SCOPE-Gradients project: Trace metal bioavailability and recycling in the North Pacific
Many trace metals in seawater such as iron, nickel, copper and cobalt are important cofactors in several enzymes that are essential for processes such as primary production, nitrogen fixation and respiration. These metals are present in extremely low concentrations in seawater and are thus often a limiting or co-limiting nutrient for phytoplankton growth. In addition to being scarce nutrients, many trace metals are also bound by a heterogeneous pool of organic compounds that influence their biological uptake, residence times and recycling. These organic compounds range from biologically-produced metabolites to uncharacterized organic compounds present in seawater with a strong affinity for trace metals. The identities of many of these compounds are unknown, and yet can greatly influence the cycling of trace metals in the ocean.
The Bundy lab explores how the chemical speciation of trace metals shapes the biological community along the transition from the North Pacific subtropical gyre to the subpolar gyre. Specifically, we are interested in how organic compounds shape the bioavailability of trace metals, and how bacteria and phytoplankton actively mediate trace metal cycling by the production of novel metal-binding metabolites such as siderophores or other metal-binding ligands.
Randelle Bundy is an assistant professor in the chemical oceanography department in the School of Oceanography at the University of Washington. She received her B.S. in earth science and chemistry at the University of California, San Diego before earning her Ph.D. in oceanography at Scripps Institution of Oceanography. She was then a postdoctoral fellow at Woods Hole Oceanographic Institution. Her research focuses on how organic compounds influence the reactivity and bioavailability of trace metals in the ocean, using a combination of fieldwork and experimental lab studies.