SGER: Science-of-Opportunity Aboard Icebreaker Oden - Phytoplankton Global Change Experiments and Vitamin/Iron Co-Limitation in the Amundsen and Ross Seas

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AbstractThis Small Grants for Exploratory Research (SGER) proposal describes global change-related experimental research designed to take full advantage of a unique science opportunity on short notice, the leasing of the Oden to conduct ice-breaking operations in McMurdo Sound. Our emphasis will be on using this opportunistic research platform to ask two questions about present day and future controls on Antarctic margin phytoplankton communities. These are: 1. How will expected alterations in pCO2, pH, and Fe availability in the Southern Ocean, due to future anthropogenic climate change affect phytoplankton species assemblages, carbon and nutrient biogeochemistry, and remineralization processes? 2. What is the current role of organic co-factors (vitamins) in limiting or co-limiting (along with iron ) phytoplankton growth and production in the Antarctic margin? The research approach includes experimental incubations with variation in iron enrichment, carbon dioxide concentration, and temperature. A second suite of experiments will examine co-limitation effects between vitamin B12 and Fe and B12 uptake kinetics. Changes in phytoplankton community structure, and carbon and nutrient cycling will be determined, in collaboration with many of the participating U.S. and Swedish investigators. Together, these two main objectives should allow us to obtain novel insights into the current and future controls on Antarctic margin phytoplankton growth, productivity, and carbon and nutrient biogeochemistry. In particular, the experiments in the Amundsen Sea represent a one-of-a-kind opportunity to understand algal dynamics and potential future responses to climate change in this little-studied ecosystem, and compare these results to those from the better-known Ross Sea. An important result of this study will be to build strong international collaborations with the Swedish marine science community. Additional broader impacts include participatin of an Hispanic Ph.D. student in cruise work and post-cruise analyses, and integration of results into graduate courses at the USC Catalina Lab facility. Public outreach will include presentations on global change impacts on the ocean targeted at audiences ranging from legislators and policymakers to the general public.