The Spirit of Mawson - Australasian Antarctic Expedition 2013 - 2014

Australasian Antarctic Expedition

Day 5 – Southern Auckland Island, Coleridge Bay and bush-bashing up to Lake Speight.

Posted by Verity - 1 December 2013

What follows is a summary of the day’s work from the perspectives of the different teams:

An exhausting day today but an extremely valuable one that has brought us one step closer to a better understanding of the glacial history of the Island. Today Lake Speight (a small corrie lochan above Coleridge Bay) was our target. The plan was to hike up through the dense forest vegetation to core peat in one of the glacial corrie features and to suss out how feasible it would be to take a boat up there to allow us to core within the lake itself. We wanted to gather data that would allow our glacial history team to reconstruct the past glacial changes on the islands. This will assist in the construction of a high-resolution model of the Sub-Antarctic ice fields. The elevation would also allow us to map on the ground some of the observed glacial features including terminal and lateral moraines. An enthusiastic team of scientists trail-blazed a route at a flying pace of 670m in two hours carrying the coring equipment (that hopefully gives the reader an idea of the difficulties hiking through this old and twisted-branch forest). Meanwhile on the ship the multibeam was aiming to extend our understanding of the glacial history and geomorphology into the fjord-like harbours of the eastern coast. The density of the forest vegetation and the thickness of the peat meant that taking samples of glacial erratics for cosmogenic isotope analysis was not possible. However, we successfully cored 185cm of peat that will give us a valuable sequence that can be analysed to look at retreat after the last glacial maximum.  An alternative route up to the lake site tomorrow (perhaps a slightly faster one) may allow us to drag a small boat up to do some more coring in the lake sediment there. Fingers crossed! Tonight we all have scratches, bruises and aching muscles but there is nobody in the group who would rather have been anywhere else today. Tonight after reviewing all the priceless go-pro footage of us falling into peatbogs and through bushes and trees, it will be time for a well-deserved sleep!

Who would have thought there was so much happening along the shoreline of these Sub Antarctic  Islands but a whole new world opened up for me as I tagged along as an assistant to Rebecca Cumming from the University of Otago in the search for the as yet undescribed terrestrial mollusc (family Onchidiidae), along the shores of Coleridge Bay, Carnley Harbour, Auckland  Island.  Although we did not find the terrestrial onchidiid today, the marine genus Onchidella was found in abundance in the intertidal zone on Masked Island. We found tiny little snails (Diloma sp.) with long antenna with the most beautiful iridescent blue and purple shells and under another rock dozens of amphipods (that look like little cockroaches) scurrying from the light.  We were so excited to find tiny mussels, not bigger than your little fingernail, only to find 1,000’s later once the tide went out.  Hey, and if you think you are safe from arachnids out here in 5 degrees, in the middle of the Sub Antarctic….. the island is covered in them (spiders that is).  But hang on –  they can’t swim or fly……so how did they get here?  All this adventure under the watchful eye of our home away from home, the Akademik Shokolskiy.

Back on the ship work continued with the CTD. Shirley and Dave worked for most of the day gathering temperature and salinity data for Carnley Harbour. Chris Turney spent the morning on the top deck, preparing for an important live interview with Weekend Sunrise. After half an hour of technical difficulties and waiting in the cold, it all came through.

In the afternoon, work began with the gravity coring apparatus on the rear deck. It was raised over the side and dropped rapidly into the sediment at the bottom of the bay, capturing a record of hundreds if not thousands of years of sediment. The highlight of the day was watching Chris T. and Chris F. try to push through the language barrier, communicating with the Russian's in a sign language all of their own making.