days since last high flow, canopy cover, and maximum water temperature. We were unable to determine a clear statistical relationship between invertebrate metrics (invertebrate richness; Ephemeroptera, Plecoptera, and Trichoptera richness; and scraper-taxa richness) and GPP, ER, or DOmin. In contrast, we found that 2 fish-assemblage metrics were associated with stream metabolism and DOmin. A fish multimetric index (FMMI) was negatively correlated with GPP ( r = −0.5, p = 0.048) and positively correlated with DOmin ( r = 0.47, p = 0.06). Percentage of omnivorous fish taxa was positively correlated with GPP ( r = 0.72, p = 0.001) and ER ( r = 0.55, p = 0.02) and negatively correlated with DOmin ( r = −0.67, p = 0.003). The lack of detected relationships for most of the biological-assemblage metrics with stream metabolism may be partially due to 1 or more factors, including high variability, low sample size, limited range in metabolism values, assemblage metrics used, and geographic distribution of sites. Comparing stream-metabolism measurement periods (in days) to biological-assemblage metrics indicated that optimum correlations occurred at 2 d for DOmin, 3 d for GPP, and 14 d for ER. Although our study found limited relationships of stream metabolism and DOmin with biological assemblages, future studies should consider a larger sample size (≥30), 14-d or longer metabolism measurement period, and assessment of other taxa-specific or assemblage metrics.

Freshwater Science↗
USGS2009

Analysis of Water-Quality Trends for Selected Streams in the Water Chemistry Monitoring Program, Michigan, 1998-2005

In 1998, the Michigan Department of Environmental Quality and the U.S. Geological Survey began a long-term monitoring program to evaluate the water quality of most watersheds in Michigan. Major goals of this Water-Chemistry Monitoring Program were to identify streams exceeding or not meeting State or Federal water-quality standards and to assess if constituent concentrations reflecting water quality in these streams were increasing or decreasing over time. As part of this program, water-quality data collected from 1998 to 2005 were analyzed to identify potential trends. Sixteen water-quality constituents were analyzed at 31 sites across Michigan, 28 of which had sufficient data to analyze for trends. Trend analysis on the various water-quality data was done using the uncensored Seasonal Kendall test within the computer program ESTREND. The most prevalent trend detected throughout the state was for chloride. Chloride trends were detected at 8 of the 28 sites; trends at 7 sites were increasing and the trend at 1 site was decreasing. Although no trends were detected for various nitrogen species or phosphorus, these constituents were detected at levels greater than the U.S. Environmental Protection Agency recommendations for nutrients in water. The results of the trend analysis will help to establish a baseline to evaluate future changes in water quality in Michigan streams.

Scientific Investigations Report↗
USGS2013

Autumn monitoring of resident avifauna on Guana Island, British Virgin Islands

Although the Caribbean region is considered a biodiversity hotspot and a priority for ecological conservation efforts, little information exists on population trends of West Indian landbirds. We combined avian survey data collected from three studies spanning a 16-year period on a small island with a minimal human presence in the British Virgin Islands. Although abundances varied among surveys, the same species were detected with rare exceptions. Despite stability in species composition, the resident landbirds were variable in their individual detectabilities. Survey detections relatively mirrored net captures for some species, but are quite different for others. We suspect that this is likely due to differences in detectability due to species-specific behaviors mediated by environmental conditions, such as rainfall, during the month or months prior to our surveys. It is difficult to assess the influence of timing or amount of precipitation on bird detections rates among our surveys due to a lack of consistent collection of location-specific weather data in the British Virgin Islands. Our study suggests monitoring efforts conducted in concert with collection of site-specific climate data would facilitate improved interpretation of survey data and a better understanding of avian species response to climate mediated changes.

