Present addresses: Cell and Molecular Biology, Michigan State University, East Lansing, MI 48824-4320, USA; ‡Department of Earth Science, University of Southern California, Los Angeles, CA 90089, USA; §Geochemistry, Department of Geology, Colorado School of Mines, Golden, CO 80401-1887, USA; ¶Socorro High School, Socorro, NM 87801, USA.
Diverse microbial communities inhabiting ferromanganese deposits in Lechuguilla and Spider Caves
Article first published online: 8 SEP 2003
Volume 5, Issue 11, pages 1071–1086, November 2003
How to Cite
Northup, D. E., Barns, S. M., Yu, L. E., Spilde, M. N., Schelble, R. T., Dano, K. E., Crossey, L. J., Connolly, C. A., Boston, P. J., Natvig, D. O. and Dahm, C. N. (2003), Diverse microbial communities inhabiting ferromanganese deposits in Lechuguilla and Spider Caves. Environmental Microbiology, 5: 1071–1086. doi: 10.1046/j.1462-2920.2003.00500.x
- Issue published online: 8 SEP 2003
- Article first published online: 8 SEP 2003
- Received 19 May, 2003; accepted 6 June, 2003.
Lechuguilla Cave is an ancient, deep, oligotrophic subterranean environment that contains an abundance of low-density ferromanganese deposits, the origin of which is uncertain. To assess the possibility that biotic factors may be involved in the production of these deposits and to investigate the nature of the microbial community in these materials, we carried out culture-independent, small subunit ribosomal RNA (SSU rRNA) sequence-based studies from two sites and from manganese and iron enrichment cultures inoculated with ferromanganese deposits from Lechuguilla and Spider Caves. Sequence analysis showed the presence of some organisms whose closest relatives are known iron- and manganese-oxidizing/reducing bacteria, including Hyphomicrobium, Pedomicrobium, Leptospirillum, Stenotrophomonas and Pantoea. The dominant clone types in one site grouped with mesophilic Archaea in both the Crenarchaeota and Euryarchaeota. The second site was dominated almost entirely by lactobacilli. Other clone sequences were most closely related to those of nitrite-oxidizing bacteria, nitrogen-fixing bacteria, actinomycetes and β- and γ-Proteobacteria. Geochemical analyses showed a fourfold enrichment of oxidized iron and manganese from bedrock to darkest ferromanganese deposits. These data support our hypothesis that microorganisms may contribute to the formation of manganese and iron oxide-rich deposits and a diverse microbial community is present in these unusual secondary mineral formations.