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Microbial lime-mud production and its relation to climate change

September 12, 2001

Microbial calcification has been identified as a significant source of carbonate sediment production in modern marine and lacustrine environments around the globe. This process has been linked to the production of modern whitings and large, micritic carbonate deposits throughout the geologic record. Furthermore, carbonate deposits believed to be the result of cyanobacterial and microalgal calcification suggest that the potential exists for long-term preservation of microbial precipitates and storage of carbon dioxide (CO2). Recent research has advanced our understanding of the microbial-calcification mechanism as a photosynthetically driven process. However, little is known of the effects of this process on inorganic carbon cycling or of the effects of changing climate on microbial-calcification mechanisms.

Laboratory experiments on microbial cellular physiology demonstrate that cyanobacteria and green algae can utilize different carbon species for metabolism and calcification. Cyanobacterial calcification relies on bicarbonate (HCO3)utilization while green algae use primarily CO2. Therefore, depending on which carbonate species (HCO3 or CO2) dominates in the ocean or lacustrine environments (a condition ultimately linked to atmospheric partial pressure PCO2), the origin of lime-mud production by cyanobacteria and/or algae may fluctuate through geologic time. Trends of cyanobacteria versus algal dominance in the rock record corroborate this conclusion. These results suggest that relative species abundances of calcareous cyanobacteria and algae in the Phanerozoic may serve as potential proxies for assessing paleoclimatic conditions, including fluctuations in atmospheric PCO2.

Publication Year 2001
Title Microbial lime-mud production and its relation to climate change
Authors K. K. Yates, L. L. Robbins
Publication Type Book Chapter
Publication Subtype Book Chapter
Series Title AAPG Studies in Geology
Series Number 47
Index ID 70124917
Record Source USGS Publications Warehouse
USGS Organization Coastal and Marine Geology Program