Ornitologia Neotropical↗
USGS2024

Broad scale community-level larval fish survey of southern Lake Erie

The early-life history stages of fish are sensitive to environmental change and therefore can indicate habitat quality as well as help predict recruitment of resident and transient fishes. In 2019, as part of the Lake Erie Cooperative Science and Monitoring Initiative, we conducted a lake-wide assessment of the ichthyoplankton community in U.S. nearshore waters and international offshore waters. The goal of this work was to characterize the larval fish community across the lake and assess species composition, phenology, and distribution of larvae. Ichthyoplankton were sampled weekly using bongo nets at ports beginning at the Detroit River and along the southern shore of Lake Erie to Dunkirk, NY, and less frequently in the Niagara River and offshore areas. Larval fish were present from March 26 through August 29, 2019. The first taxon to emerge was Lake Whitefish in all basins, followed by Walleye, Yellow Perch, and catostomids, depending on port. Mean total density peaked in mid-June due to high catches of Gizzard Shad, Morone spp., and Freshwater Drum in the western basin. Few fish were collected in the offshore sites. Taxa richness, diversity, and larval density were higher in the western basin and lower in the central and eastern basins, generally following the productivity gradient. This was the first study to provide a comprehensive community assessment of the ichthyoplankton community of Lake Erie and can provide a baseline to assess future change, especially in community composition or phenology, of larvae which are likely to respond to climate and habitat change.

Lake Erie↗
USGS1998

Assessment of the potential for biodegradation of petroleum hydrocarbons in the Railroad Industrial Area, Fairbanks, Alaska

Many technologies for the clean-up of petroleum-hydrocarbon contaminated sites depend on microbial degradation of the pollutant. In these technologies the site may be modified to enhance microbial activity, or may simply be monitored for naturally occurring microbial activity. In either case, an important aspect of site assessment for these technologies is to determine if the microorganisms present at the site have the potential to break down contaminants under the prevailing environmental conditions. We examined the numbers and activity of hydrocarbon-degrading microorganisms in ground water collected from petroleum-hydrocarbon contaminated and uncontaminated wells at the Railroad Industrial Area near Fairbanks, Alaska. We found that the population of gasoline-degrading microorganisms in ground water was correlated to the degree of contamination by benzene, toluene, ethylbenzene and xylenes (BTEX). We also found that these organisms could actively mineralize these types of compounds in laboratory mineralization assays. Increasing temperature and adding nutrients both enhanced the rate of mineralization in the laboratory, but measurable degradation still occurred under conditions similar to those found in the field. Dissolved oxygen in ground water at this site ranged from 0 to 3.6 milligrams per liter. Therefore, oxygen may not always be available to microorganisms as a terminal electron acceptor. Preliminary geochemical evidence from the field indicates that alternative electron acceptors such as Fe(III), sulfate, or nitrate may be used, contributing to degradation of contaminants at this site.

Open-File Report↗
USGS2010

Review of Trace-Element Field-Blank Data Collected for the California Groundwater Ambient Monitoring and Assessment (GAMA) Program, May 2004-January 2008

Trace-element quality-control samples (for example, source-solution blanks, field blanks, and field replicates) were collected as part of a statewide investigation of groundwater quality in California, known as the Priority Basins Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basins Project is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB) to assess and monitor the quality of groundwater resources used for drinking-water supply and to improve public knowledge of groundwater quality in California. Trace-element field blanks were collected to evaluate potential bias in the corresponding environmental data. Bias in the environmental data could result from contamination in the field during sample collection, from the groundwater coming into contact with contaminants on equipment surfaces or from other sources, or from processing, shipping, or analyzing the samples. Bias affects the interpretation of environmental data, particularly if any constituents are present solely as a result of extrinsic contamination that would have otherwise been absent from the groundwater that was sampled. Field blanks were collected, analyzed, and reviewed to identify and quantify extrinsic contamination bias. Data derived from source-solution blanks and laboratory quality-control samples also were considered in evaluating potential contamination bias. Eighty-six field-blank samples collected from May 2004 to January 2008 were analyzed for the concentrations of 25 trace elements. Results from these field blanks were used to interpret the data for the 816 samples of untreated groundwater collected over the same period. Constituents analyzed were aluminum (Al), antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), boron (B), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), lead (Pb), lithium (Li), manganese (Mn), mercury (Hg), molybdenum (Mo), nickel (Ni), selenium (Se), silver (Ag), strontium (Sr), thallium (Tl), tungsten (W), uranium (U), vanadium (V), and zinc (Zn). The detection frequency and the 90th percentile concentration at greater than 90 percent confidence were determined from the field-blank data for each trace element, and these results were compared to each constituent's long-term method detection level (LT-MDL) to determine whether a study reporting level (SRL) was necessary to ensure that no more than 10 percent of the detections in groundwater samples could be attributed solely to contamination bias. Only two of the trace elements analyzed, Li and Se, had zero detections in the 86 field blanks. Ten other trace elements (Sb, As, Be, B, Cd, Co, Mo, Ag, Tl, and U) were detected in fewer than 5 percent of the field blanks. The field-blank results for these constituents did not necessitate establishing SRLs. Of the 13 constituents that were detected in more than 5 percent of the field blanks, six (Al, Ba, Cr, Mn, Hg, and V) had field-blank results that indicated a need for SRLs that were at or below the highest laboratory reporting levels (LRL) used during the sampling period; these SRLs were needed for concentrations between the LT-MDLs and LRLs. The other seven constituents with detection frequencies above 5 percent (Cu, Fe, Pb, Ni, Sr, W, and Zn) had field-blank results that necessitated SRLs greater than the highest LRLs used during the study period. SRLs for these seven constituents, each set at the 90th percentile of their concentrations in the field blanks, were at least an order of magnitude below the regulatory thresholds established for drinking water for health or aesthetic purposes; therefore, reporting values below the SRLs as less than or equal to (=) the measured value would not prevent the identification of values greater than the drinking-water thresholds. The SRLs and drinking-water thresholds, respectively, for these 7 trace elements are Cu (1.7 ?g/L and 1,300

Scientific Investigations Report↗
USGS2021

Assessment of water quality and discharge in the Herring River, Wellfleet, Massachusetts, November 2015 to September 2017

The U.S. Geological Survey, Cape Cod National Seashore of the National Park Service, and Friends of Herring River cooperated from 2015 to 2017 to assess nutrient concentrations and fluxes across the ocean-estuary boundary at a dike on the Herring River in Wellfleet, Massachusetts. The purpose of this assessment was to characterize environmental conditions prior to a future removal of the dike, which has restricted saltwater inputs into the Herring River watershed for more than 100 years. Water temperature, dissolved oxygen, pH, and specific conductance were monitored continuously, and flow-weighted composite samples were collected approximately twice per month at the ocean-estuary boundary. Bidirectional discharge was computed for the U.S. Geological Survey Herring River at Chequessett Neck Road at Wellfleet, Massachusetts, streamgage (011058798) by using a stage-area rating and index-velocity ratings developed with acoustic Doppler current profile measurements made upstream and downstream from the dike. LOADEST regression modeling software was used to estimate nutrient fluxes (loads) from composite, paired nutrient concentration and discharge data in conjunction with continuous discharge data. Temperature, dissolved oxygen, pH, and specific conductance were also monitored continuously on two tributaries to the Herring River, Pole Dike Creek and Bound Brook, from late-May 2016 to mid-June 2017. Composite or discrete water samples were collected from the tributaries approximately twice per month in most months from late-May 2016 to mid-June 2017 and analyzed for total nitrogen, total phosphorus, and dissolved organic carbon. Flow-weighted concentrations of ammonium, nitrate, and total nitrogen on the Herring River at the dike on the ebb tide generally varied between 0.01 and 0.1, 0.003 and 0.03, and 0.3 and 0.7 milligram per liter as nitrogen, respectively. Flow-weighted concentrations of orthophosphate, total dissolved phosphorus, and total phosphorus generally varied between 0.002 and 0.02, 0.003 and 0.06, and 0.03 and 0.1 milligram per liter as phosphorus, respectively, on the ebb tide. Flow-weighted concentrations of silicate and dissolved organic carbon on the ebb tide generally varied between 0.08 and 3.0 milligrams per liter of silica (silicon dioxide), and 1.7 and 5.6 milligrams per liter of carbon, respectively. Ebb tide concentrations of nitrate were highest in winter and lowest in summer. By contrast, ebb tide concentrations of phosphorus species were highest in late summer and early fall and lowest in winter. Silica and dissolved organic carbon did not exhibit systematic variation in seasonal concentrations. There was uncertainty in estimates of nutrient fluxes, but the LOADEST-estimated fluxes indicated that annual (and in almost all cases seasonal) exports (ebb tides) exceeded inputs (flood tides). Ebb tide concentrations of ammonium, nitrate, total nitrogen, and silica were positively correlated with antecedent cumulative 7-day precipitation.

