The Expedition ANT-XXVI/2
Summary and itinerary
The expedition ANT-XXVI/2, which will bring RV Polarstern for the first time across the entire polar South Pacific to New Zealand, is dedicated to a comprehensive geoscientific program that includes marine geological sampling at ca. 40 sites and seismic surveys in seven areas. The sampling will be conducted along latitudinal transects across the Antarctic Circumpolar Current (ACC) (Fig. 1). This will be complemented by continuous echo-sounding and bathymetric surveys. Additional ANT-XXVI/2 programs include aerosol sampling and data acquisition of Pacific Southern Ocean hydrography and air-sea gas exchange. The collection of data and samples during ANT-XXVI/2 is part of national and international programs with the aim to study present and past climate-related processes such as the biological pump, the circulation and stratification of water masses, the distribution of sea ice, ocean-atmosphere exchange, atmospheric circulation, and the stability of continental ice on Antarctica. Very little information is presently available from the Pacific Southern Ocean, yet it encompasses the largest portion of the Southern Ocean. The Pacific sector is a major site of intermediate and bottom water formation and a prime candidate for studying Antarctic ice sheet stability, as it collects about 70% of the West Antarctic Ice Sheet drainage. The paleoceanographic work on sediment cores to be recovered during ANT-XXVI/2 will help to close critical gaps in our understanding of the Southern Ocean’s role in Quaternary climate cycles. The water column studies will significantly enhance our knowledge of climate-related processes in this poorly studied area of the world ocean. ANT-XXVI/2 will also include further examination of the impact area of the Eltanin asteroid, the only known impact site of a large-sized (1 km in diameter) asteroid into the deep ocean. The impact took place in the Late Pliocene (ca. 2.5 Ma). It disturbed a large area of the seafloor in the Bellingshausen Sea and generated a field of meteorite deposits that represents the most meteorite-rich region known on the surface of the Earth.
RV Polarstern will leave the port of Punta Arenas (Chile) located at the Strait of Magellan on November 27, 2009. Following work in the impact area of the Eltanin asteroid, latitudinal transects are planned across the polar South Pacific, which will cover the area between seasonal ice-covered areas and the Subantarctic Zone. The cruise will end in Wellington/New Zealand on January 27, 2010, after 61 days at sea.