Dr. Olivier Rouxel 

The importance of metals to life has long been appreciated. Nickel (Ni) is a biologically essential element for marine life, with the potential to influence diverse processes, including methanogenesis, in both modern and past oceans. Despite recent progresses in our understanding of Ni cycling in the ocean, the importance of seafloor processes remains poorly known. Through the investigation of the stable isotope composition of Ni, enabled by state-of-the-art mass spectrometry, we aim to identify impact of submarine volcanoes on the transfer of Ni between the oceanic crust and the ocean. We will investigate

hydrothermal fluids, seawater column, and mineral deposits from three active volcanic systems : Kamaʻehuakanaloa (Hawaii, Pacific Ocean), Fani Maore (Mayotte, Indian Ocean), and Brothers (New Zealand, Pacific Ocean). Since submarine volcanism is the primary mechanism through which carbon stored in the deep Earth is released to surface environments, it is essential to better understand its impact on other chemical elements, including Ni. The outlined work program, although strongly analytically based, will allow to optimize the time available during the HWK fellowship to interpret the data and share research results with local partners at ICBM and Bremen University. An extensive dataset has been already generated, with all samples in hands and methodology for Ni isotope analyses already developed, ensuring a low-risk high-reward nature of the proposed research.