Massachusetts↗
USGS2024

Genetic analysis of harvest samples reveals population structure in a highly mobile generalist carnivore

Delineating wildlife population boundaries is important for effective population monitoring and management. The bobcat ( Lynx rufus ) is a highly mobile generalist carnivore that is ecologically and economically important. We sampled 1225 bobcats harvested in South Dakota, USA (2014–2019), of which 878 were retained to assess genetic diversity and infer population genetic structure using 17 microsatellite loci. We assigned individuals to genetic clusters ( K ) using spatial and nonspatial Bayesian clustering algorithms and quantified differentiation ( F ST and GST″ ) among clusters. We found support for population genetic structure at K = 2 and K = 4, with pairwise F ST and GST″ values indicating weak to moderate differentiation, respectively, among clusters. For K = 2, eastern and western clusters aligned closely with historical bobcat management units and were consistent with a longitudinal suture zone for bobcats previously identified in the Great Plains. We did not observe patterns of population genetic structure aligning with major rivers or highways. Genetic divergence observed at K = 4 aligned roughly with ecoregion breaks and may be associated with environmental gradients, but additional sampling with more precise locational data may be necessary to validate these patterns. Our findings reveal that cryptic population structure may occur in highly mobile and broadly distributed generalist carnivores, highlighting the importance of considering population structure when establishing population monitoring programs or harvest regulations. Our study further demonstrates that for elusive furbearers, harvest can provide an efficient, broad-scale sampling approach for genetic population assessments.

South Dakota↗
USGS2023

Final report: A novel monitoring framework to assess intertidal biodiversity in mixed coarse substrate habitats across the Boston Harbor Islands

The Boston Harbor Islands National Recreation Area (BOHA) is at high risk to the impacts of sea-level rise (SLR) and erosion from coastal storms. In June 2021, the National Trust for Historic Preservation listed the islands as one of America’s 11 Most Endangered Historic Places due to climate change. BOHA partners have been working to find climate adaptive solutions to protect and sustain critical ecological and cultural resources on the islands. A range of coastal adaptation efforts are currently under consideration including increased shoreline armoring and nature-based adaptation solutions. Any action taken in the coastal zone will require an assessment of environmental and ecological communities that could potentially be impacted by disturbance caused by restoration or adaptation projects. The primary goals of the initial phase of this project were to: 1) synthesize occurrence and distribution records of biodiversity living in and using mixed coarse substrate habitats of the intertidal zone of the Boston Harbor Islands; and 2) identify and compile potential methods to develop a standard and repeatable monitoring protocol to track changes (natural or anthropogenic) in intertidal biodiversity over time and across locations; and 3) conduct preliminary site scoping of target islands to identify locations for collecting new baseline data. A biodiversity inventory list was compiled, showing a total of 451 unique species were observed in BOHA between 1861-2020. Of this list, 55 species (invertebrates: 47; algae: 8) were considered nonindigenous species; a watchlist was also developed to help BOHA partners identify potential future invaders that could colonize and impact intertidal communities due to ongoing climate change or disturbance events. Native species observed in BOHA were evaluated using existing conservation frameworks and climate vulnerability information to prioritize species at greatest risk from anthropogenic and environmental stressors for future actions. Lastly, site scoping activities during 2021 identified three types of sites for future intertidal monitoring initiatives: (1) sites with relatively high biodiversity and foundational species, (2) erosional sites near cultural areas of importance to NPS, and (3) sites with generic (common across islands) biodiversity. Overall results are anticipated to help the NPS and BOHA partners identify a suite of species and sites for future monitoring given anticipated adaptation projects and ongoing changes due to SLR, coastal storms and other stressors.

