Microbial Community Variations Recorded by Biomarkers in a Tropical Peatland During the end Permian Mass Extinction

Summary Terrestrial ecosystem is a particularly important type of ecosystems on the earth, especially on the extreme climate periods, such as the end Permian mass extinction (EPME). It also can affect the marine ecosystem directly, such as large nutrient inputs induced by terrestrial weathering. Studying the changes of it can provide a way to understand the mechanism of the EPME. Current understanding of terrestrial ecosystem crisis is often based on plant fossils. However, studies of fossil-based terrestrial ecosystem are limited, e.g., the absence of record of lower organisms, including microorganisms. The microbial changes, which are always associated with contemporaneous environmental changes, can be traced by lipid biomarkers. Here, we provide a systematic investigation on the lipid biomarkers from a paleo-tropical peatland in southwest China to explore the contemporaneous environmental changes. Our lipids biomarker data identifies that terrestrial ecosystem had begun to become unstable prior to the extinction of conventional wisdom. Our records also reveal two episodes of elevated bacterial contribution relative to eukaryotes and massive soil erosion, which may be caused by two different events: the former was related to wildfires and the latter was related to Siberian Trap intrusions.