XVI International Botanical Congess

Algae are used to assess water-quality conditions in over 50 major hydrologic basins as part of the USGS National Water Quality Assessment (NAWQA) Program. National consistency for collecting, identifying, and analyzing algal data is provided by training and quality-assurance protocols. A national database is being developed to link algal- species data with chemistry, hydrology, habitat, land use/cover, and biological data (macroinvertebrates and fish). NAWQA collaborates with the U.S. EPA and other agencies in developing regional nutrient-algal criteria relative to natural and human factors that influence water quality and biological integrity. Results from 3 climatic regions (Pacific Northwest, Midwest, and Southwest) in the U.S. are used to discuss algal community responses to agricultural and urban intensity, ground-water/surface-water relations, and landscape characteristics.