If it weren’t for the fact that the Christmas tree has disappeared from the messroom, we would not notice at all that today is Epiphany. The CTD just came back to the surface with 23 bottles of newly collected seawater (actually, it was supposed to be 24 bottles, but now and again number 20 is somewhat less than reliable...). The water samples will keep Craig busy for about nine hours. He and I take turns at the instruments to measure CO2 and alkalinity (a parameter to describe the difference between negative and positive ions in seawater). I will not have to worry about the new samples because my shift is from Midnight until noon, so now it’s my time off! Typically we get new water samples three or four times a day, and as the water does not only contain gases and ions but also plankton which will use the CO2 for photosynthesis, the samples have to be stored cold and dark and measured within 24 hours. Therefore the instruments - and we - are running 24 hours a day...
The holiday may have passed without us noticing it, but the next few days are likely to be really quiet for us. In the “normal” world, the holidays are over, and regular work is starting again, while we finished work on our transect at an instant’s notice to go on an icebreaking mission. The Naja Arctica, the container ship holding most of the parts for the Neumayer III station, has been stuck in the ice for weeks, and we are going to free her from her prison.
For us, it means (aside from getting up for dinner for a change) that we will have time to look at the data collected so far and draw first conclusions. We will compare the measured CO2 values with those from previous years to detect anthropogenic CO2. From the CO2 and alkalinity values one can also calculate the entire marine carbonate system, including the pH of the seawater. The more CO2 the ocean absorbs, the more acidic the water becomes – a catastrophe for organisms with calcareous shells or skeletons, such as algae, but also bivalves, snails, corals etc. because their tests will dissolve in water that is too acidic. The average pH of surface water before the industrial revolution was 8.2. Today it is about 8.1, and it will continue to fall.
Judith Hauck, Bjerknes Centre for Climate Research, Bergen
Fotos: J. Hauck und O. Hofmann, Universität Bergen