The Expedition ANT-XXVII/2

28 November 2010 - 5 February 2011

Cape Town - Punta Arenas

Polarstern will leave on 28 November 2010 from Cape Town for the cruise ANT-XXVII/2 to Antarctica. First, we will steam to the southwest to 51°S. There we will reach the Meridian of Greenwich where we will turn south. After the work on the Meridian of Greenwich will be terminated at the Antarctic coast , the Neumayer Station will be supplied. It follows a transect across the Weddell Sea from Kapp Norvegia to the northern end of the Antarctic Peninsula. The work will continue west of the Antarctic Peninsula and we will steam to the British Rothera Station to deliver fuel for air operations. The cruise will end on 5 February 2011 in Punta Arenas.

The physical oceanography programme intends to investigate the role of the Southern Ocean in the global climate system. Here we focus on the Atlantic sector including the Weddell Sea. The Antarctic Ocean contributes through atmosphere-ice-ocean interaction processes to the variability of the climate system. A major contribution of the global deep and bottom water formation occurs in the Weddell Sea. Recent observations indicate that the water mass properties are subject to significant variations. With the measurements, we intend to quantify the variations and to understand the causes as well as the consequences. To quantify the role of the Weddell Gyre carbon cycle, the interannual variability of relevant properties will be estimated and the exchange of CO₂ between the ocean and the atmosphere in austral summer will be determined.

Persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are being transported in the atmosphere of the marine environment into remote areas. Measurements will be made to determine “new” possible POPs (e.g., alternative flame retardants) and several legacy POPs with respect to their transport and partitioning behaviour between the atmosphere and seawater.

Observation programmes of marine mammals include visual observations and automatic detection on the basis of thermographic images from a 360° scanning IR sensor.  To this end, visual observations and thermographic images shall be collected continuously throughout the cruise. The data are needed to better understand the distribution and the behaviour of marine mammals. 

The krill study in the context of the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR) will investigate the biological and environmental key factors which affect the reproduction and determine how the breeding season relates to spawning or larval survival. Natural variations in reproduction and recruitment success between years and geographical variations in krill distribution, abundance or growth and mortality rates in relation to within-season or between-season will be assessed.  Samples of macrobenthic animals from the deep sea will complete the results from the previous expeditions about the deep-sea biodiversity.

Environmental factors like changing atmospheric CO₂ concentrations and the ongoing ocean acidification as well as to seasonal changes in CO₂ were found to also exert control on both phytoplankton structure and growth. To characterize phytoplankton populations along the cruise track on-deck CO₂/iron perturbation experiments with natural phytoplankton communities will be performed.