Killer algae blooms remain a mystery

Seattle Times

SEATTLE — The mysterious bird-killing algae that coated Washington’s ocean beaches this fall with slimy foam was the biggest and longest-lasting harmful algal bloom to hit the Northwest coast.

Now the phenomenon that killed at least 10,000 seabirds — more than any known event of its kind — has scientists consumed by questions: Was it a rogue occurrence, rarely if ever to be repeated, or a sign of some fundamental marine-world shift? And did we cause it?

Answers may come slowly. “You can think of it as a jigsaw puzzle with 500 pieces, but we only have about 50,” said Julia Parrish, a University of Washington fisheries and oceans professor.

This much is known: Toxic blooms of microscopic phytoplankton, sometimes called red tides, are exploding worldwide, even along pristine waters such as the Northwest coast.

And the organisms behind these blooms can behave unpredictably, revealing how little we know about the sea.

The culprit this fall was a mushroom-shaped single-celled species, Akashiwo sanguinea, that has bloomed in Puget Sound, Chesapeake Bay and saltwater from Europe to Australia and Japan without incident.

But something here this time caused the cells to multiply rapidly and break open in a toxic foam. It’s been recorded happening only once before — on a smaller scale, in Monterey Bay in California in 2007.

Researchers are trying to gauge whether warming surface waters or more corrosive seas might have played a role in the two blooms, or whether they were caused by a collision of shifting currents and natural atmospheric and weather cycles such as El Nino. Or maybe it’s all of the above — or something else.

“We haven’t ever seen this before, and now we’ve had two events in two years,” said Raphael Kudela, an ocean-sciences professor and toxic- algae expert at the University of California, Santa Cruz. “If it happens again, I’ll be concerned. Four times, and I’ll be really concerned.”

The incident this fall played like something out of a Hitchcock movie: White-winged scoters and surf scoters staggered and collapsed on Olympic Peninsula beaches in September. Then over the next six weeks, loons, grebes and murres were found dead from Neah Bay to Oregon. Just as in Monterey, a soaplike froth coated the natural oils that protect the birds from hypothermia.

Researchers are still unearthing its effects: Surfers and kayakers who rode through the foam near Westport, Grays Harbor County, complained of sinus problems and a lingering loss of taste and smell; a pathologist inspecting dead birds found a few whose guts lacked any trace of normal bacteria, raising the possibility they ingested something damaging. Most disturbing to algae experts: The whole incident was unexpected. Akashiwo sanguinea isn’t even among the species scientists considered harmful, said Mary Sue Brancato, a marine biologist with the Olympic Coast National Marine Sanctuary.

Toxic tides aren’t new to the Pacific. A crewman on Capt. George Vancouver’s Voyage of Discovery died in 1793 after eating poisoned mussels.

The blooms are produced by two classes of microalgae — dinoflagellates and diatoms, tiny creatures that help fuel the marine-food web.

In Puget Sound, the most problematic is a type of dinoflagellate that produces a neurotoxin that can reside in shellfish. When ingested by humans, it can cause paralysis and even death.

On the coast, the bigger problem is a diatom that blows in from off shore. It can produce domoic acid, which can cause seizures and death in humans.