Archived from:
http://web.archive.org/web/20080224121006/www.nps.gov/archive/olym/edtide.htm

Intertidal Life

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Olympic Coastline, Hands on the Land (activities), Olympic Coast National Marine Sanctuary Facts

Outside Links: Tide Predictions (Aberdeen, WA), Shoreline Aerial Photos
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The Battleground
Each day the moon and the earth battle for the ocean. Using gravity, they tug-of-war at the ocean's water. The earth always wins, but the battle doesn't go unnoticed. The water level rises when the moon is high in our sky. The tide lowers, then rises again when the moon pulls half a world away. Olympic's coastline is the battleground. In this zone, waves crash eroding the rocky shore into tiny bits of sand. The battle also spawns an array of life. Tidepool organisms depend on these daily tidal fluctuations. See a few of these animals below.

Nutrient Currents

Olympic coast tidepools are dependent on adjacent waters. The Columbia River, the Strait of Juan de Fuca, and upwelling currents from the bottom of the Pacific Ocean pump a nutrient rich soup into Olympic's intertidal zones.

Four Intertidal Life Zones (where water meets land and air)

Spray Zone - Wave-spray nourishes life here. This zone could be considered the "desert" of the intertidal community. Small acorn barnacles, lichens and a few other species live in this sun-scorched zone.
Upper Intertidal Zone - Sea water reaches this zone only during high tides. Here, you will find life that regularly survives two long droughts each day. Limpets survive by feeding on algae. They suction their shells tight to rocks for protection from the waves and sun. Sea lettuce and other marine algae thrive in this extreme zone.

Middle Intertidal Zone - Sea water regularly floods this zone.
blue mussels
mussels
ochre sea star
sea stars and anemones
blood star

Lower Intertidal Zone - This zone becomes dry only during the lowest tides. The intertidal's greatest diversity of life thrives in this stable region.
giant acorn barnacles
giant green sea anemones
sunflower star
sea lemon nudibranch

Subtidal life zone and beyond...


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