Global climate change in the past few decades has been anomalously swift in polar regions, and the effects on Southern Ocean physics, ecological structure, and biogeochemistry are likely to accelerate in the near future. This proposal focuses on the remineralization of particulate organic matter in the water column of the Ross Sea and Amundsen Sea, and takes advantage of a platform of opportunity, the transit of the Icebreaker Oden from Punta Arenas, through the Amundsen Sea and Ross Sea, to McMurdo Station. Particulate organic matter is the primary vector for carbon export in the Antarctic. The rate and composition of particulate primary production likely depend on environmental conditions (e.g. light, temperature, macro- or micro-nutrient supply, carbon dioxide) during a bloom. We will determine how the pelagic bacterial response to particles is related to particle production and composition. We are particularly interested in how the bacterial response influences the shape of the remineralization profile (or "Martin curve") and affects the efficiency of the biological pump. Ultimately, we are interested in whether conditions associated with climate change will alter the efficiency of the biological pump and therefore carbon export. The project will support graduate and undergraduate education, especially for underrepresented groups. We will also develop new international collaborations and infrastructure though our work with Swedish scientists and students and US and Swedish educators. Our results will be made widely available through research publications and databases, and through public outreach efforts.
