Figure 16.1 Competition for space. Sessile organisms that live in the rocky intertidal biome compete for open space on the rocks as a point of attachment. This photo from Olympic National Park in Washington shows a number of sessile organisms at low tide including mussels, giant green sea anemones (Anthopleura xanthogrammica), goose barnacles (Lepas anserifera), and ochre sea stars (Pisaster ochraceus).

Photo by Gary Luhm/DanitaDelimont.com.