Biogeochemical controls on ocean fertility
Low latitude nitrogen cycling
Surface ocean nutrient supply mechanisms
Bio
I am a postdoctoral research fellow in the Sigman Lab in the Department of Geosciences at Princeton University. My current research focus builds on my Ph.D. work titled “Nitrogen cycling in the South Atlantic and South Indian Oceans investigated using nitrate isotopes: implications for nutrient supply, ocean fertility, carbon export, and climate”.
I earned my Ph.D. from the University of Cape Town, South Africa, where I was part of the Fawcett Lab in the Oceanography Department. My primarily research tools include the nitrogen and oxygen isotope ratios of nitrate, and nutrient stoichiometry to investigate ocean biogeochemistry and physics to better understand nutrient supply and cycling in the low latitude surface ocean.
Current position: Postdoctoral research fellow, Department of Geosciences, Princeton University
Education
2018 – 2023 | Ph.D. Oceanography, University of Cape Town, South Africa
2017 | M.Sc. semester abroad, Integrated Climate System Science, University of Hamburg, Germany
2016 | B.Sc. Honours Ocean & Atmospheric Science, University of Cape Town, South Africa
2013 – 2015 | B.Sc. Ocean & Atmospheric Science and Environmental & Geographical Science, University of Cape Town, South Africa
Invited Talks
Marshall, T.A. “Nutrient fluxes in the southwest Indian Ocean – implications for regional fertility and carbon drawdown” IIOE-2 ECSN webinar series, September 2023.
Marshall, T.A. “The regionality of nitrogen cycling in the South Atlantic and South Indian Oceans: implications for nutrient supply, ocean fertility, and carbon export” SANCOR webinar series, August 2023.
Marshall, T.A., Altieri, K., Fawcett, S.E. “A synthesis of what we know about the supply of nutrients to southwest Indian Ocean surface waters” Keynote talk at the UN GESAMP wg38 Gqeberha meeting, October 2022.
Service
SOLAS Early Career Scientist Committee (2023 – 2026)
SOLAS Indian Ocean implementation team (2022 – present)
Advising & Teaching
Lecturing an undergraduate module
Advising graduate students