Swimmers who dive into any 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...