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Resuspended sediments can contribute to the establishment and maintenance of hypoxia on the Louisiana continental shelf - Eldridge
Citation:
BEDDICK, D. L., R. DEVEREUX, J. C. LEHRTER, D. F. YATES, AND P. M. ELDRIDGE. Resuspended sediments can contribute to the establishment and maintenance of hypoxia on the Louisiana continental shelf - Eldridge. Presented at Ocean Science Meeting, Orlando, FL, March 02 - 07, 2008.
Impact/Purpose:
Hypoxia occurs during summer on the Louisiana Continental Shelf. We investigated whether resuspension of sediment organic matter and the reduced end products of anaerobic microbial metabolism contributes to the onset and maintenance of hypoxia.
Description:
Hypoxia occurs during summer on the Louisiana Continental Shelf. We investigated whether resuspension of sediment organic matter and the reduced end products of anaerobic microbial metabolism contributes to the onset and maintenance of hypoxia. The potential oxygen demand due to resuspension of sediments was calculated using sediment concentrations of acid volatile sulfide (AVS), NH4+, and Fe(II) measured at 3 locations along the 20 m contour of the Louisiana Shelf. Reduced species were measured in 2 cm sediment increments to a depth of 10 cm using duplicate 10.15cm cores. Further, the oxygen demand of the upper 2 cm of sediments was evaluated directly using live and killed sediments to assess biological versus chemical oxygen demand. Oxygen concentrations decreased rapidly in both treatments indicating that sediment repositories of AVS, NH4+,and Fe(II) were sufficient, independent of organic matter decomposition with oxygen, to substantially draw down oxygen during re-suspension.