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Types of Tide Pools

Bench – Tide pools that have a flat or even top surface can be categorized as benches. They provide a large flat surface that is covered by water during parts of the day. These types of tidepools can maintain a variety of marine life that live in all types of tidal zones. Wave action is strong the ocean facing areas and calmer near the less exposed areas. They also contain cracks, surge channels and pools of water that can support s a wide variety of animals that is generally easy to see. Benches are also the easiest for visitors to walk on and navigate making bench tide pools the preferred geographic type.

Boulder/Rock Field – These types of tide pools are not as common as other geographic types. They are characterized by large areas with numerous small and medium sized rocks and boulders. The field is covered by water part of the day. Most tide pools of this type do not have as much wave action as other types as the waves will diminish in strength and speed as they move over the rock field. The lower wave action will limit the types of animals found in these tide pool areas. Tide pools of this type however support algae and animals ( like sea hares ) that prefer calmer areas and not normally found in more exposed areas.

Rocky Outcrop – Tide pools of this type area characterized by large rock formations that extend into the ocean and have part if not all of the rock formation covered by water at some time during the day. Formations of this type are typically not very easy to navigate and walk on. They do however support a wide variety of algae and animals that prefer high wave action and lots of water movement. Tidepools of this nature do not have animals that prefer calmer areas.

The bare spots are grazed over by large Owl limpets

Open spaces in mussel and barnacle beds

Visitors to a tide pool often see large bare patches in the rocks that are surrounded by large beds of mussels and barnacles. There are several reasons this pattern may occur.

The first possible reason is wave action. Mussels and Barnacles will live in very wave exposed areas. They prefer these locations as they provide more food. Large wave events however have the power to dislodge mussels and barnacles. Large waves in the right conditions will rip the mussels and barnacles off the rocks.

Another reason is due to impacts of objects. In the Pacific Northwest, large trees and logs are swept out to sea during stronger store events. These logs will frequently crash into the tide pool areas and dislodge vast areas of mussels and barnacles.

Limpets can also cause large bare areas in mussel beds. Limpets will graze on rocks eating the algae on the surface. As these limpets move around grazing exposed rock, they will also prevent juvenile mussels and barnacles from settling by dislodging the juveniles. These bare areas are clear of most all other forms of live. Owl limpets in particular will farm these open areas for a period of time.

The most common reason for bare spots in rocks is predation by sea stars. Sea stars will devour large amounts of mussels and barnacles in a short amount of time.