Aquatic Sciences Meeting, Albuquerque 2001

SS08 Processes at the Benthic Interface (Environmental Connections)

Date: Wednesday, February 14, 2001, Time: 11:45:00 AM

Location: Ruidoso/Pecos

Wenzhöfer, F, , Max Planck Institute for Marine Microbiology, Bremen, Germany, fwenzhoe@mpi-bremen.de

DeBeer, D, , Max Planck Institute for Marine Microbiology, Bremen, Germany, debeer@mpi-bremen

OXYGEN AND H2S DYNAMICS DURING A DAILY AND SEASONAL CYCLE IN A TIDAL INFLUENCED PERMEABLE SANDY SEDIMENT

Aerobic respiration and sulfate reduction are the dominant microbial degradation processes in marine ecosystems. Coastal sediments are subjected to strong daily and seasonal physico-chemical changes, influencing the metabolic pathways and the benthic communities. In sediments aerobic mineralization is limited by oxygen transport from the overlying water. In permeable sediments this transport is forced by advection. Surface waves and tidal cycles cause pressure oscillations that increase the flow through these permeable sands. In situ microelectrode measurements of oxygen, H2S and resistivity were performed during a daily and seasonal cycle. The profiles exhibited a highly dynamic environment with dramatic changes in the distribution of oxygen and H2S during a tidal and seasonal cycle. Oxygen penetration varied between zero and 8 cm. The H2S distribution was similarly dynamic, and no overlap between O2 and H2S profiles was observed. In situ measured resistivity profiles were used to visualise the sediment topography changes during a tidal cycle. The sediment surface changed repeatedly and consequently influences the distribution of oxygen and H2S in this environment.

This Session Listing

Aquatic Sciences Meeting, Albuquerque 2001

Quicklinks