Dr. Xiaolei Liu
University of Oklahoma

Topic: Photic Zone Euxinia-induced overexposure of phytoplankton

Abstract: Photosynthesis by phytoplankton is the primary sink of CO2, representing the base of food web and a central component of marine biogeochemical cycles. The degradation of photosynthesis exported organic carbon leads to the consumption of dissolved oxygen. Subsequent shoaling of chemocline during the development of extreme ocean anoxic conditions, will not only limit nutrient supply for photosynthesis, but also compel the phytoplanktonic community to migrate to shallower waters with increased light exposure. Conducting a thorough analysis of lipid biomarkers produced by planktonic microbes offers valuable insights into the dynamics of marine microbial ecology during ocean anoxic events. Our recent study demonstrates that fossil derivatives of chlorophyll and tocopherols, preserved in the black shales of the Late Devonian and Late Cretaceous periods, serve as indicators of the effects of starvation and overexposure on phytoplankton resulting from extensive photic zone euxinia.

Academic host: Seb Kopf and Boz Wing