USGS Science⌕ Search

SEARCH · USGS Science

Results for “Aquatic Biology”

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 73 records · Page 4Linked to original sources
USGS2025

Development of regression equations to estimate flow durations, low-flow frequencies, and mean flows at ungaged stream sites in Connecticut using data through water year 2022

To aid Federal and State regulatory agencies in the effective management of water resources, the U.S. Geological Survey, in cooperation with the Connecticut Department of Energy and Environmental Protection and the Connecticut Department of Transportation, updated flow statistics for 118 streamgages and developed 47 regression equations to estimate selected flow duration, low flow, and mean flow statistics for the entire State of Connecticut, for the following: 1-, 5-, 10-, 25-, 50-, 75-, 90-, 99-percent flow durations; 7-day, 10-year low-flow frequency and 30-day, 2-year low-flow frequency; and mean flow, spring mean flow, and harmonic mean flow. In addition, regression equations were developed for monthly and seasonal flow durations, ranging from 25 to 99 percent for aquatic biological processes of salmonid spawning (November), overwinter (December–February), clupeid spawning (May), resident spawning (June), and rearing and growth (July–October) periods, and for flow durations ranging from 1 to 99 percent for the habitat forming (March–April) period. Statistics were derived from daily mean streamflow data collected from streamgages with at least 10 years of data through water year 2022 in southern New England and eastern New York. Forty streamgages in Connecticut and adjacent areas of neighboring States were used in the regression analysis. Regression methods of weighted least squares and generalized least squares were used to derive the final coefficients and measures of uncertainty for the regression equations. The equations used to estimate selected streamflow statistics were developed by relating the flow statistics to different basin characteristics (physical, land cover, and climatic) at the 40 streamgages. Nine basin characteristics served as the explanatory variables in the statewide regression equations: drainage area, percentage of area with coarse-grained stratified deposits, stream density, mean basin slope, mean basin elevation, percentage of area with hydrologic soil group A, mean monthly precipitation for November, mean seasonal precipitation in the winter (December, January, and February), and mean annual temperature. The root mean square error of the 47 equations ranged from 7.9 to 121.9 percent, with an average of 27.9 percent. The equations estimate flows most accurately near the mean (50-percent flow duration), become less accurate for low flows, and are the least accurate for extreme low flows. The root mean square error for the 50-percent flow duration is 15.1 percent, with an average of 17.6 percent across the six periods. The extreme low flow statistics of 7-day, 10-year low-flow frequency, 99-percent flow duration, and 99-percent rearing and growth period flow durations have root mean square errors of 121.9, 105.1, and 121.9 percent, respectively. The adjusted coefficient of determination of the 47 equations ranged from 73.4 to 99.5 percent, with an average of 95.1 percent.

Connecticut↗
USGS2000

Water-resources-related information for the St. Croix Reservation and vicinity, Wisconsin

The St. Croix Chippewa Tribe is interested in documenting water-quality conditions in lakes and streams adjacent to their Reservation lands in northwestern Wisconsin and developing management plans to protect these water resources. This report provides the Tribe with a retrospective summary and analysis of available water-resources-related information for their Reservation and vicinity. The study area is divided into four main watersheds: Big Round Lake, Clam River at Clam Lake Outlet, Yellow River at Danbury, and Loon Creek at Danbury. The Clam River Watershed includes the subwatersheds of Bashaw and Sand Lakes. The Yellow River Watershed includes the subwatersheds of Big Sand and Gaslyn Lakes. In all, 41 surface-water studies or reports that include information relevant to the study area were identified. Most of the surface-water studies were regional or statewide summaries. Fifteen of these studies include lake information and 36 include stream information. Twenty-eight of the studies include water-quality data and 16 include information describing aquatic biology. Water- and sediment-quality data were obtained for 80 lakes and 23 streams in the study area. Lake information includes data for 101 water-quality characteristics from nearly 4,300 water and sediment analyses of samples collected between 1972 and 1998. Stream information summarized in this report includes data for 135 water-quality characteristics and nearly 4,500 water and sediment analyses of samples collected at 23 sites between 1964 and 1999. A total of 41 ground-water studies or reports that include information relevant to the study area were identified. Most of the ground-water studies were regional or statewide summaries. Of the 41 studies, 33 include water-quality information, 9 include information regarding water use, and 23 provide descriptions of geology and aquifer characteristics relevant to the study area. Water-quality information for 773 wells was compiled. Most of the sampled wells were used for drinking water, and most of the drinking-water wells represent domestic supplies. Water-quality data summarized in this report represent 270 characteristics and more than 10,300 analyses of samples collected from drinking-water wells between 1911 and 1999; however, most of the water-quality data were collected after about 1990.

