HR: 09:00h
AN: NB21E-03    [Abstracts]
TI: Response of Periphyton to Seasonal Changes in Nutrient Concentrations in Central Illinois Agricultural Streams
AU: * Kirkham, K G
EM: kgkirkh@ilstu.edu
AF: Illinois State University, Department of Biological Sciences Campus Box 4120, Normal, IL 61790 United States
AU: Perry, W L
EM: wlperry@ilstu.edu
AF: Illinois State University, Department of Biological Sciences Campus Box 4120, Normal, IL 61790 United States
AB: Headwater streams in central Illinois have been dredged and channelized to drain surrounding agricultural fields and has led to extensive erosion and eutrophication. Restoration of these systems through farmer implementation of Best Management Practices (BMPs) may be one solution. Examination of algal population dynamics may be useful in assessment of BMP effectiveness. We have monitored two small headwater streams, Bray Creek and Frog Alley, for a suite of physicochemical parameters focusing on dissolved oxygen, nitrogen, and phosphorus for three years. Nutrient concentrations suggested potential nutrient limitation by nitrates during late summer and phosphorus limitation in early summer. To determine seasonal algal dynamics with seasonally varying nutrient limitation in agricultural headwater streams, we used nutrient diffusing substrata (NDS). NDS with agar (controls) or amended with either nitrogen, phosphorus, or both were deployed for 21-24 days in both streams each month for a year. Slight nutrient limitation was observed in Bray Creek during August and November while phosphorus was limiting in September (P<0.05). We suggest agricultural streams are more dynamic than previously thought and algal populations may be seasonally nutrient limited and with consequent effects on dissolved oxygen concentrations.
DE: 1806 Chemistry of fresh water
DE: 9810 New fields (not classifiable under other headings)
DE: 9901 NABS Student Award - Basic Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly