Sunday, June 04, 2023

Bright orange ocean water being tested by B.C. scientists

Such blooms regularly appears in the Strait of Georgia, but it's not the most common or most harmful algae.

Scientists are taking a close look at a bright orange algae bloom found in the ocean off Vancouver Island and the Sunshine Coast. 

Svetlana Esenkulova, a biologist with Pacific Salmon Foundation, is trying to determine if the phytoplankton bloom is negatively impacting salmon. 

“Noctiluca blooms can disrupt the overall balance of marine ecosystems as they ‘steal’ food from zooplankton,” she said. 

Under a microscope, the organisms "look like giant watermelons with pigtails and they wave those pigtails," said Esenkulova, who has a sample of the orange ocean water in her kitchen. When the water is cold, she can see the organisms trying to catch food.

Such blooms regularly appears in the Strait of Georgia — this one has been seen off Vancouver Island, Salt Spring Island and the Sunshine coast — but it’s not the most common or harmful algae. It also draws a lot of attention from the public, Esenkulova said, for its bright colour. 

Sarah Merriam was at Maple Bay Marina near Duncan last Saturday when she spotted the bright orange water. 

“It was thick. You couldn’t even see the water, like under the water. It was just straight orange,” said Merriam, who recorded the phenomenon on video. 

Merriam thought it looked like red tide, an algae bloom that has toxic effects on people, fish, shellfish, marine mammals and birds. 

Esenkulova said Noctiluca blooms do not produce biotoxins and do not cause shellfish poisoning. But that doesn't mean they don't have an impact.

Ocean ecosystem could be impacted by orange bloom 

Every year, the Pacific Salmon Foundation provides a summary of its annual observations on oceanography and harmful algae to Fisheries and Oceans Canada. The foundation aims to restore wild Pacific salmon populations and their habitats in British Columbia and the Yukon. 

So far, it’s too early to say if the salmon are being impacted by this particular bloom, Esenkulova said. 

“We’re not there yet. Right now, we have a lot of data. It takes years to determine this level of impact.” 

However, there are short-term impacts that are known, she said. 

“It could potentially have a very big impact on the ecosystem,” Esenkulova said. “Once this bloom dies off, there is a decomposition process happening and the dissolved oxygen level in the water drops down and causes hypoxia,” or low oxygen levels. 

The Pacific Salmon Foundation will continue to study the algae. The organization relies on the public to alert them to the blooms. 

If you see anything unusual in the water, you’re asked to take a photo, note the time and location and collect a water sample. Esenkulova can be reached at sesenkulova@psf.ca.

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