Robert T. Letscher

Robert Letscher

Phone: (603) 862-1008
Office: Earth Sciences, 142 Morse Hall, Durham, NH 03824

Assistant Professor of Chemical Oceanography
Earth Sciences &
Assistant Director, Ocean Process Analysis Laboratory

I am a marine biogeochemist meaning I work to uncover and quantify the interrelated chemical, biological, and physical processes occurring within the ocean that result in transformations of the important bioactive elements carbon, nitrogen, phosphorus, and oxygen. My focus is understanding the production, transformation, and fate of biologically produced organic matter and the related cycling of chemical nutrients in the sea. My research program studies these processes at the largest scales – the global ocean, annual to millennial. I am particularly interested in studying the low nutrient ecosystems of the ocean subtropics. Covering 60% of the Earth’s surface they are the world’s largest biome, responsible for a quarter of all biological productivity. My group uses a variety of techniques and tools including collection of new chemical observations at sea, development of ocean biogeochemistry within Earth System Models, laboratory experiments, and analysis of data from autonomous platforms such as BGC-Argo.

Courses Taught

  • ESCI 400: Freshman Field Seminar
  • ESCI 501: Introduction to Oceanography
  • ESCI 747/847: Aqueous Geochemistry
  • ESCI 752/852: Chemical Oceanography
  • ESCI 795/895: Top/Ocean Biogeochemistry
  • INCO 590: Student Research Experience
  • INCO 790: Advanced Research Experience


  • Ph.D., University of Miami
  • B.S., University of Miami

Research Interests

  • Biogeochemistry
  • Ocean Modeling
  • Oceanography

Selected Publications

  • Letscher, R. T., & Aluwihare, L. I. (n.d.). A simple method for the quantification of amidic bioavailable dissolved organic nitrogen in seawater. Limnology and Oceanography: Methods. doi:10.1002/lom3.10622

  • Wang, W. -L., Fu, W., Le Moigne, F. A. C., Letscher, R. T., Liu, Y., Tang, J. -M., & Primeau, F. W. (2023). Biological carbon pump estimate based on multidecadal hydrographic data.. Nature, 624(7992), 579-585. doi:10.1038/s41586-023-06772-4

  • Liang, Z., Letscher, R. T., & Knapp, A. N. (2023). Global Patterns of Surface Ocean Dissolved Organic Matter Stoichiometry. Global Biogeochemical Cycles, 37(12). doi:10.1029/2023gb007788

  • Letscher, R. T., Moore, J. K., Martiny, A. C., & Lomas, M. W. (2023). Biodiversity and Stoichiometric Plasticity Increase Pico‐Phytoplankton Contributions to Marine Net Primary Productivity and the Biological Pump. Global Biogeochemical Cycles, 37(8). doi:10.1029/2023gb007756

  • Liang, Z., McCabe, K., Fawcett, S. E., Forrer, H. J., Hashihama, F., Jeandel, C., . . . Knapp, A. N. (2022). A global ocean dissolved organic phosphorus concentration database (DOPv2021).. Sci Data, 9(1), 772. doi:10.1038/s41597-022-01873-7

  • Letscher, R. T., Primeau, F., & Moore, J. K. (2016). Nutrient budgets in the subtropical ocean gyres dominated by lateral transport. NATURE GEOSCIENCE, 9(11), 815-+. doi:10.1038/NGEO2812

  • Letscher, R. T., & Moore, J. K. (2015). Preferential remineralization of dissolved organic phosphorus and non-Redfield DOM dynamics in the global ocean: Impacts on marine productivity, nitrogen fixation, and carbon export. GLOBAL BIOGEOCHEMICAL CYCLES, 29(3), 325-340. doi:10.1002/2014GB004904

  • Letscher, R. T., Moore, J. K., Teng, Y. -C., & Primeau, F. (2015). Variable C: N: P stoichiometry of dissolved organic matter cycling in the Community Earth System Model. BIOGEOSCIENCES, 12(1), 209-221. doi:10.5194/bg-12-209-2015

  • Letscher, R. T., Hansell, D. A., Carlson, C. A., Lumpkin, R., & Knapp, A. N. (2013). Dissolved organic nitrogen in the global surface ocean: Distribution and fate. GLOBAL BIOGEOCHEMICAL CYCLES, 27(1), 141-153. doi:10.1029/2012GB004449

  • Letscher, R. T., Hansell, D. A., & Kadko, D. (2011). Rapid removal of terrigenous dissolved organic carbon over the Eurasian shelves of the Arctic Ocean. MARINE CHEMISTRY, 123(1-4), 78-87. doi:10.1016/j.marchem.2010.10.002

  • Most Cited Publications