Surface and Intermediate Water hydrography, planktonic and benthic biota in the Caribbean Sea – Climate, Bio and Geosphere linkages (OPOKA) - Cruise No. M78/1 - February 22 – March 28, 2009 - Colón (Panama) – Port of Spain (Trinidad and Tobago) (English)

The main scientific objective of R/V METEOR cruise M78/1 was to describe the linkage of western Atlantic Warm Pool variability with changes of North Atlantic thermohaline circulation during the late Pleistocene and Holocene. In particular, the spatial and temporal dynamics of the Loop Current as link between the central Caribbean and Gulf Stream system had to be assessed. Emphasis was given to temperature and salinity preconditioning of Caribbean surface waters, the short-term dynamics of the Gulf Stream, and its impact on benthic communities in Caribbean sea straits. Sediment, water and plankton samples were collected in order to describe the recent and paleoceanographical impact of freshwater shedding from the main rivers into the Caribbean. Plankton tows and hydrographic measurements revealed the environmental conditions and physical fine structure of the surface ocean in the central Caribbean and close to the Orinoco mouth. The topography and internal structures of sedimentary drifts, deep-water mounds and lag sediments in Caribbean sea straits were surveyed with hydroacoustics. Benthic biota and sedimentary processes were documented with OFOS observations and surface sediment samples. The environmental settings in Caribbean sea straits were assessed with sea floor observatory deployments. Historical climate archives from the intermediate water were retrieved with piston and gravity coring. The new data and samples from this cruise will allow to describe the variability of Orinoco river shedding, to validate geochemical proxies for reconstructions of surface ocean properties, to reveal the population dynamics of planktonic foraminifera, and to characterise the past near-surface and intermediate water mass dynamics in the Caribbean. This will accomplish the objectives of cruise M78/1.