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Silent Lake
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Reflecting on Macroinvertebrates
High atop mountainous ridges and nestled within forested basins
hide the liquid sapphire gems of the North Cascades. Hikers visit
these quiet realms, where little is to be heard, save the distant
spiraling song of a hermit thrush or the rhythmic lapping of tiny
waves upon the rocky, talus shoreline.
One might think that mountain lakes are immune from the problems
of the world, but today some of these lakes contain pollution from
sources as close as Puget Sound and as distant as Asia. Airborne
pollutants—such as mercury, sulfur, pesticides and nitrates,
from industries and agriculture—come in with the weather and
collect in these wilderness waters. Deterioration of lake habitats
can also occur through the introduction of nonnative fish (once
introduced for fishing purposes) and by visitors trampling the shoreline.
Scientists are searching for ways to help these lakes recover.
The first step to recovery is to learn more about the lakes. Researchers
have gathered baseline information (such as water depth and elevation)
from many of the lakes at North Cascades. They have also collected
macroinvertebrates, which can be used as indicators of water quality.
Macroinvertebrates are tiny organisms, such as the larvae of insects,
which live in the water. With this information they have created
models that are designed to predict
the health of mountain lakes.
If lakes are determined to be unhealthy, there are a number of
ways to approach restoration. One of the most simple methods is
to do just what the 'doctor orders': to allow the lake to rest.
However, discovering ways to limit pollution from locations outside
park boundaries, especially locations as far away as Asia, may prove
to be a difficult task.
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Critical
Thinking: 