Microbialites are emblematic sedimentary rocks formed by phylogenetically and metabolically complex microbial communities thriving under specific physicochemical conditions. Most microbialites are photosynthesis-based ecosystems frequently formed by carbonates, thereby capturing inorganic carbon in the form of both, organic matter and mineral precipitates. However, little is known about the amount of sequestered carbon and the kinetics of the process, that is, microbialite growth rate. To assess microbialite growth rate and the influence of substrates on carbonate formation in Alchichica, an alkaline crater lake harbouring well-developed carbonate microbialites, we incubated in situ sterilized Nylon mesh, hydromagnesite and aragonite crystals, and bleached-coral aragonite for 2 years. We observed the rapid formation of nascent hydromagnesite and aragonite-containing microbialites on Nylon mesh, with an average growth rate of ~0.6 (and up to 1) mm year⁻¹. By contrast, only thin (< 0.2 mm) biofilms developed on exposed hydromagnesite and aragonite crystals and bleached-coral aragonite, suggesting decoupled microbial colonization and biomineralization and/or potential interference of those mineral surfaces with new carbonate nucleation. Microbial communities associated with 2-year-old microbialites and biofilms were fully comparable to mature communities populating Lake Alchichica indigenous microbialites.

中文翻译：

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墨西哥阿尔奇奇卡湖成熟微生物岩的快速形成

微生物岩是由系统发育和代谢复杂的微生物群落在特定物理化学条件下繁衍生息形成的标志性沉积岩。大多数微生物岩是基于光合作用的生态系统，通常由碳酸盐形成，从而以有机物和矿物沉淀物的形式捕获无机碳。然而，关于固碳量和过程动力学（即微生物生长速率）知之甚少。为了评估微生物岩生长速率和底物对 Alchichica 中碳酸盐形成的影响，Alchichica 是一个含有发育良好的碳酸盐微生物岩的碱性火山口湖，我们进行了原位培养灭菌尼龙网、水菱镁矿和文石晶体以及漂白珊瑚文石 2 年。我们观察到新生的水菱镁矿和含文石的微生物岩在尼龙网上快速形成，平均增长率为~0.6（和高达1）毫米年^-1。相比之下，仅在暴露的水菱镁矿和文石晶体以及漂白珊瑚文石上形成了薄 (< 0.2 mm) 生物膜，这表明微生物定殖和生物矿化和/或这些矿物表面与新的碳酸盐成核的潜在干扰是解耦的。与 2 岁微生物群落和生物膜相关的微生物群落与居住在 Alchichica 湖本土微生物群落的成熟群落完全可比。