Microbial diversity and biogeochemical cycling in soda lakes

Abstract

Soda lakes contain high concentrations of sodium carbonates resulting in a stable elevated pH, which provide a unique habitat to a rich diversity of haloalkaliphilic bacteria and archaea. Both cultivation-dependent and -independent methods have aided the identification of key processes and genes in the microbially mediated carbon, nitrogen, and sulfur biogeochemical cycles in soda lakes. In order to survive in this extreme environment, haloalkaliphiles have developed various bioenergetic and structural adaptations to maintain pH homeostasis and intracellular osmotic pressure. The cultivation of a handful of strains has led to the isolation of a number of extremozymes, which allow the cell to perform enzymatic reactions at these extreme conditions. These enzymes potentially contribute to biotechnological applications. In addition, microbial species active in the sulfur cycle can be used for sulfur remediation purposes. Future research should combine both innovative culture methods and state-of-the-art ‘meta-omic’ techniques to gain a comprehensive understanding of the microbes that flourish in these extreme environments and the processes they mediate. Coupling the biogeochemical C, N, and S cycles and identifying where each process takes place on a spatial and temporal scale could unravel the interspecies relationships and thereby reveal more about the ecosystem dynamics of these enigmatic extreme environments.

Patterns and Determinants of Halophilic Archaea (Class Halobacteria) Diversity in Tunisian Endorheic Salt Lakes and Sebkhet Systems

“…Members of the Halobacteria are encountered in a wide range of environments where their absolute requirement for salt is satisfied. Within various hypersaline (Ͼ25% salt), thalassohaline (e.g., crystallizer ponds in solar salterns), and athalassohaline (e.g., the Dead Sea, hypersaline lakes, and soda lakes) water bodies, members of the Halobacteria represent the majority of the cellular biomass (1)(2)(3)(4)(5)(6). However, in environments with relatively lower salinity and/or fluctuating salinities, e.g., saline soils (salt plains and alpine salt sediments, soils adjacent to salt-processing plants), traditional Asian salted and fermented seafood products (e.g., jeotgal), and marine sponges, they usually coexist as a smaller fraction of the more diverse prokaryotic community inhabiting these settings (7)(8)(9)(10)(11)(12)(13).…”

Antimycobacterial and cytotoxic activities of extracts from fungal isolates of Lake Magadi

“…During dry seasons, carbonate salts become more concentrated due to increased evaporation rates. This leads to the formation of natural sodium carbonate/bicarbonate buffered systems with elevated pH values in the range of 9.5 -11 and salt concentrations reach saturation (Sorokin et al, 2014). This chemical composition put pressure on the biota and only haloalkaliphiles microorganisms thrive in such conditions.…”

Niche for high abundant extremophilic microbial communities in an ancient crater

“…Many studies have investigated species compositions in soils of extreme environments (Bontognali et al 2010(Bontognali et al , 2012Farías et al 2014;Jay et al 2014); however, most of these have focused on the top layers or subsurface of soils from areas such as hypersaline sediments and Sabkhas (Kjeldsen et al 2007;Abdeljabbar et al 2013;Al-Najjar et al 2014), or saline/soda lakes (Sorokin et al 2014). In such environments, the biogeochemical cycle of nitrogen and sulphur is very important and shapes the microbial communities (Oren 2008;Al-Thani et al 2014).…”