An international cooperative project A contribution to IPY-GEOTRACES, ICED, CASO & CLIVAR-Southern Ocean

In the framework of the International Polar Year (IPY), BONUS-GOODHOPE aims to understand the interactions between the contemporary dynamic, circulation, biogeochemistry and geochemistry in the Southern Ocean in its atlantic sector and its exchanges with the Indo-Atlantic connection on the wake of the south-Africa continental margin in the Agulhas system. Oceanographic physicians, bio- and geo-chemisters, and modellers will closely collaborate in this multidisciplinary project. Thus coupling i) the oceanic dynamics, ii) with the biogeochemistry in the water column, the atmosphere and the sediments, iii) with the study of trace elements and isotopes that are tracers of terrigenous sources, of circulation and ventilation of the water-masses, of biogeochemical processes and that can serve to quantify the particulate export fluxes to deep waters, and iv) with modelling that encompass configurations at large and regional scales, idealized and biogeochemical modelling, and simulations using trace elements and isotopes; this project will provide significant advances in the physical, chemical and biological processes taken place in the Southern Ocean and at the climatic scale. This french initiative federates about 9 French laboratories (~58 people), as well as 9 European (~22 people) and 8 International (~21 people) Laboratories. This project based on a 5 years research (2007-2011) relies on two oceanographic cruises, i) a large scale cruise (LEG1) from Capetown in South Africa to the southern frontier of the ACC (~57°S) in the Southern Ocean on board the French RV Marion Dufresne during the austral summer 2008 (Feb.-mid March), and ii) a meso-scale cruise (LEG2) within the Agulhas Bank ideally one year later (austral summer 2009). BONUS-GOODHOPE has been endorsed by the International Scientific Committee ICSU/WMO of the IPY (EoI#584), and stands under three lead IPY-activities (GEOTRACES ID#269, ICED ID#417, CASO ID#132). Its objectives are also relevant to International Programs GEOTRACES (SCOR), IMBER (IGBP/SCOR) and CLIVAR/CliC/SCAR-Southern Ocean. It will have strong interactions with the IPY ZERO&DRAKE project (EoI#880, PI H. de Baar, NL) which plans an IPY-GEOTRACES & CASO study along the Greenwich meridian in the atlantic Austral and through the Drake passage on board the German RV POLARSTERN (ANT-XXIV/3 cruise, Chief scientist: E. Fahrbach) during the austral summer in 2008. This collaborative effort will provide a full section between South Africa and Antarctica. Moreover BONUS-GOODHOPE will also benefit of a strong collaboration with L. Beal (RSMAS, USA) who applied to NSF to study the deep eddies formation of the North Atlantic Deep Water in the wake and within the Agulhas system.