Massachusetts↗
USGS2003

Use of retrospective data to assess ecotoxicological monitoring needs for terrestrial vertebrates residing in Atlantic coast estuaries

The “Contaminant Exposure and Effects–Terrestrial Vertebrates” (CEE-TV) database contains 4,336 records of ecotoxicological information for free-ranging amphibians, reptiles, birds, and mammals residing in Atlantic and Florida Gulf coast estuaries and their drainages. To identify spatial data gaps, those CEE-TV records for which the specific study location were known ( n =2,740) were combined with watershed and wildlife management unit boundaries using Geographic Information Systems software. The US Environmental Protection Agency's Index of Watershed Indicators (IWI), which classifies watersheds based on water quality and their vulnerability to pollution, was used to prioritize these data gaps. Of 136 watersheds in the study area, 15 that are classified by the IWI as having water quality problems or high vulnerability to pollution lacked terrestrial vertebrate ecotoxicological monitoring or research in the past decade. Older studies within some of these watersheds documented high levels of contaminants in wildlife tissues. Of 90 National Wildlife Refuge units, 42 without current data fall within watersheds of concern. Of 40 National Park units larger than 1 km 2 , 17 without current data fall within watersheds of concern. Issues encountered in this analysis highlighted the need for spatially and temporally replicated field monitoring programs that utilize random sampling. Without data from such studies, it will be difficult to perform unbiased assessments of regional trends in contaminant exposure and effects in terrestrial vertebrates.

Ecotoxicology↗
USGS2012

Seasonal activity and morphological changes in martian gullies

Recent studies of martian dune and non-dune gullies have suggested a seasonal control on present-day gully activity. The timing of current gully activity, especially activity involving the formation or modification of channels (which commonly have been taken as evidence of fluvial processes), has important implications regarding likely gully formation processes and necessary environmental conditions. In this study, we describe the results of frequent meter-scale monitoring of several active gully sites by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter (MRO). The aim is to better assess the scope and nature of current morphological changes and to provide improved constraints on timing of gully activity on both dune and non-dune slopes. Our observations indicate that (1) gully formation on Mars is ongoing today and (2) the most significant morphological changes are strongly associated with seasonal frost and defrosting activity. Observed changes include formation of all major components of typical gully landforms, although we have not observed alcove formation in coherent bedrock. These results reduce the need to invoke recent climate change or present-day groundwater seepage to explain the many martian gullies with pristine appearance.

Icarus↗
USGS2017

A record of change - Science and elder observations on the Navajo Nation

A Record of Change - Science and Elder Observations on the Navajo Nation is a 25-minute documentary about combining observations from Navajo elders with conventional science to determine how tribal lands and culture are affected by climate change. On the Navajo Nation, there is a shortage of historical climate data, making it difficult to assess changing environmental conditions. This video reveals how a team of scientists, anthropologists, and translators combined the rich local knowledge of Navajo elders with recent scientific investigation to effectively document environmental change. Increasing aridity and declining snowfall in this poorly monitored region of the Southwest are accompanied by declining river flow and migrating sand dunes. The observations of Navajo elders verify and supplement this record of change by informing how shifting weather patterns are reflected in Navajo cultural practices and living conditions.

Navajo Nation↗
USGS2025

Experimental evaluation of Eastern box turtle (Terrapene carolina carolina) detectability in visual search surveys

Understanding how detection probability varies over time, space, or in response to measurable covariates is important to inform the monitoring and assessment of many species. A standard model to understand detectability, the availability/perception model, admits that detection probability is the composite of two components: availability and ability of surveyors to detect the target. Availability is largely affected by environmental and behavioral factors, whereas perception is primarily affected by attributes of individual observers and survey protocols, and thus can potentially be partially controlled by survey design. We designed and implemented a field study to understand the perception component of detection for Eastern Box Turtles ( Terrapene carolina carolina ) using visual encounter surveys. We obtained and deployed museum specimens of Eastern Box Turtle shells and subjected them to visual search surveys by observers in realistic field situations. Overall, about 50% of the box turtle shells were detected by observers, including 41.5% in what we categorized as partially visible and 63.0% as fully visible. There were significant differences among observers, which may be due to observer-specific variation in search technique; the observers varied in how well they achieved the protocol guidance. Therefore, in visual search surveys, care in study design and analysis should be taken to account for variation in perception to determine detectability, as our study suggests 37% of perceptible targets are missed by surveyors.

