Atmosphere-ocean oxygen and productivity dynamics during early animal radiations.

ABSTRACT: The proliferation of large, motile animals 540 to 520 Ma has been linked to both rising and declining O₂ levels on Earth. To explore this conundrum, we reconstruct the global extent of seafloor oxygenation at approximately submillion-year resolution based on uranium isotope compositions of 187 marine carbonates samples from China, Siberia, and Morocco, and simulate O₂ levels in the atmosphere and surface oceans using a mass balance model constrained by carbon, sulfur, and strontium isotopes in the same sedimentary successions. Our results point to a dynamically viable and highly variable state of atmosphere-ocean oxygenation with 2 massive expansions of seafloor anoxia in the aftermath of a prolonged interval of declining atmospheric pO₂ levels. Although an

SUBMITTER: Dahl TW 

PROVIDER: S-EPMC6765300 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature