Award: PLR-1142117

Tracing the fate of Algal Carbon Export in the Ross Sea Tiny plants suspended in the sunlit ocean (phytoplankton) are very important sources of energy to ocean animals. Like the grasses of the Serengeti being grazed by wildebeests, the ocean plants are grazed by small animals that in turn release their waste products to the deep ocean as sinking particles. These sinking particles effectively move carbon (originally as carbon dioxide, then as plant material, then as animals, then as waste) from the atmosphere to the deepest ocean layers. Most of the sinking material is consumed by bacteria living deep in the ocean, but a fraction is transformed to fine suspended and/or dissolved organic materials, a process often suggested but rarely observed or quantified. The work we conducted studied the transformation from sinking-to-solubilized phases of the sinking organic materials in the Ross Sea, a model system for the process. These processes are important to understand as they play an important role in sequestering carbon at great ocean depths for centuries. The work also resulted in the training of a student wishing to become a professional research scientist. Ms. Sarah Bercovici, a graduate student in the Department of Ocean Sciences at the University of MiamiÆs Rosenstiel School of Marine and Atmospheric Science (RSMAS), worked on this project with the principal investigator, Prof. Dennis A. Hansell. She is conducting her dissertation research on the cycling of carbon in the Ross Sea and the Southern Ocean, supported by this grant from the National Science Foundation. Her research project began with the 2 month expedition aboard an ice-breaker in the Ross Sea in 2013. Her specific interest is to understand how the circulation and biology of the Ross Sea impact the nutrient and carbon signatures found in the bottom waters of the Southern Ocean. Bercovici aims to use data obtained during the expedition to understand the transformations of carbon and nutrients in the Ross Sea, to ultimately determine the Ross SeaÆs overall role in global ocean dynamics. Bercovici collected and analyzed samples for nitrate, phosphate, silicate, and dissolved organic carbon in the Ross Sea water column. She is collaborating with scientists at the Institute for Systems Biology (Seattle, Washington), a graduate student at Stanford University (Palo Alto, California) and a postdoctoral scholar at the University of Vienna, Austria, to link the circulatory, chemical, and biological processes observed during the expedition. Bercovici additionally collaborated with scientists at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility at Woods Hole Oceanographic Institute (WHOI), having been awarded a student fellowship to analyze samples. Bercovici has presented her findings from the expedition in three student seminars at RSMAS and in a seminar at WHOI. She has attended three scientific conferences and presented her work through both posters and oral presentations. Bercovici gave a presentation at the Scientific Committee on Antarctic Research meeting in Auckland, New Zealand, in August 2014. She additionally presented at the Association for the Sciences of Limnology and Oceanography meeting in Granada, Spain, in February, 2015. Bercovici further presented her research at the TRACERS workshop at the Ocean Sciences meeting in February, 2014. Bercovici presented posters of her research at the Ocean Carbon Biogeochemistry workshop at WHOI in July, 2014, and at the Polar Sciences Gordon Research Conference in Lucca, Italy, in March, 2015. Based on her research in the Ross Sea and Southern Ocean, Bercovici currently has one paper in review and one paper in preparation. BercoviciÆs research from the TRACERS cruise provides the basis of her dissertation. Her dissertation (to be completed in 2017) is an important contribution to understanding the Southern Ocean and its Antarctic shelves. The science conducted by the Principal Inves...