Week 7

Busy analysing data leading up to Christmas

David Thomas and Christian Haas coring the ice © David N Thomas

David Thomas and Christian Haas coring the ice © David N Thomas

Emails and faxes from home tell us of the hustle and bustle of getting ready for Christmas, but so far I have heard no one on board complain that they are missing any of this. Christmas is of course a hard time to be away from families and friends, but maybe it is harder for those we leave at home than for us. At least we have sampling programmes and experiments to distract us.

Melting snow crystals are a fair substitute for Christmas decorations © David N Thomas

Melting snow crystals are a fair substitute for Christmas decorations © David N Thomas

But it certainly will not be just work for us - there are even geese on board, sponsored by the company who run the helicopters, and we have real Christmas trees that have been kept in cold storage since Cape Town. There will be ample opportunity to eat good food and drink despite the fact that we will still work half days on the 24th and 25th.

Our floe has remained pretty well intact this week, although some of the sites that had broken off previously are now getting more difficult to get to. The rubber boat ferry crossing (described last week) is now several hundred metres across, and realistically we are using the helicopters more and more.

We are beginning to see changes in the ice and the biology living within it over the past weeks. This was of course exactly the reason why we planned an ice camp attached to just one ice floe for the whole expedition period. It is an extremely rare opportunity to be able to record temporal changes in Antarctic pack ice, and record the transition from cold winter temperatures to warmer summer conditions. As ice warms it becomes more porous, and the biological assemblages living within and on the peripheries of the floes are becoming more prolific.

Brown soup of algae and crustaceans lying beneath the snow © David N Thomas

Brown soup of algae and crustaceans lying beneath the snow © David N Thomas

In particular large flooded patches are developing on top of the ice, but still underneath the snow. These are comprised of an icy slush layer, which in many places is a rich coffee colour indicating that it is full of microscopic algae. The samples are also full of tiny crustaceans (about a millimetre long) that graze on these large accumulations of algae. These layers are a particular interest to our group, and the easiest way to sample them is with a soup ladle (from the kitchen at home) and a plastic kitchen sieve: Not all science has to be high-tech!

Once past the ladle stage, the samples are returned to the ship. There they are divided, filtered through a host of different types of filters, stored in plastic bottles, glass vials and flame-sealed glass ampoules. Much of our job is to get samples processed in such a way that they are stable for transport to home laboratories. They will remain on board ship and we will pick them up in May when the ship finally returns to Germany. So the freezers are quickly filling up!

Can you spot our ship seen from the air - for scale the ship is 118 metres long © David N Thomas

Can you spot our ship seen from the air - for scale the ship is 118 metres long © David N Thomas

However, on board we are able to analyse a suite of different chemical and biological properties, including the concentrations of nutrients (e.g. nitrate, ammonium phosphate and silicate) as well as oxygen, pH and carbon dioxide measurements. Bacteria, algae and crustaceans are counted, their activities measured and cold-adapted biochemistries studied.

The contrasts between conditions at home and here are of course stark and easy to make. In Europe you have just experienced the shortest day of the year, whereas we of course have just had the longest day. At midnight, although the sun was partially obscured by clouds, golden sunlight played on the water and picked out the boulders of ice that litter the floe surfaces.

Midnight sun on the longest day © David N Thomas

Midnight sun on the longest day © David N Thomas

Watching it - with only the company of a crabeater seal lazily scratching its head - it was hard to imagine a more beautiful scene: As far as the eye could see huge expanses of ice floes were highlighted by the perfectly quiet waters surrounding them. But most provocative of all was a magical silence that accompanied it all. So few of us get to enjoy complete silence these days, and it is such a privilege to experience such wonders at the end of the Earth. Happy Christmas!

David Thomas
23rd December
67°S 55°W