Monday, May 26, 2008 - 9:15 AM
17

Towards the development of nutrient standards: Relationships among nutrients, algal biomass, and dissolved oxygen in Illinois streams and rivers

Todd V. Royer1, Amy R. Childers2, Mark B. David2, and Matt R. Whiles3. (1) School of Public and Environmental Affairs, Indiana University, 611 N Walnut Grove, Room #S103, Bloomington, IN 47405, (2) Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign, Turner Hall, 1102 S. Goodwin Ave., Urbana, IL 61801, (3) Department of Zoology and Center for Ecology, Southern Illinois University, Carbondale, IL 62901-6501

Development of nutrient criteria leading to standards for flowing waters is currently a major effort across the U.S., yet the efficacy of such criteria has not been fully assessed, particularly regarding effects on dissolved O2 concentrations.  We examined relationships among nutrients, algal biomass, and dissolved O2 in 53 stream and river sites across Illinois.  Dissolved O2 concentrations were monitored continuously for 72 hours at each site and a series of metrics calculated.  No occurrences of hypoxia were observed and overall the data did not indicate a strong link between nutrient concentrations and dissolved O2 metrics.  Cluster analysis was used to identify variables which explained differences among similar groups of sites.  Results indicated that streams and rivers in Illinois could be placed into one of three groups with regard to the efficacy of nutrient standards to improve biotic integrity of flowing water ecosystems.  The first two groups differed in size, supported different forms of algal biomass (sestonic vs. benthic), and likely would be responsive to nutrient standards.  The third group included 56 % of the sites and biotic integrity in these sites likely would be non-responsive to nutrient standards without concurrent improvements in physical habitat quality.


Web Page: nutrient standards, dissolved oxygen, algal biomass

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