Radioisotope tracer studies of inorganic carbon and Ca in microbially derived CaCO3
October 10, 1999
Microbial calcification significantly impacts the cycling and deposition of inorganic carbon. This research employs 45Ca and 14C techniques as radioisotopic tracers to examine the role of cellular cycling of Ca2+ and inorganic carbon in CaCO3 precipitation by the unicellular green alga Nannochloris atomus. Implications of the effects of these physiological aspects on CaCO3 precipitation and the effects of microbial calcification on CaCO3 δ13C ratios are discussed. Results from pulse/chase experiments indicate that intracellular Ca2+ is incorporated into extracellular CaCO3. Intracellular inorganic carbon leaks from cells within 10 to 12 s after injection of unlabelled NaHCO3, providing a source of inorganic carbon for extracellular CaCO3. Cellular expulsion of calcium plays a key role in increasing the CaCO3 saturation state at the site of calcification. The δ13C ratios of microbial carbonates may vary depending on the amount of photorespiratory CO2 incorporated.
Citation Information
Publication Year | 1999 |
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Title | Radioisotope tracer studies of inorganic carbon and Ca in microbially derived CaCO3 |
DOI | 10.1016/S0016-7037(98)00297-X |
Authors | Kimberly K. Yates, Lisa L. Robbins |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Geochimica et Cosmochimica Acta |
Index ID | 70128628 |
Record Source | USGS Publications Warehouse |
USGS Organization | Coastal and Marine Geology Program |