|High prokaryote diversity and analysis of community structure in mobile mud deposits off French Guiana: identification of two new bacterial candidate divisions|Madrid, V.M.; Aller, J.Y.; Aller, R.C.; Chistoserdov, A.Y. (2001). High prokaryote diversity and analysis of community structure in mobile mud deposits off French Guiana: identification of two new bacterial candidate divisions. FEMS Microbiol. Ecol. 37: 197-209. dx.doi.org/10.1016/S0168-6496(01)00165-9
In: FEMS Microbiology Ecology. Federation of European Microbiological Societies: Amsterdam. ISSN 0168-6496, more
16S rDNA library; Bacterial diversity; Archaeal diversity; Mobile mud sediment
|Authors|| || Top |
- Madrid, V.M.
- Aller, J.Y.
- Aller, R.C.
- Chistoserdov, A.Y., correspondent
Bacterial and archaeal community compositions in highly mobile nearshore muds typical of the Guiana coastline of South America were examined by sequence analysis of a 16S rDNA clone library. DNA was extracted from a subsurface sediment layer (10-30 cm) collected at a subtidal (~1 m deep) mud wave site between Kourou and Sinnamary, French Guiana. Analysis of 96 non-chimeric sequences showed the majority to be bacteria (98%), that diversity was high with 64 unique sequences, and that proteobacteria were dominant (46%). Two crenarchaeota sequences were found (2%). Bacterial sequences belonged to the Cytophaga-Flexibacter-Bacteroides (18%), Actinobacteria (11.5%), Planctomycetes (6.3%), Cyanobacteria (3.2%), low-GC Gram-positive (1%), alpha, gamma, and delta-subdivisions of Proteobacteria (27%, 16%, and 9%, respectively). Additional bacterial sequences belonged to the candidate division TM6 (1%) and to two newly proposed candidate divisions: KS-A (2%) and KS-B (3%). A sizeable fraction (22%) of sequences from the Kourou-Sinnamary library are normally found in water column populations, reflecting frequent entrainment of suspended debris into physically reworked underlying sediments. Dominant sequences (56%) were related to Gelidibacter algens (Cytophaga-Flexibacter-Bacteroides group), Actinobacteria, Sulfitobacter and Ruegeria spp. (alpha-proteobacteria), all of which are chemoorganotrophs, consistent with abundant labile organic carbon. The presence of sequences from potential sulfate reducers and sulfide oxidizers suggests the likelihood of sulfur cycling in these sediments, despite the dominance of suboxic (iron-reducing), non-sulfidic diagenetic properties. Rarefaction analysis indicated that bacterial diversity in the French Guiana library is not only unusually high in comparison with other marine sedimentary environments, but among the most diverse of all environments reported to date.