On the open sea, we are already seeing many more whales, sometimes we see whole pods on their journeys. They don't seem to be disturbed by the presence of the large blue research ship, and just continue to follow their own internal navigation systems. Sometimes, you can just see their backs with their fins poking out of the water, impressive sea mammals from the deep sea, coming to the surface and then falling again, back into the water, then finally leaving with a wave of the tail as if to say goodbye. It is very entertaining, one can watch them for hours on end and still be impressed to be in the presence of such giants of the sea.
But usually there isn't so much time. Open water means work need to be done. The main job on this day is to set out floats belonging to Olaf Klatt and his scientific assistant Katarina Muhle. So far, already 12 such floating measuring buoys have been released, which move in a westerly direction following the Antarctic currents, collecting data and transmitting these data by satellite for oceanographic research purposes.
Another activity on the Polarstern is collecting water samples. There are several different ways in which we bring back samples from the depths of the ocean back to the deck of the Polarstern. One option is a deep shaft in the middle of the ship, found on the working deck level, deck E, through which water samples can be taken up from under the ship during the journey.
The second method allows us to take samples at various depths. In order to do this the ship needs to be stationary , so that the CTD (Conductivity, Temperature, Density) device is hoisted into the water. The name CTD only describes what the instrument measures. It is actually a metal casing that contains 24 large plastic bottles arranged in a circle. The measuring equipment is located at the centre of this circle.
The hoist on deck lowers the CTD to the desired sample collecting depth, and the scientists are then able to collect their samples. The bottles are closed at the desired depths. After all the samples are collected the 24 bottles are brought back to the surface, containing a vast amount of information from various levels of the South Polar Sea.
Christian Schlosser, a geologist from Kiel, uses a different piece of equipment to obtain his water samples: the so-called "fish", a torpedo-shaped instrument that is pulled by a rope through the water whilst the ship is moving.
With the help of an arm, the collecting "fish" is kept a few meters from the side of the ship in order to avoid contaminating the water samples. A pump on deck allows the water samples to be collected through a hose and transported to collecting tanks in the laboratory. Schlosser's main objective is to measure iron levels in the water. Iron can influence the development and growth of phytoplankton, which are a primary component of the marine environment. Any changes and developments in the food chain of the South Polar seas can thus be detected.
Photos, text: Michael Trapp / Alfred Wegener Institute
Submitted: February 22, 2007