Bull Kelp Facts
Bull kelp (Nereocystis luetkeana) is vital to the health of marine ecosystems because it provides a healthy variety of biodiversity. Kelp forests provide numerous animals with nutrients and habitat, including kelp crabs, red sea urchins, kelp greenling, kelp perch, and Pacific herring. Found along the coast from Alaska to central California, bull kelp uses a holdfast to anchor itself to rocks on the seafloor while a stalk grows towards the surface, reaching for rays of sunlight. The upper part of the stalk is a gas-filled float that enhances exposure to sunlight and promotes photosynthesis. This structure allows for the long, flat blades to sway in the current.
DID YOU KNOW?
Marine snails and kelp crabs consume kelp, but neither are quite as voracious as sea urchins. Urchins have been known to consume great quantities of kelp very quickly, completely decimating once-flourishing ecosystems. Because kelp is both a home and a source of nutrients for many species, their absence can cause other marine life to disappear as well.
Bull kelp dies in the winter and only produces one stipe and several blades in its lifespan. However, the blades are reproductive and the plant itself will produce trillions of zoospores for propagation in the future.
Bull kelp is an annual seaweed, meaning it grows from a spore to maturity in a single year. It can reach heights of up to 30 m (about 100 ft) and grow at a rate of up to 25 cm (about 10 in) per day! While bamboo (subfamily Bambusoideae) still hold the record for fastest growth in a single day - up to 100 cm (about 40 in) per day - bull kelp is still one of the fastest-growing plants around.
Sea star wasting syndrome has caused declines in sunflower sea star populations, causing a cascading effect on kelp forests. Without the sunflower sea stars to keep the sea urchin populations in check, these spiny creatures can clear cut bull kelp forests.
Photo by Caleb Slemmons (Creative Commons Flickr). Banner photo by Florian Graner.