When the going gets tough, purple sea urchins appear to get tougher, or at least tough enough to possibly cope with climate change. Purple sea urchins are referred to as a “keystone” species because the ecosystem needs enough of them to feed marine mammals, fish, seabirds and other predators, but not so many that they overrun the place. Increasing carbon dioxide levels in the atmosphere may threaten that balance. As oceans absorb more carbon dioxide, the water becomes more acidic, which decreases calcium carbonate levels.
In Print: February 1, 2015