Efficacy of algal metrics for assessing nutrient and organic enrichment in flowing waters

Autor: David K. Mueller, Neil M. Dubrovsky, Norman E. Spahr, Mark D. Munn, Stephen D. Porter
Rok vydání: 2008
Předmět:
Zdroj: Freshwater Biology. 53:1036-1054
ISSN: 1365-2427
0046-5070
DOI: 10.1111/j.1365-2427.2007.01951.x
Popis: 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 landuse classifications, and was only weakly correlated with nitrate (positive) and suspendedsediment (negative) concentrations. Estimates of periphyton chlorophyll a indicated an oligotrophic–mesotrophic boundary of about 21 mg m )2 and a mesotrophic–eutrophic boundary of about 55 mg m )2 based on upper and lower quartiles of the biovolume data
Databáze: OpenAIRE
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