Kelp forests are one of the most productive ecosystems

Kelp forests are one of the most productive ecosystems
Kelp may be a nuisance while swimming in the ocean, but it is one of the most productive ecosystems on Earth. Photo by Kyle Stock


You see it when you gaze out over the ocean from one of our sublime coastal bluffs. It looks like an oil slick in the water about half-a-mile from shore.You are only seeing a fraction of one of the most productive ecosystems on Earth.

The kelp forest contains astonishing biodiversity and is connected to the history and well being of our community.

Giant kelp (Macrocystis pyrifea) is brown algae, native to the western coast of North America. Although most people think of it as a marine plant, brown algae are actually in the kingdom chromista.

These organisms are not plants but still use photosynthesis to make food. Many varieties of algae are microorganisms, however, brown kelp is macroalgae, meaning they grow in large colonies.

Anchoring themselves to off-shore reef structures with a root-like system called the holdfast, Macrocystis are some of the fastest growing organisms on Earth, rising up to 2 feet per day!

They grow upwards towards the sun with small, air filled bladders called pneumatocysts, providing the buoyancy.

The golden brown blades are like leaves, containing the chlorophyll for photosynthesis. Marine algae are very important to all organisms on earth, as they produce 70 percent to 80 percent of the oxygen in the atmosphere.

Giant kelp acts as the ecosystem engineer in the underwater forests off our coast. Individuals can grow from the seafloor to the surface in 200 feet of water.

The California Current, running south down the western coast of North America causes upwelling in the near shore environment.

This upwelling brings nutrients from the seafloor to the surface where algae use it like fertilizer. Dense, underwater forests of giant kelp form a remarkable ecosystem under these conditions.

There are numerous varieties of algae that grow in the kelp forest. Other brown algae include bull kelp, feather boa kelp, laminaria and southern palm kelp.

Red and green algae grow in the lower levels of the kelp forest and benefit from the decomposition of larger brown algae.

Sea lions, harbor seals, brittle stars, spiny lobsters, innumerable invertebrates, including nudibranchs and a grand variety of fish all inhabit the kelp forest.

In the early 20th century, giant kelp provided Cardiff-by-the-Sea with its first industry as a kelp processing plant was built on the beach at San Elijo Lagoon.

Once used as a main ingredient in gunpowder, kelp continues to prove its value in human endeavors. It is currently used in many food and cosmetic products.

Local surfers appreciate the kelp forest’s ability to smooth the chop off the water when the wind blows on-shore.

For many of us, kelp is mostly the odorous stuff that washes up on the beach after a storm. Even this dead kelp has value as it decomposes to provide nutrients for invertebrates living in the sand. The ecosystems of our shoreline are dynamic and wonderful. Next time you visit the beach, take a look at the kelp, not as nasty stuff on the beach, but as the foundation for life in local ocean environment.


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