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Lake Superior is the cleanest, clearest and coldest of North America's Great Lakes.
It contains 3 quadrillion gallons of water - that's a 3 with 15 zeroes after it.
And the lake itself is about the size of the state of Maine.
Lake Superior could hold water from all of the other Great Lakes and still have room for
three more Lake Eries.
Yet with all of the hard facts we have about this large lake,
scientists are still trying to figure out its inner workings,
including how the lake is responding to climate change.
Lake Superior is big, it's cold, it's fairly inaccessible,
or it has been historically, and there's lower population in the basin, so it has received
less attention than the other Great Lakes.
Because we don't have a lot of information, it means that
we don't have a good sense of how the lake really functions over time.
So in order to really understand what the impacts of climate change are going to be
down the road, we need to
understand some of the fundamental processes.
Lucinda Johnson, a founding fellow of the University of Minnesota's Institute on the Environment,
is teaming up with colleagues at the Large Lakes Observatory and Minnesota Sea Grant
to address the environmental challenges facing Lake Superior.
What we were able to show
pretty conclusively is that
Lake Superior is warming,
at least in the summertime -
that's the only time we measure the temperature is in the summer -
the summer water temperatures are increasing much faster than we would have anticipated.
They're rising
about twice as fast as the local air temperatures are rising.
The air temperatures are rising here faster than other places,
and then the water temperature is rising even faster than that.
Every warmer winter we're getting
less ice, and we will have less ice over time
and so we have this acceleration of warming of our lakes.
Ice is very reflective - it reflects most of the energy back into space,
whereas liquid water
absorbs most of the energy.
If you have a tendency to
have less and less ice,
then the water absorbs more energy and you
reinforce the tendency
to have less and less ice.
This immediately has consequences. For example, in the fisheries, because fish
are very sensitive to temperature - it often determines their growth rates, often determines which
fish can be in the system.
Virtually all chemical
and biological processes are temperature-dependent,
so if you change the temperature,
you're going to change
anything from the rate of photosynthesis of algae to the rate of decomposition of organic matter.
We have what we call a cold water fauna in our Great Lakes, primarily,
and we have a lot of cold water, but we're going to have less of it.
Working together across disciplines is critical to uncovering new information about climate change.
Through creative collaborations and cutting-edge research, scientists like a Hecky, Colman
and Johnson are beginning to solve the mysteries of Lake Superior -
and of the Great Lakes in general.