Aquatic Sciences Meeting, Albuquerque 2001

SS08 Processes at the Benthic Interface (Environmental Connections)

Date: Monday, February 12, 2001, Time: 3:00:00 PM

Location: Ruidoso/Pecos

Hartnett, H, E, Rutgers University, New Brunswick, USA, hartnett@imcs.rutgers.edu

Boehme, S, E, Rutgers University, New Brunswick, USA, boehme@imcs.rutgers.edu

Thomas, C, J, North Carolina State University, Raleigh, USA, cjthomas@unity.ncsu.edu

Nitrogen, oxygen and nutrient fluxes in continental shelf sediments from the western antarctic peninsula

Porewater oxygen and nutrient profiles, and nitrogen gas fluxes from chamber incubations were determined at three stations along the continental shelf of the western Antarctic peninsula in the vicinity of the Palmer LTER site during March 2000. The inner-most station had shallow oxygen penetration depths (2-7mm) and porewater nitrate profiles that monotonically decreased to zero at about 25mm. The outer stations had deeper oxygen penetration depths (10-25mm) and sub-surface porewater nitrate maxima. Nitrate penetration depths were greater than 30mm at the outer stations. Oxygen fluxes determined from porewater profiles ranged from 1.7-4.8 mmol O2/m2/day and were comparable to fluxes determined from chamber incubations (2.1-4.9 mmol O2/m2/day). Porewater nitrate fluxes ranged from -1.2-0.13 mmol N/m2/day. The average benthic nitrogen gas flux measured in ship-board chamber incubations was 1.28 mmol N/m2/day. These results suggest that more than 80% of the denitrification in these sediments may be due to coupled nitrification-denitrification and that Antarctic shelf denitrification may be a significant contribution to the global nitrogen budget.

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Aquatic Sciences Meeting, Albuquerque 2001

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