Rosie joined the Zehr lab at the University of California, Santa Cruz in spring 2017 after finishing her Ph.D in Ocean Ecology and Biogeochemistry at Oregon State University. As part of her postdoctoral research, Rosie is examining the abundance, diversity, and activity of nitrogen-fixing microorganisms in the North Pacific These nitrogen-fixers are especially important in the North Pacific Subtropical Gyre, where they help to fertilize the open ocean with bioavailable nitrogen. Onboard the R/V Falkor, Rosie will be collecting samples for nanoSIMS to investigate how nitrogen fixation by the cyanobacterium UCYN-A varies with depth and light conditions.