A water biology expert on Prince Edward Island has identified sea lettuce, a marine plant, as the cause of color changes and foul odors in some local waterways. Sea lettuce, an algae species found naturally in marine environments, thrives in nutrient-rich 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 green and grey-white, indicative of low dissolved oxygen levels.
Monitoring of oxygen levels in affected water bodies is conducted annually by the province, in collaboration with Fisheries and Oceans Canada. Long-term data trends from estuaries over the past decade are being reviewed to understand the situation better.
The expert advised caution for individuals suspecting anoxic conditions in water bodies, recommending avoiding contact due to the foul smell resembling rotten eggs. While some wildlife has adapted to low oxygen levels, many marine species struggle to survive in such environments, either relocating or perishing.
Concerned individuals in P.E.I. can report suspected anoxic waterways to the Land and Environment Department for investigation.
