Marine Biology

2. Wave action

 Wave Action

Wave action is very strong. Waves break with tremendous force offshore or on the rocks. This is compounded by the fact that the rocky substrate does not absorb the energy of waves as a sandy substrate does. Rather, much of the energy is directed up the shore. As a result, organisms living in these areas must cope with the breaking waves. Some of the adaptations they exhibit include:

· Moving out of the impact zone: Many organisms can move to positions between or under rocks, or even move into other areas to escape severe wave action

· Making depressions and burrows: Some organisms actually, by mechanical or chemical means, make depressions in rocks (chitons and sea urchins)

· Attaching to the substrate: many animals and plants use attachments to keep from being washed away with the waves

· Having a low, thin, streamlined profile is adopted by many intertidal animals so that water will flow over their shells/bodies

· Bending with the waves: flexibility permits bending with the force as well as dispelling secondary drag currents. Algae are a wonderful example of this!

· Orientation plays a role in resisting wave shock. The direction the organism is facing will determine whether water will be taken broadside or have its effect minimized by streaming along the lines of least resistance.