Constraining the oxygen requirements for modern microbial eukaryote diversity

• 成果类型: Article
• 署名作者: Mills, Daniel B.; Simister, Rachel L.; Sehein, Taylor R.; Hallam, Steven J.; Sperling, Erik A.; Crowe, Sean A.
• 署名单位: University of Munich; Stanford University; Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park; University of British Columbia; Smith College; University of British Columbia; University of British Columbia; University of British Columbia; University of British Columbia; University of British Columbia; University of British Columbia
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-11202
• DOI: 10.1073/pnas.2303754120
• 发表日期: 2024-01-09
• 关键词: atmospheric oxygen; record; EVOLUTION; rise; reveals; HISTORY; ocean

摘要

Eukaryotes originated prior to the establishment of modern marine oxygen (O2) levels. According to the body fossil and lipid biomarker records, modern (crown) microbial eukaryote lineages began diversifying in the ocean no later than -800 Ma. While it has long been predicted that increasing atmospheric O2 levels facilitated the early diversification of microbial eukaryotes, the O2 levels needed to permit this diversifi-cation remain unconstrained. Using time- resolved geochemical parameter and gene sequence information from a model marine oxygen minimum zone spanning a range of dissolved O2 levels and redox states, we show that microbial eukaryote taxonomic richness and phylogenetic diversity remain the same until O2 declines to around 2 to 3% of present atmospheric levels, below which these diversity metrics become signif-icantly reduced. Our observations suggest that increasing O2 would have only directly promoted early crown- eukaryote diversity if atmospheric O2 was below 2 to 3% of modern levels when crown- eukaryotes originated and then later met or surpassed this range as crown- eukaryotes diversified. If atmospheric O2 was already consistently at or above 2 to 3% of modern levels by the time that crown- eukaryotes originated, then the subsequent diversification of modern microbial eukaryotes was not directly driven by atmospheric oxygenation.