A bloom of blue-green algae could be responsible for the recent vibrant turquoise water in Stanley Park’s Lost Lagoon, the Stanley Park Ecological Society said Thursday.

Patricia Thomson, executive director of the society, said such blooms can occur late in the summer in response to warmer temperatures, increased light and nutrients.

The turquoise water was first noticed on Wednesday and is contained to a small area surrounding a concrete pedestrian bridge on the east side of the lagoon.

Swans, ducks, raccoons and a heron were in the water on Thursday.

A spokesperson for the Vancouver Park Board said there have been algae blooms in the lagoon before, but not with such a vibrant colour.

Thomson said the water is being analyzed to see if the colour change is indeed blue-green algae and whether it may contain toxins. Parks expects to have preliminary results in a couple of days.

“At this point, we’re not raising any alarms,” Thomson said. “But if it was a blue-green algae, there are some types that may carry some toxins.”