June 27, 2008
Leading journal honors science dean for research
CARBONDALE, Ill. -- Research by a scientist at Southern Illinois University Carbondale examines the quality of water in Lake Michigan and offers a glimpse into its possible future.
The research co-conducted Jay C. Means, dean of the College of Science at SIUC, is based on a groundbreaking seven-year study of the lake, which plays a crucial role in the fresh water supply of much of North America. A leading journal focused on Great Lakes research recently honored an article co-authored by Means that described the research.
The research combined satellite imagery with field sampling and carefully designed algorithms to determine the meaning of the data in relations to the lake’s water quality It involved a team of researchers from the University of Michigan, Russia and Means, who at the time was associate director of the Environmental Research Center at Western Michigan University.
The researchers examined variables such as water temperature, suspended particulate matter and chlorophyll content. The researchers gathered the data -- both on site and from space using a National Oceanic and Atmospheric Administration satellite called SeaWiFS -- on an almost continuous basis for seven years.
The satellite took images of the lake using various light spectrums several times each day, except on days clouds covered it. The images could determine water temperature and estimate chlorophyll and suspended inorganic particulate matter quantities in the lake.
Means said the length of the study, coupled with large amount of data and sophisticated algorithms used to crunch it, added up to a meaningful investigation.
“We pulled it all together and made some interesting findings regarding annual cycles of water quality parameters,” Means said. “Not only that, but because of the long time series involved, we could see things like the algae blooms around sewage discharges as they moved around the lake over time.
“Mostly we were interested in seasonal changes and what implications those might have in terms of a number of other factors, such as productivity as a fishery, what happens to contaminants brought in by rivers and how those interact with suspended sediments. Those contaminants end up either on the bottom of the lake or re-suspended, so you could tell where those contaminants might go.”
The publishers of The Journal of Great Lakes Research awarded the paper its Chandler-Misener Award for being most influential published in the journal that year. The journal makes the award annually based on the paper’s originality, contribution and presentation.
The paper is titled “Verification and Application of a Bio-optical Algorithm for Lake Michigan using SeaWiFS: A Seven-Year Inter-Annual Analysis.”
Means said the study marked the first time researchers used such an approach on a body of water as small as Lake Michigan. Typically, researchers use such methods to study oceans. Consequently, the Russian team of scientists had to scale the algorithms to the lake, merging the satellite data with field data from the lake itself.
The study also for the first time documented the role of the ratio between suspended inorganic material and total carbon, including biological components such as chlorophyll, in the lake, and how that varying ratio impacts other facets of water quality.
Using the vast data, the team also examined possible long-term trends --10 to 50 years -- for water quality, extrapolating what might happen given certain warming trends or increases in contaminants or nutrients.
Water quality for the Great Lakes, which includes Lake Michigan, is extremely important, Means said.
“The Great Lakes together hold about 70 percent of the fresh water in the world,” he said. “Lake Michigan is one of the larger lakes, and because of its proximity to many cities -- Grand Rapids, Chicago, Milwaukee -- it makes a significant contribution to a large number of people. They depend on it quite a bit.”