The Expedition ARK-XXVI/3

Tromsø - Bremerhaven (5 August – 7 October 2011)

The expedition ARK-XXVI/3 "TransArc“ (Trans-Arctic survey of the Arctic Ocean in transition) serves to capture the physical, biological and chemical variations in the Arctic Ocean. While the retreat of the summer sea ice cover can be monitored from satellites, all other changes such as those of the thickness and properties of the sea ice, the water mass properties and the ocean circulation, as well as changed chemical and biological systems, have to be measured in-situ through repeated ice-breaker expeditions. Reduction of sea ice and ocean temperature, fresh water and circulation changes have significant impact on biogeochemical fluxes and ecosystem processes in the sea ice and in the entire water column.

During “TransArc” these interactions will be studied through measuring the respective parameters jointly on stations along gradients from the Eurasian Shelf Seas into the Canadian Basin and from the open ocean into the pack ice. Ship-borne observations will be comprehended by measurements with autonomous measurements obtained with ice-tethered and bottom moored instruments. This will greatly enhance the spatial and temporal coverage.

Four years after the International Polar Year 2007/08 “TranArc” constitutes the first repeat survey of the complex Arctic marine system. The repeat study will be complemented by sampling of sediment for geological and microbiological studies at the difficult to access Alpha-Mendelejew-Ridge and the Gakkel Ridge.

The working program starts north of Franz Joseph Land. From there we will head north across the North Pole into western Canadian Basin. A long section will bring us back to the Eurasian Basin and into the shallow Laptev Sea from where we will return to Bremerhaven.