This afternoon we got a taste of Arctic winter at a bizarre ice formation called "aufeis," which means "ice on top" in German. After hiking through through a small forest of willows, we emerged from the trees to the sight of the shockingly bright aufeis at the base of a mountain. The ice forms when warm spring water bubbles up from the ground and freezes, creating ice shelves and blocks that cover the tundra in large swaths. Our leader Chris Neill and Rich McHorney, a research assistant, let us loose to wander through the ice fields, and -- though it was risky -- most of us clambered on the ice to capture that perfect photo. The ice shelves, lined with rows of delicate icicles, were an incredible shade of aqua, like a coral reef lagoon. Gradually, the aufeis will melt -- the ice overhangs were slowly dripping -- so in a few weeks the formations will likely look much different. Of course in just a few months, this tundra will again revert to the frigid darkness that defines it nine months out of the year. (As a side note, despite the perils of ice and winter storms, the Dalton Highway -- which I traveled on the way to Toolik last week -- stays open all year-round for long-haul truckers returning from Prudhoe Bay.)
Before our foray onto the ice, we spent the day splashing about in three streams near the field station. We broke up into groups, some of us sampling water for nutrients, others calculating the stream velocity, and still more capturing bugs that live in the water. As one of the critter catchers, I pulled on my waders, traipsed into the middle of the stream, and reached into the freezing water to pick up rocks and force bugs into a net. The glacial streams I sampled had fewer bugs than the groundwater streams, since the heavily silted water of glaciers tends to scour the rocks and remove any moss or algae that the insects might eat -- like "water sandpaper," scientist Linda Deegan told us. We also sampled rivers that had been treated with phosphorus and control rivers that had not been treated at all. After we returned to the lab, we learned that the bugs caught in the fertilized rivers were more diverse and more plentiful, since the treated rivers have more algae, the bugs' main food source. One fantastically strange insect, the caddisfly, uses found objects in the river -- such as twigs and pebbles -- to build itself a solid cocoon, where it lives until adulthood.