Wisconsin↗
USGS1995

Environmental Setting and Implications on Water Quality, Upper Colorado River Basin, Colorado and Utah

The Upper Colorado River Basin in Colorado and Utah is 1 of 60 study units selected for water-quality assessment as part of the U.S. Geological Survey's National Water-Quality Assessment program, which began full implementation in 1991. Understanding the environmental setting of the Upper Colorado River Basin study unit is important in evaluating water-quality issues in the basin. Natural and human factors that affect water quality in the basin are presented, including an overview of the physiography, climatic conditions, general geology and soils, ecoregions, population, land use, water management and use, hydrologic characteristics, and to the extent possible aquatic biology. These factors have substantial implications on water-quality conditions in the basin. For example, high concentrations of dissolved solids and selenium are present in the natural background water conditions of surface and ground water in parts ofthe basin. In addition, mining, urban, and agricultural land and water uses result in the presence of certain constituents in the surface and ground water of the basin that can detrimentally affect water quality. The environmental setting of the study unit provides a framework of the basin characteristics, which is important in the design of integrated studies of surface water, ground water, and biology.

Water-Resources Investigations Report↗
USGS1996

Sampling design for assessing water quality of the Red River of the North basin, Minnesota, North Dakota, and South Dakota, 1993-1995

This map report describes the sampling design for a comprehensive regional assessment of water quality in the Red River of the North Basin, a study unit under the U.S. Geological Survey’s National Water-Quality Assessment Program. The sampling design was developed to address questions about the presence, distribution, and loads of nutrients and pesticides associated with large agricultural regions in the basin and across the Nation. The design also begins to address major local and regional concerns about suspended sediment in surface water and naturally occurring salinity in ground water. Recognizing that the Red River of the North Basin study unit realistically could not be analyzed as a single homogeneous area, a hierarchical sampling stratification for assessing water quality was developed. Landscape features consisting of physiography, soils, land cover and land use, and cropping patterns provided the environmental framework for stratification of streams and surficial aquifers. The environmental framework characterizes the climate and hydrology and relates closely to an ecoregions framework. The environmental and ecoregions frameworks were considered in locating ecological sampling sites. For the subsurface framework, buried sand and gravel aquifers in study unit were subdivided into two general subregions of differing potential saline recharge from underlying bedrock aquifers. Actual sampling sites for streams, aquatic biology, and ground water were described within the proposed sampling stratification. Practical considerations of previously established sampling sites, background information from previous hydrologic investigations, and site suitability for sampling protocols also were considered for final site selection.

Minnesota, North Dakota, South Dakota↗
USGS1996

Chlordane, DDT, PCB's, and other selected organic compounds in Asiatic clams and yellow bullhead in the Potomac River Basin, 1992

Chlordane, DDT (dichlor-diphenyl-trichloroethane), and PCB's (polychlorinated biphenyls) were the most widespread organic contaminants detected during a 1992 survey of aquatic biological tissues in the Potomac River Basin. On the basis of existing U.S. Food and Drug Administration criteria, no new threats to human health were discovered, although chlordane concentrations may pose a threat to fish-eating wildlife. Chlordane exceeded the National Academy of Science and National Academy of Engineering recommended maximum concentration for the protection of fish-eating wildlife at two sites. The survey, conducted by the U.S. Geological Survey's National Water-Quality Assessment Program, sampled Asiatic clams (Corbicula fluminea) and yellow bullhead (Ameiurus natalis) at 16 sites to determine the occurrence and distribution of 29 hydrophobic organic compounds. Thirteen of these organic compounds were detected in the survey. Sites with the greatest number of compounds detected include the Potomac River near Alexandria, Va., with 6 compounds detected in Asiatic clam tissue, and Accotink Creek near Annandale, Va., with 11 compounds in yellow bullhead tissue. Chlordane was detected at six sites, with maximum concentrations of 31.1 ?g/kg (micrograms per kilograms) in Asiatic clam tissue and 127 ?g/kg in yellow bullhead whole-fish tissue. DDT was detected at five sites, with maximum concentrations of 12.9 ?g/kg in Asiatic clam tissue and 7.6 ?g/kg in yellow bullhead whole-fish tissue. PCB's were detected at nine sites, with maximum concentrations of 162 ?g/kg in Asiatic clam tissue and 146 mg/ kg in yellow bullhead whole-fish tissue.

