TORONTO, C.A. (WROC) — Every year during the spring, summer, and fall, many researchers are out attentively studying Lake Ontario. But one time you won’t see studies of the water is the winter, due to the ice.
“No boats go out in the winter, and we generally take all our moorings out in the winter because we’re worried about damaging them with ice,” said Dr. Mathew Wells from the University of Toronto.
Dr. Wells along with many others is working on an international project between the United States and Canada to study how the temperature of Lake Ontario below the surface changes throughout the year. Previous to now though, they weren’t able to collect much data over the winter outside of surface temperatures
“There’s a big gap in our knowledge in the great lakes about what happens in the winter. Basically, we don’t know anything from late October to early April,” said Dr. Wells.
Specifically what they’re studying is known as the lake’s thermocline, a boundary that separates different layers of water that vary in temperature. The process that forms these layers is called stratification.
“They usually have layers, during the summer there’s a warm layer at the top of the lake, and a cold layer at the bottom of the lake, and these don’t mix because they’re different densities,” said Dr. Wells. “Freshwater lakes have this interesting property, in winter they’re actually stratified again. So the bottom of the lake is 4 degrees celsius […] the tops close to freezing. So water is actually most dense at 4 degrees celsius so in winter you actually have inverse stratification.”
While they’re still analyzing their first year’s worth of data they have found some interesting observations already.
“This layer between the warm and cold water can move up or down 20 or 30 meters throughout a single day,” said Dr. Wells. “Most fish in Lake Ontario like the cold water, so they’re tracking this layer. So if you’re a fisherman you really want to know where that layer is.”
This can create along with other processes such as upwelling, large changes, or gradients, in water temperature across the lake which so far is theorized to impact fish populations in the lake.
“If there [are] lake-wide gradients in water temperature […] the fish are either responding to it or it’s affecting their metabolism so maybe it’s too hot or it’s too cold and they don’t grow as big as you expect or they move”, said Dr. Wells. “We just finished the first year, hoping to collect 3 years of data and then we’ll be able to see how the fish are actually responding to, or how do the fish respond to these gradients.”
While there is still a lot of data to analyze, and two more years of the project to complete they are already preparing to release the data collected so far for free. This is only the beginning too in Dr. Wells’ eyes, as in his own words: “just because you don’t see something doesn’t mean nothing happened.”
“We really need more instruments out, more measurements in winter to understand how the chemistry gets set up for summer. A lot of the water quality issues of, can we eat the fish? Do the fish survive? […] Are they going to form bad algal blooms?” Dr. Wells said.
None of this would be possible as well without collaboration across borders, and between government and academic organizations. Something that Dr. Wells is highly thankful for.
“It’s been really great to have an opportunity [with] this GLOS funding to collaborate with scientists from various institutions in the United States and Canada that’s been a great example of collaborations for university and government teams on both sides of the border,” said Dr. Wells.