A scientist wearing plastic boots and crampons knelt on Gulkana Glacier and pointed at the king of beasts, a snow flea.
"He is the top of the food chain on this glacier," said biologist Nozomu Takeuchi.
The snow flea, a tiny wingless insect also known as a springtail, sprung away at the advance of Takeuchi's finger, landing near a stream of meltwater. Takeuchi opened a notebook and scribbled with a pencil.
He was on the Alaska Range glacier on a rainy day to study algae, the food of the snow flea and the key to life on the surface of glaciers.
Algae are microscopic plant-like organisms that use the energy of sunlight to make their own food.
The many species of algae on Earth capture more of the sun's energy and produce more oxygen than all plants combined. In adapting to life on ice, algae have provided food for the snow flea and many other wee creatures of the ice.
On that day, Takeuchi, a professor at Chiba University in Japan, was collecting algae with a stainless steel scoop. Millions of algae living on the surface of ice and snow stain the glacier red in some areas, and give it a dusty appearance in others.
A former researcher at the International Arctic Research Center at UAF, Takeuchi has spent hours crouching on the surface of Alaska glaciers, scooping up individual alga too small to see without a microscope.
His face is tanned the color of leather, except for light patches beneath his sunglasses. He calls himself a glacial biologist.
Takeuchi gathered ice from the glacier surface in clean plastic bags. Later, he would dry the bags to measure the earthy material produced by the algae.
In plastic bottles the size of his palm, he scooped snow samples in which he will later count the algae. With these, he will try to figure out the population of algae on Gulkana Glacier. It is a staggering amount of life, so dense in areas that it can alter the face of a glacier.
Walking up the glacier, Takeuchi pointed out tiny pocks in the ice filled with water.
Called cryoconite holes, they are produced when an accumulation of algae and the organic material it attracts form a dark spot that absorbs sunlight and melts its own pool. Here, the algae have everything they need: plenty of water and sunlight, and a buffer from streams on the surface of the glacier that would flush algae away.
"They want to stay in the same place," Takeuchi says.
Bacteria, snow fleas, ice worms and dozens of invisible species congregate in the cryoconite holes to eat algae. Algae thrive in the summer but die in the winter, when water on the top of a glacier turns to ice. Algae survive by producing spores that "hatch" the following spring.
In addition to counting algae, Takeuchi also takes note of how they affect the surface of a glacier. Gulkana, for example, is a rather dirty glacier, due in large part to algae and the organic material broken down by creatures that live with the algae. Dark patches of the glacier absorb more sunlight than light patches, and Takeuchi said melting beneath dark areas can be three times as great as that beneath clean surfaces. As part of his studies, he checks the reflection of light from different parts of the glacier with a spectrometer he carries in a backpack.
While scientists have blamed the increased warmth of the air for the shrinking of Alaska's glaciers, the sun absorbed by algae also plays a part.
Takeuchi wants to find out how the tiny world on the surface of the glacier affects these giant sheets of ice. To do this, he walks on glaciers, stopping now and then to ponder a snow flea, the glacial equivalent of a polar bear on sea ice.
Ned Rozell is a science writer at the Geophysical Institute, University of Alaska Fairbanks. He can be reached by email at firstname.lastname@example.org.