Water-Resources Investigations Report↗
USGS1998

Water-quality assessment of the lower Illinois River Basin: Environmental setting

The lower Illinois River Basin (LIRB) encompasses 18,000 square miles of central and western Illinois. Historical and recent information from Federal, State, and local agencies describing the physiography, population, land use, soils, climate, geology, streamflow, habitat, ground water, water use, and aquatic biology is summarized to describe the environmental setting of the LIRB. The LIRB is in the Till Plains Section of the Central Lowland physiographic province. The basin is characterized by flat topography, which is dissected by the Illinois River. The drainage pattern of the LIRB has been shaped by many bedrock and glacial geologic processes. Erosion prior to and during Pleistocene time created wide and deep bedrock valleys. The thickest deposits and most major aquifers are in buried bedrock valleys. The Wisconsinan glaciation, which bisects the northern half of the LIRB, affects the distribution and characteristics of glacial deposits in the basin. Agriculture is the largest land use and forested land is the second largest land use in the LIRB. The major urban areas are near Peoria, Springfield, Decatur, and Bloomington-Normal. Soil type and distribution affect the amount of soil erosion, which results in sedimentation of lakes and reservoirs in the basin. Rates of soil erosion of up to 2 percent per year of farmland soil have been measured. Many of the 300 reservoirs, lakes, and wetlands are disappearing because of sedimentation resulting from agriculture activities, levee building, and urbanization. Sedimentation and the destruction of habitat appreciably affect the ecosystem. The Illinois River is a large river-floodplain ecosystem where biological productivity is enhanced by annual flood pulses that advance and retreat over the flood plain and temporarily expand backwater and flood-plain lakes. Ground-water discharge to streams affects the flow and water quality of the streams. The water budget of several subbasins show variability in ground-water contribution from runoff and storage. More than half of the drinking water, including domestic and public-supply use, in the LIRB is from ground water. Fifty-two percent of the public-supply water is from surface water. Ground-water withdrawals mostly are from glacial sand and gravel aquifers. Structural features, such as monoclines, synclines, and anticlines, in the buried bedrock affect the water quality of the aquifers. There are five natural environmental divisions in the LIRB. The Grand Prairie covers most of the northeastern half of the basin, and the Western Forest-Prairie covers most of the southwestern half. Implications of environmental setting for water quality in the LIRB are related primarily to land use. The balanced fish community indicates that the lower Illinois River is affected less from urban and industrial waste than the upper Illinois River. A decrease in dissolved oxygen concentrations and turbidity in the lower reaches of the basin in 1993 have resulted from the recent influx of European zebra mussels to the LIRB. Many factors affect water quality in the LIRB. Bedrock and surface topography, type of glacial material, and land use most directly affect water quality in the basin.

Illinois↗
USGS1998

Water quality assessment of the Sacramento River Basin, California: Environmental setting and study design

This report describes the environmental setting and investigative activities of the Sacramento River Basin study unit of the National Water-Quality Assessment Program. The Sacramento River Basin is one of 60 study units located throughout the United States that has been scheduled for study as part of the National Water-Quality Assessment Program. The Sacramento River Basin is the most important source of freshwater in California. Water quality studies in the Sacramento River Basin study unit focus on the Sacramento Valley because it is here that the principal uses of water and potential impacts on water quality occur. Investigative activities include a network of surface water sites, where water chemistry and aquatic biological sampling are done, and a variety of ground water studies. In addition, investigations of the cycling and distribution of volatile organic compounds in the urban environment and the distribution of total and methyl mercury in the Sacramento River and tributaries will be completed.

