A water biology expert has identified sea lettuce, a marine plant, as the cause of color changes and foul odors in certain waterways on Prince Edward Island. Sea lettuce, a type of algae, naturally thrives in marine environments, particularly under high-nutrient conditions. According to Kyle Knysh, a provincial surface water biologist, the decomposition of sea lettuce consumes a significant amount of oxygen in the water, leading to anoxic events.
Several discolored waterways have been reported to the province this year, including an estuary in the Oyster Bed area, where the water appeared green and grey-white on July 9. The Department of Land and Environment attributed this color change to low dissolved oxygen levels in the water. Regular monitoring of oxygen levels in various waterways, including the reported estuary, is carried out by the province in partnership with Fisheries and Oceans Canada.
Knysh advised caution for individuals suspecting an anoxic water body, recommending avoiding contact with it to prevent the unpleasant smell of rotten eggs on skin. He highlighted that while some wildlife species have adapted to low oxygen conditions, many marine organisms struggle to survive in such environments due to their reliance on oxygen for respiration. Concerned individuals can contact the Land and Environment Department to report any issues with water quality on Prince Edward Island.