Microbial communities in the sedimentary substrate of the Laguna Timone maar, southern Patagonia (52ºS)
Abstract
The Laguna Timone corresponds to a lake-filled maar of the Pali Aike Volcanic Field (PAVF), located at an elevation of ca. 110 m.a.s.l., produced by Late Pleistocene phreatomagmatic eruptions, involving melt water from streams and permafrost. Surficial waters of Laguna Timone are characterized by saline and alkaline brines. As in many crater-lakes off the PAVF stationary inorganic carbonate precipitation occurs in the flood zone of the lakes. In order to establish or discard the hypothesis of biogenically induced carbonate precipitation two samples from the lake sediments were studied for identifying the microbial communities through 16S rRNA Gene Sequencing. Samples of laminated silts and very fine sands were extracted at 50 cm and 100 cm depth in the substrate in the eastern shore of Laguna Timone maar. The identified bacterial genera are known for their role in biogenic processes such as nitrification of decomposed organic matter (ammonia) and methane oxidation at shallow and deep levels, respectively. Rhodoferax and Sideroxydans have been related to the redox-cycle of Fe which is a key factor in the Carbon flux, speciation and mobility of elements in aqueous fluids in a wide spectrum of natural environments. The preliminary results reveal the nonexistence of bacteria capable to induce the carbonate precipitation in the shallow sediments near the shore of the lagoon. This work was funded by LAMIR/UFPR/PETROBRAS Research Project Nº 2016/00141-1 and FONDECYT Grant 1161818.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMPP41C1559C
- Keywords:
-
- 1039 Alteration and weathering processes;
- GEOCHEMISTRY;
- 1051 Sedimentary geochemistry;
- GEOCHEMISTRY;
- 4217 Coastal processes;
- OCEANOGRAPHY: GENERAL;
- 4912 Biogeochemical cycles;
- processes;
- and modeling;
- PALEOCEANOGRAPHY