Gregory Cutter
Old Dominion University, VA·Earth & Environmental Science
Seawater contains tiny amounts of metals and sulfur compounds that matter far more than their concentrations suggest. Metals such as iron and zinc are nutrients for phytoplankton, the microscopic plants at the base of ocean food webs, while others, such as mercury, are toxic.
- Fields
Earth & Environmental Science
Chemistry
- Topics
chemical oceanography
marine biogeochemistry
dissolved organic sulfur
- Grants
- 3 known grants, through Feb 2028
What they work on
- Quantify the total inventory of dissolved organic sulfur (DOS), trace carbon-bound sulfur compounds, across the Pacific Ocean using archived samples from over 100 sites between Alaska and Antarctica.
- Identify the biological and abiotic processes that produce and remove DOS along Pacific transects that cross hydrothermal plumes and low-oxygen zones, by measuring total DOS and its individual compounds.
- Test how reactive DOS and its components are using monthly depth profiles collected over one year at the Bermuda Atlantic Time-series Study (BATS) site.
- Quantify sources and sinks of dissolved and particulate hydrogen sulfide in the oxygen-rich upper ocean and link them to cycling of cadmium, copper, zinc and mercury on the GEOTRACES GP17-OCE cruise.
- Determine when free sulfide reacts with and precipitates trace metals, and test whether nanoparticle pyrite, an iron sulfide mineral, carries iron in hydrothermal plumes, using shipboard measurements, lab studies and speciation modeling.
- Plan and run the 55-day GP17-OCE expedition from Tahiti to Chile, collecting trace-metal-clean samples and hydrographic data under GEOTRACES quality-control protocols and delivering them to public repositories.
More about the research
Whether a metal helps or harms depends on its chemical form, and sulfur compounds are among the strongest partners that metals bind to. The lab's grants trace how sulfur, in both inorganic and organic forms, moves through the ocean and how it controls the behavior of trace metals. They draw on samples and data from the U.S. GEOTRACES program, an international effort to map trace elements and their isotopes in the ocean.
Why it matters
Sulfur compounds help decide whether trace metals in seawater nourish phytoplankton or remain toxic, as with mercury, and some form atmospheric particles that block sunlight. Better measurements of these cycles in the Pacific and Southern Ocean could improve global ocean models of nutrient and carbon cycling and of climate-relevant sulfur gases. The cruise data will be publicly available for other oceanographers to use.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Collaborative Research: An examination of dissolved organic sulfur biogeochemistry
NSF · Mar 2025 – Feb 2028
US GEOTRACES GP17-OCE: Hydrogen sulfide as a strong ligand affecting the speciation and solubility of key trace metals
NSF · Oct 2021 – Sep 2026
Collaborative Research: Management and Implementation of US GEOTRACES GP17 Section: South Pacific and Southern Ocean (GP17-OCE)
NSF · Oct 2020 – Sep 2026
Closest labs
Brandy Toner
University of Minnesota, MN·Earth & Environmental Science
Determine how dissolved organic carbon and iron-binding organic ligands control the 'colloidal shunt', in which tiny suspended iron particles clump with organic carbon and sink, using experiments across seasons and locations.
Yuan Gao
Rutgers University-Newark, NJ·Earth & Environmental Science
Determine aerosol composition and mineral content over the Amundsen Sea and trace the sources of dust and trace elements such as iron, aluminum, and zinc, using ICPMS, electron microscopy, and air-mass back-trajectory cluster analysis.
Jennifer Middleton
Columbia University, NY·Earth & Environmental Science
Test whether settling particles, rather than ocean circulation, mainly control beryllium-10 (a cosmic-ray-made radioactive isotope) in the South Pacific, using co-located seawater, particle and sediment samples from GEOTRACES GP16 and GP17-OCE.
The school
Old Dominion University: 8 labs on PI Pages, $76M a year on research, 143 research doctorates a year.
Reach out
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