February 28, 2008 - Sailing to Antarctic: Grandidier Channel
by Kate Laird

While we're having a terrific visit to Antarctica so far this season, and we couldn't ask for a better group aboard - helping out with everything, and in good humor all the time - this trip has not been all rosy. Too often we are seeing brutal examples of the effect of climate change on the peninsula. Hamish has been coming here steadily over the last twenty years, Kate for the last ten, and in each anchorage, we see examples of retreating glaciers and further melting. Great swaths of snow are now dirty with pink and green algae - bits of snow have always been tinted, but where there's been severe melting, the color is much darker, since the algae doesn't melt and simply becomes more concentrated. As the color darkens, melting accelerates, and when the dark rock is exposed, the glacial edges retreat even faster.

The first picture below shows Dorian Bay now, in 2008. Before 2000, when we came at this season of the year, this part of the beach was usually snow-covered. This season has been unusually rainy...at Port Lockroy we were told that the entire season had been wet, and that the pack ice had never formed up in its usual quantity this season. Krill survive the Antarctic winter by feeding on the algae that grows on the underside of the sea ice, and if the pack doesn't form, they have no food. Krill is the keystone species for this entire region. There are very few steps in the Antarctic food chain - even the biggest predators often eat krill as some percentage of their diet. Only the orcas don't partake directly - and they are only one step removed.

We saw severe melting in Dorian Bay - a marked change from February 26 last year.

Photo of sea ice from a previous visit. We're seeing no sea ice like this in the summer of 2008.

We met two underwater wildlife filmmakers yesterday and they had been filming leopard seals eating krill all season (they will switch to penguins when the young ones molt in the next few weeks and start to swim.)

Other observers have told us that the krill and wildlife is concentrated unusually far south this year. Seals and whales can move with ease between the regions, and change their range to suit annual conditions. But penguins are creatures of habit, and they return to the same colonies year after year. So, as long as the krill can survive, the seals and whales should be able to find them, but it will be harder for the penguins.

Fortunately, the penguins are doing well this season, at least at Port Lockroy. With the rain that they had in the past few months, they said they expected the population of chicks to be decimated, but the chicks have done quite well this year. Chicks often die of exposure if they are rained on, as their down has evolved to cope with snow but not rain. But perhaps (and this is pure speculation), it was simply not cold enough to kill the chicks, even with all the rain.

Over all, it has grown steadily warmer on the peninsula over the last 20 years. We've expanded our range of anchorages, because the glaciers have retreated, leaving behind bare rock where we can tie shore lines. There are normal seasonal variations in sea ice cover, and the time of the ice break up is largely dependant on spring storms, but the trend is clear.

- Kate

For more about Seal see http://www.expeditionsail.com.