Aquatic Biology and Ecosystems

Pesticides are chemicals designed to kill pests, including insects (insecticides), weeds (herbicides), and fungi (fungicides). The USGS assesses the occurrence and behavior of pesticides in streams, lakes, and groundwater and the potential for pesticides to contaminate our drinking-water supplies or harm aquatic ecosystems.

Mercury is a potent neurotoxin that can affect the human nervous system. Eating fish contaminated with mercury can cause serious harm to people and wildlife.

Metals, metalloids, and radionuclides all are trace elements that occur naturally in the Earth's crust. In small quantities many trace elements are essential for health in all living organisms, but some trace elements can be toxic or cause cancer, and some can bioaccumulate. The USGS investigates where and how trace elements make their way into our Nation's surface water and groundwater.

Humans, just like aquatic organisms, need water. Flood control, urban infrastructure, irrigation of agriculture, and myriad other ways we manage water affect the natural flow of streams and rivers. How do the ways we manage land and water affect the natural patterns of streamflow that ecosystems depend on?

The sources, biogeochemistry, and ecotoxicology of selenium (Se) combine to produce a widespread potential for ecological risk such as deformities in birds and fish. Linking the understanding of source characteristics to a mechanistic, biodynamic dietary model of Se exposure on an ecosystem-scale improves the prediction of Se effects and its potential remediation.

Regional groundwater availability studies enable information about groundwater to be integrated and consistent, so that this resource can be analyzed and understood on an aquifer–wide scale. These studies provide decision–makers with a better understanding of the status and trends in the Nation's groundwater availability.

The FIM Toolbox contains comprehensive information on the Flood Inundation Mapping program, including how to develop a flood inundation map library. Resources include process documents, scientific and technical requirements, forms and templates, outreach and educational materials, and contact information. The FIM Toolbox is updated as new resources become available.

The clams Potamocorbula amurensis and Corbicula fluminea were collected at a variety of sites in the San Francisco Bay/ Delta beginning July 1990 and ending February 2010. These invasive species were used as biosentinels of the fate, transport, and effects of trace metals in the San Francisco Bay ecosystem.

The goals of the Regional Stream Quality Assessment (RSQA) are to characterize multiple water-quality factors that are stressors to aquatic life (contaminants, nutrients, sediment, and streamflow alteration) and to develop a better understanding of the relation of these stressors to ecological conditions in streams throughout the region.

The USGS is undertaking a 3-year study of water availability and use to investigate competing societal and ecological needs in Southeastern Atlantic Coastal Basins of the Carolinas. This study will compile existing information, add new scientific data and interpretation, and develop tools to help resource managers and stakeholders address current and future water-use challenges.

The USGS is undertaking a 3-year study of water use, availability, and change in the Red River basin, which covers more than 93,000 square miles in New Mexico, Texas, Oklahoma, Arkansas, and Louisiana. Water resources are being stressed by increasing water demands and increasingly severe droughts, and a comprehensive water-resource assessment of the basin is needed to enable sustainable water use.

USGS is undertaking a 3-year study of water use, availability, and change in the Upper Rio Grande Basin. This study area runs 670 miles from its headwaters in Colorado through New Mexico and northern Mexico to Texas, and will compile existing information and add new scientific data and interpretation to help stakeholders face current and future water issues.