Seasonal Variability of Mineral Formation in Microbial Mats Subjected to Drying and Wetting Cycles in Alkaline and Hypersaline Sedimentary Environments
Seasonal Variability of Mineral Formation in Microbial Mats Subjected to Drying and Wetting Cycles in Alkaline and Hypersaline Sedimentary Environments
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DOI：
10.1007/s10498-018-9333-2
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发表时间：
2018-02-01
影响因子：
1.6
通讯作者：
Visscher, P. T.
中科院分区：
文献类型：
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作者：
Cabestrero, O.;Sanz-Montero, M. E.;Visscher, P. T.
在两个水化学和矿物学明显不同的浅水、短暂湖泊中评估了微生物席群落与沉积环境的相互作用。通过光学显微镜观察和荧光原位杂交对生长和腐烂的微生物垫进行表征，并辅以生物地球化学和矿物学测量。研究的湖泊是 Eras 湖和 Altillo Chica 湖，它们都位于西班牙中部，代表多重极端环境。艾拉斯湖是一个高碱性、微咸到咸水的湖泊，含有高浓度的氯化物，其中碳酸盐浓度超过硫酸盐浓度。镁的存在对于该湖微生物岩中水菱镁矿的沉淀至关重要。 Altillo Chica 是一个中盐至高盐湖，硫酸盐和氯化物浓度高，有利于石膏微生物岩的形成。两个湖泊微生物群落组成和微生物岩矿物学的差异主要受碱度和盐度控制。艾拉斯湖以蓝藻属颤藻门、α变形菌门、γ变形菌门和厚壁菌门为主。当垫子腐烂时，Alphaproteobacteria和Deltaproteobacteria增加并成为占主导地位的异养生物，而不是厚壁菌门。相比之下，Deltaproteobacteria 是 Altillo Chica 湖中最丰富的菌群，在蒸发岩形成过程中，干燥导致垫子腐烂。除了Deltaproteobacteria之外，在Altillo Chica中还发现了蓝藻菌、放线菌、Alphaproteobacteria和Gammaproteobacteria，主要是在微生物垫的生长过程中发现的。在这两个地点，微生物垫有利于硫酸盐和碳酸盐矿物的沉淀。由于碱性引擎较强，并且可能较高的胞外聚合物降解率，苏打湖中碳酸盐的沉淀较高。我们的研究结果阐明了短暂湖泊中微生物群落组成在整个群落水平上的分布模式，这些湖泊所面临的环境条件与地球早期可能存在的环境条件相似。
Interactions of the microbial mat community with the sedimentary environment were evaluated in two shallow, ephemeral lakes with markedly different hydrochemistry and mineralogy. The characterization of growing and decaying microbial mats by light microscopy observations and fluorescence in situ hybridization was complemented with biogeochemical and mineralogical measurements. The lakes studied were Eras and Altillo Chica, both located in Central Spain and representing poly-extreme environments. Lake Eras is a highly alkaline, brackish to saline lake containing a high concentration of chloride, and in which the carbonate concentration exceeds the sulfate concentration. The presence of magnesium is crucial for the precipitation of hydromagnesite in microbialites of this lake. Altillo Chica is a mesosaline to hypersaline playa lake with high concentrations of sulfate and chloride, favoring the formation of gypsum microbialites. Differences in the microbial community composition and mineralogy of the microbialites between the two lakes were primarily controlled by alkalinity and salinity. Lake Eras was dominated by the cyanobacterial genus Oscillatoria, as well as Alphaproteobacteria, Gammaproteobacteria and Firmicutes. When the mat decayed, Alphaproteobacteria and Deltaproteobacteria increased and became the dominant heterotrophs, as opposed to Firmicutes. In contrast, Deltaproteobacteria was the most abundant group in Lake Altillo Chica, where desiccation led to mats decay during evaporite formation. In addition to Deltaproteobacteria, Cyanobacteria, Actinobacteria, Alphaproteobacteria and Gammaproteobacteria were found in Altillo Chica, mostly during microbial mats growth. At both sites, microbial mats favored the precipitation of sulfate and carbonate minerals. The precipitation of carbonate is higher in the soda lake due to a stronger alkalinity engine and probably a higher degradation rate of exopolymeric substances. Our findings clarify the distribution patterns of microbial community composition in ephemeral lakes at the levels of whole communities, which were subjected to environmental conditions similar to those that may have existed during early Earth.