Kelp is the primary food for many types of ocean life, including sea urchins. Kelp is a type of algae that grows in forests off the coast of southern California. An overpopulation of sea urchins can strip the ocean of kelp forests that serve as home to many animals, including sea otters. Fortunately, sea otters eat sea urchins to maintain a balance in the ocean, according to About.com.
Abalone and other sea snails also consume kelp as their diet. Humans eat the muscle of abalone and use the shell in decorative items, such as mother of pearl.
Several fish eat kelp as a part of their diet. Both the halfmoon and the opaleye live in the kelp forest and consume this algae.
According to SF Gate, humans also eat kelp, sometimes knowingly, but they are often unaware that they are consuming it. In many Asian cultures, kelp is an important part of the diet, and scientists believe it lowers the number of hormone-dependant cancers. Powdered brown kelp is an ingredient in several nutritional supplements. Algin, a substance in kelp, is able to absorb large quantities of water. The food industry uses it in foods where a creamy texture is desirable, such as salad dressing. It is added to ice cream to prevent the formation of ice crystals.