The Expedition ANT-XXV/4
Weekly Reports
28 March 2009: Departure and successful mooring recovery
05 April 2009: Work in Drake Passage and visit of King George Island
Summary and itinerary
The expedition ANT-XXV/4 will start on 21 March 2009 in Punta Arenas (Chile) and will terminate on 9 April 2009 in Punta Arenas after two crossings of the Drake Passage. Before leaving the Magellan Channel, Polarstern will occupy a high-resolution hydrographic section across the eastern mouth of the channel. After the section, Polarstern will head southeast towards the north of Drake Passage. Then she will follow ground track 104 of Jason-2 satellite until a depth of 200 m is reached on the continental slope of Antarctica. Afterwards, she will head west towards King George Island for a stop in Jubany for logistics purposes and fish trap deployment and recovery in Admiralty Bay (KGI). Then she will cross back Drake Passage northward along Jason ground track 28. The southern part of track 28 happens to ride exactly over the Schackleton fracture zone, the crest of which reaches only 1,500 m below the sea surface.
On the way south, the 5 currentmeter moorings (M1 to M5) deployed in 2008 during ANT-XXIV/3 will be retrieved and CTD/LADCP measurements will be carried out on approximately 50 hydrographic stations with water samples taken at 22 different depths to determine the concentration of dissolved nutrients, oxygen, tracers (helium isotopes, neon, freons), CO2 parameters, abundance and species in phytoplankton in the water column.
About 50 CTD/LADCP stations will be carried out on the way back above the Schackleton Fracture Zone. A few microprofiling stations will be performed on the way south and on the way north.
The final number of hydrological and microstructure stations will be adjusted to the progress of work. Time losses due to unexpected events or slower progress than expected will be buffered by a reduction of station time.
In Admiralty Bay, alive fish will be caught with traps to be brought to Bremerhaven in order to carry out physiological investigations to understand the temperature dependance of biologial processes.
This expedition is a contribution to POGO, the Partnership for Observation of the Global Oceans, http://www.ocean-partners.org/
Cruise itinerary
21 March 2009: Departure from Punta Arenas
9 April 2009: Arrival in Punta Arenas