Why is the water so green around southern B.C.?

If you've noticed the waters off the shores of southern B.C. looking greener than usual, give yourself a pat on the back for being attuned to the shades of the sea.

There is a massive algae bloom in the Strait of Georgia, extending into Howe Sound, that's left the colour of the water looking more emerald than usual.  

Waters off the southern tip of Vancouver Island, in Desolation Sound and around the Malaspina Inlet have also been affected.

The colour is so vibrant, it can be seen in NASA's satellite view of the area.

The scientist behind Vancouver Island University's harmful algae monitoring program, says coccolithophorids are the cause.

"Coccolithophorids are tiny algae with calcium carbonate scales," explained Nicky Haig. "They reflect the light so they give this chalky sort of blue colour to the bloom."

It's mixed with what she believes are diatoms in the water — another group of algae — and together, it's made the water appear green.

Despite the unusual colour, Haig says, the water should not be harmful to fish or humans.

"I was swimming in it this weekend and I'm still fine," she said with a laugh.

Haig says coccolithophorids bloom near B.C. during the summertime are normal but where it's blossomed this year, is notable.

"It's a group that blooms quite often off the west coast of [Vancouver] Island in June or July of most years, but we don't usually see it in the Strait of Georgia."

She says she doesn't think warmer ocean temperatures are the cause, but it could be related to increasing ocean acidification which signals climate change.

With the bloom ongoing, she says more time and research is needed to truly understand what is going on in the water.

"It could be a climate change story, but it could also be a once in 20 year or 50-year event," she said. "We're still trying to figure that out."

With files from Elizabeth McArthur