Sea lettuce is a type of green algae, it can be found at low tide on most beaches of the BC coast, sea lettuce leaves, along with other adrift seaweeds, are deposited on the beach as the seawater retreats. It looks surprisingly like store-bought lettuce.
Its dead look can be quite misleading, however, because the detached lettuce can continue to live on even after breaking away from the plant, as a living plant. This lettuce-like seaweed and its relatives are able to use the intense sunlight of inter-tidal water. You might see lettuce blades out of the water on inter-tidal rocks in bright sunlight where they may appear quite dried out. But the leaves will soak up the water from the incoming tide and be completely regenerated, and still alive.
This seaweed is one of some 600 species of seaweed in the pacific northwest and is a member of a group that makes up at least half of all living matter on Earth. They are the most important food source for many forms of sea life. They, as we know, also take carbon dioxide from the water and give off oxygen as a waste product that fish and other organisms absorb. Algae create 87% of the earth’s oxygen.