I went to the eastern Aleutians for The Atlantic to see firsthand the impacts of harmful marine algae. Warming temperatures are spurring these algae—which produce one of the most potent neurotoxins on Earth—to bloom in northern places where they’ve never been a problem before. We’ve always known they could make humans sick from eating tainted clams and mussels, but now researchers are finding them across the food web…in seabirds, walrus, and whales. Read the essay here.