Data/hora: 10/06/2024 18:24:49

Provedor de dados: | 5
País: | France
Título: | Key Role of Alphaproteobacteria and Cyanobacteria in the Formation of Stromatolites of Lake Dziani Dzaha (Mayotte, Western Indian Ocean)
Autores: | Gerard, Emmanuelle; De Goeyse, Siham; Hugoni, Mylene; Agogue, Helene; Richard, Laurent; Milesi, Vincent; Guyot, Francois; Lecourt, Lena; Borensztajn, Stephan; Joseph, Marie-beatrice; Leclerc, Thomas; Sarazin, Gerard; Jezequel, Didier; Leboulanger, Christophe; Ader, Magali.
Data: | 2018-05
Ano: | 2018
Palavras-chave: | Stromatolites; Alkaline lake; Pleurocapsales; Mg-silicate; Alphaproteobacteria; Anoxygenic phototrophic bacteria; Aragonite; Hydromagnesite.
Resumo: | Lake Dziani Dzaha is a thalassohaline tropical crater lake located on the "Petite Terre" Island of Mayotte (Comoros archipelago, Western Indian Ocean). Stromatolites are actively growing in the shallow waters of the lake shores. These stromatolites are mainly composed of aragonite with lesser proportions of hydromagnesite, calcite, dolomite, and phyllosilicates. They are morphologically and texturally diverse ranging from tabular covered by a cauliflower-like crust to columnar ones with a smooth surface. High-throughput sequencing of bacterial and archaeal 16S rRNA genes combined with confocal laser scanning microscopy (CLSM) analysis revealed that the microbial composition of the mats associated with the stromatolites was clearly distinct from that of the Arthrospira-dominated lake water. Unicellular-colonial Cyanobacteria belonging to the Xenococcus genus of the Pleurocapsales order were detected in the cauliflower crust mats, whereas filamentous Cyanobacteria belonging to the Leptolyngbya genus were found in the smooth surface mats. Observations using CLSM, scanning electron microscopy (SEM) and Raman spectroscopy indicated that the cauliflower texture consists of laminations of aragonite, magnesium-silicate phase and hydromagnesite. The associated microbial mat, as confirmed by laser microdissection and wholegenome amplification (WGA), is composed of Pleurocapsales coated by abundant filamentous and coccoid Alphaproteobacteria. These phototrophic Alphaproteobacteria promote the precipitation of aragonite in which they become incrusted. In contrast, the Pleurocapsales are not calcifying but instead accumulate silicon and magnesium in their sheaths, which may be responsible for the formation of the Mg-silicate phase found in the cauliflower crust. We therefore propose that Pleurocapsales and Alphaproteobacteria are involved in the formation of two distinct mineral phases present in the cauliflower texture: Mg-silicate and aragonite, respectively. These results point out the role of phototrophic Alphaproteobacteria in the formation of stromatolites, which may open new perspective for the analysis of the fossil record.
Tipo: | Text
Idioma: | Inglês

Identificador:

https://archimer.ifremer.fr/doc/00443/55451/56970.pdf

https://archimer.ifremer.fr/doc/00443/55451/56971.pdf

DOI:10.3389/fmicb.2018.00796

https://archimer.ifremer.fr/doc/00443/55451/

Editor: | Frontiers Media Sa
Formato: | application/pdf
Fonte: | Frontiers In Microbiology (1664-302X) (Frontiers Media Sa), 2018-05 , Vol. 9 , P. 796 (20p.)

Fonte:

2018 Gérard, De Goeyse, Hugoni, Agogué, Richard, Milesi, Guyot, Lecourt, Borensztajn, Joseph, Leclerc, Sarazin, Jezequel, Leboulanger and Ader. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cite

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