Geomicrobiology of Cave Ferromanganese Deposits: A Field and Laboratory Investigation
Abstract:Unusual ferromanganese deposits are found in several caves in New Mexico. The deposits are enriched in iron and manganese by as much as three orders of magnitude over the bedrock, differing significantly in mineralogy and chemistry from bedrock-derived insoluble residue. The deposits contain metabolically active microbial communities. Enrichment cultures inoculated from the ferromanganese deposits produced manganese oxides that were initially amorphous but developed into crystalline minerals over an 8-month period and beyond; no such progression occurred in killed controls. Phylogenetic analyses of sequences from clone libraries constructed from culture DNA identified two genera known to oxidize manganese, but most clones represent previously unknown manganese oxidizers. We suggest that this community is breaking down the bedrock and accumulating iron and manganese oxides in an oligotrophic environment.
Document Type: Research Article
Affiliations: 1: Institute of Meteoritics, University of New Mexico, Albuquerque, New Mexico, USA 2: Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA 3: Earth and Environmental Science Department, New Mexico Institute of Mining and Technology, Socorro, New Mexico, USA 4: Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico, USA
Publication date: April 1, 2005