California↗
USGS1999

Biotic integrity of the Boise River upstream and downstream from two municipal wastewater treatment facilities, Boise, Idaho, 1995-96

Aquatic biological communities were used to assess the biotic integrity of the Boise River upstream and downstream from the Lander Street and West Boise municipal wastewater treatment facilities (WTFs) in Boise, Idaho. Samples of epilithic periphyton, benthic macroinvertebrates, and fish were collected in late February and early March 1995, in late October 1996, and in early December 1996. Epilithic periphyton biomass, expressed as chlorophyll- a and ash-free dry weight, declined substantially between 1995 and 1996. Chlorophyll- a concentrations were higher at sites downstream from WTFs in both years, but differences in concentrations between sites upstream and downstream from WTFs were not statistically significant. High withinsite variance suggests that greater sampling intensity would improve statistical comparison. Index of Biotic Integrity (IBI) scores calculated for benthic macroinvertebrates were higher for the sites upstream from WTFs in 1995 and were the same for all sites in 1996. Similarly, IBI scores calculated for fish were higher for the sites upstream from WTFs in 1995, were higher for the site upstream from the Lander Street WTF in 1996, and were the same for sites upstream and downstream from the West Boise WTF in 1996. Two species of sculpin ( Cottus ) were abundant at the site upstream from both WTFs but were absent at all other sites downstream from WTFs in 1995 and composed only 2 percent of the total number of fish collected downstream from the Lander Street WTF in 1996.

Idaho↗
USGS1998

A demonstration of the instream flow incremental methodology, Shenandoah River, Virginia

Current and projected demands on the water resources of the Shenandoah River have increased concerns for the potential effect of these demands on the natural integrity of the Shenandoah River system. The Instream Flow Incremental Method (IFIM) process attempts to integrate concepts of water-supply planning, analytical hydraulic engineering models, and empirically derived habitat versus flow functions to address water-use and instream-flow issues and questions concerning life-stage specific effects on selected species and the general well being of aquatic biological populations. The demonstration project also sets the stage for the identification and compilation of the major instream-flow issues in the Shenandoah River Basin, development of the required multidisciplinary technical team to conduct more detailed studies, and development of basin specific habitat and flow requirements for fish species, species assemblages, and various water uses in the Shenandoah River Basin. This report presents the results of an IFIM demonstration project, conducted on the main stem Shenandoah River in Virginia, during 1996 and 1997, using the Physical Habitat Simulation System (PHABSIM) model. Output from PHABSIM is used to address the general flow requirements for water supply and recreation and habitat for selected life stages of several fish species. The model output is only a small part of the information necessary for effective decision making and management of river resources. The information by itself is usually insufficient for formulation of recommendations regarding instream-flow requirements. Additional information, for example, can be obtained by analysis of habitat time-series data, habitat duration data, and habitat bottlenecks. Alternative-flow analysis and habitat-duration curves are presented.

Virginia↗
USGS2018

Technical note: False low turbidity readings from optical probes during high suspended-sediment concentrations

Turbidity, a measure of water clarity, is monitored for a variety of purposes including (1) to help determine whether water is safe to drink, (2) to establish background conditions of lakes and rivers and detect pollution caused by construction projects and stormwater discharge, (3) to study sediment transport in rivers and erosion in catchments, (4) to manage siltation of water reservoirs, and (5) to establish connections with aquatic biological properties, such as primary production and predator–prey interactions. Turbidity is typically measured with an optical probe that detects light scattered from particles in the water. Probes have defined upper limits of the range of turbidity that they can measure. The general assumption is that when turbidity exceeds this upper limit, the values of turbidity will be constant, i.e., the probe is pegged ; however, this assumption is not necessarily valid. In rivers with limited variation in the physical properties of the suspended sediment, at lower suspended-sediment concentrations, an increase in suspended-sediment concentration will cause a linear increase in turbidity. When the suspended-sediment concentration in these rivers is high, turbidity levels can exceed the upper measurement limit of an optical probe and record a constant pegged value. However, at extremely high suspended-sediment concentrations, optical turbidity probes do not necessarily stay pegged at a constant value. Data from the Colorado River in Grand Canyon, Arizona, USA, and a laboratory experiment both demonstrate that when turbidity exceeds instrument-pegged conditions, increasing suspended-sediment concentration (and thus increasing turbidity) may cause optical probes to record decreasing false turbidity values that appear to be within the valid measurement range of the probe. Therefore, under high-turbidity conditions, other surrogate measurements of turbidity (e.g., acoustic-attenuation measurements or suspended-sediment samples) are necessary to correct these low false turbidity measurements and accurately measure turbidity.

