My research group and I are using natural radionuclides to study Earth surface processes. The fact that different chemical elements are represented in the suite of radioactive nuclides permits studies of chemical behavior, and the property of radioactivity provides a clock with which to measure rates. Much of my recent research has focused on using naturally occurring radionuclides to determine rates of particle cycling and particulate organic carbon fluxes in the open ocean. This work has as its goal an understanding of the fate of carbon in the ocean and has been carried out in the North Atlantic, Pacific and Southern Oceans, as well as the Mediterranean Sea Radionuclides such as ²³⁴Th and ²¹⁰Po provide a means of determining the export of particulate organic carbon from the upper ocean and provide information on this important aspect of the carbon cycle.

In coastal waters and estuaries, naturally occurring particle-reactive radionuclides provide tracers to determine rates of removal of contaminants from the water column and the subsequent transport and deposition of sediments and associated contaminants. Radionuclides that tend to remain in solution, such as the Ra isotopes, serve as tracers of submarine groundwater discharge to the coastal ocean. These applications are part of ongoing projects in New York’s coastal lagoons (Jamaica Bay, Great South Bay) and in Long Island Sound. A related area of research in regional settings is the health and resiliency of the area’s salt marshes. Marshes are increasingly being lost and we seek to understand the causes of loss. I am applying an integrated approach to examine both the biogeochemical and physical dynamics of natural and restored salt marshes.

In addition to broad applications of natural radionuclides to recent Earth surface processes, I am collaborating with colleagues in the Stony Brook Dept. of Geosciences, the American Museum of Natural History and Brooklyn College (CUNY) to characterize the geochemical setting of the Late Cretaceous (~70 Ma) Western Interior Seaway of North America and oceanographic conditions prior to and immediately after the Cretaceous-Paleogene boundary (66 Ma). This research involves measurements of carbon, oxygen and strontium isotopes in well-preserved shells of fossil molluscs, authigenic carbonate deposits and sediment formations.