Dale Andersen's Antarctic Field Report 2 December 2013

We made the first dives beneath the thick, perennial ice (3.6 m) of Lake Obersee yesterday.  

It was nice being back under the ice again, and its always interesting. Yesterday morning I went in for the first dive to collect samples of the benthic microbial mats (a lush garden of cyanobacteria forming pinnacle mats), and after lunch Andrew Abercromby dove as well with Alfonso Davila and Klemens Weisleitner working as dive tenders.

Andrew is a very experienced diver (for example he has worked  a number of NEEMO missions, worked at the NBL, with PLRP etc.) but this was his first opportunity to dive beneath ice. Andrew set out two small experiments and then spent another 20 min or so taking swimming beneath the ice getting used to the dive gear, tether, communications etc. Our maximum depth was ~50 ft.

Following the dive, samples were returned to our lab tent for processing by Vladimir Akimov, Alfonso and me.  Lake Obersee is quite different from Lake Untersee and appears to be much more diverse. As far as we can tell, there are no large conical stromatolites forming in this lake as they do at Untersee. A big question we have is why are these two lakes so dramatically different despite their proximity (7 km).

All in all it was a pretty productive day and so far the weather has been very reasonable with sunny skies. Its still windy (15-20 kts, gusting to 30 kts at times) but having some blue sky and sunshine is a real plus.

Dale

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