Dr. Chuxian Li

Does the Southern Ocean act as a net source, or sink, of CO2?

• SNF (TMPFP2_210183 /1). PI: Dr. Chuxian Li
• November 2022 – October 2024
• https://data.snf.ch/grants/grant/210183 
• Summary: The Southern Ocean is a critical sink for human-caused atmospheric CO₂, accounting for approximately one third of the amount produced since industrialization. The Southern Westerly Winds (SWW) are an important driver for both air-sea gas exchange of CO₂ and biological pump, which draw CO₂ into the Southern Ocean. But the processes involved in the interaction between SWW and oceanic CO₂ dynamics are still unclear due to poorly constrained long-term SWW changes.This project aims to quantify the long-term role of the SWW and how they control ocean mixing, and the rates of CO₂ uptake and outgassing. First, we will do this by developing and applying novel mercury (Hg) isotope indicators of past wind dynamics from peat cores over the Southern Ocean. Then we will validate the new Hg isotope method with other established qualitative geochemical, botanical and ecological indicators. Finally, we will employ climate models to determine if long term changes in wind behavior are linked with CO₂ concentrations in the atmosphere. The results will seek to determine whether the Southern Ocean will act as a net source, or sink, of CO₂ under future climate warming scenarios.

As a geochemist and paleoclimatologist, I am focusing on climate change in the Holocene and beyond using different geochemical and isotopic chemical proxies in the climate archives (e.g., peatlands). I also work on biogeochemical cycles of heavy metals, especially mercury (Hg). Due to my strong passion and curiosity to science, my research interests span a wide range of topics from geochemistry, paleoclimate, isotopic chemistry to botany, ecology and Holocene climate modeling. Because of my enthusiasm and appreciation of collaboration, I have developed a rich network of international collaborations. I am also interested in doing public science and have participated in relevant events, e.g., European Researchers’’ Night 2021 in Umea, Sweden and Future Day 2022 in Bern, Switzerland.