Aquatic Sciences Meeting, Albuquerque 2001

SS01 Submerged Aquatic Vegetation and the Water Column (Environmental Connections)

Date: Tuesday, February 13, 2001, Time: 2:15:00 PM

Location: Galisteo

Simjouw, J, P, Old Dominion University, Norfolk, USA, jsimjouw@odu.edu

Burdige, D, J, Old Dominion University, Norfolk, USA, dburdige@odu.edu

Zimmerman, R, C, Moss Landing Marine Labs, Moss Landing, USA, RZimmer197@aol.com

CARBONATE DISSOLUTION IN BAHAMAS SEDIMENT WITH CONTRASTING SEAGRASS DENSITIES

Carbonate dissolution can occur within shallow water sediments by aerobic respiration of organic matter. This process generates acidity, as CO2(aq), within the pore waters, and lowers the carbonate saturation state of the pore waters so that carbonate dissolution occurs. The presence of seagrasses (submerged vascular plants) is thought to have a major effect on these processes by pumping photosynthetically produced O2 in the sediment and promoting aerobic respiration. To assess carbonate dissolution rates as a function of the seagrass density, whole sediment core incubation experiments were performed in shallow water Bahamian sediment. Pore water samples were taken over time for alkalinity, TCO2, SO4, and Ca2+, generating a time series of depth profiles for these constituents. In dense grass cores alkalinity, TCO2, and Ca2+ values increase over time, while the sparse grass cores show minimal changes. No apparent sulfate reduction was measured in any core. In this talk we will discuss these results and the predicted carbonate dissolution rates in the different sediment environments. We will also use the results to further understand the role of seagrasses in promoting carbonate dissolution.

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Aquatic Sciences Meeting, Albuquerque 2001

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