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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Biogeochemistry
BIOTIC AND ABIOTIC SORPTION-DESORPTION OF PHOSPHORUS FROM MID-WEST FORESTED AND AGRICULTURAL STREAMS.
K.W. Bush and S.P. Hendricks. Department of Biological Sciences, Murray State University, Murray, KY, USA, 42071
Biotic and abiotic sediment phosphorus sorption-release characteristics were determined for a forested and an agricultural stream, and the agricultural stream’s confluence with a reservoir in 2001. Stream sediments were collected from the three sites during early and late summer. Abiotic characteristics (equilibrium phosphorus concentration (EPC), phosphate sorption indices (PSI), and forms of phosphorus) and biotic release patterns (alkaline phosphatase activity (APA)) were determined in mesocosms. The forested stream exhibited the highest EPC ranging from 1 μg P L-1 during early summer and increasing to 23 μg P L-1 during late summer. Phosphorus adsorbed to FeOOH was the highest fraction in sediments at all sites. PSI’s showed high correlations with sediment organic matter content (r = 0.69-0.85), but widely varied by site. Sediment APA was not related to sediment organic matter or stream SRP. APA was highest at all sites during early summer (e.g., up to 175 μm NPP produced g-1 organic matter h-1) and then decreased through late summer. Finer sediment particles in the agricultural stream and in the stream-reservoir confluence may have been an important factor responsible for the higher APA and PSI’s, and for the lower EPC’s.
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