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Sediment metabolism on the Louisiana continental shelf - Eldridge
Citation:
LEHRTER, J. C., R. DEVEREUX, D. L. BEDDICK, B. FRY, AND P. M. ELDRIDGE. Sediment metabolism on the Louisiana continental shelf - Eldridge. Presented at Ocean Science Meeting, Orlando, FL, March 02 - 07, 2008.
Impact/Purpose:
Rates of aerobic and anaerobic sediment metabolism were measured on the Louisiana Continental Shelf during 5 cruises in 2006 and 2007.
Description:
Rates of aerobic and anaerobic sediment metabolism were measured on the Louisiana Continental Shelf during 5 cruises in 2006 and 2007. On each cruise, 3-4 stations were occupied in regions of the shelf that experience summer bottom-water hypoxia. Net DIC, O2, N2, and nutrient fluxes across the sediment-water interface were measured in static core incubations. Sulfate and iron reduction rates were measured in vertical core cross sections. Sediment cores were also exposed to varying levels of light to assess the photosynthetic potential of benthic microalgae. Whole sediment metabolism was estimated via sediment diagenesis model. DIC fluxes did not vary greatly across the shelf with a range of 13 to 20 mmoles m-2 d-1. O2 and N2 fluxes ranged from 0 to -29 and 0 to 1.9 mmoles m-2 d-1, respectively. Experimental and modeling results indicated sulfate and iron reduction were important carbon remineralization pathways. Surface sediments exposed to 0.5 to 1.0% ambient light showed rapid increases in O2 indicating the potential for benthic photosynthesis. Sediment metabolism will be compared with rates of water-column metabolism measured at the same stations.