Mother Jones
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From the air, the Pacific algal bloom doesn’t look like much of a threat: a wispy, brownish stream, snaking up along the West Coast. But it’s causing amnesia in birds, deadly seizures in sea lions, and a crippling decline in the West Coast shellfish industry. Here’s what you need to know about it, from what this bloom has to do with the drought to why these toxins could be a real threat to the homeless.
What’s causing it? The culprit is a single-celled plant called pseudo-nitzschia, one of thousands of species of algae that produce more than 50 percent of the world’s oxygen through photosynthesis. They’re a hardy variety usually found in cool, shallow oceans, where they survive on light and dissolved nutrients, including silcates, nitrates, and phosphates. “They’re sort of like the dandelions of the sea,” says Vera Trainer, who manages the Marine Biotoxin Program at the Northwest Fisheries Science Center in Seattle. “They’re always there in some low numbers, just waiting for nutrients to be resupplied to the ocean’s surface.” In most years, blooms in the eastern Pacific are contained near “hot spots” that dot the West Coast—relatively shallow and sheltered places like California’s Monterey Bay or the Channel Islands. They usually flare up in April or May as trade winds cycle nutrient-rich waters from offshore depths to the coast in a process called “upwelling,” but they fade after only a few weeks.
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