Abstract:
Marine-based carbon dioxide removal (mCDR) strategies have recently gained attention as potential tools to mitigate climate change. Among them, ocean iron fertilization (OIF), the deliberate adding iron to surface waters, has been explored as a method to stimulate phytoplankton growth and enhance carbon sequestration, particularly in regions where iron limits productivity.

This talk highlights several examples of natural iron fertilization that trigger phytoplankton blooms, including atmospheric dust deposition from Asia, aerosols from Australian wildfires, volcanic eruptions, and iron transport via ocean eddies. Despite more than 14 mesoscale OIF field experiments conducted over the past three decades, key uncertainties remain regarding the effectiveness, scalability, permanence, and ecological risks of this approach.

Using a coupled physical-biogeochemical model that incorporates both biological processes and iron cycling, constrained by observational data from the Pacific Ocean, I evaluate the outcomes of simulated OIF scenarios across different patch sizes, seasons, and regions, including subarctic HNLC, subtropical LNLC, and equatorial HNLC zones. The results reveal spatial and temporal variations in biological responses, carbon export efficiency, and potential side effects. Furthermore, the modeling framework offers practical recommendations for optimizing field sampling strategies to enhance the monitoring and assessment of mesoscale OIF interventions.
 
Biography:
Prof. Fei Chai received his Ph.D. from Nicholas School of the Environment at Duke University in 1995. Prof. Chai was a faculty member at the University of Maine between 1994 and 2021, he became Professor Emeritus in 2021. Since 2022, Prof. Chai has joined Xiamen University and become a Chair Professor in Marine Science. Prof. Chai studies physical and biological processes contributing to global carbon cycle, ocean acidification, open ocean and coastal hypoxia, and climate variability affecting marine ecosystems and fisheries, ocean-based CDR. Prof. Chai is an expert in developing and testing physical-biological models and using models along with observations from multiple platforms including BGC-Argo and satellite remote sensing to address key regional and global questions and issues. Recently, Prof. Chai has been involved in developing digital twins of the oceans (DITTO) and apply its framework for the coastal waters. Prof. Chai has led and participated in over 40+ large interdisciplinary research projects, and he published over 200+ papers in international journals. Prof. Chai serves as committee chairs and member for several international scientific organizations and programs promoting interdisciplinary research and international collaboration. 
https://scholar.google.com/citations?user=PAS2AgoAAAAJ&hl=en 

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