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Seth John Seth John, Ph.D.

Assistant Professor
Department of Earth and Ocean Sciences
University of South Carolina


Project: Biological cycling of trace-metals and their isotopes in the North Pacific

Trace metals dissolved in seawater, such as iron, zinc, and cadmium, are crucial for life in the ocean. Marine organisms require metals for a wide variety of life processes, from photosynthesis and carbon assimilation to nutrient acquisition. While the importance of metals has been long known, their low concentration in seawater (parts-per-trillion levels) make analysis challenging, leading to a paucity of data on metals compared to other nutrients.

In conjunction with the SCOPE project we will measure trace metals in the ocean at unprecedented temporal and spatial resolution. Important biological processes such as seasonal cycling, nutrient upwelling, and species succession occur rapidly and over short distances. High resolution metal datasets can therefore be used in conjunction with other data to understand the role of metals in biological processes. For example, Fe isotopes will be used to trace sources of Fe, Cd concentrations and isotopes will be used to quantify nutrient uptake, mixing and nitrogen fixation, and Zn and Zn isotopes will be used to quantify biological production and export.


Seth John is an Assistant Professor at the University of South Carolina. He received a BA in chemistry from Carleton College, followed by graduate studies in the MIT/WHOI Joint Program and a postdoc at Caltech. John studies the biogeochemical cycling of trace metals and their stable isotope ratios in the oceans. His research has included the first high-spatial resolution sections of trace metal isotopes in the ocean, as well as laboratory experiments and numerical modeling to interpret this natural data.