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Determination of the Settling Rate of Clay/Cyanobacterial Floccules
Published on: June 11, 2018
Light-dependant biostabilisation of sediments by stromatolite assemblages
David M Paterson1, Rebecca J Aspden, Pieter T Visscher
1Sediment Ecology Research Group, Gatty Marine Laboratory, School of Biology, University of St Andrews, St Andrews, United Kingdom. dp1@st-andrews.ac.uk
Plos One
|September 11, 2008
Summary
Microbial mats in living stromatolites rapidly stabilize sediment, a process requiring light and potentially linked to early photosynthesis. This research sheds light on ancient ecosystem engineering and the evolution of life.
Area of Science:
- Ecosystem Science
- Microbiology
- Paleontology
Background:
- Stromatolites, ancient microbial ecosystems, dominated Precambrian oceans.
- Little is known about their functional ecology and persistence against environmental forces.
- Sediment capture and binding are crucial for stromatolite formation and stability.
Purpose of the Study:
- Investigate the ecosystem engineering capacity of stromatolitic microbial assemblages.
- Quantify their ability to stabilize sediment.
- Explore the role of light and microbial processes in this stabilization.
Main Methods:
- Studied living stromatolites from Highborne Cay, Bahamas.
- Measured sediment stabilization over 228 hours.
- Used microelectrode profiling (oxygen, calcium) and microscopy (low-temperature scanning electron, confocal laser).
Main Results:
- Microbial assemblages significantly increased sediment stability within 12-24 hours.
- Stabilization effect was light-dependent and partially reversible in darkness.
- Extracellular polymeric substances breakdown under anaerobic conditions was implicated.
Conclusions:
- Microbial mats are effective ecosystem engineers, stabilizing sediment.
- Light and photosynthesis are critical for stromatolite formation and persistence.
- This has implications for understanding early life and the evolution of photosynthesis.
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