Biological agents commonly form and destroy carbonates. Some cyanobacteria are among the most common, widespread and environmentally significant agents of bio-erosion. They actively dissolve calcareous substrates, excavating microscopic galleries as they grow within them. Their activity explains several phenomena of geological importance, ranging from the morphogenesis of coastal limestone to the cementation of stromatolites, and may be sensitive to global climate change. In spite of this, the mechanism by which phototrophic organisms are able to bore remained in the dark for more than a century. In a previous project we developed a workable mineral / microbial borer experimental system based on a new cyanobacterial isolate (strain BC008) that allowed us to use micro-analytical imaging techniques to monitor the boring process in real time. This work significantly changed our mechanistic understanding of the process. We now know that boring is likely driven by the action of membrane-bound Ca2+ transporting ATPases, powered directly by photosynthetically derived ATP, acting to maintain the levels of free Ca2+ in the interstitial space of the distal borehole very low, a situation that promotes local calcite dissolution, with Ca2+ then travelling intracellularly down a concentration gradient in the filament to be released into the outside medium.
|Effective start/end date||9/1/12 → 8/31/16|
- National Science Foundation (NSF): $449,861.00
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