Abstract:
Future ocean deoxygenation as a result of climate change has dire impacts on the marine biological carbon pump (BCP), especially in the tropical oceans. Yet, the direction and extent of change of the latter remain largely unconstrained. Quantification of the temporal-spatial variations in carbon export and subsequent remineralization within oxygen minimum zones (OMZ) is technically challenging, but is key to understand how nutrient supply and marine biota will respond to future OMZ extension. This talk takes the Peruvian OMZ as an example exploring the use of multiple metal isotope systems to assess potential changes in the BCP strength and efficiency under continuing ocean deoxygenation. The metal isotope systems involved are 234Th as a flux tracer, and Cd and Ba isotopes as new tracers for marine biogeochemical processes. We present evidence that (1) carbon export efficiency is not scaled with net PP (NPP) within the Peruvian OMZ, and (2) contrary to previous studies, particulate Cd and Ba isotopes might better serve as qualitative tracers for remineralization strength rather than NPP or export production.
Biography:
Dr. Ruifang Xie is a tenure-track associate professor in the School of Oceanography at Shanghai Jiao Tong University. She received her bachelor degree at the University of Science and Technology of China in 2007 and a PhD degree at Texas A&M University in 2013. She worked at the Max Planck Institute for Chemistry and GEOMAR Helmholtz Centre for Ocean Research as a postdoc and PI from 2013 until 2021. She was a PI on a German DFG project before moving back to China. Her research focuses on the development and application of metal isotopes (e.g. Cd, Ba, Th, Nd, Sr, Ph isotopes) as tracers in the modern and past ocean for circulation, fluxes, sources and sinks, and biogeochemical processes.
