A water biology expert has identified sea lettuce, a marine plant, as the cause of color changes and foul odors in some waterways in Prince Edward Island (P.E.I.). Sea lettuce, a type of algae, naturally thrives in marine environments, especially under high-nutrient conditions. As it decomposes, organic material depletes oxygen levels in the water, leading to anoxic events.
Several discolored waterways, including an estuary in the Oyster Bed area of P.E.I., have been reported to the provincial authorities this year. The Department of Land and Environment noted a case on July 9 where the water appeared greenish-grey and white, indicative of low dissolved oxygen conditions.
Monitoring of oxygen levels in various waterways is conducted annually by the province, in partnership with Fisheries and Oceans Canada. Data trends over the past decade will be reviewed to assess oxygen levels in monitored estuaries.
Individuals are advised to avoid contact with water bodies suspected of being anoxic, as exposure may result in a lingering rotten egg odor on skin. While some wildlife species have adapted to low oxygen environments, many marine organisms struggle to survive during such events due to their reliance on oxygen for respiration.
Those concerned about water quality in P.E.I. can report issues to the Land and Environment Department for investigation.