RESPONSE OF THE BIOLOGICAL PUMP TO END-PERMIAN WARMING (Invited Presentation)

Climate warming, ocean anoxia, and mass extinction co-occur at the Permian-Triassic boundary. Perturbations in both marine biogeochemistry and physical circulation of the ocean likely resulted from rapid warming during Siberian Traps volcanism. The evidence for protracted anoxia and euxinia into the Early Triassic has been interpreted as both evidence for a weak biological pump due to reduced overturning circulation and an invigorated biological pump due to increased nutrient delivery. Here we use Earth system modeling to examine the impacts of high atmospheric CO₂, enhanced nutrient availability, and changes in the biological pump on the distribution of shallow-water anoxia in the end-Permian and Early Triassic. Additionally, we investigate the impact of these changes on the vertical carbon isotope gradient. We find that climate and ocean circulation changes, increased nutrient inputs, and a reduction in the remineralization depth of the biological pump all enhance the expression of shallow-water anoxia and increased carbon isotope gradients at continental shelf depths.