A Wave of Woes for the Great Lakes

The Milwaukee Journal Sentinel covers the three day conference on the health of the Great Lakes:

More than 300 Great Lakes experts are gathered in Milwaukee this week for what is essentially a two-year checkup on the health of the world's largest freshwater ecosystem. The conference kicked off with an overview of some of the major issues facing the Great Lakes basin, which holds about 20% of the world's surface freshwater and is a source of drinking water for about 40 million people.

From the rise of invasive species to the prospect of falling water levels to the paving of coastal habitats and the apparent - and perplexing - meltdown of the bottom of the food chain in Lake Huron, most all the news was grim.

Among the most alarming of the problems detailed Wednesday is the disappearance in many areas of Lake Huron of tiny species that are a critical source of nutrition that most every fish in the lake directly or indirectly depends on. The drop is likely tied to the arrival of invasive mussels, though the direct link has yet to be established. The result, however, is a dramatic loss in biomass from the bottom of the food web. Lake Huron is, according to a presentation by Carri Lohse-Hanson of the Minnesota Pollution Control Agency, beginning to resemble the much less productive waters of Lake Superior, the biggest and coldest of the Great Lakes.

The news isn't all bad for the lakes. The latest studies show that concentrations of some of the nastiest chemical pollutants have dropped substantially since the 1970s. And, thanks largely to water treatment facilities, the lakes remain a healthy source of drinking water. Projects to remove toxic sediments are also under way.