Kelp frond showing pneumatocysts, Macrocystis pyrifera, San Clemente Island

Giant kelp frond showing pneumatocysts which make the algae bouyant. Macrocystis pyrifera, San Clemente Island, California

A kelp forest, with sunbeams passing through kelp fronds.  Giant kelp, the fastest growing plant on Earth, reaches from the rocky bottom to the ocean's surface like a terrestrial forest, Macrocystis pyrifera, San Clemente Island

A kelp forest with sunbeams passing through kelp fronds. Macrocystis pyrifera, San Clemente Island, California.

A SCUBA diver swims through a giant kelp forest which is tilted back by strong ocean currents.   Giant kelp, the fastest plant on Earth, reaches from the rocky bottom to the ocean's surface like a submarine forest, Macrocystis pyrifera, San Clemente Island

A SCUBA diver swims through a giant kelp forest which is tilted back by strong ocean currents. Giant kelp, Macrocystis pyrifera, the fastest growing plant on Earth, reaches from the rocky bottom to the ocean's surface like a submarine forest.

Macrocystis pyrifera kelp forms huge beds along the western coast of North America. Individual kelp plants extend from the rocky reef and sand bottom to the surface, where they grow out and form a canopy.

Ocean sunfish recruiting fish near drift kelp to clean parasites, open ocean, Baja California, Mola mola

Ocean sunfish recruiting fish to clean it of parasites, near a patch of drifting kelp in the open ocean, Baja California, Mexico. Mola mola, Macrocystis pyrifera.

Bryozoan grows on a red gorgonian on rocky reef, below kelp forest, underwater.  The red gorgonian is a filter-feeding temperate colonial species that lives on the rocky bottom at depths between 50 to 200 feet deep. Gorgonians are oriented at right angles to prevailing water currents to capture plankton drifting by, Lophogorgia chilensis, San Clemente Island

Bryozoan grows on a red gorgonian on rocky reef, below kelp forest, underwater. The red gorgonian is a filter-feeding temperate colonial species that lives on the rocky bottom at depths between 50 to 200 feet deep. Lophogorgia chilensis, California.

Kelp frond showing pneumatocysts, Macrocystis pyrifera, Santa Barbara Island

Giant Kelp, Santa Barbara Island

These kelp beds are home to a rich array of life. Kelp offers protection for prey, a hiding place for predators, and a substrate upon which smaller creatures can grow. The kelp forest is also a magnificent place to dive.

Red gorgonian on rocky reef, below kelp forest, underwater.  The red gorgonian is a filter-feeding temperate colonial species that lives on the rocky bottom at depths between 50 to 200 feet deep. Gorgonians are oriented at right angles to prevailing water currents to capture plankton drifting by, Lophogorgia chilensis, San Clemente Island

Lophogorgia chilensis, red gorgonian, grows below a towering forest of giant kelp, San Clemente Island, California.

Kelp fronds and pneumatocysts.  Pneumatocysts, gas-filled bladders, float the kelp plant off the ocean bottom toward the surface and sunlight, where the leaf-like blades and stipes of the kelp plant grow fastest.  Giant kelp can grow up to 2' in a single day given optimal conditions.  Epic submarine forests of kelp grow throughout California's Southern Channel Islands, Macrocystis pyrifera, San Clemente Island

Kelp Fronds And Pneumatocysts, San Clemente Island

Drift kelp, a kelp paddy, floating patch of kelp on the open ocean which attracts marine life and forms of moving oasis of life, an open ocean habitat, aerial photo, Macrocystis pyrifera

Aerial Photo Of Kelp Paddy, Drift Kelp, Pacific Ocean, California

Kelp plants are anchored to the rocky reef with a holdfast. In a dense kelp forest, the rocky reef can hardly be seen beneath the many kelp plants. The holdfast must withstand surge, back and forth water movement caused by large swells passing by.

Giant kelp, blades, stipes and pneumatocysts, backlit by the sun in shallow water, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Boat Horizon above kelp forest, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Garibaldi swims in the kelp forest, sunlight filters through towering giant kelp plants rising from the ocean bottom to the surface, underwater, Hypsypops rubicundus, Catalina Island

Garibaldi Swims In The Kelp Forest, Catalina Island

Small gas bladders -- pneumatocysts -- connect the kelp's stipes (stems) to its blades (leaves). These bladders help elevate the kelp plant from the bottom, towards sunlight and the water's surface. New growth occurs at the elevated end of the plant. When it reaches the surface, the kelp plant continues to grow and will spread out at the surface to form a thick canopy.

Red gorgonian on rocky reef, below kelp forest, underwater.  The red gorgonian is a filter-feeding temperate colonial species that lives on the rocky bottom at depths between 50 to 200 feet deep. Gorgonians are oriented at right angles to prevailing water currents to capture plankton drifting by, Lophogorgia chilensis, Macrocystis pyrifera, San Clemente Island

Red gorgonian on rocky reef, below kelp forest, oriented at right angles to prevailing water currents to capture plankton drifting by.

