Under the ice of lakes: 'There is a lot alive and active down there'

Life is thriving under the ice of our lakes, and Brian Hayden wants to know why.

Hayden, a Research Fellow with the Biology Department at the University of New Brunswick and the Canadian Rivers Institute, recently participated in a study involving 63 researchers and some 100 lakes from around the world. Theywanted to know what goes on below the surface in the winter.

Surprisingly, quite a lot, Hayden says.

"We assumed that there would be very, very little activity under the ice," he said in an interview.

"But when we started to pool this data from across over 100 lakes, we saw some really striking trends that there was far more plankton in these lakes during the winter than we expected."

Plankton consists of microscopic organisms that live in the sea or fresh water. Much of it is made up of tiny plants and small animals, such as crustaceans.

As the extent of ice is decreasing, it becomes crucial for us to understand that better, to really figure out what we are losing when we lose this lake ice, what component of the lake ecosystem do we lose.- Brian Hayden, UNB

The researchers always knew that fish lived in the waters year-round, said Hayden.But they never expected to see so much plankton, as fish eat it during the summer but feed on insects and worms in winter.

"The extent of the food web, of the productivity, of the diversity of organisms was far greater than anything we'd expected," he said. "There is a lot alive and active down there."

Climate-change impacts

Although no New Brunswick lakes were part of the study, the researchersdid look at data from lakes elsewhere in Canada in Ontario, Quebec, Manitoba and Saskatchewan.

Hayden said the study started when scientists noticed how climate change has caused changes to seasonal ice covers.

With little research available on ecosystems in lakes during the winter, they pooled data from researchers around the world.

Now they want to study how changes in climate will affect the plankton population, and what this could mean for the lakes in the summer.

He added that these studies are important, not only for the species living in the lakes but alsofor humans, who use freshwater systems for drinking water and recreation.

"As the extent of ice is decreasing, it becomes crucial for us to understand that better, to really figure out what we are losing when we lose this lake ice, what component of the lake ecosystem do we lose," he said.