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SULFATE REDUCTION RATES IN A THALASSIA TESTUDINUM SEAGRASS BED, NORTHWEST FLORIDA USA GULF OF MEXICO COAST
Citation:
Devereux, R D., D F. Yates, AND R L. Quarles. SULFATE REDUCTION RATES IN A THALASSIA TESTUDINUM SEAGRASS BED, NORTHWEST FLORIDA USA GULF OF MEXICO COAST. Presented at ASLO, Savannah, GA, 6/13-18/04.
Description:
Devereux, R., D.F. Yates and Robert L. Quarles. In press. Sulfate Reduction Rates in a Thalassia testudinum Seagrass Bed, Northwest Florida USA Gulf of Mexico Coast (Abstract). To be presented at the ASLO 2004 Summer Meeting: The Changing Landscapes of Oceans and Freshwater, 13-18 June 2004, Savannah, GA. 1 p. (ERL,GB R981).
Sulfate reduction rates (SRR) were determined in a northwest Florida, coastal T. testudinum seagrass bed. Triplicate sediment cores were taken at four six week intervals from three stations in progressively deper water (1,2,3 m), thus progressively less light at the seagrass canopy. SRR were highest in June and July (maximum 300-500nm/ml/d) during seagrass growth when temperatures were warm (28-30 C) and low in November (maximum 100-275 nm/ml/d) when temperatures were cold (20 C) and the seagrasses were dormant. However, September SRR when temperatures were still warm (28 C) were as low as November SRR. This suggests that although September temperatures might have supported higher SRR, that electron donors provided by seagrasses becoming dormant or from the degradation of benthic algae had decreased. Differences in SRR between depths at any one sampling date were insignificant. Although reduced sulfur pools appeared stable with time, sulfate appeared to become enriched in sediments during plant growth. Sulfate depletion in seagrass bed sediments during the growing season might be developed to indicate seagrasses are stressed and unable to oxidize the free sulfides.