California golden gorgonian and small juvenile sheephead fishes on rocky reef, below kelp forest, underwater.  The golden gorgonian is a filter-feeding temperate colonial species that lives on the rocky bottom at depths between 50 to 200 feet deep.  Each individual polyp is a distinct animal, together they secrete calcium that forms the structure of the colony. Gorgonians are oriented at right angles to prevailing water currents to capture plankton drifting by, Muricea californica, Semicossyphus pulcher, San Clemente Island

California golden gorgonian and small juvenile sheephead fishes on rocky reef. Muricea californica and Semicossyphus pulcher, San Clemente Island, California.

A kelp forest.  Giant kelp grows rapidly, up to 2' per day, from the rocky reef on the ocean bottom to which it is anchored, toward the ocean surface where it spreads to form a thick canopy.  Myriad species of fishes, mammals and invertebrates form a rich community in the kelp forest.  Lush forests of kelp are found through California's Southern Channel Islands, Macrocystis pyrifera, San Clemente Island

A giant kelp forest, Macrocystis pyrifera, San Clemente Island, California.

Sometimes the kelp's holdfast will fail, and the kelp plant will drift off. It will float at the surface and continue to grow until it is beached or reaches water that is too warm. While drifting in the open ocean, it becomes a gathering point for offshore marine life. Baitfish, flying fish and juvenile fish seek protection amidst drift kelp. Ocean sunfish (Mola mola) approach kelp paddies, hoping to encounter other fishes that will clean them of parasites. Yellowtail (Seriola lalandei dorsalis) and other game fish visit drift kelp looking for smaller fishes to eat. Opportunistic blue sharks (Prionace glauca) and ocean sunfish (Mola mola) can often be found hanging around drift kelp. Pacific white-sided dolphins (Lagenorhynchus obliquidens) have been known to play with pieces of drift kelp. Various invertebrates attach to drift kelp, including nudibranchs and barnacles. Even seabirds utilize kelp, such as this diving grebe observed hunting small fish under drift kelp.

Kelp fronds and pneumatocysts.  Pneumatocysts, gas-filled bladders, float the kelp plant off the ocean bottom toward the surface and sunlight, where the leaf-like blades and stipes of the kelp plant grow fastest.  Giant kelp can grow up to 2' in a single day given optimal conditions.  Epic submarine forests of kelp grow throughout California's Southern Channel Islands, Macrocystis pyrifera, San Clemente Island

Kelp Fronds And Pneumatocysts, San Clemente Island

Kelp canopy, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Jack mackerel schooling amid kelp forest, Trachurus symmetricus, Macrocystis pyrifera, San Clemente Island

Pacific Jack Mackerel In Kelp Forest, San Clemente Island

California bat ray in kelp forest, Myliobatis californica, Macrocystis pyrifera, San Clemente Island

California Bat Ray In Kelp Forest, San Clemente Island

Kelp canopy, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Kelp canopy, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Red gorgonian, Lophogorgia chilensis, San Clemente Island

Red Gorgonian, San Clemente Island

Kelp frond showing pneumatocysts, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

California sea lion, juveniles at play in kelp forest, Zalophus californianus, Santa Barbara Island

California Sea Lion In Kelp Forest, Santa Barbara Island

Kelp frond showing pneumatocysts, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Salema schooling amid kelp forest, Xenistius californiensis, Macrocystis pyrifera,, Catalina Island

Salema In Kelp Forest, Catalina Island

Kelp plants with fronds extended in current, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Garibaldi in kelp forest, Hypsypops rubicundus, Macrocystis pyrifera, San Clemente Island

Garibaldi, San Clemente Island

Kelp fronds, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Kelp plants growing toward surface and spreading to form a canopy, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Kelp fronds and forest, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Kelp fronds, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Kelp canopy, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Kelp frond in motion, time exposure, Macrocystis pyrifera, Santa Barbara Island

Giant kelp frond in motion, time exposure, Macrocystis pyrifera, Santa Barbara Island, California.

Kelp forest, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Kelp frond showing pneumatocysts, Macrocystis pyrifera, Santa Barbara Island

Giant Kelp, Santa Barbara Island

Kelp detail showing pneumatocysts (air bladders), Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Divers and kelp forest, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Diver amid kelp forest, Macrocystis pyrifera, San Clemente Island

SCUBA diver swimming through a giant kelp forest, San Clemente Island.

Diver amidst kelp forest, Macrocystis pyrifera, San Clemente Island

Diver amidst kelp forest, Macrocystis pyrifera, San Clemente Island, California.

Kelp fronds, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Garibaldi swimming over surfgrass in kelp forest, Hypsypops rubicundus, Phyllospadix, Macrocystis pyrifera, San Clemente Island

Garibaldi In Kelp Forest, San Clemente Island

Diver amidst kelp forest, Macrocystis pyrifera, San Clemente Island

Underwater photographer amid a giant kelp forest, Macrocystis pyrifera, San Clemente Island, California.

