Fast Ice

Fast ice: it sounds so exciting. In a ship surrounded by bobbing icebergs, mountains shrugging glaciers off like very slow coats, and pack ice dotted with penguin footprints drifting by, “fast ice” sounds adventuresome. What’s fast about it? Well, it turns out that it’s “fast” to land. Fast ice is essentially sea ice that is connected to unmoving ground along its edge- much less thrillingly speedy than I had expected. Chief Mate Lubo must have noticed my slight disappointment at his explanation of the concept, because he was quick to explain that “looking for fast ice” was, in fact, going to be just as fun as I had originally hoped. The Orion was a sturdy little ship, and she was going to find some pack ice that was just the right thickness… and run right into it.

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And so she did! With much crunching and cheering, the bow of the ship went right into the ice.

Where we went in, the fast ice was at least two years old- not old enough to have become too thick for our hull to break, but thick enough that a hundred people walking around on it wasn’t likely to end in disaster. From what I could tell watching from the tip of the bow, it was somewhere between four and six feet thick, though my estimate is by no means professional or trustworthy. Having formed from seawater as the temperature dropped far below the freshwater freezing point of 32 degrees F (0 degrees C, for scientists and pretty much anyone outside of the US, Palau, Belize, the Cayman Islands, and the Bahamas), much of the salt had worked its way out of the ice and back down into the ocean below.

The intersection of ice and sea is always an interesting one. Justin Hofman, the “Undersea Specialist” aboard the Orion, took a dive at the edge of the ice and brought back video of the creatures living below. Krill requires ice, as a substrate for their algae food, and since krill make up an almost incalculably large part of the Antarctic food web, the ice/water border is imperative for life in the polar region. But besides krill, the rocky bottom was covered with limpets, giant isopods, sea spiders, and the occasional zooming penguin. Under fast ice, they’re relatively safe. Under the shadow of a glacier, they’re fairly likely to be scraped off of the bottom by grinding bergs, falling or pushed by fierce winds. The scars are visible for a long time, as life returns slowly to rocks scoured clean by moving ice.

Surface-side, the fast ice looked clean and bare. It was only slowly that we started to notice the little bumps and cracks running through it, and with all the hullaballoo around the ship itself, it was almost an hour before we actually started paying attention to the local fauna. In the meantime, the crew (who had never experienced this particular adventure before) piled off of the ship with the guests, bundled up with coats and cameras, to pose for a series of adorable pictures with their boat/home.

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More on fast ice and penguins to come!

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