Marine Production of DMS and its Interaction with Climate Meike Vogt University of East Anglia (UEA) and MP-BGC Supervision: Peter Liss Corinne Le Quéré In collaboration with: Michael Steinke, Sue Turner, Erik Buitenhuis, Laurent Bopp, Sergio Vallina, Jim Gunson, CODIM Consortium, members of the Dynamic Green Ocean Project

The marine DMS cycle Gaia theory Gaia theory CLAW hypothesis CLAW hypothesis Complex oceanic S cycle Complex oceanic S cycle Many ecosystem compartments involved: Many ecosystem compartments involved:phytoplanktonzooplanktonbacteria Processes: Processes: Grazing, Mortality, Leakage Bacterial consumption, Photolysis

Mesocosm Experiment: DMS and Ocean Acidification CO 2 enrichment experiment CO 2 enrichment experiment Study natural phytoplankton bloom under present, double, triple pCO 2 Study natural phytoplankton bloom under present, double, triple pCO 2 Reseach highlight: DMS production affected by CO 2 concentration! Reseach highlight: DMS production affected by CO 2 concentration! Vogt et al., submitted

DMS Methods Intercomparison: Purge & Trap versus SolidPhaseMicroExtraction Most commonly used technique: Purge & Trap is laborious and equipment- expensive Most commonly used technique: Purge & Trap is laborious and equipment- expensive New technique (SPME) is inexpensive and easy to set up New technique (SPME) is inexpensive and easy to set up Research highlight: Research highlight: Measurements are in very good agreement! New perspectives for large scale monitoring of DMS concentrations! New perspectives for large scale monitoring of DMS concentrations! Vogt et al., to be submitted in April 2007

Comparison of Ocean DImethylsulphide Models: DMS model intercomparison study (CODIM) Understanding the processes leading to DMS production – The “Summer Paradox”: Understanding the processes leading to DMS production – The “Summer Paradox”: Correlation maps between SeaWifs chlorophyll and Kettle DMS show: DMS and chlorophyll concentrations delayed by ~3 months in between 40S and 40N? Why is that so? Why don’t models capture this effect? Vézina et al., in preparation observation model

Global DMS Modelling: Modelling the DMS cycle in PlankTOM5.1 PlankTOM5.1 Model ecosystem

Global DMS Modelling: Modelling the DMS cycle in PlankTOM5.1 Apart from marine ecosystem composition: Apart from marine ecosystem composition: Environmental conditions (T, Light) very important for DMS production (Vallina et al., Science 02/2007) ! Improvement of model formulations taking into account newly explored mechanisms (exudation) and causalities (stress) Improvement of model formulations taking into account newly explored mechanisms (exudation) and causalities (stress)

And if there are other DMS producers out there…. We’ll find you! ?

Thank you!