August 08, 2016 09:44 AM
Lake Superior is the subject of fascination for those who live nearby and visitors, and it's also been the subject of a trend-setting study. A UMD faculty/student team is working to understand what impact humans have on the lake.
Last month, UMD senior Shannon McCallum and assistant professor of biology Ted Ozersky brought their equipment to the stoney beach right below Leif Erikson Park in Duluth.
Both in wetsuits, Ozersky dove beneath the waves and pulled up a landscaping tile outfitted with rows of clear cups: the fruits of the research.
Each cup had been diffusing a specific nutrient, nitrogen, phosphorus and a combination of the two into to ecosystem
"It's been in the water for four weeks just letting the algae grow, McCallum explained. "We'll take that back to the lab and we'll freeze it, we'll dry it and weigh it.
What's important is how much algae had grown on top of the cups.
"We're trying to see which of these nutrients will stimulate the growth of algae on the lake bottom," Ozersky said.
The team collected a tile not just at the Leif Erikson but nine others stretching the lake's northern and southern shore.
"We wanted all different influences from the land, so some of the areas are agricultural areas, some are urban, some are industrial," McCallum said.
Along with other data including water temperature and PH-levels, the patterns could point to what causes over-proliferation of algae.
"If we can figure it out, we might be able to say something about what nutrients we have to manage," Ozersky said.
Whether it's sewage or fertilizer runoff, the two said humans can impact nutrient levels.
"By studying it, we can maybe point to things that maybe we're doing that are causing these changes in the lake," McCallum said.
As a large lakes researcher Ozersky, cited similar studies on Lake Baikal. The large lake in Russia, like Lake Superior is a very pristine system, however, in recent years there's been trouble with algae growth near the shore.
"There are these kind of big growth of gross green algae that will wash up on shore and reduce water quality," Ozersky said. "Lake Superior doesn't have the same problems that Lake Baikal is having, but we're trying to figure out what might cause it to have similar problems in the future."
Maintaining the right balance is key.
"A little bit of algae growth is good, too much algae growth can reduce water quality," Ozersky said.
Because even as the tides change, Lake Superior's cool, blue depths never should.
"The Great Lakes have always been important to me," McCallum said. "I grew up around them. I think it's important to have a greater understanding and for people to understand their actions affect the lake either directly or indirectly."
The study is McCallum's summer research project and funded by a special UMD biology department grant.
Updated: August 08, 2016 09:44 AM
Created: August 07, 2016 05:42 PM
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