This week at Davis: 18 October 2019
Expeditioners supporting science
Nice day for a seal survey
While we all have our individual roles on station, there are always additional tasks which involve a co-operative effort. These range from emergency management to general station support, or just lending a hand where and when it is needed. This spring at Davis one of the additional tasks to which we have all contributed is, once per week as a group of four, to travel around a designated area in Long Fjord and record the occurrence of seals on the sea ice. The information we gather is of interest to the AAD Davis Aerodrome Project.
We have found the most efficient strategy is to work in pairs as one team in a Hägglunds and two on quad bikes. It is an all-day-outdoors activity so we try to pick the better weather days of the week. These deliberations have led to a common saying on station which has become a bit of a laugh - the title of this article.
The first few weeks of Seal Survey came up empty - no critters sighted, although a number of rocks were closely investigated until they revealed themselves to be - well, rocks. More recently we have seen the first Weddell seal arrivals of the season, and as of last week the first newborn pups. We expect the sightings to steadily increase over coming weeks.
My position as Electronics Engineer has for a number of years supported monthly observations at Deep Lake. Deep Lake is a feature in the Vestfold Hills about 10km northeast of Davis. It is one of several hyper-saline lakes in the Vestfolds which never freeze. At 27% w/v Deep Lake is slightly less saline than the Dead Sea and about 10 times more than typical seawater. Maximum lake depth is 36m, but the real "depth" is in its surface - about 52m below sea level. Since the mid 1970's observations of the lake water temperature, level and appearance have been recorded on a regular basis as a long-term indicator of environmental change. This year we have observed the lake level steadily decrease by 3cm per month to a minimum just before mid-Winter, then a rise over the past two months back to levels observed last summer. Last year it varied by only a few centimetres year-round. Water temperature this month was -13 degrees. The coldest so far this year was -15 in September.
We record the details on-site in log book. The current log book dates back to 2004 and it is remarkable how many of the names in it are familiar from seasons past. The book is only about half-used now, so years from now maybe someone will recognise our names and contribution to the Australian Antarctic Program.
I have visited the lake on several occasions this year in conditions varying from a very windy overcast day in March, gently falling snow in May, to the eerie quiet and subdued light of early July. The following photos are from a glorious sunny spring day. This day we combined a Seal Survey with the relatively short walk to Deep Lake made possible by vehicle access across the sea ice. It was indeed a nice day for all of those tasks.
Mike (AGS Electronics Engineer)