Dissolved iron (Fe), copper (Cu), and cobalt (Co) are essential elements for phytoplankton growth which in turn influences the marine carbon cycle; however, despite this important role, the cycling, distribution, and bioavailability of these bioactive elements remains poorly understood. For example, strong organic ligands influence bioavailability and solubility, but it is unclear how interactions change throughout the water column under variable conditions. Recognizing a need for this data, researchers from the Bermuda Institute of Ocean Sciences, Woods Hole Oceanographic Institution, and Scripps Institute of Oceanography will measure the organic complexation of dissolved Fe, Cu, and Co as well as total dissolved Co concentrations during the 2013 GEOTRACES cruise which will transect the coastal upwelling zone off Peru, an intense oxygen minimum zone, the East Pacific Rise hydrothermal plume, and the oligotrophic waters near Tahiti. This study will result in a significant dataset on the speciation of these bioactive elements throughout the water column which will help assess the relationships between dissolved Fe, Cu, and Co distributions and ligand concentration gradients and will likely reveal large chemical gradients over this dynamic oceanographic region. As regards dissolved Co concentrations, these measurements should provide new insights on the marine biogeochemistry of the element, especially in relation to oxygen minimum zones and hydrothermal plumes.
In terms of the broader impacts, for the outreach efforts, the researchers plan to disseminate results from their work to the public via the web, during tours at the Bermuda Institute of Ocean Sciences (BIOS), and at the annual BIOS Marine Science Service Day open house, as well as through a five-part webinar series produced in collaboration with the Center for Ocean Sciences Education Excellence-Ocean Systems at the University of Maine and classroom curricula. One graduate student from Woods Hole Oceanographic Institution and one graduate student from Scripps Institute of Oceanography would be trained and supported as part of this project.
