Lake Superior is among the fastest-warming lakes on the planet. Climate change may be the culprit behind its algae blooms too
Erin Hooley/Chicago Tribune/TNS

APOSTLE ISLANDS NATIONAL LAKESHORE, Wis. — The kayakers stood for a moment on the beach, marveling at the clear sweep of blue. On a warm fall day along the south shore of one of the world’s largest freshwater lakes, the sun lolled toward the horizon, miles out from the peppered, coppered grains of sand anchoring the kayaks. Fresh off their first trip through the sea caves of the Apostle Islands National Lakeshore, the twin sisters from Chippewa Falls, Wisconsin, listed off Lake Superior’s “Caribbean blue” water and cold temperatures, its vastness. “I would never have guessed it would have happ...