Bull Kelp (Nereocystis luetkeana)

Description: Bull kelp is a type of brown algae. Bull kelp often grows very close together and forms dense kelp forests underwater. To reach the light near the surface of the ocean, bull kelp makes use of its float—a sort of spherical bulb—located near the tip that helps it stay upright. This float is what makes bull kelp easily identifiable, along with its long stalk (called a stipe), and the many blades that grow from the top of the float. Since algae is not a plant, this means that bull kelp does not have roots. Bull kelps have something called a holdfast, which looks similar to roots, that anchors them to the ocean floor. 

Habitat: Its geographic distribution ranges from the Aleutian Islands to down south in California and is a common species of algae along the Pacific Coast of the United States.

Tide Pool Tidbits:

• A species of algae similar to bull kelp is the giant kelp. One of their differences is that rather than having one spherical float, giant kelp has many little pear-shaped floats. Despite its name, giant kelp is actually smaller than bull kelp.

• Similar to many other species of algae, bull kelp is harvested by humans mainly to eat both fresh and dried, but also sometimes to make fertilizer.

• Bull kelp is a very important part of marine ecosystems since kelp forests provide food and shelter for many marine species. Even when the forests die in the winter, the bull kelp floats along in the ocean and is still useful for many other species. 

• Bull kelp has a very close relationship with sea otters and sea urchins. When sea otters are not present in ecosystems, urchins feed endlessly on bull kelp and decimate kelp forests, turning them into “urchin barrens.” Not only is this bad for the kelp, but urchins are also left to starve when no food remains. This harms many other species outside of this relationship, especially those that rely on kelp forest habitats for food and shelter. In Oregon, sea otter populations were hunted out completely by the end of the 19th century due to the fur trade. Fortunately, many people are working to reintroduce sea otters to Oregon’s coastline, which bull kelp forests will greatly benefit from.

Reference: Central Coast Biodiversity