Wednesday 26 June 2013

Cutting the dive hole

Others heading out for sea ice training.

In order to go diving, one needs a hole in the ice in the first place. No, unfortunately, they are not the comedy round ones – not really practical enough I guess. The chainsaw which is used to cut the hole needs warming up at base first and then gets wrapped up to stay as warm as possible. Once on the ice, the rectangle is marked and the outline cut into the ice with the chainsaw. The rectangle is cut out

Steam coming out of the tide cracks.

with divisions of 6-8 blocks. Each block gets an ice screw so that two people can get the block out. We always cut 2 holes so that we have got a back up hole in case one of them is used by seals as breathing holes. While the holes are not being used, they are covered with bit boards and marked with 4 flags. Hopefully, I can use the chainsaw myself the next time we need to cut holes. However, for now the holes are there and we just need the good weather to go diving through them! (no need to mention the excitement ...)

Amber taking the ice cores and others
watching world class science being done.

Amber (Dutch Marine Assistant but actually Canadian) came out with us to take some sample ice cores in preparation for taking proper ones in the other bay with a CTD. When the cores are being melted, salty water needs to be added so that the solution ends up being the right salinity for salt water to avoid any of the organisms dying too early (they would break up and spill a lot of the things which are measured into the water and hence mess up any data). At the same time Amber looked at how long it would take for the cores to melt. They cannot be warmed up too quickly (fridge at +4 degrees is ideal) as this again would kill all the organisms trapped in the ice. At the same time if the cores are left too long, too many variables (ie gases in the water) would change and organisms would be active and hence influence measurements as well. 

Tommo telling Pete how to cut the hole.
Marking out where to cut.
Proper cutting action!

Dive hole is ready!
Putting ice screws in so the blocks can be
lifted out later.
And now getting the blocks out (since than
we have lifted out much bigger ones ...)

Tuesday 25 June 2013

Sea ice training

Despite all the other exciting stuff happening on base, I couldn’t wait for the sea ice to come in! Once it was here and we were not able to do boating again, the waiting game started. The ice has to be here for a certain amount of time and has to have survived quite substantial wind before our field assistants get permission to go and test the ice. But finally the day was there and the ice was thick enough to enter! Once we had a calm day, we were taken onto the ice to complete our sea ice training after which we would be allowed on it without a field assistant to go diving and maybe eventually CTDing. So far, only the North/Hangar Cove side is frozen enough to enter. We entered the ice on one side. There is a tide crack visual where the ice connects to the shore and the ice moves up and down with the ice (silly me always thought that once the ice is there and solid it wouldn’t move anymore ...). We all went on with skis for the first time and wandered away from the shore for a good couple of hundred metres. Every 50-100 meters we tested the ice which involves drilling a small hole, measuring the thickness of the ice (mostly around 35cm) and recording the point by taking the GPS. Once we got back from our tour, only the most fun bit was left to do: we had to proof that we would be able to climb out of a hole in the ice in case we break in. With our more or less sealed boating suits, attached to a line we jumped into a pre-cut hole and it was so much fun (the closest I have gotten to swimming since I have been here, apart from diving ... hence why I obviously had to jump in a second time before we went back home). Now, we are allowed on the ice, so the diving through it can finally begin!!! More about those adventures later.

Just before entering the ice.

Boring the hole.

Measuring the dephts of the ice with the highly technical measuring device.

Icebergs trapped in the ice ...
Penguin footsteps in the snow: Someone must have been here before us ... 
I tried calling, but did not receive an answer ...

BIG JUMP (Photo: Pete Webster)
No it's not cold ... And no, no water is running down despite the neck seal ... (Photo: Pete Webster)