Several scientists told reporters that the world's largest freshwater lake is in generally good health but that pressures from humans -- development, pollution, rising temperatures and the movement of foreign species into the lake -- threaten the lake's cold, sensitive ecosystem.
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Sea lampreys are the Great Lakes' biggest predators. They attach to valuable fish and feed on their victims blood and body fluids.
Water Withdrawals Threaten the Great LakesPredicted lower Great Lakes water levels due to climate change and increased water use are looming threats to the Great Lakes. While the Great Lakes are large, they are very fragile. Less than 1% of Great Lakes water is renewed annually through rainfall and snowmelt.
Because Lake Superior is nourished by forests and watered by streams, changes on the land become changes in the lake. We find algae blooms in Lake Superior bays, decreasing clarity in the western arm of the lake, contaminated sediment in the Duluth-Superior harbor and toxic contaminants building up in the food chain.
The Great Lakes are more than capable of generating waves over 10 feet high, despite being smaller than our oceans. This lack in size actually increases the danger over the water. This is because the wave period in the Great Lakes (the time between two wave crests) is much shorter than in the ocean.
Geology of Lake InferiorLake Inferior is an underground lake that is located beneath Lake Superior. It is believed to be formed by a process known as karstification, which is the dissolution of limestone and dolomite rock. This process creates sinkholes, caves, and underground rivers and lakes.
While there have been past “sightings,” most have turned out to be pranks or misidentifications. The reality is that the largest of the Great Lakes (Lake Superior and Michigan) are extremely deep lakes that are too cold for sharks.
The most renowned of these Great Lakes sea monsters supposedly resides in Lake Erie. Sightings of the lake monster Bessie were first made in the late 1700s but appeared again with some regularity in the 1980s. Bessie is described as being about 20 feet long, serpent-like but with appendages that resemble arms.
What would happen if Lake Superior dried up? Without Lake Superior, areas near the lake would see far less snow each winter, and the distribution of snow in the central and eastern regions around the lake would be far different. The effects would not be limited to snow.
Lake Superior's beaches are open and safe for swimming over 90% of the time, and the water is extremely clear, with an average underwater visibility of 8.3 m (27 ft).
Lake MichiganThe Great Lakes are all water bodies that swimmers should think twice about entering. Lake Michigan in particular is the roughest of the Great Lakes, and poses a major risk to those thinking of taking a dip. This body of water is often named the most dangerous lake in the United States.
These lakes are the perfect backdrop for swimming, boating, and other water-related activities. But there can be more danger in these Great Lakes waves than what you'd find in the ocean. The Great Lakes are more than capable of generating waves over 10 feet high, despite being smaller than our oceans.
The Great Lakes are struggling under the combined weight of many ailments, from invasive species and toxic chemicals to the nutrient runoffs that fuel Lake Erie's chronic algae problem. And in many cases, climate change is making it worse.