Researchers from Scripps Institute of Oceanography, the University of Hawaii, and Skidaway Institute of Oceanography plan to test the hypothesis that iron-light co-limitation at the deep chlorophyll maxima (DCM) is a widespread feature of oceanic stratified euphotic zones, and an important control on phytoplankton community composition and size structure. Three different types of DCM will be investigated: mesotrophic, relatively shallow maxima, deeper, chlorophyll per cell based DCM characteristic of oligotrophic gyres, and the Prochlorococcus maximum found just below the oxic/suboxic boundary in the Eastern Tropical North Pacific. To attain their goals, the scientists will carry out the following tasks during the cruises: (1) characterize water column parameters including basic hydrography, nutrient distributions, iron concentration and speciation, phytoplankton community structure, and primary productivity and photosynthetic efficiency; (2) conduct co-limitation incubation experiments at the three types of DCMs; and (3) determine picoplankton cell division and grazing rates.
As regards broader impacts, the researchers plan to recruit undergraduates from both the University of California-San Diego and from an historically black college or university such as Savannah State University via the Collaborations in Integrating Research and Education Program using Research Experience for Undergraduates supplemental funds. A science teacher from California and one from Georgia will be asked to participate in research cruises using supplemental funds from Research Experiences for Teachers. Both teachers will be expected to produce educational materials based on their field experiences. One graduate student from the University of California-San Diego, one from the University of Hawaii and one from Skidaway Institute of Oceanography will be trained and supported as part of this study.
