When a winter storm lies on the horizon, the salt trucks spring into action. By spreading salt—regular old sodium chloride, the same kind we put on our food—over every inch of our roads, we’ve figured out how to make them safe for drivers even as slick snow and ice coat the asphalt, turning hazards into mere inconveniences. But that salt doesn’t just disappear after a storm.
That saltiest pond is probably especially salty because it’s been surrounded by a large parking lot for around 25 years, Relyea says. And the remarkable survival of its frogs may not be coincidental. Relyea notes that wood frogs return to the same ponds and wetlands each year to lay eggs—meaning the eggs they collected may stem from a micro-population of frogs that has bred in that same parking lot-adjacent pond for more than two decades, or roughly 10 generations.