ECOSYSTEMS: KELP FOREST PART 2
Last week’s adventures took us through the California Science Center Exhibit- Ecosystems. Continue the Journey with us this week as we learn about life inside wild Kelp forests.
In the wild, the bottom level of the ocean is known as the benthic zone. All bodies of water have a benthic zone where creatures like snails, sea stars, oysters lobsters, and other crustacean reside. Organisms living in the benthic zone are called benthos and play a fundamental role in ecosystem management. Since light does not often penetrate the benthic zone, benthos feed on the dead and decaying matter found on the ocean floor, benthic algae, and young kelp. Areas outside of the ocean’s benthic zone are either a part of the supratidal and subtidal zones (the areas found on the coastline that are impacted by high and low tide), the neritic zone (the shallow part of the ocean that extends to up to 200 meters in depth) or the pelagic zone (the area between the benthic and neritic zones). Most of the sea life that lives away from land or outside of the benthic zone is found in the pelagic zone.
Often miscategorized as a plant, kelp is actually a species of brown algae (Macrocystis pyrifera), that grows in dense groupings, similar to the way a wooded forest grows on land. The strands of kelp found in the controlled environment of the California Science Center grow to an impressive height, but are significantly smaller than the wild kelp forests, which can reach up to 175 feet in length. Kelp is prolific in growth and in ideal circumstances, can gain anywhere from 10 and 12 inches in a single day.
Giant Kelp. Photo Credit: Alex Havasi
Much like a buoy, the gas-filled bladders located at the base of the kelp leaf are responsible for holding up the kelp as it spreads from the bottom of the ocean floor to the surface of the water. Once the kelp has reached the surface, it forms a dense canopy that provides shelter and food for thousands of invertebrates, fish, and marine mammal species.
Kelp forests cross the benthic, pelagic, and neritic zones, and are home to a diverse group of marine life. In fact, the kelp forests found off of the California coast can accommodate over 1,000 species in a single forest, and are among the most diverse ecosystems found on earth! Many organisms use the dense blades of the kelp to hide from predators and rear their young. Seals, sea lions, whales, sea otters, fish, gulls, and other sea birds are some of the many animals found in the canopy’s
armor. Rich in varied food sources, the kelp forest ecosystem offers a perfect example of the hierarchical nature of the food web. As numerous species thrive in the shelter of the kelp, predators have greater access to food. For example, kelp is eaten by tubeworms who are then gobbled up by birds and fish. Fish are the principal food source for baleen whales and sea lions. Sea lions become the prey of the ocean’s top carnivores including sharks and killer whales (pictured below).
Like the tubeworm and other small invertebrates, the primary food source of the sea urchin is kelp. However, urchins present a huge problem in kelp forest management because of the alarming rate in which they consume the algae matter. Sea otters and spiny lobsters are the natural predator of the sea urchin, and as such their role in the ecosystem is vital. When an urchin population balloons, kelp forests run the risk of depletion and the animals that use the canopy as shelter
become vulnerable to predation. In order to manage urchin populations and conserve the delicate ecosystem, California Science Center staff and volunteer divers have joined local forces to remove over 100,000 sea urchins from the Palos Verde Peninsula. Considered a delicacy in fine dining cultures around the world, these sea urchins are often captured and sold to the restaurant industry.
Currently, the California Science center offers visitors the opportunity to pet urchins, sea slugs, eninimes, and other invertebrates. During our visit, I felt like a child who had returned to the coastal tide pools I loved so much as a kid. Using two gentle fingers (as advised), I stroked the back sides of sea slugs, explored the spines of urchins, and shook tentacles with an anemone.
Throughout history, humans have devised numerous uses for kelp. During World War I, kelp was harvested to make potash, a manufactured salt that contains potassium in water soluble form. During the war, potash was a major component of fertilizer and gunpowder. Following a German embargo on potash in 1914, American scientists and businessmen turned to the sea to extract potash from California’s giant kelp. By the 1930s, food and pharmaceutical corporations began extracting algin, a thickening, stabilizing, and gelling agent from kelp. Currently, algin is a popular additive used in a number of processed foods.
Visiting the synthetic kelp forest at the California Science center was truly a treat. Now, it is time to put on my fins and explore the wild forests off of the California Coast. I know that not everyone will have the opportunity to dive into the ocean ecosystems, but no matter where you live, some form of wilderness is available to you. Remember to get outside, ask questions, search for answers, and explore your world!
Kelp Forest Exploration!
Find out what it’s like to experience the kelp forest from inside the tank and you will get a chance to talk first-hand with a diver! Don’t miss the Science Spectacular Kelp Forest Exploration dive show that happens twice daily. Divers interact with animals in the tank and also take questions from guests in the audience—like you! Visit California Science
Monday – Friday: 11:00 a.m. and 1:30 p.m.
Saturday and Sunday: 11:00 a.m. and 3:00 p.m.