Collections > Master's Papers > Gillings School of Public Health > Phosphorus Dynamics in The Epilimnion of B. Everett Jordan Lake
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Phosphorus Dynamics in The Epilimnion of B. Everett Jordan Lake

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  • Date Deposited: 2016-06-22
  • Date Created: 1985-12-01

Path:  Collections > Master's Papers > Gillings School of Public Health > Phosphorus Dynamics in The Epilimnion of B. Everett Jordan Lake

Gross uptake rates of filterable reactive phosphorus were measured in surface waters of B. Everett Jordan Lake from December 1983 to January 1985. In conjunction, laboratory experiments examining the phosphorus adsorption/desorption potential of suspended sediments and bioavailability of suspended sediment-bound phosphorus were performed on suspended sediments obtained from the Haw River, the major tributary of Jordan Lake, during five periods of high flow from January 1985 to May 1985. Phosphorus uptake rates were highly variable, ranging from 0.007 to 9.78 ug P 1[-1] h[-1]. The highest uptake rates were measured during the warm months in the New Hope Creek basin of the lake when filterable reactive phosphorus concentrations were low and algal biomass high, which when combined with high nitrogen to phosphorus ratios, indicate conditions of potential phosphorus limitation. Lower uptake rates were measured throughout the study in the Haw River basin of the lake and during the winter months in the New Hope Creek basin. Biotic uptake, which comprised most of the uptake during the warm months, was dominated by uptake in the small size fraction (< 8.0 um). Abiotic uptake often comprised the majority of the total uptake in the winter months. Sampling sites near tributary inputs, especially in the Haw River arm, had the highest rates of abiotic uptake due to large inputs of suspended sediments during periods of high stream flow. Sorption isotherms of suspended sediments obtained from the Haw River exhibited equilibrium phosphorus concentrations significantly below ambient stream filterable reactive phosphorus concentrations, indicating that the sediments were likely acting as a sink for soluble phosphorus present in the stream. Algae grown with suspended sediment-bound phosphorus under conditions otherwise optimal for growth were able to utilize a relatively small amount (mean = ll.3%) of the sediment-bound phosphorus. Potential impacts of these results on lake management were discussed.

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