Getting our feet wet
The ice floe we have been calling our home for the past 2 weeks finally disintegrated in front of our eyes, virtually in a split second – something we had feared (or expected) every day since anchoring to the floe.
For the last phase (or leg 6 as we call it) of N-ICE2015 field campaign, we have been drifting with a rather thin ice floe, which at the beginning was several kilometers across, near the ice edge north of Spitsbergen. Winds and currents have been pushing us around and closer and closer to the open ocean. And thus we have worked hard every single day, as any day could be the last day on our floe.
We followed the fate of the floe with great interest, to understand the factors controlling the melting of sea ice in this region. It is a challenging time of year to work on the ice, but also a period that has seldom been observed; All the more rewarding for us to follow it to the bitter end.
Some days have seen tens of centimeters of ice melt due to warm waters, while other days passed without much melt at all.
This is the time of year the ice starts to melt at these latitudes. The forces driving the melt are solar radiation and heat accumulated in the ocean. As the snow melts, more and more sunlight reaches the ocean every day, allowing phytoplankton to bloom underneath the ice.
The phytoplankton form a layer that stays at the sunlit surface because of the fresher waters accumulating there from the ice and snow melt.
Operating an ROV under the ice has lately been like driving in spinach soup. The waters are full of phytoplankton, and zooplankton that is feeding on them, with visibility as low as driving a car during a snow blizzard. Just weeks ago the waters were as clear as mineral water you buy in the shop.
It is a combination of factors, such as sunlight, melting ice, and nutrients, that makes this possible here at the ice edge. Understanding these massive under-ice blooms can give us an insight into the Arctic future, when more and more ice will melt every summer.
As the snow and ice melts, puddles (or melt ponds, as the sea ice scientists call them) form at the surface. These puddles melt the ice from the top, and the snow becomes soft and wet.
All this makes travelling on the ice more difficult. The ice gets thinner in places and one has to be careful when moving about. And so we do. With survival suits on, and safety gear at the ready, scientists venture out on the ice every day to understand how the ice is melting.
Or so we did, until that «final morning»; our floe was almost in open water when suddenly cracks appeared by the ship. We were right by the ice edge, and exposed to the dynamics of the open sea. A small swell was all it took. Within minutes our floe had disintegrated into smaller floes, no bigger than some tens of meters in size.
Our equipment and camp was spread out over several of these small floes, and a rescue operation to salvage all the gear out on the ice was initiated. But, with all the earlier experiences, this was done swiftly and safely, despite the challenging conditions, and we managed to salvage all the equipment that was floating away.
The last days of leg 6 we spent drifting alongside the small floes to find out what happens with them, and how the cracking up and larger areas of open water affect the biology in the water column.