When the ice creaks, groans, and finally breaks up on Lake Superior next spring, a team of limnologists and oceanographers will launch a five-year study of a dramatic near-shore current in the lake. The current is called the Keweenaw Current because of its proximity to Michigan’s Keweenaw Peninsula, and is considered the strongest current of its kind in the world.
"Lake Superior contains some 10 percent of the freshwater on earth," explains program director Larry Clark of NSF’s ocean sciences division, which funded the project. "That’s more water than all of the lower lakes combined. Lake Superior also has the largest area of any lake on this planet. But, despite those facts, Lake Superior has not been adequately studied, in part because of the daunting environment it presents for researchers. KITES marks the first time that such an array of resources has been applied to Superior. What we learn from a comprehensive study of Lake Superior will have direct relevance to our understanding of many of the physical features of the world’s coastal oceans."
Scientists working on the KITES project will identify the physical processes that control the current’s position and strength, and investigate how the current affects the distribution of nutrients, and therefore, plankton and fish, in a 150-mile study region. They will place current meters in Lake Superior as well as analyze its water chemistry, collect samples of plankton and juvenile fish and sample sediment distribution and transport along the western shore of Michigan’s Keweenaw Peninsula from the Wisconsin border to the northernmost point in Michigan.
"The Keweenaw Current forms a semi- permeable barrier along the ‘coast’ of Lake Superior that inhibits material from shore and from rivers flowing into the lake from crossing into Superior’s central basin," explains limnologist Sarah Green of Michigan Technical University (MTU) in Houghton, the project’s coordinator. "We expect the effects of this barrier to be apparent throughout the entire Lake Superior ecosystem."
Adds the project’s associate coordinator, scientist Elise Ralph of the University of Minnesota’s Large Lakes Observatory, "Currents running parallel to shore are common in the oceans and in lakes, so what we learn here will help us understand similar processes in other aquatic environments. We have an excellent site to identify the effects of such a massive current."
It’s been estimated that the Keweenaw Current, at its peak flow, carries as much water as the outflow of the Mississippi River. KITES scientists say that water movement in the current is the primary means by which materials are transported from the lake’s western to eastern basins, and is therefore likely to be important in processes throughout Lake Superior.
Other institutions involved in KITES are the University of Washington in Seattle, the University of Georgia, the University of Maryland and the University of Wisconsin-Madison. KITES is also supported in part by the National Oceanic and Atmospheric Administration (NOAA).
National Science Foundation. October 1997.