National Geographic : 2016 Sep
HEAT WAVE 71 Lefebvre about an otter she’d seen shuddering in spasms the week before. Lefebvre perks up. “The thing you’re describing, the tremors in the whole body?” Lefebvre says. “I’ve seen that. In sea lions.” In 1998, as a Ph.D. student at the Universi- ty of California, Santa Cruz, Lefebvre learned that dozens of sea lions were turning up sick and twitchy. Lefebvre had a hunch why: Each spring, a single-celled toxic alga called Pseudo- nitzschia blooms in small patches, usually for a week, maybe two, producing a neurotoxin called domoic acid, which accumulates in shellfish. When ingested by people, this toxin can cause seizures, memory loss, even death. It also can harm wildlife. In 1961, a Santa Cruz newspaper told of a mysterious invasion of sooty shear- waters “fresh from a feast of anchovies.” The seabirds bashed into windows and died on streets. Alfred Hitchcock used the incident as part of his inspiration for The Birds. Scientists tracking the mystery decades later unearthed old samples of plankton pulled from Monte- rey Bay in 1961. They detected high levels of Pseudo-nitzschia. When Lefebvre found domoic acid in the fe- ces of sick sea lions in 1998, it was the first ev- idence that this type of toxic bloom could hurt marine mammals. And blooms that year were particularly bad. El Niño had brought withering ocean heat to California, igniting the most fero- cious bloom on record—until last year. In April 2015 algae bloomed, but instead of dissipating after a few weeks, the bloom grew into a monster, morphing and shifting, stretching over 2,000 miles, from California’s Channel Islands to Kodiak. No one had seen anything like it. Some shellfish harvests closed along the coast. Toxin concentrations were 30 times greater than what would normally be considered high. Tests found domoic acid in some fish, such as anchovies, at amounts too dangerous for people to eat, a rarity. The tox- in appeared to sicken hundreds of sea lions, A dying wolf eel curls up among dead prawns in Washington State’s Hood Canal. Eels and other animals died when warm seawater washed into the canal in 2014. The canal’s southern reaches didn’t fully flush, which depleted oxygen.