ENVIRONMENT:No-Longer-Mysterious Goo Balls Make a Lake Superior Comeback.
Aug. 22--The gobs of clear gelatinous goo that briefly baffled scientists around Lake Superior in 2001 are back again this month.
Thousands of transparent pea-sized balls are showing up along Park Point in Duluth and in several other locations around the lake -- including near Bad River in Wisconsin, along the Keewenaw Peninsula in Michigan and Michipicoten Bay in Ontario.
But don't panic, there's a natural explanation.
The goo balls are the cast-off shells of a zooplankton called holopedium gibberum, said Marie Zhuikov, communications coordinator for Duluth-based Minnesota Sea Grant.
Zhuikov found some of the goo balls firsthand Sunday.
"I was out there playing on the Lafayette Beach on Park Point with my kids.... They asked me what the blobs were and, luckily, I knew," Zhuikov said. "We're getting reports from all over the lake now.... This is the first time we've seen it like this since 2001."
Holopedia are native and the balls are harmless, experts say.
Adult holopedia create a gelatinous mantle or shell that encases a pea-sized amount of water, and then leave the small glob when they reproduce. That leaves the empty blob of mucous-encased water floating in the lake.
In 2001, before scientists confirmed the gobs' nature, several News Tribune readers guessed the gobs may have been from disposable baby diapers or even tapioca that spilled off a ship.
It's not clear why the goo balls appear only in some years. Some scientists have surmised that a rising population of spiny water fleas, an exotic species, has been feasting on smaller zooplankton, which leaves more to eat for larger zooplankton such as holopedia.
Zooplankton are tiny little critters that make up the backbone of the ecosystem and food chain for fish.
"Holopedium are native, but it's thought that spiny water fleas and their feeding patterns are making the holopedium more abundant," Zhuikov said. "And the weather and water action may be a factor in when and if we find them in large numbers like this year."
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