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Ice is nice but wetter is better…

May 9, 2009

Sea ice is very dynamic, it is constantly changing, and is very quick to change. You’ll have noticed that when we first arrived in Ny Alesund the fjord was completely full of sea ice – very nice for photos but not a good start for trying to collect animals and sediment…

Frozen fjord

At the end of the first week the ice breaker had come in and broken up the ice. Luckily  this was followed by an easterly strom-force wind, which blew the broken ice out the fjord – maybe we’ll get some experiments going after all…

Fjord opening up during the storm

This was good news because we were able to launch to the dive boat. However storms don’t last forever and there was still a lot of ice in the fjord. The last few days we have had very nice sunny weather but this has made everything quite cold again – its been between -2 oC and -5 oC. We woke the other morning to find the fjord re-freezing, and the dive boat in the middle of it – oh dear, and still not a mud sample in sight…

Dive boat stuck in new "pancake" ice

Sea water freezes at about -1.8 oC but the exact value depends on how salty it is. When it starts to freeze it happens in small patches which slowly grow outwards and look a bit like lilly-pads or pancakes (in fact it is called pancake ice). When they get big enough they bump up against the neighbouring pancakes and these then get thicker and thicker and melt and freeze together. Sea ice can crack down these joins quite easily and this is what forms leads or paths in the ice, which ships can use to pass through.

In the distance we could also see that the thicker, whiter, sea ice was starting to block up the end of the fjord as well as new ice forming nearer the shore – I’m getting a feeling of de ja vu…

Freezing fjord

And so the game begins again… This afternoon it has slowly got more stormy, the wind has picked up (easterly again) and the ice is being pushed out and the divers are doing their best to keep us happy – the sediment might be here by this evening, then its only another few hundred serripes, urchins and gastropods left for them to collect, no problem!

Storm over the fjord again

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