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Carbon and oxygen dynamics on the Louisiana continental shelf: role of water column primary production and respiration
Murrell, M., J. Lehrter, Jim Hagy, J. Pauer, AND T. Feist. Carbon and oxygen dynamics on the Louisiana continental shelf: role of water column primary production and respiration. Presented at ASLO 2013 Aquatic Sciences Meeting, February 17 - 22, 2013.
The is a report on studies of the Gulf of Mexico hypoxic zone
We conducted a multi-year study of the Louisiana continental shelf (LCS) to better understand the linkages between water column net metabolism and the formation of hypoxia (dissolved oxygen <2 ml O2 L-1) in the region. Rates of water column community respiration (R) and primary production (P) were measured on seven cruises from 2005-2007 at multiple sites distributed across the Louisiana continental shelf, overlapping the region where bottom-water hypoxia occurs. Both P and R volumetric rates were highest at inner shelf stations (<30 m depth) and decreased with increasing water depth. Viewed by salinity zone, P and R peaked in mid-salinity plume waters (salinity 18-27). Integrated rates of P and R suggested that water column metabolism was more autotrophic in plume waters and become more heterotrophic in high salinity waters (>32). Spatial interpolations of the entire dataset indicated that the LCS is net heterotrophic with an organic carbon deficit on the order of 11 mol C m-2 y-1. We offer observation and model based budgeting exercises to suggest that riverine and inshore coastal waters can be significant sources of organic carbon to account for this deficit.
Record Details:Record Type: DOCUMENT (PRESENTATION/SLIDE)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LABORATORY
GULF ECOLOGY DIVISION