Brown Algae

bull kelp

Scientific name: Nereocystis luetkeana

Family: Lessoniaceae

Phylum: Ochrophyta

Typical size: Up to 20 meters tall, blades up to 3 meters long. Bulb diameter up to 12 centimeters

Depth range: Up to 20 meters

Description: Grows on rocks with a holdfast that is extremely strong stalk, or stype. The stalk is hollow, and at the end of each stalk there is a gas filled bladder that allows the plant to float on the surface, where long, flat blades grow.

Habitat and ecology: One of the fastest growing organisms, averaging 10 centimeters per day. Growth season is in the summer, and kelp dies off in the winter, washing up on shore. Kelp beds form a canopy. Bryophytes grow on leaves, kelp crabs are often found on leaves and stems. 

pacific rockweed

Scientific name: Fucus gardneri

Family: Fucaceae

Phylum: Ochrophyta

Typical size: 25 centimeters

Depth range: Intertidal zone

Description: Algae is brown or dark, light green in color with forked thalli, or leaves.

Habitat and ecology: Grows attached to rocks, with thalli filled with goo or gas.

sugar kelp

Scientific name: Saccharina latissima 

Family: Laminariaceae

Phylum: Ochrophyta

Typical size: A blade can reach 5 meters long

Depth range: Up to 30 meters but prefer shallow water typically 5 to 10 meters.

Description: This brown algae is dark brown in color, and can be identified by it’s long, undivided blade with bumps and ridges along the surface and narrow stem with holdfast.

Habitat and behavior: Sugar kelp is found in sandy or rocky areas in protected subtidal zones. It uses its holdfast to attach to rocks and grows the most in early spring. Blades may host bryozoans and will decompose in the winter. This kelp is edible to humans.