부산대학교 도서관

To purchase or authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1365-2427.2007.01951.x Byline: STEPHEN D. PORTER (*), DAVID K. MUELLER (*), NORMAN E. SPAHR (*), MARK D. MUNN ([dagger]), NEIL M. DUBROVSKY ([double dagger]) Keywords: land use; metrics; National Water-Quality Assessment; nutrients; periphyton Abstract: Summary 1. Algal-community metrics were calculated for periphyton samples collected from 976 streams and rivers by the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Programme during 1993-2001 to evaluate national and regional relations with water chemistry and to compare whether algal-metric values differ significantly among undeveloped and developed land-use classifications. 2. Algal metrics with significant positive correlations with nutrient concentrations included indicators of trophic condition, organic enrichment, salinity, motility and taxa richness. The relative abundance of nitrogen-fixing algae was negatively correlated with nitrogen concentrations, and the abundance of diatom species associated with high dissolved oxygen concentrations was negatively correlated with both nitrogen and phosphorus concentrations. Median algal-metric values and nutrient concentrations were significantly lower at undeveloped sites than those draining agricultural or urban catchments. 3. Total algal biovolume did not differ significantly among major river catchments or land-use classifications, and was only weakly correlated with nitrate (positive) and suspended-sediment (negative) concentrations. Estimates of periphyton chlorophyll a indicated an oligotrophic-mesotrophic boundary of about 21 mg m.sup.-2 and a mesotrophic-eutrophic boundary of about 55 mg m.sup.-2 based on upper and lower quartiles of the biovolume data distribution. 4. Although algal species tolerance to nutrient and organic enrichment is well documented, additional taxonomic and autecological research on sensitive, endemic algal species would further enhance water-quality assessments. Author Affiliation: (*)Water Resources Discipline, U.S. Geological Survey, Denver, CO, U.S.A. ([dagger])Water Resources Discipline, U.S. Geological Survey, Tacoma, WA, U.S.A. ([double dagger])Water Resources Discipline, U.S. Geological Survey, Sacramento, CA, U.S.A. Article History: (Manuscript accepted 10 December 2007) Article note: Stephen D. Porter, Edwards Aquifer Research & Data Center, Texas State University, 248 Freeman Aquatic Building, San Marcos, TX 78666, U.S.A. E-mail: sp31@txstate.edu