ASHINGTON – If red means trouble – and in this case, it does – a map of the Great Lakes published by their binational overseer identifies Lakes Erie and Ontario as the places where the region’s many environmental concerns come together.
On that map, Lake Ontario is mostly a sea of red, with a few spots in the center of the lake shaded orange, signaling that they are only slightly less troubled. Meanwhile, the map of Lake Erie features a deep red blotch stretching from metro Buffalo westward along the Canadian shoreline for about 130 miles. A similar red blotch stretches westward from Erie, Pa., past Cleveland and Toledo and into Michigan.
Neither Lake Ontario nor Lake Erie features the deep blue hue that dominates Lake Superior, signaling that it is comparatively free of environmental stress.
That map illustrates what an International Joint Commission panel found when it looked at the major challenges the lakes face – climate change, invasive species, excessive nutrients, pollution, habitat loss and others – cumulatively rather than as individual issues.
“The stress was greatest in Lake Erie and Lake Ontario because you have the confluence of strong stressors,” said David Allan, a professor emeritus at the University of Michigan and the author of the report. “You have the most population, the most wastewater contributions, the most agricultural runoff contributions. You have an abundance of other stressors influencing those lakes as well.”
“In terms of the magnitude of the damage that results from the interaction between two stressors, sometimes the relationship between stressors is additive, so one plus one equals two,” he said. “But sometimes there’s a synergy, so one plus one can exceed two. And, occasionally, one stressor can counteract the other stressor.”
The study did not focus on the flooding that has occurred on the Lake Ontario shoreline in recent years. Instead, it focused on environmental concerns.
Lake Ontario is mostly shaded in red on the map in part because of longstanding data showing that invasive mussels are common there, Allan said. Substantial pollution from farm run-off and shoreline development are issues along Lake Ontario as well.
The eastern portion of Lake Erie is shaded red because of the influence of industrialized cities such as Buffalo. Meantime, the Canadian shoreline west of Buffalo faces issues with agricultural runoff, while western Lake Erie in Ohio has suffered from algal blooms thanks to excess nutrients such as phosphorus.