Some species can be very long and form kelp forests.
As a result the sea urchin population has increased dramatically over time and the health of kelp forests is threatened.
It forms thick beds on rocks, and is an important part of kelp forests.
Yet the experience I remember best was in quite a different place - one of the Japanese kelp forests.
Until the last few centuries, however, there had been little incentive to do so; the great kelp forests provided for all their needs.
All of these are examples of ecosystem services provided specifically by kelp forests.
Also common along the coast are kelp forests and rock reefs.
A dependable food source, such as kelp forest or coral reef is usually nearby.
Darwin noted the immense number of organisms dependent on the kelp forests.
It was like looking at a kelp forest when the tide drags the strands outward.