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Sediment Microbial Community Dynamics and Geochemistry During Oxic and Hypoxic Periods in the Gulf of Mexico
Citation:
Palumbo, A. V., J. J. Mosher, T. A. Vishnivetskaya, S. D. Brown, D. Klingeman, C. Johnson, AND R. DEVEREUX. Sediment Microbial Community Dynamics and Geochemistry During Oxic and Hypoxic Periods in the Gulf of Mexico. Presented at 111th General Meeting American Society for Microbiology, New Orleans, LA, May 21 - 24, 2011.
Impact/Purpose:
This study applied metagenomic methods to compare changes in microbial communities found in Gulf of Mexico sediments during periods when oxygen concentrations in the overlying waters were normal and when they were hypoxic. Biogeochemical data indicated differences in the levels of oxidized and reduced iron between norm-oxic and hypoxic periods. Analyses of the microbial communities were undertaken to determine the basis for changes in the oxidation state of the sediment iron. Results showed significant differences in microbial community composition relative to changes in iron, manganese, dissolved inorganic carbon, and nitrate. These changes suggest that microbial cycling of manganese and iron are influenced by hypoxia which can drive the sediments to a lower redox state and contribute to the persistence of hypoxia. This new understanding can help refine tools used to estimate the extent of hypoxia.
Description:
Seasonal hypoxia in the benthic waters of the Louisiana Coastal Shelf contributes to the Gulf of Mexico "dead zone" phenomena. Limited information is available on sedimentary biogeochemical interactions during periods of hypoxia.