The Death and Life of the Great Lakes

by Dan Egan

Other giant freshwater bodies that have evolved over tens of thousands or even millions of years have been subjected to epic changes in temperature, salinity, water levels as well as wave upon wave of invading and evolving organisms, all in a manner that leaves those water bodies inhabited by a cast of species steeled by the crucible of evolution. This gives them something of an “immune system” when it comes to maintaining ecological stability in the face of disruptions from the outside world. The Great Lakes of Cartier’s time, on the other hand, were what biologists today call “ecologically naïve.” This means the lakes were inhabited by fish and other aquatic species whose isolation left them uniquely exposed to foreign perturbances. None of this, of course, was pondered by the early explorers desperate to exploit their ecological bounty.