Tzu-Hao (David) Wang

My research interests are paleoenvironment reconstruction using trace metal and isotope geochemistry, and proxy development.

My DPhil project is to understand the behaviors of Ni in the ocean, and ultimately the implication of Ni and its isotope in natural archives like sediments and rocks.

As a bioessential trace metal in the ocean, Ni also plays important roles in several enzymes for a number of critical biological functions. Its strong correlations with TOC in marine sediments suggest that it would be a potentially powerful proxy to assess past micronutrient and carbon cycle. With Ni isotope system applied on oceanic Ni budget, a two-dimensional resolution can be given. However, the understanding of Ni cycle in the  ocean is still insufficient, which makes it challenging for us to reconstruct paleoprocesses based on Ni isotope currently. My project aims to enhance the understanding of Ni isotope system and verify its potential and robustness for being a geochemical tracer.

During this project, we would like to answer questions below :

• To characterize Ni isotope fractionations during biological uptake in the upper ocean, sulfide precipitation and incorporation into porphyrins, the processes which could possibly be important sinks of Ni in the ocean but have not been well studied yet
• To understand the signal that Ni isotope in sediments preserves. What kind of process does Ni go through in the ocean? What kind of process will change Ni isotope composition from photic zone, seawater column, seawater-sediment interface and sediments?
• To apply Ni isotope as an indicator to reconstruct the environmental change in Namibian upwelling region as a case study
• To have a glimpse of the potential porphyrins have for being a powerful archive

I had both my BSc and MSc in the Department of Earth Sciences at National Cheng Kung University in Taiwan. My master projects were to reconstruct the ocean acidification rate for the past 300 years in South China Sea based on B isotope in coral skeleton and the development of purifying technique for B. My BSc thesis focused on the environmental change after Marinoan Snowball Earth event using boron isotope as a seawater pH proxy in the carbonate phase of black shale from central China.

My supervisors are Prof. Gideon Henderson and Dr. Alan Hsieh in Oxford.