Hydrology and Earth System Sciences↗
USGS2005

The role of organic matter in sediment budgets in forested terrain

The production and transport of suspended particulate matter usually are major components of a sediment budget, but the organic and inorganic fractions of this material are not commonly differentiated. In four forested streams in the northwestern United States, the organic content of suspended sediment samples ranged from 10 to 80 weight percent for individual flood events. For a given stream, as a percentage of suspended sediment, organic content was highest during base flows and the early rising and late falling limbs of hydrographs, but on an annual cumulative basis, most organic flux occurred during a few days of high flow. By weight, the inorganic component of suspended sediment dominated the annual sediment flux in three of the catchments, but organics represented more than half the suspended sediment load in an old growth redwood stream. Although commonly minor by weight, organic suspended sediment can have important effects on aquatic biological communities, turbidity measurements, and eutrophication in estuaries.

Conference Paper↗
USGS2015

Representativeness of soil samples collected to assess mining-related contamination of flood plains in southeast Kansas

Historical lead and zinc mining in the Tri-State Mining District (TSMD), located in parts of southeast Kansas, southwest Missouri, and northeast Oklahoma, has resulted in a substantial ongoing input of lead and zinc to the environment (Juracek, 2006; Juracek and Becker, 2009). In response to concern about the mining-related contamination, southeast Cherokee County, Kansas, was listed on the U.S. Environmental Protection Agency’s (USEPA) National Priority List as a Superfund hazardous waste site (fig. 1). To provide some of the information needed to support remediation efforts in the Cherokee County Superfund site, a study was begun in 2009 by the U.S. Geological Survey (USGS) that was requested and funded by USEPA. As part of the study, surficial-soil sampling was used to investigate the extent and magnitude of mining-related lead and zinc contamination in the flood plains of the Spring River and several tributaries within the Superfund site. In mining-affected areas, flood-plain soils had lead and zinc concentrations that far exceeded background levels as well as probable-effects guidelines for toxic aquatic biological effects (Juracek, 2013). Lead- and zinc-contaminated flood plains are a concern, in part, because they represent a long-term source of contamination to the fluvial environment. An important issue is the within-site representativeness of the surficial-soil samples collected. Specifically, the question is whether or not the samples collected provide an acceptable representation of the lead and zinc concentrations at each site for the purpose of characterizing and comparing sites. The distribution of mining-contaminated sediment on flood plains is determined by several factors including the size and density of the contaminated particles, flood-plain width and topography, flood characteristics (frequency, magnitude, duration), and fluvial geomorphic processes. To evaluate within-site representativeness, additional samples were simultaneously collected to assess within-site variability. In this paper, the specific objectives were to: Describe the collection and analysis of surficial-soil samples using a 5-point sampling technique; Describe the collection and analysis of additional surficial-soil samples to assess within-site variability; and Evaluate the within-site representativeness of the original 5-point samples for assessing mining-related contamination.

Conference Paper↗
USGS2018

Open hydrology courseware using the United States Geological Survey’s National Water Census Data Portal

The U.S. Geological Survey (USGS) is the primary U.S. Government agency for water data collection and dissemination. In this role, the USGS has recently created and deployed a National Water Census Data Portal (NWC-DP) which provides access to streamflow, evapotransporation, precipitation, aquatic biology and other data at the national level. Recognizing the value of these data sets for hydrologic science education, this paper presents an effort to bridge the gap between pencil–and-paper-based hydrology curriculum and the USGS NWC-DP resource. Specifically, we have developed an R package, National Water Census Education (NWCEd), and five associated laboratory exercises that integrate R- and web-services-based access to the NWC-DP data sets. Using custom functions built into the NWCEd, students are able to access unprecedented amounts of hydrologic data from the NWC-DP, which can be applied to current hydrology curriculum and analyzed using NWCEd and a number of other open-source R tools.