Maryland↗
USGS2022

Getting ahead of flash drought: From early warning to early action

Flash droughts, characterized by their unusually rapid intensification, have garnered increasing attention within the weather, climate, agriculture, and ecological communities in recent years due to their large environmental and socioeconomic impacts. Because flash droughts intensify quickly, they require different early warning capabilities and management approaches than are typically used for slower-developing “conventional” droughts. In this essay, we describe an integrated research-and-applications agenda that emphasizes the need to reconceptualize our understanding of flash drought within existing drought early warning systems by focusing on opportunities to improve monitoring and prediction. We illustrate the need for engagement among physical scientists, social scientists, operational monitoring and forecast centers, practitioners, and policy-makers to inform how they view, monitor, predict, plan for, and respond to flash drought. We discuss five related topics that together constitute the pillars of a robust flash drought early warning system, including the development of 1) a physically based identification framework, 2) comprehensive drought monitoring capabilities, and 3) improved prediction over various time scales that together 4) aid impact assessments and 5) guide decision-making and policy. We provide specific recommendations to illustrate how this fivefold approach could be used to enhance decision-making capabilities of practitioners, develop new areas of research, and provide guidance to policy-makers attempting to account for flash drought in drought preparedness and response plans.

Bulletin of American Meteorological Society (BAMS)↗
USGS2016

Integrating subsistence practice and species distribution modeling: assessing invasive elodea’s potential impact on Native Alaskan subsistence of Chinook salmon and whitefish

Alaska has one of the most rapidly changing climates on earth and is experiencing an accelerated rate of human disturbance, including resource extraction and transportation infrastructure development. Combined, these factors increase the state’s vulnerability to biological invasion, which can have acute negative impacts on ecological integrity and subsistence practices. Of growing concern is the spread of Alaska’s first documented freshwater aquatic invasive plant Elodea spp. (elodea). In this study, we modeled the suitable habitat of elodea using global and state-specific species occurrence records and environmental variables, in concert with an ensemble of model algorithms. Furthermore, we sought to incorporate local subsistence concerns by using Native Alaskan knowledge and available statewide subsistence harvest data to assess the potential threat posed by elodea to Chinook salmon ( Oncorhynchus tshawytscha ) and whitefish ( Coregonus nelsonii ) subsistence. State models were applied to future climate (2040–2059) using five general circulation models best suited for Alaska. Model evaluations indicated that our results had moderate to strong predictability, with area under the receiver-operating characteristic curve values above 0.80 and classification accuracies ranging from 66 to 89 %. State models provided a more robust assessment of elodea habitat suitability. These ensembles revealed different levels of management concern statewide, based on the interaction of fish subsistence patterns, known spawning and rearing sites, and elodea habitat suitability, thus highlighting regions with additional need for targeted monitoring. Our results suggest that this approach can hold great utility for invasion risk assessments and better facilitate the inclusion of local stakeholder concerns in conservation planning and management.

Alaska↗
USGS2010

Policies and practices of beach monitoring in the Great Lakes, USA: a critical review

Beaches throughout the Great Lakes are monitored for fecal indicator bacteria (typically Escherichia coli) in order to protect the public from potential sewage contamination. Currently, there is no universal standard for sample collection and analysis or results interpretation. Monitoring policies are developed by individual beach management jurisdictions, and applications are highly variable across and within lakes, states, and provinces. Extensive research has demonstrated that sampling decisions for time, depth, number of replicates, frequency of sampling, and laboratory analysis all influence the results outcome, as well as calculations of the mean and interpretation of the results in policy decisions. Additional shortcomings to current monitoring approaches include appropriateness and reliability of currently used indicator bacteria and the overall goal of these monitoring programs. Current research is attempting to circumvent these complex issues by developing new tools and methods for beach monitoring. In this review, we highlight the variety of sampling routines used across the Great Lakes and the extensive body of research that challenges comparisons among beaches. We also assess the future of Great Lakes monitoring and the advantages and disadvantages of establishing standards that are evenly applied across all beaches.

