Abstract
Lake Salda, located in the lakes district of Turkey, is a closed system, extremely alkaline lake within ophiolites. For the first time gemicrobiology of Lake Salda and its influence on present–day stromatolite formation have been investigated with a combined, molecular ecology, microbiology and geochemical approach. Next generation sequences results showed that 97.3 % and 2.7 % of prokaryotic population of the lake belongs to bacteria and archea domain, respectively. Dominant bacteria classes are Gam-maprotobacteria (% 39.6), Alphaprotobacteria (% 25.6), Bacilli (% 23.7), Cyanobacteria (% 5.3) Betaproteobacteria (% 2.0) and Actinobacteria (% 1.77). Dominant archea classes are Methanobacteria (% 76.1), Halobacteria (% 21.4) and Thaumarchaeota (% 1.4). Microscope studies on the recent living stromatolite structure showed intimate relation between hydromagnesite precipitation and exopolimeric organic substances (EPS) produced by phototrophic and heterotrophic microorganims. Diatoms are commonly identified around the living stromatolite. These data suggest a symbiotic relationship between phototrophic and heterotrophic microorganims during stromatolite formation. Petrographic investigation of fosil stromatolite revealed filament traces of living cyanobacteria or algae. The results indicate that stromatolite forms under a complex biological, chemical and physical biogeochemical processes and also indicate that bacteria serve as a nucleation site and control kinetic factors such as precipitation rate by lowering activation energy rather than thermodynamic factors (e.g alkalinity, pH). Furthermore, the results demonstrated that in contrast to microbial factors mineralogical composition and spatial distribution of stromatolite are influenced by lake water chemistry controlled by water-rock interactio. Overall, the current study in the Lake Salda suggest that fosil and present-day stromatolite formation may provide valuable information about traces of early life preserved in the geological records.
| Translated title of the contribution | Geomicrobiology of lake salda and microbial influences on present-day stromatolite formation |
|---|---|
| Original language | Turkish |
| Pages (from-to) | 19-40 |
| Number of pages | 22 |
| Journal | Yerbilimleri/ Earth Sciences |
| Volume | 39 |
| Issue number | 1 |
| Publication status | Published - 2018 |
Bibliographical note
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