Open Water Journal↗
USGS2018

Habitat mosaics and path analysis can improve biological conservation of aquatic biodiversity in ecosystems with low-head dams

Conserving native biodiversity depends on restoring functional habitats in the face of human-induced disturbances. Low-head dams are a ubiquitous human impact that degrades aquatic ecosystems worldwide. To improve our understanding of how low-head dams impact habitat and associated biodiversity, our research examined complex interactions among three spheres of the total environment. i.e., how low-head dams ( anthroposphere ) affect aquatic habitat ( hydrosphere ), and native biodiversity ( biosphere ) in streams and rivers. Creation of lake-like habitats upstream of low-head dams is a well-documented major impact of dams. Alterations downstream of low head dams also have important consequences, but these downstream dam effects are more challenging to detect. In a multidisciplinary field study at five dammed and five undammed sites within the Neosho River basin, KS, we tested hypotheses about two types of habitat sampling (transect and mosaic) and two types of statistical analyses (analysis of covariance and path analysis). We used fish as our example of biodiversity alteration. Our research provided three insights that can aid environmental professionals who seek to conserve and restore fish biodiversity in aquatic ecosystems threatened by human modifications. First, a mosaic approach identified habitat alterations below low-head dams (e.g. increased proportion of riffles) that were not detected using the more commonly-used transect sampling approach. Second, the habitat mosaic approach illustrated how low-head dams reduced natural variation in stream habitat. Third, path analysis, a statistical approach that tests indirect effects, showed how dams, habitat, and fish biodiversity interact. Specifically, path analysis revealed that low-head dams increased the proportion of riffle habitat below dams, and, as a result, indirectly increased fish species richness . Furthermore, the pool habitat that was created above low-head dams dramatically decreased fish species richness. As we show here, mosaic habitat sampling and path analysis can help conservation practitioners improve science-based management plans for disturbed aquatic systems worldwide.

Kansas↗
USGS2002

Physical data and biological data for algae, aquatic invertebrates, and fish from selected reaches on the Carson and Truckee rivers, Nevada and California, 1993-97

This report, a product of the National Water- Quality Assessment Program, is a compilation of physical data and biological data for algae, aquatic invertebrates, and fish collected in the Carson and Truckee River Basins, Nevada and California. Most of the data were collected between 1993 and 1996 at selected reaches on the Carson and Truckee Rivers. Algae and aquatic invertebrate samples were collected from cobble riffles, submerged woody-snag habitats, and from depositional areas such as pools. Between 1993 and 1996, fish and crayfish were collected from all wadeable habitats at each of seven basic-fixed sites using either electroshocking methods or seining. Additional fish and crayfish were collected at one site on the Truckee River in 1997. Fish were identified to species, measured for total and standard length, checked for anomalies, and weighed at the collection site. Fish were returned to the stream after measurements were taken. Measurements of water depth, stream velocity, determinations of substrate type and substrate embeddedness were made at each sampling site. Algae and aquatic invertebrate samples were sent to the U.S. Geological Survey National Water-Quality Laboratory for identification and enumeration. A total of 103 semi-quantitative and 55 qualitative algae samples were collected at 20 river reaches on the Carson and Truckee Rivers between 1993 and 1996. These samples represent algae in cobble riffles, on submerged woody snags, and on sediment surfaces in depositional areas. In those 158 samples, 514 algal species, varieties, or forms were identified. Of the 8 algal phyla represented, the diatoms (Phylum Bacillariophyta) were the most abundant with 351 species, varieties, or forms. The green algae (Phylum Chlorophyta) were next in abundance with 108 species, varieties, or forms followed by the blue-green algae (Phylum Cyanophyta) with 41 species, varieties, or forms. A total of 49 semi-quantitative aquatic invertebrate samples were collected at 27 river reaches on the Carson and Truckee Rivers between 1993 and 1996. These samples represent invertebrates in cobble riffles and on submerged woody snags. In those 49 samples, members of 6 phyla were identified. Roundworms were identified only to phylum (Nematoda) and free-living flatworms and snails were identified only to class (Turbellaria and Gastroda). Organisms were identified as belonging to 19 invertebrate orders. Most of the invertebrates that could be identified to genus or species belonged in the orders Ephemeroptera, Plecoptera, and Trichoptera of the arthropod class Insecta. Fish and crayfish populations in the Carson and Truckee Rivers were sampled 29 times between 1993 and 1997. These collections resulted in the identification of 18 fish species and one endemic crayfish species. Twelve of the 18 fish species identified are not native to the Carson and Truckee River Basins.

