Acid Rain Has Turned Canadian Lakes into a Kind of Jelly

Swimmers who dive into a number of Canadian lakes might not emerge clean and refreshed, but dripping with globs that resemble slimy fish eggs. A legacy of industrial pollution has caused great changes in the country's water chemistry, creating a boom in tiny organisms that transform lakes into "jelly."

That's the gooey news from scientists behind a new paper in Proceedings of the Royal Society B, who say that populations of this particular organism have doubled since the 1980s in many of Ontario's lakes. The reasons involve a complex dance of species, but here's the short version: Acid rain caused by smelting operations and other human activity removed calcium from the soil in drainage areas. That depleted the calcium levels in many lakes, which has hurt a kind of plankton (Daphnia) that needs the element to build armor. Enter a competing plankton, Holopedium, which requires far less calcium to bulk up and is coated with a gel that's excellent at repelling predators.