This seems to be a big week for the Great Lakes, especially their restoration and preservation. The Great Lakes Legacy Act is making its way through Congress; presidential candidate Barack Obama has promised to set up a five billion dollar trust fund for protection of the 5 inland seas (in the spirit of non-partisan fairness here’s the Republicans’ response); the new Omnifilm, Mysteries of the Great Lakes just opened and is playing here at the SMM Omnitheater; and a new debate has started regarding the long-held practice of swabbing debris from the decks of Great Lake freighters once they get out on the lakes.

Great Lakes from space: Photo by NASAThe five Great Lakes, Superior, Michigan, Huron, Erie, and Ontario contain something like 20 percent of the world’s fresh water, and are the source of drinking water for millions of Canadians and Americans who live around them. I grew up along the shores of Lake Superior (our hillside neighborhood in Duluth set on the prehistoric lake bottom of a larger Ice Age ancestor) so I’m partial to good old Gichigami and its siblings, and I’m really glad to see some serious attention is being paid to their clean-up and preservation.

Tags : Omnifilm, Lake Superior, Great Lakes, environmental protection, environment, ecology, water, freshwater

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I have to admit that at first we thought it was a joke. We heard that a Science Museum volunteer had brought in a "freshwater jellyfish" to the Collector's Corner. We were even momentarily fooled when we looked at the jar full of water because it looked empty. However, as we peered closer we saw three amazing creatures about the size of a quarter bobbing around in a jar of Minnesota lake water.

Science Museum volunteer Will Hirsch and his neighbor Tim McDonough found these unique creatures in Lake Jane near the city of Lake Elmo, MN. What they found was the subject of a question to the Minnesota Department of Natural Resources a couple years ago:

In August 2003 I was fishing on a Minnesota-Ontario border lake and noticed hundreds of round, translucent discs about the size of a quarter rising to the surface. The discs had an irregular bluish central pattern and were soft, flexible, and slimy. What were they?

Jim Collinge
Detroit Lakes

You likely were looking at freshwater jellyfish (Craspedacusta sowerbii), says DNR research scientist Gary Montz. These little animals grow attached to under-water surfaces for part of their lives, then form buds that turn into the floating form, called a medusa. Freshwater jellyfish can appear in large numbers in lakes during late summer. Like ocean jellyfish, they capture their food-mainly zooplankton-with stinging -tentacles. Unlike ocean jellyfish, they cannot sting or harm you.

So what Will and Tim had discovered was the medusa form of a Craspedacusta sowerbii. These little creatures have been reported in Minnesota and almost every other state in the continental US. These animals like still waters, so they won't be found in rivers or streams. As they float around they passively feed on even tinier animals that are found in almost all lakes called zooplankton. They are easiest to spot in August and September, so keep an eye out for them next time you go swimming or fishing at your local lake.

How do they reproduce? How did they get here? What kind of water do they live in? Researchers at the Indiana University of Pennsylvania, Japan, and Australia are all studying these strange creatures to come up with answers to these questions.

Have you seen a jellyfish in any of Minnesota's lakes?

Tags : minnesota, lakes, jellyfish, freshwater, amazing, video, MN jellyfish

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