Aquatic Sciences Meeting, Albuquerque 2001

SS08 Processes at the Benthic Interface (Environmental Connections)

Date: Monday, February 12, 2001, Time: 2:00:00 PM

Location: Ruidoso/Pecos

Eriksson, S, P, Marine Science Research Center, State University of New York, Stony Brook, USA, seriksson@ms.cc.sunysb.edu

Aller, R, C, Marine Science Research Center, State University of New York, Stony Brook, USA,

TRANSIENT BIOGEOCHEMICAL SUCCESSION IN ORGANIC-RICH MARINE SEDIMENT

The burrowing and irrigation activities of infauna commonly expose anoxic sediment to oxygen. We experimentally simulated such sudden exposure and documented the time-dependent evolution of biogeochemical properties during oxygen penetration. Unsteady anoxic to oxic transition was monitored over a 16 day period in organic-rich sediment plugs. Sediment was kept in darkness, with fully oxygenated overlying water, at T=12°C. A suite of inorganic compounds (O2, TCO2, NO3, NO2, NH4+) were measured in the porewater at millimeter intervals, and total C, N and S measured in solids. Oxygen and N distributions evolved sequentially and reached a pseudo steady state within 9 d while dissolved C distributions continued to evolve. Distributions showed evidence for intense coupling between chemoautotrophic and heterotrophic activity as time and biogeochemical complexity progressed. Nitrification was maximal in the top ~ 1 mm, well above the oxic - anoxic transition, and anaerobic nitrification was evident at depth. Solute patterns were modeled and explanations for deviations from theory discussed.

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Aquatic Sciences Meeting, Albuquerque 2001

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