Superior still a great lake, but it's under threat

The biggest surprise came from Gov. Tim Pawlenty and explorer Will Steger. There was widespread speculation the pair would use the Lake Superior conference to announce that Pawlenty would join Steger on a dogsled trip to northern Canada's Ellesmere Island next spring. But Pawlenty sounded a little pessimistic over the prospects.

"If it's going to happen between March and May, right during the legislative session, it would be very difficult for me to be gone for any length of time. I'm interested, but it's unclear whether I'm actually going to be able to do it," said Pawlenty.

Steger's trip to the Canadian Arctic is intended to raise awareness of how global warming is changing the region. Steger says Pawlenty will join him in a venture closer to home -- a series of global warming forums with experts. Steger says they began that planning last winter.

"We came up with the idea of maybe touring the state around four areas of global warming. And he asked me to choose what might be a good four areas to look at," Steger said. "Lake Superior, of course is a perfect one, and forests, lakes and rivers, and then western Minnesota, and then the cities."

It was a Duluth conference on Lake Superior that brought the two together. The three-day conference gives researchers and academics a chance to share information on lake levels, the warming of the lake, the fisheries and pollution.

There was good news. Some of the nastiest pollutants in the lake, like DDT and PCBs, are in decline. Some fish, like lake trout, that were once in trouble are now self-sustaining. That's something to be proud of, according to Carl Richards, who directs the EPA lab in Duluth.

"I think the amazing thing about Lake Superior, in my experience of working with other aquatic systems around the country, is it's a great lake. We just have to keep it that way," said Richards.

With that said, the lake still has problems with things like pollution, according to Deborah Swackhamer, director of the University of Minnesota's Institute on the Environment.

Part of the problem, she says, comes from Lake Superior's massive size.

"This makes the lake vulnerable, in a sense that although it can dilute pollutants, because of its size, the water stays in the lake for so long that it means that any pollutant in the lake lasts for a very long time," said Swackhamer.

Take, for example toxaphene, an insecticide that was once used as a replacement for DDT. Toxaphene is considered an endocrine disrupter which can affect growth and development of fish, reptiles and mammals. It's now banned, but it's still in the lake, and isn't going away any time soon.

"Toxaphene is going away slower than the other chemicals, in particular within Lake Superior," said Swackhamer. "Because it's colder than the other Great Lakes, it has not left the lake to the air the way it has in Lake Michigan and the lower Great Lakes. However, it is declining. It's just that the decline is much more slow."

More challenging now, Swackhamer says, are new chemicals -- what she calls emerging contaminants. The good news is there are now reliable tests to see if new chemicals will create long-lasting problems -- hopefully before they're sprayed on fields or added to products like detergents.

Researchers agree the biggest threat to Lake Superior comes from people, especially the people who want to live and work close to the lake.

"The biggest threat to Lake Superior is development along the shoreline," said Swackhamer. "As we develop the shoreline, many of these chemicals of emerging concern and chemicals of emerging effects are going to be coming in from shoreline, from nearshore use. And so they're coming in from cities and development. And it's those nearshore areas that we need to be very cognizant in protecting."

Clearly, researchers agreed, there's a huge threat from global warming. A warmer climate means a warmer Lake Superior. That could be bad for coldwater fish like lake trout. It could wreak havoc with lake levels, affecting regional economies dependent on shipping. And it could even change the way Lake Superior deals with toxic chemicals like toxaphene.

The conference continues in Duluth through Wednesday.

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