Oct – The end of Winter

30 October, 2007 Rothera

Hi, I’m Ali the Marine Assistant; I arrived at Rothera in December 2006 and shall be based here for a total of 2½ years.

The month of October marked the end of winter and in preparation for the busy summer season normal work was put aside for base scrub-out at the beginning of the month. The end of winter scrub-out involves cleaning the inside of all the buildings, unearthing extra plates, cutlery and chairs which had been tidied away for winter, setting up the line of drums at Vals to mark the limits of the Ski-Way (an alternative landing site for the Twin Otter planes) and clearing the runway and pathways of winter snow.

After 4 days the base was ready for summer and we spent the weekend celebrating. Following the success of last year Friday night saw the return of the Rothera Film Festival, this year combined with a Bovarian evening in recognition of Oktoberfest and Birgit’s birthday. Many people had spent months, weeks, even days preparing a high calibre of films which included collections of winter photos set to music by Ali S; a Rothera version of ‘Stomp’ (a group who produce music using household items such as brooms and dustbin lids) from Rob & Jim; underwater adventures filmed by Tris’ amazing home-built ROV; a psychological analysis of the wintering team from Cyril; films of a winter trip to Carvajal and skiing from Roger; a photographic insight into the BAS clothing system from Liz and a horror film from the Bonner Lab team. It was a very enjoyable evening with the films being shown in between courses of traditional Bovarain food expertly prepared by Cyril and Birgit. Saturday night took the form of a traditional party in the sledge-store where many chose to dress in traditional ‘FID’ clothing (“Falklands Islands Dependencies Survey” was the original name for the “British Antarctic Survey”. Members of FIDS referred to themselves as Fids and the name stuck).

Another tradition – the winter photo competition – was also held this month. The categories were ‘people’, ‘landscape’, ‘wildlife’ and ‘other’ with some outstanding entries it was very difficult to vote for a winner. Mike Maling our Winter Base Commander topped the votes with his stunning picture of our very special visitor over winter – an Emperor Penguin.

Following six months of isolation from the outside world there were mixed feelings on base about the arrival of the first planes– the 22 of us had a brilliant winter and it was sad to think that this was the beginning of the end, on the other hand it was exciting to see new people (especially ones bearing gifts of fresh fruit and vegetables). The first planes to arrive were the Canadian Borek Twin Otters – en route to Patriot Hills, followed 3 days later by the BAS Dash 7.

One of the best things about summer is the opportunity to get trips into the field; this can be in the form of a day trip as a ‘co-pilot’ (the Twin Otter planes have one pilot but always take a 2nd person who is rarely a pilot, they have a seat in the cockpit and are called ‘co-pilot’); a stay of a week or more at Fossil Bluff, Sky Blu or one of the fuel depots re-fuelling planes and giving hourly weather observations; or, for the field GAs it can mean up to 3 months spent in a tent assisting scientists with data collection. So it happened that one Sunday I was approached asking if I had any plans for the afternoon and if not was I available for a co-pilot to Fossil Bluff, I jumped at the chance and 10 minutes later I was boarding a Twin Otter plane for my 1st trip off Adelaide Island in 9 months.

Early on in the month I had the opportunity to visit Anchorage Island with Dickie (the terrestrial biologist), as he had to download some data from a small weather station there. At this time of year the Island is popular with Weddell seals and we were lucky enough to see 8 females all with pups, some only a few days old.

As the marine assistant a lot of my work involves scuba diving for marine-life surveys photography and collection of samples. Despite the lack of any decent sea ice this year we have had a fairly small but stable patch in Hangar Cove for nearly 3 months. This means that we have been able to conduct dives under the ice (see Kelvin the dive officer’s July diary for more about ice diving).

One of the regular surveys we do is to photograph ‘settlement plates’ located in Hangar Cove, South Cove and off Anchorage Island. These are small plastic panels secured to the seabed that have been in place for 5 years. They are photographed every 3 months to assess what marine life is growing on them, this tells scientists about what sort of marine life lives in the waters around Rothera and how they settle, develop and grow.

Occasionally we collect marine organisms for study in the large aquarium facility at Rothera. Scuba diving is an excellent way of collecting samples, as it doesn’t cause as much damage as trawling and we are able to specifically collect just the organisms we are looking for thus causing minimal impact on the wildlife. A lot of work is done looking at the potential impacts of global warming on Antarctic marine life. It is a very important area to study, if water temperatures rise the only options for any organism is to adapt to the new temperature, migrate further North or South into colder areas or to die. Should water temperature increase in the Antarctic organisms here would have no option of migrating as there would be nowhere colder for them to go, so it is important to understand how they would react.

Another important part of my job is conducting regular CTD casts and water sampling in Ryder Bay. The CTD measures Conductivity (from which we can ascertain the salinity / saltiness of the water), Temperature and Depth. In addition there is a fluorometer to measure fluorescence from which we can tell how much phytoplankton (micro algae) is in the water and a PAR sensor (standing for Photosynthetically Active Radiation the PAR sensor measures the amount of sunlight which is available to the phytoplankton). In the summer I have to go out once every 5 days and hand winch the CTD down to 500m and back, a task for which I usually recruit a few willing volunteers (a small price to pay for a boat trip on a sunny day). We then collect water samples from 15m, which I later analyse in the lab to look at the amount of phytoplankton and nutrients (ammonia) in the water. The deeper waters remain fairly stable throughout the year but above 100m temperature, salinity, nutrients and phytoplankton levels can vary dramatically between summer and winter. This type of sampling was started at Rothera in 1997 and continues throughout the year. Such a large continuous data set is invaluable as it enables scientists to determine whether changes in the water are just variations between years or are part of a long-term change.

The typical summer CTD cast above shows high surface temperatures, fluorescence (due to large amounts of phytoplankton) and PAR (high levels of sunlight) the salinity is low due to the freshwater input from melting of snow, ice and sea ice.

The typical winter CTD cast above shows low surface temperatures (sea water freezes at a lower temperature than fresh water due to the salts contained within it), low fluorescence (in winter there is not enough sunlight available for the phytoplankton to grow) and low PAR (as there is little / no sunlight). Salinity is high in winter as salt is exuded as the sea ice forms.

Finally, love to my friends and family back home and thanks to the 2007 Rothera wintering team for making this winter such a memorable experiences.