Great Lakes↗
USGS2026

Investigation of drivers and sources of potential harmful algal blooms in Lake Anna, Virginia, 2023-24

Algal blooms in freshwater reservoirs are an increasing concern because of the risk to aquatic ecosystem health, recreational use, and water quality. Among the taxa that comprise an algal bloom, cyanobacteria are of particular concern due to the potential to produce toxic compounds which can cause acute and chronic illness in humans if ingested through contaminated water or shellfish. When toxins are above a toxin-specific threshold in the water column, the Commonwealth of Virginia categorizes the bloom as a harmful algal bloom (HAB), distinguishing it from an algal bloom without toxins present. Toxins are of particular concern in bodies of water which serve as major recreational areas, such as Lake Anna in central Virginia. Lake Anna is a 27 km-long and 47 km2 reservoir in central Virginia. Since the Commonwealth of Virginia revised the HAB monitoring framework in 2018, algal bloom advisories for potentially toxigenic blooms have been issued in the western, riverine zone of the reservoir. There were detections of microcystin and anatoxin production but no detections of cylindrospermopsin and saxitoxin production in Lake Anna; however, toxin concentrations were low, at values less than 0.65 µg/L. In 2023, the U.S. Geological Survey, in cooperation with Virginia Department of Environmental Quality, initiated a 19-month intensive and extensive study of western Lake Anna and its tributaries (North Anna River and Pamunkey Creek) to (1) characterize the algal community, biomass, and toxin production; (2) identify potential drivers leading to algal bloom initiation, persistence, and decline; and (3) assess the primary sources of the drivers contributing to algal blooms. Continuous and discrete monitoring of water quality within the lake, watershed inputs, meteorological conditions, and algal communities were monitored. Multiple modeling scenarios identified that the formation and persistence of algal blooms in Lake Anna are driven by interactions among chemical, macro- and micronutrient, and physical factors. Key drivers include total nitrogen, total phosphorus, water temperature, suspended sediment concentration, wind speed, copper, iron, molybdenum, nickel, sodium, and alkalinity. During this study, winter stormflow events delivered the highest loading of macro- and micronutrients from the tributaries to the lake. The lake is a sink for these nutrients in the water column or in the lake-bed sediments. During high-occupancy and recreation periods on the lake in the summer months, boating activity can promote internal loading by the resuspension of the lake-bed sediments, thereby increasing the nutrient availability for algal uptake. Thermal stratification and hypoxic conditions were observed, which can contribute to the passive release of nutrients into the water column, further facilitating algal bloom proliferation. These processes may create a positive feedback loop that supports the formation, persistence, and annual recurrence of algal blooms in the western region of Lake Anna. Continued water-quality monitoring of early warning indicators may improve the detection and forecasting of algal growth in the lake and help managers proactively manage water quality and algal growth.

EarthArXiv↗
USGS1999

Pesticides in stream sediment and aquatic biota: distribution, trends, and governing factors

More than 20 years after the ban of DDT and other organochlorine pesticides, pesticides continue to be detected in air, rain, soil, surface water, bed sediment, and aquatic and terrestrial biota throughout the world. Recent research suggests that low levels of some of these pesticides may have the potential to affect the development, reproduction, and behavior of fish and wildlife, and possibly humans. Pesticides in Stream Sediment and Aquatic Biota: Distribution, Trends, and Governing Factors assesses the occurrence and behavior of pesticides in bed sediment and aquatic biota-the two major compartments of the hydrologic system where organochlorine pesticides are most likely to accumulate. This book collects, for the first time, results from several hundred monitoring studies and field experiments, ranging in scope from individual sites to the entire nation. Comprehensive tables provide concise summaries of study locations, pesticides analyzed, and study outcomes. Comprehensive and extensively illustrated, Pesticides in Stream Sediment and Aquatic Biota: Distribution, Trends, and Governing Factors evaluates the sources, environmental fate, geographic distribution, and long-term trends of pesticides in bed sediment and aquatic biota. The book focuses on organochlorine pesticides, but also assesses the potential for currently used pesticides to be found in bed sediment and aquatic biota. Topics covered in depth include the effect of land use on pesticide occurrence, mechanisms of pesticide uptake and accumulation by aquatic biota, and the environmental significance of observed levels of pesticides in stream sediment and aquatic biota.

Book↗