Flourishing ocean drives the end-Permian marine mass extinction

Abstract

The end-Permian mass extinction, the most severe biotic crisis in the Phanerozoic, was accompanied by climate change and expansion of oceanic anoxic zones. The partitioning of sulfur among different exogenic reservoirs by biological and physical processes was of importance for this biodiversity crisis, but the exact role of bioessential sulfur in the mass extinction is still unclear. Here we show that globally increased production of organic matter affected the seawater sulfate sulfur and oxygen isotope signature that has been recorded in carbonate rock spanning the Permian−Triassic boundary. A bifurcating temporal trend is observed for the strata spanning the marine mass extinction with carbonate-associated sulfate sulfur and oxygen isotope excursions toward decreased and increased values, respectively. By coupling these results to a box model, we show that increased marine productivity and successive enhanced microbial sulfate reduction is the most likely scenario to explain these temporal trends. The new data demonstrate that worldwide expansion of euxinic and anoxic zones are symptoms of increased biological carbon recycling in the marine realm initiated by global warming. The spatial distribution of sulfidic water column conditions in shallow seafloor environments is dictated by the severity and geographic patterns of nutrient fluxes and serves as an adequate model to explain the scale of the marine biodiversity crisis. Our results provide evidence that the major biodiversity crises in Earth's history do not necessarily implicate an ocean stripped of (most) life but rather the demise of certain eukaryotic organisms, leading to a decline in species richness.sulfur cycle | end-Permian mass extinction | primary productivity

Impact of the Late Triassic mass extinction on functional diversity and composition of marine ecosystems

“…; Schobben et al . , ). Such a scenario may also explain the earlier exclusion of suspension feeding guilds after the Carnian as a result of the CPE (Dal Corso et al .…”

Latest Permian carbonate carbon isotope variability traces heterogeneous organic carbon accumulation and authigenic carbonate formation

“…This could have been caused by decreased seawater oxygenation instigated by stagnating ocean circulation (Wignall and Twitchett, 1996;Winguth et al, 2015). Alternatively, a higher OC sinking flux might have led to increased O 2 drawdown through aerobic respiration and H 2 S production by sulfate-reducing microbes, leading to widespread marine euxinia (Meyer et al, 2008;Algeo et al, 2013;Schobben et al, 2015). However, δ 13 C variability complies most compellingly with at least continuing OC accumulation over the studied interval and thereby largely undermines scenarios of reduced primary productivity (e.g., Rampino and Caldeira, 2005).…”

Redox chemistry changes in the Panthalassic Ocean linked to the end-Permian mass extinction and delayed Early Triassic biotic recovery

“…Several lines of evidence from the low paleolatitude Paleotethys and high paleolatitude Boreal oceans, which accounted for ∼10-15% of the contemporaneous global ocean area, suggest that sulfidic (H 2 S-rich) conditions may have developed widely during the end-Permian extinction (7)(8)(9)(10)(11)(12)(13). However, redox chemistry changes in the Panthalassic Ocean, comprising ∼85-90% of the global ocean area, remain controversial, with competing hypotheses proposing extensive deepwater anoxia ("superanoxic ocean") or suboxic deep waters in combination with spatially constrained thermocline anoxia (14)(15)(16)(17)(18).…”