Scientists acidified an Ontario lake for 17 years; decades later, trout remain below half their former level

Representative Image (AI-generated) A lake in northwestern Ontario became the setting for a landmark experiment on the effects of acid rain. For 17 years, scientists deliberately added sulfuric acid to Lake 223 every week, gradually changing the water's chemistry to mimic the effects of acid rain that was damaging lakes across North America and Europe. Between 1976 and 1993, the lake's pH fell from 6.8 to 5.2 as researchers watched how the changing conditions affected its ecosystem. The experiment ended decades ago, and the lake's water chemistry has since returned to conditions similar to those that existed before the experiment. But the ecosystem has not recovered at the same pace. According to the International Institute for Sustainable Development's Experimental Lakes Area (IISD-ELA), the lake trout population remains at less than half its pre-experiment level, and the fish are also growing more slowly.A lake turned into a laboratoryLake 223 is part of the IISD Experimental Lakes Area, a collection of 58 lakes and their watersheds in northwestern Ontario that have been set aside for scientific research. Rather than studying individual organisms in a laboratory, researchers can ...