期刊
EARTH AND PLANETARY SCIENCE LETTERS
卷 460, 期 -, 页码 180-191出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.epsl.2016.12.015
关键词
biomarkers; aryl isoprenoids; green sulfur bacteria; moretanes; Guadalupian-Lopingian boundary; Permian-Triassic boundary
资金
- State Key R&D Program of China [2016YFA0601104]
- National Natural Science Foundation of China [41330103, 41202240, 41290262]
- 111 Project [B08030]
- State Key Laboratory of Geological Processes and Mineral Resources (CUG-Wuhan) [GPMR201301]
Microbial communities are known to expand as a result of environmental deterioration during mass extinctions, but differences in microbial community changes between extinction events and their underlying causes have received little study to date. Here, we present a systematic investigation of microbial lipid biomarkers spanning similar to 20 Myr (Middle Permian to Early Triassic) at Shangsi, South China, to contrast microbial changes associated with the Guadalupian-Lopingian boundary (GLB) and Permian Triassic boundary (PTB) mass extinctions. High-resolution analysis of the PTB crisis interval reveals a distinct succession of microbial communities based on secular variation in moretanes, 2-methylhopanes, aryl isoprenoids, steranes, n-alkyl cyclohexanes, and other biomarkers. The first episode of the PTB mass extinction (ME1) was associated with increases in red algae and nitrogen-fixing bacteria along with evidence for enhanced wildfires and elevated soil erosion, whereas the second episode was associated with expansions of green sulfur bacteria, nitrogen-fixing bacteria, and acritarchs coinciding with climatic hyperwarming, ocean stratification, and seawater acidification. This pattern of microbial community change suggests that marine environmental deterioration was greater during the second extinction episode (ME2). The GLB shows more limited changes in microbial community composition and more limited environmental deterioration than the PTB, consistent with differences in species-level extinction rates (similar to 71% vs. 90%, respectively). Microbial biomarker records have the potential to refine our understanding of the nature of these crises and to provide insights concerning possible outcomes of present-day anthropogenic stresses on Earth's ecosystems. (C) 2016 Elsevier B.V. All rights reserved.
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