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Sheena Young - Nutrient Lab

Spelman College, Atlanta, GA

Phosphorus is a mineral critical for metabolic processes. It exists in the water in several forms: orthophosphate, organic phosphate, total phosphorus, and polyphosphate. It is transferred throughout the ecosystem by the phosphorus cycle.  Human interference with this cycle causes negative impacts on the ecosystem.  Such interferences are the application of phosphates as fertilizers causes soil and groundwater phosphorus levels too high.  On farmlands, plants do not absorb all phosphate, causing eutrophication.  To study the biogeochemistry of phosphorus in the Patuxent River several experiments will be performed using the SEDEX procedure and several HCl extractions on sediment cores and sediment traps.  Inorganic phosphorus levels will be compared to total Phosphorus levels to determine the concentration of Organic Phosphorus in the sediment samples.  These results will indicate whether organic phosphorus is lost in the SEDEX procedure. The concentration of inorganic phosphorus in the HCl extraction can be related to the concentrations in the SEDEX procedure.  Then by studying the effects of stronger acid concentrations such as 2N, 3N, and 4N HCl on the phosphorus extraction, the efficiency of using 1N HCl will be determined.  The samples will be analyzed on the spectrophotometer, and from the absorbance, the concentration of phosphorus extracted will be determined.

Funding provided by NOAA/Sea Grant