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Biogeochemical consequences of macrofauna burrow ventilation
1Naval Research Laboratory, Seafloor Sciences Branch, Stennis Space Center, MS 39529, USA. yoko.furukawa@nrlssc.navy.mil
Geochemical Transactions
|June 9, 2006
Summary
Macrofauna burrows significantly alter aquatic sediment chemistry. Periodic ventilation causes chemical oscillations near burrow walls, impacting minerals and microbes.
Area of Science:
- Geochemistry
- Environmental Science
- Microbiology
Background:
- Burrow walls in aquatic sediments are hotspots for chemical mass transfer.
- Quantifying this transfer is challenging due to the dynamic chemical environment near burrows caused by periodic ventilation.
Purpose of the Study:
- To model and quantify the magnitude and temporal dynamics of chemical mass transfer near burrow walls.
- To assess the impact of these dynamics on the surrounding sediment environment.
Main Methods:
- Development and application of a temporally dynamic, 2D multicomponent diffusion-reaction model.
- Simulation of chemical conditions in the immediate vicinity of burrow walls and at the water/sediment interface.
Main Results:
- Significant oscillations in pH (up to two units) and dissolved oxygen (saturation to near anoxia) were observed within millimeters of burrow walls.
- These oscillations were absent at the water/sediment interface.
- Model results highlight the localized and dynamic nature of burrow wall geochemistry.
Conclusions:
- Geochemical oscillations near burrow walls are expected to influence mineral stability.
- Microbial activity, community structure, and diagenetic reaction rates are likely affected by these dynamic chemical changes.
- Understanding these localized effects is crucial for aquatic sediment biogeochemistry.