Aquatic Sciences Meeting, Albuquerque 2001

PC09 River and Margin Biogeochemistry

Date: Wednesday, February 14, 2001

Location: Southwest Hall

Komada, T, , Inst. of Marine and Coastal Sci., Rutgers Univ., New Brunswick, USA, tkomada@imcs.rutgers.edu

Reimers, C, E, College of Oceanic and Atmospheric Sci., Oregon State Univ., Corvallis, USA, clare.reimers@hmsc.orst.edu

RESUSPENSION-INDUCED PARTITIONING OF ORGANIC CARBON BETWEEN SOLID AND SOLUTION PHASES IN A COASTAL ENVIRONMENT

Experiments were conducted to explore the effects of bottom resuspension on net exchange of organic carbon between sediments and overlying water. Surface sediments from six locations in the Hudson River Estuary and the New York Bight were resuspended in bottom water for 30 seconds to 2 hours. In most tests, the dissolved organic carbon (DOC) concentration after resuspension was greatly enhanced compared to that predicted by conservative mixing of interstitial and bottom waters, suggesting net conversion of particulate organic carbon (POC) to DOC. For a unit mass of dry sediment, the rate of DOC release during resuspension was 2 to 3 orders of magnitude greater than the combined rate of dissolved organic and inorganic carbon production within the uppermost 0.4 meters of the sediment column. This suggests that desorption or dissolution, rather than enhanced microbial activity, are the mechanisms responsible for the net conversion of POC to DOC during resuspension. As a consequence, the abundance and/or chemical composition of particulate organic matter associated with mineral phases may be efficiently altered during resuspension events as particles are exported from coastal environments to the ocean.

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Aquatic Sciences Meeting, Albuquerque 2001

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