Open-File Report↗
USGS1982

Biota and biological principles of the aquatic environment

This is the third of several compilations of briefing papers on water quality by the U.S. Geological Survey. Each briefing paper is prepared in a simple, nontechnical, easy-to-understand manner. This U.S. Geological Survey Circular contains papers on selected organic substances in water. Briefing papers are included on ' Why study organic substances in water. ', ' Taste and odor in water ', and ' Classification and fractionation of organic solutes in natural waters'. (USGS)

Circular↗
USGS2002

Comparison of dissolved oxygen and aquatic biota between a State 303(d)-listed stream segment and USGS biological reference sites in the San Jacinto River Basin, Texas, 2000

About 30 percent of the 238 water bodies on the 2000 State of Texas 303(d) list of impaired or threatened waters are included for not meeting optimum conditions for aquatic life (Texas Natural Resource Conservation Commission, 2000). Most of the water bodies on the list were assessed using water-column measures such as concentrations of dissolved oxygen (DO) and total metals as surrogates for aquatic biological data. Many water bodies were listed because of low concentrations of DO or potentially toxic dissolved metals such as lead; ambient toxicity to nonresident (laboratory) aquatic organisms also could have been a reason for listing. The Texas Natural Resource Conservation Commission (TNRCC) has emphasized the use of aquatic biological data to determine if a water body should be included or removed from the 303(d) list. The standards used to determine whether a water body should be on the State 303(d) list generally are statewide standards that have not been adjusted for regional or watershed-scale differences that reflect variability across Texas. Such is the case for DO, which is one of the more common surrogate measures used in the listing of stream segments that do not meet optimum conditions for aquatic life. The statewide minimum concentration of DO to meet optimal conditions for aquatic life is 5.0 milligrams per liter. Many water bodies in Texas with few, if any, anthropogenic influences might have DO concentrations below 5.0 milligrams per liter, especially in the late summer when water temperatures peak and streamflows are at minimums for the year.

Texas↗
USGS2020

Biological control of Aedes mosquito larvae with carnivorous aquatic plant, Utricularia macrorhiza

Background Biological controls with predators of larval mosquito vectors have historically focused almost exclusively on insectivorous animals, with few studies examining predatory plants as potential larvacidal agents. In this study, we experimentally evaluate a generalist plant predator of North America, Utricularia macrorhiza, the common bladderwort, and evaluate its larvacidal efficiency for the mosquito vectors Aedes aegypti and Aedes albopictus in no-choice, laboratory experiments. We sought to determine first, whether U. macrorhiza is a competent predator of container-breeding mosquitoes, and second, its predation efficiency for early and late instar larvae of each mosquito species. Methods Newly hatched, first instar Aedes albopictus and Aedes aegypti larvae were separately exposed in cohorts of 10 to field collected U. macrorhiza cuttings. Data on development time and larval survival were collected on a daily basis to ascertain the effectiveness of U. macrorhiza as a larval predator. Survival models were used to assess differences in larval survival between cohorts that were exposed to U. macrorhiza and those that were not. A permutation analysis was used to investigate whether storing U. macrorhiza in laboratory conditions for extended periods of time (1 month vs. 6 months) affected its predation efficiency. Results Our results indicated a 100% and 95% reduction of survival of Ae. aegypti and Ae. albopictus larvae respectively, in the presence of U. macrorhiza relative to controls within five days, with peak larvacidal efficiency in plant cuttings from ponds collected in August. Utricularia macrorhiza cuttings, which were prey-deprived, and maintained in laboratory conditions for 6 months were more effective larval predators than cuttings, which were maintained prey-free for 1 month. Conclusions Due to the combination of high predation efficiency and the unique biological feature of facultative predation, we suggest that U. macrorhiza warrants further development as a method for larval mosquito control.

Rhode Island↗