Tide Pools
A habitat defined by twice-daily extremes.
Tide pools are rock depressions holding seawater at low tide. Organisms there endure temperature swings, changing salinity, wave force and exposure to air, twice a day.
Zonation
| Zone | Exposure | Typical life |
|---|---|---|
| Splash | Rarely submerged | Lichens, periwinkles |
| High | Briefly submerged | Barnacles, limpets |
| Middle | Regularly covered | Mussels, anemones, sea stars |
| Low | Rarely exposed | Kelp, urchins, nudibranchs |
Zonation is set at the top by physical tolerance and at the bottom by competition and predation — a classic result in ecology.
Plankton tows from tide pools are a standard wet-mount exercise. Living plankton is nearly transparent, which is the classic case for phase contrast rather than brightfield.