A water biology expert has identified sea lettuce, a marine plant, as the cause of color changes and unpleasant odors in some waterways on Prince Edward Island (P.E.I.). Sea lettuce, a type of algae, naturally occurs in marine environments and thrives in high-nutrient conditions. When sea lettuce begins to decompose, it depletes oxygen in the water due to organic material consumption by decomposers, leading to anoxic events.
Several discolored waterways, including an estuary in the Oyster Bed area of P.E.I., have been reported to the province this year. The Department of Land and Environment noted a case on July 9 where the water appeared green and grey-white, indicating low dissolved oxygen levels.
The province regularly monitors oxygen levels in waterways, including collaboration with Fisheries and Oceans Canada to assess oxygen data trends from estuaries over the past decade. Those suspecting an anoxic water body are advised to avoid contact as it may result in a strong rotten egg smell on skin or clothes.
While some wildlife species have adapted to low oxygen conditions, many marine organisms struggle to survive in such environments due to their dependence on oxygen for respiration. Concerned individuals can report issues with waterways on P.E.I. to the Land and Environment Department for investigation.