Urania basin in the deep Mediterranean Sea houses a lake that is more than 100 m deep, devoid of oxygen, six times more saline than seawater, and has very high levels of methane and particularly sulfide (up to 16 mM), making it among the most sulfidic water bodies on Earth. Along the depth profile there are two chemoclines, a steep one with the overlying oxic seawater, and another between anoxic brines of different density, where gradients of salinity, electron donors and acceptors occur. In order to identify and differentiate the microbes and processes contributing to the turnover of organic matter and sulfide along the water column, these chemoclines were sampled at a high resolution. Bacterial cell numbers increased up to a hundred fold in the chemoclines as a consequence of elevated nutrient availability, with higher numbers in the upper interface where redox gradient was steeper. Bacterial and archaeal communities, analyzed by DNA-fingerprinting, 16S rRNA gene libraries, activity measurements and cultivation, were highly stratified and metabolically more active along the chemoclines compared with seawater or the uniformly hypersaline brines. Detailed analysis of 16S rRNA gene sequences revealed that in both chemoclines delta- and epsilon-Proteobacteria, predominantly sulfate reducers and sulfur oxidizers, respectively, were the dominant bacteria. In the deepest layers of the basin MSBL1, putatively responsible for methanogenesis, dominated amongst archaea. The data suggest that the complex microbial community is adapted to the basin’s extreme chemistry and the elevated biomass is driven largely by sulfur cycling and methanogenesis.
Sulfur cycling and methanogenesis primarily drive microbial colonization of the highly sulfidic Urania deep hypersaline basin / S. Borin, L. Brusetti, F. Mapelli, G. D’Auria, T. Brusa, M. Marzorati, A. Rizzi, M. Yakimov, D. Marty, G.J. De Lange, P. Van der Wielen, H. Bolhuis, T.J. Mcgenity, P.N. Polymenakou, E. Malinverno, L. Giuliano, C. Corselli, D. Daffonchio. - In: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. - ISSN 0027-8424. - 106:23(2009), pp. 9151-9156.
|Titolo:||Sulfur cycling and methanogenesis primarily drive microbial colonization of the highly sulfidic Urania deep hypersaline basin|
|Parole Chiave:||Deep anoxic hypersaline lake; Element cycling; Geosphere-biosphere interaction; Mediterranean Sea; Microbial diversity|
|Settore Scientifico Disciplinare:||Settore AGR/16 - Microbiologia Agraria|
Settore BIO/07 - Ecologia
Settore BIO/19 - Microbiologia Generale
|Data di pubblicazione:||2009|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1073/pnas.0811984106|
|Appare nelle tipologie:||01 - Articolo su periodico|
File in questo prodotto:
|Borin_et_al,_sulphur_cycling_and_methanogenesis_Urania_colonisation_PNAS 2009.pdf||Post-print, accepted manuscript ecc. (versione accettata dall'editore)||Open Access Visualizza/Apri|