Whether the problem is called global warming or climate change, something is occurring to the Great Lakes
and other water bodies.
While all three of Saturday’s Reddin Symposium speakers addressed the issue, as scientists with expertise
in freshwater bodies, Dr. Michael McKay and Dr. John Smol spoke about it in detail.
McKay, the Ryan Professor of Biology at Bowling Green State University, shared his research in "Life
Under Ice: Lake Erie’s winter biodiversity and implications of climate change." Of the five Great
Lakes, Lake Erie is the most prone to having the heaviest ice covering in winter because it is the most
shallow.
But that is no longer true because of changes in the climate. McKay expressed concern that all five Great
Lakes have seen a reduction in their ice cover. Less ice cover will affect changes in the water level of
all but Lake Superior, the deepest, possibly a loss of 18 inches, expected late into the 21st century.
In addition, increases in lake-effect snow are possible, up to 200 inches in some places.
"Warming waters diminish the ice cover, and ice is good for Lake Erie," he stated. "We
don’t know what will happen in Lake Erie with changes in the ice cover. It could have serious
implications for the food web. We need to look at more what’s happening in other lake systems."
Up to now there has been very little research done on Lake Erie in winter, but McKay and his team have
been able to study it for four years, including riding a Canadian Coast Guard ice breaker to collect
their samples.
On their first two-day research trip in February, 2007, McKay said brown water was observed when the ice
was broken. Instead of being sediment churned up, it was actually diatom algae, a "good" algae
which transfers carbons to the food chain.
McKay described challenges to taking samples in winter, such as water collection bottles freezing up
along with plankton trapped on a special net.
Initial results revealed, "far from being dormant, the environment of Lake Erie seemed full of
life," with diatom biomass (masses of diatom phytoplankton) in the ice, under the ice and in the
open water.
Next month McKay is scheduled to return for more research. This time his team will use a remote-operated
vehicle with cameras, a sampling device and pressure sensors.
The scientist and professor also explained a hypothesis that winter diatoms are forming the
oxygen-depleted dead zones in Lake Erie’s Central Basin. The biomass moves to a deeper part of the lake
where it is colder, but bacteria aren’t as efficient at breaking down the carbon as they are in summer.
When bacteria break down carbon they use up oxygen, forming the dead zone.
Smol, professor of biology at Queen’s University, Kingston, Ontario, is an expert in studying sediments.
His talk was "Lessons from the Past: Using sediments to assess effects of multiple stressors on
lakes."
Things such as oil spills, agricultural toxins, aerial pollutants, point-source pollutants and dredging
are multiple stressors on the Great Lakes.
But studying their sediments gives Smol a look into their "biological footprint," and he can
apply what he learns from small lakes to large ones.
"In that mud will be a tremendous library of information," Smol stated. "It can be dated.
There is information coming from the atmosphere; carbon particles, fly ash from coal combustion,
materials and other pollutants from industry, mercury, lead, cadmium."
In addition, the sediment will contain pollen, mineral particles and insect remains, as well as diatoms
and other miniscule water organisms so small that, according to Smol, "100s can fit on the head of
a pin."
For 28 years he has studied lakes and ponds in the Canadian Arctic which have a thriving bird population.
Smol is concerned because the birds show high DDT and PCBs in their system, and some of the 30 lakes
he’s studied are not only losing their ice and snow cover, but completely evaporating.
He showed photos taken of some of the lakes over the last three decades and how they went from thriving
to disappearing completely.
"Ice cover is intimately linked with climate," stated Smol. He said temperatures are up; ice
covers are down; water levels are down; evaporation is up; and conductivity is up. "Even the
wetlands are drying up."
