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Published on: October 15, 2015
Aerobic sulfate reduction in microbial mats.
1National Aeronautics and Space Administration-Ames Research Center, Space Science Division, Moffett Field, CA 94035, USA.
Science (New York, N.Y.)
|March 22, 1991
Summary
Bacterial sulfate reduction was observed in oxygenated zones of hypersaline mats, challenging the anaerobic requirement for this process. Light and oxygen levels had minimal impact on sulfate reduction rates over a 24-hour cycle.
Area of Science:
- Microbiology
- Geochemistry
- Environmental Science
Background:
- Dissimilatory sulfate reduction is traditionally considered an anaerobic process.
- Hypersaline environments harbor unique microbial communities with specialized metabolic pathways.
Purpose of the Study:
- To investigate the occurrence and rates of bacterial sulfate reduction in oxygenated hypersaline microbial mats.
- To challenge the paradigm that sulfate reduction is exclusively anaerobic.
Main Methods:
- In situ measurements of bacterial sulfate reduction rates.
- Monitoring of dissolved oxygen (O2) levels within hypersaline mats.
- Comparative analysis of sulfate reduction in oxygenated and anoxic conditions.
Main Results:
- Bacterial sulfate reduction consistently occurred within the well-oxygenated photosynthetic zone of hypersaline mats.
- Sulfate reduction rates in oxygenated mats during daytime were comparable to rates in anoxic mats at night.
- Variations in light and O2 over a 24-hour cycle showed minimal effect on sulfate reduction rates.
Conclusions:
- Dissimilatory sulfate reduction can occur in the presence of oxygen, contradicting established views.
- Microbial sulfate reduction in hypersaline mats is less sensitive to diurnal oxygen fluctuations than previously assumed.
- These findings have implications for understanding biogeochemical cycles in extreme environments.
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