Aquatic Sciences Meeting, Albuquerque 2001

SS08 Processes at the Benthic Interface (Environmental Connections)

Date: Monday, February 12, 2001, Time: 10:45:00 AM

Location: Ruidoso/Pecos

Burdige, D, J, Old Dominion University, Norfolk, VA, USA, dburdige@odu.edu

The Cycling of Dissolved Organic Matter (DOM) in Estuarine Sediments

Comparative analyses of pore water DOM and DOM benthic flux data from bioturbated and non-bioturbated estuarine sediments have been undertaken to further understand the controls on the cycling and reactivity of DOM in such sediments. Several observations result from this analysis. First, in both sediment types there appears to be enhanced production of nitrogen-rich DOM near the sediment-water interface, consistent with recent models of sediment DOM remineralization. Second, the presence/absence of sediment macrofauna, as well as differences in sediment redox conditions (anoxic vs. “mixed” redox conditions), alter the pathways of sediment DOM remineralization and lead to the buildup of refractory, low molecular weight DOM under anoxic conditions. Third, a comparison of elemental (C/N) ratios in pore water DOM and DOM benthic fluxes suggests that bacterial sources of DOM (due to, e.g., macrofaunal grazing) are important in bioturbated sediments. And finally, the observation of changes in the composition and reactivity of pore water DOM as a result of varying sediment redox conditions suggests a possible way that sediment redox conditions may affect overall sediment carbon preservation.

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Aquatic Sciences Meeting, Albuquerque 2001

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