Pacific torpedo ray in kelp forest, filming lights, Torpedo californica, Macrocystis pyrifera, Santa Rosa Island

Pacific Torpedo Ray In Underwater Kelp Forest, Santa Rosa Island

Giant kelpfish amidst kelp, Heterostichus rostratus, Macrocystis pyrifera, San Clemente Island

Giant Kelpfish In Underwater Kelp Forest, San Clemente Island

California Golden gorgonian in kelp forest, Muricea californica, Macrocystis pyrifera, San Clemente Island

Two California Golden gorgonians (Muricea californica) in kelp forest (Macrocystis pyrifera), San Clemente Island, California.

Red gorgonian on rocky reef below kelp forest, Lophogorgia chilensis, Macrocystis pyrifera, San Clemente Island

Red Gorgonian And Underwater Kelp Forest And Reef, San Clemente Island

Northern kelp crab crawls amidst kelp blades and stipes, midway in the water column (below the surface, above the ocean bottom) in a giant kelp forest, Pugettia producta, Macrocystis pyrifera, San Nicholas Island

Northern Kelp Crab On Kelp Blade, San Nicholas Island

A parent and child admire the fascinating kelp forest tank at the Birch Aquarium at Scripps Institution of Oceanography, San Diego, California, Macrocystis pyrifera

Giant kelp and aquarium, mother and child

A kelp forest.  Giant kelp grows rapidly, up to 2' per day, from the rocky reef on the ocean bottom to which it is anchored, toward the ocean surface where it spreads to form a thick canopy.  Myriad species of fishes, mammals and invertebrates form a rich community in the kelp forest.  Lush forests of kelp are found through California's Southern Channel Islands, Macrocystis pyrifera, San Clemente Island

Morning sunbeams, a submarine forest, Macrocystis pyrifera, California.

A kelp forest.  Giant kelp grows rapidly, up to 2' per day, from the rocky reef on the ocean bottom to which it is anchored, toward the ocean surface where it spreads to form a thick canopy.  Myriad species of fishes, mammals and invertebrates form a rich community in the kelp forest.  Lush forests of kelp are found through California's Southern Channel Islands, Macrocystis pyrifera, San Clemente Island

A Kelp Forest, San Clemente Island

Kelp forest, Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Kelp fronds and pneumatocysts.  Pneumatocysts, gas-filled bladders, float the kelp plant off the ocean bottom toward the surface and sunlight, where the leaf-like blades and stipes of the kelp plant grow fastest.  Giant kelp can grow up to 2' in a single day given optimal conditions.  Epic submarine forests of kelp grow throughout California's Southern Channel Islands, Macrocystis pyrifera, San Clemente Island

Kelp Fronds And Pneumatocysts, San Clemente Island

Kelp fronds and pneumatocysts.  Pneumatocysts, gas-filled bladders, float the kelp plant off the ocean bottom toward the surface and sunlight, where the leaf-like blades and stipes of the kelp plant grow fastest.  Giant kelp can grow up to 2' in a single day given optimal conditions.  Epic submarine forests of kelp grow throughout California's Southern Channel Islands, Macrocystis pyrifera, San Clemente Island

Kelp Fronds And Pneumatocysts, San Clemente Island

Half-moon perch schooling under offshore drift kelp, open ocean, Medialuna californiensis, Macrocystis pyrifera, San Diego, California

Halfmoon Perch Swimming Below Floating Kelp, San Diego

Kelp fronds with encrusting bryozoans, Macrocystis pyrifera, San Clemente Island

Kelp fronds with encrusting bryozoans. San Clemente Island

Purple urchins destroying/eating giant kelp holdfast, Strongylocentrotus purpuratus, Macrocystis pyrifera, Santa Barbara Island

Purple Urchin Consume Kelp Holdfast, Santa Barbara Island

Blue shark and offshore drift kelp, Prionace glauca, Macrocystis pyrifera, San Diego, California

Blue Shark Swims Through Kelp, San Diego

Gorgonian, garibaldi, kelp bass (calico bass) in kelp forest, San Clemente I, Muricea californica, Hypsypops rubicundus, Macrocystis pyrifera, San Clemente Island

California Golden Gorgonian And Underwater Kelp Forest, San Clemente Island

Blacksmith amidst kelp forest, Chromis punctipinnis, Macrocystis pyrifera, Santa Barbara Island

Blacksmith School In Underwater Kelp Forest, Santa Barbara Island

Kelp frond showing pneumatocysts (air bladders), Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Kelp frond showing pneumatocysts (air bladders), Macrocystis pyrifera, San Clemente Island

Giant Kelp, San Clemente Island

Kelp fronds reach the surface and spread out to form a canopy, Santa Barbara Island, Macrocystis pyrifera

Giant Kelp, Santa Barbara Island

Giant kelp rises from the ocean depths toward sunlight and the surface.  San Clemente Island, Macrocystis pyrifera

Giant Kelp, San Clemente Island