title: Does iron inhibit cryptoendolithic microbial communities?
abstract: Photosynthetic activity of three cryptoendolithic microbial communities was studied under controlled conditions in the laboratory.  In two of these communities, the dominant organisms were lichens, collected from Linnaeus Terrace and from Battleship Promontory.  The third community, dominated by cyanobacteria, was collected from Battleship Promontory.  Both sites are in the ice-free valleys of southern Victoria Land.  Previous efforts have shown how physical conditions can influence metabolic activity in endolithic communities (Kappen and Friedmann 1983; Kappen, Friedmann, and Garty 1981; Vestal, Federle, and Friedmann 1984).  Biological activity can also be strongly influenced by the chemical environment.  Inorganic nutrients such as nitrate, ammonia, and phosphate are often limiting factors, so their effects on photosynthetic carbon-14 bicarbonate incorporation were investigated.  Iron and manganese are two metals present in Linnaeus Terrace and Battleship Promontory sandstones, and their effects on photosynthesis were also studied.  The results may add to our understanding of biogeochemical interactions within this unique microbial community.
authors.affiliation: Department of Biological Sciences, University of Cincinnati, Ohio 45221-0006, USA.
authors.forename: C G
authors.initials: CG
authors.lastname: Johnston
authors.forename: J R
authors.initials: JR
authors.lastname: Vestal
mesh_terms: D000641:Ammonia / Q000494:pharmacology; D000864:Antarctic Regions; D001639:Bicarbonates / Q000378:metabolism; D002250:Carbon Radioisotopes; D000458:Cyanobacteria / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D055593:Geological Phenomena; D005844:Geology; D007501:Iron / Q000494:pharmacology*; D008011:Lichens / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D008345:Manganese / Q000494:pharmacology; D009566:Nitrates / Q000494:pharmacology; D010710:Phosphates / Q000494:pharmacology; D010788:Photosynthesis / Q000187:drug effects* / Q000502:physiology
chemical_list: D001639:Bicarbonates; D002250:Carbon Radioisotopes; D009566:Nitrates; D010710:Phosphates; D008345:Manganese; D000641:Ammonia; D007501:Iron