title: Photosynthesis-induced biofilm calcification and calcium concentrations in Phanerozoic oceans.
abstract: Photosynthetic carbon assimilation is commonly invoked as the cause of calcium carbonate precipitation in cyanobacterial biofilms that results in the formation of calcareous stromatolites. However, biofilm calcification patterns in recent lakes and simulation of photosynthetically induced rise in calcium carbonate supersaturation demonstrate that this mechanism applies only in settings low in dissolved inorganic carbon and high in calcium. Taking into account paleo-partial pressure curves for carbon dioxide, we show that Phanerozoic oceans sustaining calcified cyanobacteria must have had considerably higher calcium concentrations than oceans of today. In turn, the enigmatic lack of calcified cyanobacteria in stromatolite-bearing Precambrian sequences can now be explained as a result of high dissolved inorganic carbon concentrations.
authors.affiliation: Göttinger Zentrum für Geowissenschaften, Abteilung Geobiologie, Universität Göttingen, Goldschmidtstrasse 3, D-37077 Göttingen, Germany. garp@gwdg.de
authors.forename: G
authors.initials: G
authors.lastname: Arp
authors.forename: A
authors.initials: A
authors.lastname: Reimer
authors.forename: J
authors.initials: J
authors.lastname: Reitner
mesh_terms: D018441:Biofilms; D002113:Calcification, Physiologic; D002118:Calcium / Q000032:analysis* / Q000378:metabolism; D002119:Calcium Carbonate / Q000737:chemistry; D002244:Carbon / Q000032:analysis; D002245:Carbon Dioxide; D011232:Chemical Precipitation; D003460:Crystallization; D000458:Cyanobacteria / Q000502:physiology*; D005580:Fossils; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology; D006863:Hydrogen-Ion Concentration; D009792:Oceans and Seas; D010313:Partial Pressure; D010788:Photosynthesis; D012623:Seawater / Q000737:chemistry* / Q000382:microbiology; D012995:Solubility; D013995:Time
chemical_list: D002245:Carbon Dioxide; D002244:Carbon; D002119:Calcium Carbonate; D002118:Calcium