Human sewage and fertilizer runoff effects the health of lakes. It often causes huge algal blooms, kills fish, and creates other problems.
For 37 years researchers have examined the best ways to control this "cultural eutrophication" process of lakes by varying the levels of phosphorous and nitrogen added to the lake.
After completing one of the longest running experiments ever done on a lake, researchers from the University of Alberta, University of Minnesota and the Freshwater Institute, contend that nitrogen control, in which the European Union and many other jurisdictions around the world are investing millions of dollars, is not effective and in fact, may actually increase the problem of cultural eutrophication.
"David Schindler, professor of ecology at the University of Alberta, and one of the leading water researchers in the world, wants to change current practice in controlling nitrogen runoff by stating that
"Controlling nitrogen does not correct the polluted lakes, and in fact, may actually aggravate the problem and make it worse."
This study done by the University of Alberta, University of Minnesota and the Freshwater Institute appears in the journal, Proceedings of the National Academy of Sciences.
Courtesy Mark RyanHow do you celebrate one of the largest pools of freshwater on Earth? By participating in the annual Lake Superior Day, that’s how! This Sunday, July 20, is Lake Superior Day, a day of celebrations for the world’s largest and cleanest freshwater lake.
Towns and communities lining the shores of Superior in Michigan, Minnesota, and Wisconsin, and the Canadian province of Ontario are planning all sorts of events in tribute to the greatest of the Great Lakes.
Picnics, beach clean-ups, library displays, kite flying, concerts, hikes, an essay contest, and government proclamations are all part of the day’s celebration to bring attention to this huge body of water that holds 10 percent of Earth’s fresh water. Events are planned all around the lake. For example, games and activities promoting water conservation will take place in Red Rock, Ontario. A family picnic is scheduled at Silver Harbour in Thunder Bay, Canada. Afternoon events will take place on Barker’s Island Festival Park in the city of Superior, Wisconsin, and scientists and lake area experts will be on hand at the Lake Superior Maritime Visitor Center at Canal Park in Duluth with information about the lake’s natural history, regional culture, and invasive aquatic species.
The annual event takes place on the third Sunday of July, and is sponsored by the Lake Superior Binational Forum, the U.S. Environmental Protection Agency, and Environment Canada. So, if you're anywhere near Gichigami this coming Sunday, join in the festivities, or just go jump in the lake!
Geological processes don't always occur over long stretches of time. Landslides triggered by recent 7.9 magnitude earthquake in China have blocked rivers causing new - and perhaps unstable - lakes to form in the devastated landscape.
Satellite photos taken of the region around Beichuan County show formation of a lake in one of the worst hit areas. Twenty other lakes have formed in Beichuan because of the massive tremor and are being monitored closely according to a story in Chinese Daily.
Death estimates are nearing 60,000, and the quake is thought to have destroyed more than 5 million buildings.
A glacial lake in Chile has suddenly disappeared according to park rangers at Bernardo O’Higgins National Park in the southern Andes.
“In March we patrolled the area and everything was normal,” said Juan Jose Romero from CONAF Chile’s National Forestry Corporation. “We went again in May and to our surprise we found that the lake had completely disappeared. All that was left were chunks of ice and an enormous fissure.”
The fissure could mean an earthquake may be responsible for the disappearance, since the Magallanes region is known to experience lots of tremors, but the problem is there haven’t been any quakes recently in the park.
“No one knows what happened,” Romero said.
However, an earthquake hasn’t been completely ruled out as the cause. A recent quake in nearby Aysen last April could be the culprit. According to glacial specialist, Andres Rivera, the Magallenes area has seen interesting changes in the last few decades. He noted that the lake didn’t exist 30 years ago.
When the lake was there, it covered about 5 acres, (330 ft by 660 ft) and was about 100 feet deep. It’s not a huge lake, but it’s no backyard fish pond either. Here’s a link that will give you a better idea just how large an area 5 acres is.
Geologists and other experts are heading to the area 1250 miles south of Santiago to investigate so maybe they’ll come up with some answers.
In geological terms lakes are considered ephemeral events, and sometimes changes in the landscape happen gradually, sometimes they happen quite rapidly. This is a good example of the latter.
I defy anybody to read this site without humming the song "There's a Hole in the Bottom of the Sea."
Hey do you like to fish, canoe, or swim in Minnesota lakes? I can't imagine our hot humid summers without the relief of a dip in cool Lake Nokomis. But how are those wonderful lakes that make our state so unique doing? Well, our pals across the river at the Bell Museum of Natural History are hosting a cool event next week about just that:
Tuesday, June 13, from 6 to 8 p.m., Varsity Theater, Dinkytown, Free
Deborah Swackhamer and Roland Sigurdson of the U's Water Resources Center will discuss the state of our lakes, including how chemicals can affect water quality, fisheries, and human health. The Café Scientifique event, hosted by the U's Bell Museum of Natural History, precedes a Thursday evening fishing trip with Sigurdson on the shores of Lake Como in St. Paul. To learn more about both events, call 612-624-7083.
Should be a cool event with some good discussion and a chance to get your questions answered. See you there.
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A small freshwater jellyfish swims around a jar as science museum visitors look on.
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
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?