Signs suggest warm 'blob' partially to blame for Pacific algae bloom
Published Saturday, August 29, 2015 10:05PM EDT
A large, warm blob of water in the Pacific Ocean is thought to be one of the causes behind a toxic algae bloom off the West Coast, which experts say is having a significant and harmful impact on aquatic life from California to Alaska.
Experts say the massive ribbon of brown algae is producing dangerous levels of domoic acid, a neurotoxin that can be deadly to marine life and harmful to humans. The algae is easily absorbed by small fish and passed on through the food chain, affecting everything from crabs and sea birds to whales and, potentially, humans.
The algal bloom – commonly known as a red tide – first appeared in May and has been growing ever since, outlasting the typical lifespan of an algal bloom, which usually lasts a few weeks. The ribbon was an estimated 60 kilometres wide and as deep as 200 metres in early August, and it has shown no signs of declining since then.
"The extent of this bloom is unusual, and how long it's lasted," said Ian Perry, a B.C.-based researcher with Fisheries and Oceans Canada. "In the U.S. they've been really worried about it."
Many fisheries have been closed along the West Coast of the United States, out of fear that the domoic acid may have worked its way up the food chain into commercially-sold fish and shellfish. Washington State, for instance, has shut down its fisheries for the first time since 2003.
Supermarket-sold seafood is regularly inspected and considered safe, but many are being cautioned against eating recreationally-caught mussels and other aquatic life.
When ingested, domoic acid can induce amnesic shellfish poisoning, which can cause permanent short-term memory loss or even death.
A team of surveyors with the National Oceanic and Atmospheric Administration is now in B.C. to study the bloom and its potential causes. They started their survey mission analyzing the algal bloom earlier this summer, in California, and also spent time near Seattle before arrive at Vancouver Island. Another survey vessel is analyzing the bloom off the coast of Alaska.
The NOAA survey has not yet concluded, but many experts are already pointing to a warm patch of water in the Pacific Ocean, dubbed "the blob," as a major contributing factor behind the algae's growth.
"It's been occupying the entire northeast Pacific, and it's about 3-4 degrees (Celsius) warmer than it normally is," Richard Dewey, of Ocean Networks Canada, told CTV Vancouver.
The blob is also thought to be a contributing factor in the deaths of 30 whales in Alaska since May, as well as a die-off in the aquatic bird population along the coast of Oregon. Warm temperatures tend to force fish to live deeper beneath the surface, which can make it hard for aquatic birds to find a meal.
Experts say they're unsure at this point whether the blob and the algae are symptoms of global warming, or merely part of a cyclical process. Whatever the reason, this algal bloom has lasted much longer than most, and it will likely take cooling fall temperatures and a few ocean storms to break up the ribbon.
And that may not be the end of these large algae blooms, with an El Nino expected to warm the Pacific Ocean once again next year.
With files from CTV Vancouver