Sugar Kelp
Saccharina latissima

Hand raising a rope covered in long, brown kelp leaves out of the water.

Cascadia Seaweed

This brownish-yellow seaweed looks like lasagne noodles. It is one of the many species of kelp cultivated around the world.

Good to Know . . .

Room filled with two levels of glass tanks stacked along the walls, divided by an alley with a piece of machinery in the middle of the floor.

Cascadia Seaweed

Farmers grow kelp seedlings in nurseries. The farmers cut pieces from full-grown kelp to get spores. The spores are then grown in tanks to produce kelp seedlings.

Brown kelp leaves hanging from a rope floating on the surface of the water.

Cascadia Seaweed

Seedlings are suspended on floating lines in the ocean. This network of lines creates a kelp farm.

A Strange Lifecycle

Illustration of the circular cycle of seaweed growth. At the top, female and male spores, both labelled 1, change in shape from cell-like spores to keyhole-shaped spores. They then become gametophytes, both labelled 2, with multiple limb-like structures. Multi-limbed male gametophytes produce sperm. One of the sperm, labelled 3, attaches itself to the round egg, also labelled 3, at the end of one of the four limbs of the female gametophyte. After fertilization, labelled 4, a small leaf emerges from the egg, which grows into a juvenile, labelled 5. The adult plant, a sporophyte labelled 6, has the same green colour and blade-like shape, but is more than five times larger in size. The adult releases tiny male and female spores, completing the cycle.

Kelp has a two-part lifecycle: a microscopic stage, and a large plant-like stage. The plant-like kelp produces spores that grow into tiny gametophytes. These miniature growths release sperm and eggs into the water. After fertilization, the plant-like kelp starts growing, and the cycle begins again.

Small piece of green-brown kelp washed up on a sandy beach.

© Pingyang/Dreamstime

Kelp sheds as it grows. The pieces it sheds sink into the deep ocean, taking with them any carbon captured through photosynthesis. That’s how seaweed farming helps to fight climate change.