Unveiling microbial life in new deep-sea hypersaline Lake Thetis. Part I: Prokaryotes and environmental settings
Article first published online: 25 APR 2011
© 2011 Society for Applied Microbiology and Blackwell Publishing Ltd
Thematic Issue: Extremophiles. Guest Editors: Ricardo Cavicchioli, Ricardo Amils, Dirk Wagner, Terry McGenity
Volume 13, Issue 8, pages 2250–2268, August 2011
How to Cite
La Cono, V., Smedile, F., Bortoluzzi, G., Arcadi, E., Maimone, G., Messina, E., Borghini, M., Oliveri, E., Mazzola, S., L'Haridon, S., Toffin, L., Genovese, L., Ferrer, M., Giuliano, L., Golyshin, P. N. and Yakimov, M. M. (2011), Unveiling microbial life in new deep-sea hypersaline Lake Thetis. Part I: Prokaryotes and environmental settings. Environmental Microbiology, 13: 2250–2268. doi: 10.1111/j.1462-2920.2011.02478.x
- Issue published online: 21 AUG 2011
- Article first published online: 25 APR 2011
- Received 24 November, 2010; accepted 28 February, 2011.
In September 2008, an expedition of the RV Urania was devoted to exploration of the genomic richness of deep hypersaline anoxic lakes (DHALs) located in the Western part of the Mediterranean Ridge. Approximately 40 nautical miles SE from Urania Lake, the presence of anoxic hypersaline lake, which we named Thetis, was confirmed by swath bathymetry profiling and through immediate sampling casts. The brine surface of the Thetis Lake is located at a depth of 3258 m with a thickness of ∼157 m. Brine composition was found to be thalassohaline, saturated by NaCl with a total salinity of 348‰, which is one of highest value reported for DHALs. Similarly to other Mediterranean DHALs, seawater-brine interface of Thetis represents a steep pycno- and chemocline with gradients of salinity, electron donors and acceptors and posseses a remarkable stratification of prokaryotic communities, observed to be more metabolically active in the upper interface where redox gradient was sharper. [14C]-bicarbonate fixation analysis revealed that microbial communities are sustained by sulfur-oxidizing chemolithoautotrophic primary producers that thrive within upper interface. Besides microaerophilic autotrophy, heterotrophic sulfate reduction, methanogenesis and anaerobic methane oxidation are likely the predominant processes driving the ecosystem of Thetis Lake.