Modern microbial mats constitute rich repositories of biogeochemical information regarding the community structure and carbon flow within the mat ecosystem through time and provide valuable insights into Earth’s earliest communities. Using a hypersaline microbial mat core from Guerrero Negro, Mexico, we analysed the lipid constituents from the active microbial layers and the underlying sediments. Our comprehensive lipid survey considered the free (extractable) lipid assemblages as well as the distributions and abundances of bound lipid structures released from fragmentation of insoluble macromolecular organic matter (IMOM). A wide variety of lipid types, including abundant steroids and hopanoids, were recovered from both organic phases, reflecting the rich microbial diversity within this mat ecosystem. A major contribution from photosynthetic mat organisms was preserved by binding into the IMOM phase; including hydrocarbons derived from phytol and long-chain alkanes from fragmentation of algaenans. The stable carbon isotopic composition (δ¹³C_org) of the mat organic matter was faithfully recorded, even in the deepest sedimentary layers that had experienced the highest degree of diagenetic alteration. The consistently ¹³C-enriched signatures for bulk organic matter observed through the core (ranging from −8.9‰ to −11.5‰) reflected low net isotopic fractionation associated with autotrophic carbon fixation in this alkaline pond setting. A major finding was the rapid dominance of IMOM as the major organic matter phase (>95%) after only a few years of diagenesis and burial. Such studies on modern microbial ecosystems aid toward a better understanding of the molecular taphonomic controls on the recent and ancient biomarker records.

现代微生物垫构成了丰富的生物地球化学信息库，这些信息涉及垫层生态系统中随着时间流逝的群落结构和碳流量，并为了解地球上最早的群落提供了宝贵的见解。我们使用墨西哥格雷罗格罗（Guerrero Negro）的高盐微生物垫芯，分析了活性微生物层和下层沉积物中的脂质成分。我们全面的脂质调查考虑了游离的（可提取的）脂质组合以及不溶性大分子有机物（IMOM）碎裂释放的结合脂质结构的分布和丰度。从这两个有机相中回收了多种脂质类型，包括丰富的类固醇和类胡萝卜素，反映了该垫生态系统中丰富的微生物多样性。通过结合到IMOM相中，保留了光合作用垫生物的主要贡献。包括衍生自植醇的烃和藻类分解产生的长链烷烃。稳定碳同位素组成（δ甚至在经历了最高成岩作用改变程度的最深沉积层中，也忠实地记录了垫层有机物的¹³ C _org）。一贯¹³散装有机物通过核心观察到C-富集签名（范围从-8.9‰〜-11.5‰）反映了自养碳固定在该碱性池塘设定相关联的低的净同位素分馏。一个主要发现是成岩和埋葬仅几年后，IMOM就迅速成为主要有机质相（> 95％）。对现代微生物生态系统的此类研究有助于更好地了解近期和古代生物标志物记录中的分子分子学控制。