Award: OCE-1558841

Although iron is abundant in the Earth’s crust, its abundance in the ocean is extremely limited due to the very scarce solubility of iron in seawater. As a necessary nutrient for all life, lack of iron can limit productivity in large regions of the ocean. Organic molecules that bind to iron (iron ligands) can have an important influence on the availability of iron to marine producers (phytoplankton) by keeping iron soluble. This award has helped us understand how marine bacteria, which are important in recycling organic matter in the ocean, are also key players in producing strong iron binding ligands (siderophores) which help regulate the ocean iron cycle. Bacteria living in association with phytoplankton appear to produce iron ligands like siderophores in response to the peak bloom and crash of the algal population, and marine bacteria have distinct responses to iron vs carbon availability. Siderophores also enable bacteria to access iron from minerals, and from weaker iron ligand complexes. This award has helped further our understanding of the many linkages that exist between the carbon cycle and the iron cycle in our oceans. Graduate students Lauren Manck (PhD), Kiefer Forsch (PhD), Alfonso Poire (M.S.), and Josh Espinoza (PhD) have been supported by this award, and have contributed to the "Beach Science" 6th grade outreach program sponsored by the Birch Aquarium at Scripps. Last Modified: 08/08/2021 Submitted by: Katherine Barbeau