Lake 223

From 1976 to 1993, scientists conducted weekly additions of sulfuric acid to the lake, simulating acid rain and gradually lowering the pH of the lake from 6.8 to 5.2. The resulting ecosystem shift and the loss of a number of fish and invertebrate species showed how sensitive the aquatic food chain is to acid rain. This research was instrumental in changes to air emissions regulations in Canada and the United States.

In 2019, IISD-ELA began adding the invertebrate Mysis diluviana back into Lake 223 after it had been extinguished—all to evaluate how the exosystem responds to an intentional re-introduction of Mysis. In 2021, we found evidence of a new Mysis population in that lake. Researchers will continue to examine the implications on growth rates, survivorship, and mercury concentration in lake trout, as well as evaluate the legacy impacts of acid rain settling at the bottom of the lake.