Sea lettuce

Description:

Ulva lactuca is a green seaweed that forms dense clumps of membranous blades, only two cells thick. These blades or thallus resemble lettuce leaves and can grow one meter long. This is an incredible fast growing seaweed, reaching a growth rate of 40% a day in optimal conditions. Sea Lettuce is bright green and is often seen on the beaches or free floating on the waves. Sea lettuce is edible.

Habitat:

Spotted at Kopachuck State Park. Beach at low tide.

Notes:

Bacteria feeding on the decomposing sea lettuce use up a large amount of oxygen in the water, depleting it from oxygen: Decaying sea-lettuce on the beach produces a large amount of hydrogen sulfide. In some instances, the odor can be strong enough to make people feel sick, making the beach unsuitable for recreation. This happens every summer on the french Normandy and Brittany beaches, but also at Puget Sound an inlet of the Pacific Ocean along the northwestern coast of the U.S. state of Washington.