|
Life on a Glacier
Is there life on a glacier?
Of course there is!
The surface of a glacier is
a jumble of rock and dirty snow which has been folded and
contorted by stress. If you look at it up close it looks like a barren
wasteland. What could possibly live there?
The wind is responsible for
bringing life to the glacier. As wind moves over land, it
gathers bits of dust and debris. When the wind sweeps over
the glacier it deposits part of the load. Tiny insects such
as spiders, beetles, and flies, grains of pollen from flowers, and minerals are mixed in with the
dust. As these are spread over the snow and ice, they become
a feast for tiny creatures such as the snow flea. The snow
flea is a tiny insect that crawls around on the glacier in search
of pollen.
Another creature which
exists on a glacier is the ice worm. It is a relative of the
earthworm, but less than an inch long. It lives hidden in the cold
glacial ice. Ice worms wriggle between ice crystals near the
glacier's surface, but sometimes can be found as deep as six
feet. Ice worms burrow into the glacier's
ice during the heat of the day and inch to the surface around dusk
to feed. They depend mainly on the wind to bring their
dinner of pollen and other plant materials.
Ice worms can survive only
under certain conditions. Temperatures around freezing (32
degrees F.) are perfect. If they get caught in the sun's
heat where it is warmer than 40 degrees F., they will die.
When the ice around them freezes solid and becomes colder than 22
degrees F., their bodies freeze. Therefore, ice worms are
found only in glaciers near the ocean, or where the climate is
warm enough for melt water to be in the ice at all times.
A special algae that grows
on the surface of the snow provides food for the ice worm.
Snow alga is a type of green alga. Its color is red, which
provides a screen against the bright rays of the sun.
Birds flying over a glacier
feed on ice worms and insects, plucking them from the ice.
Other animals use glaciers as a temporary home and a resting
place.
|
