Giant Kelp | Oceana
Home / Giant Kelp

Marine Life Encyclopedia

Corals and Other Invertebrates

Giant Kelp

Macrocystis Pyrifera

Distribution

Temperate Eastern Pacific Ocean and Temperate Waters of All Oceans in the Southern Hemisphere

ECOSYSTEM/HABITAT

Coastal

FEEDING HABITS

Photosynthesis

TAXONOMY

Class Phaeophyceae (Brown Algae), Family Laminariaceae (Kelps and Relatives)

Since the giant kelp is not a plant, it does not have roots. Instead, it obtains all of the necessary nutrients directly from the water and is attached to the rocky bottom by a structure known as a holdfast. Like plants, however, the giant kelp harvests the sun’s energy through photosynthesis and does not feed on other organisms. This species is one of the fastest growing species in the world, and under perfect conditions, it has been known to grow up to two feet (60 cm) in a single day. Once and individual giant kelp reaches the sea surface, it continues to grow horizontally, floating in large mats that shade the water column and sea floor below. In order to remain upright, each giant kelp blade (leaf) includes a gas-filled pod that floats. Several individuals growing together can create dense forests that are an important ecosystem in temperate, coastal areas where they live. Several species eat giant kelp, and fluctuating populations of purple sea urchins are known to play a role in kelp forest formation and destruction. Several species of sharks, bony fishes, lobsters, squids, and other invertebrates are known to live in or near kelp forests.

Humans use giant kelp for food and use chemicals derived from this species as components in several other products. It is rarely harvested from natural forests, however, and is instead often grown in aquaculture operations. Its fast growth rate and natural means of generating energy (from the sun) make it an ideal species to grow in these sea farms.

Fun Facts About Giant Kelp

1. Giant kelp grow to 100 feet (30 m) on average but can reach lengths of 175 feet (53 m) in ideal conditions.

2. Giant kelp grow at an average rate of 11 inches (28 cm) a day but can grow 24 inches (61 cm) a day in ideal conditions.

3. Decomposing kelp that sinks to the seafloor provides food for animals in the deep sea.

4. Sea otters wrap themselves in giant kelp to keep from floating away while sleeping.

5. Giant kelp grows faster than bamboo.1

6. Giant kelp hold onto rocky substrates using their “anchors” (or holdfasts) at the bottom of the kelp.

7. Giant kelp are not plants, but rather extremely large brown algae.2

Engage Youth with Sailors for the Sea

Oceana joined forces with Sailors for the Sea, an ocean conservation organization dedicated to educating and engaging the world’s boating community. Sailors for the Sea developed the KELP (Kids Environmental Lesson Plans) program to create the next generation of ocean stewards. Click here or below to download hands-on marine science activities for kids.

Kids Environmental Lesson Plans

References:

1 Monterey Bay Aquarium

2 NOAA Sanctuaries

Get Involved

Donate Today

SUPPORT OUR WORK TO PROTECT THE OCEANS BY GIVING TODAY

With the support of more than 1 million activists like you, we have already protected nearly 4 million square miles of ocean.

Donate Now

TAKE ACTION NOW

Support policy change for the oceans

Decision-makers need to hear from ocean lovers like you. Make your voice heard!

Sign Now

VISIT OUR ADOPTION CENTER

SYMBOLICALLY ADOPT AN ANIMAL TODAY

Visit our online store to see all the ocean animals you can symbolically adopt, either for yourself or as a gift for someone else.

Shop Today

DOWNLOAD OCEAN ACTIVITIES

HELP KIDS DISCOVER OUR BLUE PLANET

Our free KELP (Kids Environmental Lesson Plans) empower children to learn about and protect our oceans!

Learn More

FEATURED CAMPAIGN

Save the Oceans, Feed the World

We are restoring the world’s wild fish populations to serve as a sustainable source of protein for people.

Learn More

More CAMPAIGNs

Protect Habitat

Bycatch

Plastics

View All

CONTACT

Oceana International Headquarters
1025 Connecticut Avenue, Suite 200
Washington, DC 20036 USA

General Inquiries
+1(202)-833-3900
info@oceana.org

Donation Inquiries
+1(202)-996-7174
wavemaker@oceana.org

Press Inquiries
+1(202)-833-3900
press@oceana.org

OCEANA'S EFFICIENCY

BECOME A WAVEMAKER

Sign up today to get weekly updates and action alerts from Oceana.

SHOW YOUR SUPPORT WITH A DONATION

We have already protected nearly 4 million square miles of ocean and innumerable sea life - but there is still more to be done.

Donate Now

QUICK LINKS: