New Delhi, Sept. 2 -- In northwestern Ontario, Canada, a decades-old experiment on a small lake has reportedly helped scientists understand the lasting effects of acid rain on freshwater ecosystems.

Researchers at the International Institute for Sustainable Development Experimental Lakes Area (IISD-ELA) started adding sulfuric acid to Lake 223 every week to simulate acid rain. The experiment began in 1976 and, over the next 17 years, researchers witnessed its pH level drop from 6.8 (close to neutral) to 5.2 (slightly acidic), triggering major changes to its ecosystem that continued even after the experiment ended.

According to media reports, Lake 223 is one of 58 lakes and their watersheds that the IISD-ELA set aside to carry out whole-...