Taking the waters

So far it looks like the acupressure wrist bands are doing the trick - the wind got up to 25 knots yesterday and I’m feeling OK. Canadian coast guard crew member Marianne tells me that most people who get seasick would have started to feel it by now so I’m optimistic.

View imageThe sea is too rough for researchers to leave the icebreaker on its flat-bottomed barge. Recently they’ve been using the barge to collect samples away from the ship where the surface water hasn’t been affected by the Amundsen churning it up or contaminating it. But today they improvise by throwing buckets off the icebreaker. Once the mid-leg crew change takes place tomorrow the engineers will have the spare part they need to fix the Zodiac that can leave the ship in all weathers.

Jens Ehn of the University of Manitoba tells me how light reflects from the surface of the ice as it starts to melt. Both snow and ice reflect a large proportion of the energy from the sun’s rays back into the sky. But once the snow has gone, pools of water known as melt ponds appear on the ice, decreasing its reflectivity. On this trip Jens has found that as melting proceeds the melt ponds drain away and the ice briefly becomes more reflective again. Finally the wind and waves break up the now thin and brittle ice and expose the less-reflective ocean below.

Surface reflectivity is of great interest to climate scientists as it affects how much heat the Earth absorbs. One of the problems of climate change in the Arctic is that as air temperatures rise and more ice melts, that exposes a greater area of the darker ocean below. The ocean then absorbs more heat from the sun and causes additional warming, in what’s known as a positive feedback loop.

  View imageToday’s fishing nets prove more successful than earlier in the week - Stephane Thanassekos and Samuel Lauzon of Laval University catch several Arctic cod larvae. They’re transparent with a faint pink tinge and around 5 mm long, making them likely to be about 10 days old. Arctic cod contain a form of antifreeze in their bodies that enables them to live under the ice, where they can hide from predators such as seals and seabirds. Stephane will use his data to create computer models of the growth of the fish so that he can predict how climate change will affect them. As climate change kicks in and the ice disappears they will lose their protective habitat. What’s more, fish from warmer waters could move north and compete with the Arctic cod for food. On the other hand the warmer temperatures may help them to grow faster - it’s not yet clear which of these factors will have the greatest effect.