Collaborative Research: The seasonal dynamics of CO2, primary production, and DMS in the Western Antarctic Peninsula: Measurements of pools and processes using mass spectrometry

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The Southern Ocean plays a key role in marine biogeochemistry and global climate. Along the Western Antarctic Peninsula (WAP), winter air temperatures have increased by more than 5 ºC over the past five decades, and sea ice duration and extent have decreased substantially, leading to dramatic ecological perturbations. The sensitivity of primary production and climate-active gas cycling to on-going changes in the physical and chemical environment of the WAP is the key to understanding potential biogeochemical climate feedbacks in this region. The objective of this project is to characterize and understand the seasonal dynamics of primary production and climate-active gases carbon dioxide (CO2) and dimethylsulfide (DMS) in the WAP. The project will examine (1) the relationships among seasonal changes in pCO2, temperature and light with respect to gross primary production, net primary production, and net community production; (2) the extent to which changes in surface water pCO2 and temperature drive ecological shifts in the dominant phytoplankton species assemblage composition, and alter key processes in the DMS cycle. The research will employ membrane inlet mass spectrometry to monitor dissolved gases in ambient seawater at the Palmer Station LTER site and conduct physiological/biochemical assays with tracer compounds. The research will provide unprecedented information on the temporal evolution of primary production and dissolved gas concentrations in the WAP in relation to surface hydrography and sea ice cover. Field studies will be supported by laboratory experiments with model species subjected to detailed studies of carbon metabolism. This project will contribute significantly to the understanding of seasonal biogeochemical dynamics in a region that is particularly sensitive to ongoing climate perturbations and important for the global air-sea exchange of CO2. The project will train two graduate students and will be integrated in the undergraduate teaching program at Princeton University, including new lectures and new laboratory modules. Through the PIs community activities the project will also contribute to public outreach and policy.