A site in the northeast Mediterranean Sea is providing MSRC researchers with new information about the ocean’s role in the global carbon cycle. The MedFlux project – a large international collaborative effort including MSRC professors Cindy Lee, Kirk Cochran and Rob Armstrong, Research Scientist Anja Engel, postdoc Markus Schartau, and six MSRC Ph.D. students – aims to answer questions about the sinking of particles from surface waters to the deep ocean. The removal of particles in the surface ocean is important because it controls the rate at which the ocean absorbs CO₂ from the atmosphere. CO₂ – a major greenhouse gas affecting the earth’s climate – continues to increase in the atmosphere as a result of fossil fuel combustion. Determining the ocean’s response to increased C0₂ concentrations is critical in predicting the global carbon cycle response to environmental changes.
Graduate students Jenni Szlosek and Lynn Abramson explained that the project is investigating two main hypotheses. The first looks at how ocean minerals – from organisms or dust- aid in sinking (ballast) and protection of organic carbon. The second examines the ratio of organic carbon to the ballast minerals to predict variability in carbon export and sinking velocities. To do this, a variety of techniques, such as radiotracers, trace metals, and organic biomarkers, are being used to identify and quantify particle fluxes. The techniques developed to answer these questions in the Mediterranean Sea will eventually be applied to ocean sites around the globe.
The 2005 field season includes three cruises to the Mediterranean at a site in the Ligurian Sea. The site was chosen for its open ocean characteristics – deep (2300 m) and separated from coastal influences by the Ligurian current – in a coastal location, making it easy to access. Seventeen scientists from MSRC, Skidaway Institute of Oceanography, University of Washington, Marine Environmental Laboratory in Monaco, Universitat Autonoma de Barcelona in Spain, and Universite de Ia Mediterranee (aix-Marseille) Marine Microbiology Laboratory in France boarded the R/V Endeavor this past March for a week-long cruise to sample during the spring plankton bloom. An unusually cold winter and rough sea conditions made for an unpredictable trip.
Distinguished Profess or Cindy Lee noted, “The current results are quite exciting showing how minerals aid in aggregation of particles as well as act as ballast to promote sinking. By using a new sediment trap capable of measuring particle sinking rates, using information gained from tracers measured in the traps, and by applying statistical techniques, we can produce a mechanistic model of particle sinking and remineralization.”
For further information, the MedFlux project website is