Bacterial colonization and weathering of terrestrial obsidian in Iceland
Bacterial colonization and weathering of terrestrial obsidian in Iceland
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DOI：
10.1080/01490450701828982
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发表时间：
2008-01-01
影响因子：
2.3
通讯作者：
Tindle, Andrew G.
中科院分区：
文献类型：
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作者：
Herrera, Aude;Cockell, Charles S.;Tindle, Andrew G.
通过风化过程，火山岩有助于营养物质流入生物圈和大气CO2下降。由于流纹岩的二氧化硅含量较高，生物重要元素的浓度低于玄武岩，因此预计它们不太容易被生物群风化。本文报道了对冰岛一个熔岩流中富含硅质流纹质玻璃（黑曜石）的微生物多样性和风化作用的研究。岩石全基因组DNA的16S rDNA分析表明，岩石中真细菌的多样性显著。如FISH所示，不规则的点蚀风化纹理对应于真细菌定植区域。风化过程中进行的蚀变锋，具有潜在的营养丰富的地区含有斜长石和辉石晶体的偏好，虽然这些功能是不太明确的比以前报道的玄武岩玻璃，与较低的化学风化率以前报道的流纹玄武岩相比。在体外风化的岩石进行了测试，在实验室中培养，通过纤维束扫描电镜检查的生物膜。该生物膜包含一个由一种优势生物组成的种群，该生物不对应于环境16S rDNA分析中的任何序列，表明实验室风化实验不能代表自然界中原核生物风化的潜在复杂性。
Through weathering processes, volcanic rocks contribute both to nutrient flux into the biosphere and atmospheric CO2 drawdown. As rhyolitic rocks are of higher silica content and have lower concentrations of biologically-important elements than basalts they might be expected to be less easily weathered by a biota. Investigations on the microbial diversity and weathering of silica-rich rhyolitic glass (obsidian) from a lava flow in Iceland are reported. 16S rDNA analysis of rock whole genome DNA shows that the rock hosts remarkable eubacterial diversity. Irregular pitted weathering textures correspond to regions of eubacterial colonization as shown by FISH. Weathering processes proceed at alteration fronts, with a preference for potentially nutrient-rich regions containing plagioclase and pyroxene crystals, although these features are less well defined than those previously reported from basaltic glass, consistent with the lower rates of chemical weathering previously reported for rhyolites compared to basalts. In-vitro weathering of the rock was tested by culturing in the laboratory resulting in a biofilm examined by FIB-SEM. This biofilm contained a population consisting of one dominant organism that did not correspond to any sequence in the environmental 16S rDNA analysis, showing that laboratory weathering experiments are unrepresentative of the potential complexity of prokaryotic weathering in nature.