Sandy beach

 

As you move away from the protected back bays of Puget Sound to the mouths or open channels, high tidal currents and wind-driven wave action leave fewer fine sediments in the intertidal zone. The beaches become sand dominated rather than mud dominated.  As a result the kinds and numbers of plants and animals change.


Tolmie State Park beach, west of the Nisqually River delta, is characteristic of sand dominated local beaches (see below photograph).  The upper intertidal zone is composed of gravel and cobbles (and occasionally a short strip of sand) where wave action makes them act like millstones crushing any animals or plants. In addition, water easily moves through the course sediment leaving the upper few inches dry. Further down slope lies the more stable sand/gravel/boulder zone with a dramatic increase in life. The sand binds the gravel and cobbles resisting wave action and holding moisture. Here are Littleneck and Manila clams, green sea lettuce, a red seaweed called Nori, amphipods under the seaweed, juvenile shore crabs under larger boulders and juvenile fish (such as Staghorn Sculpins and various flatfish) in small tide pools.  If there are hard  surfaces consisting of untreated wood you may find Gribbles and Teredos burrowing into it.


The sand flat extends out to a minus four feet and beyond. The upper portion is home to small beds of a short, small-bladed eelgrass, sand dollar beds, a variety of burrowing polychaete worms, the white sand clam , cockle clam, horse clams and ghost shrimp. As the lower intertidal grades into the subtidal zone, beds of the large-bladed eelgrass may be present along with their rich diversity of associated animals and plants.


Other organisms that are associated with sandy beaches include:  Colonial Diatom, Green String Lettuce, Red String Seaweed, Rockweed, Turkish Washcloth, Wireweed, PickleweedMoonglow Anemone, Aggregating Anemone, Burrowing Sea Cucumber, Moon Snail, Bay Mussel, Spotted Aglaja Nudibranch, Dungenese Crab, Graceful Crab, Red Rock Crab, Smooth Bay Shrimp, Ostracod, Cumacean, Jointed-tube Worm, Spaghetti Worm, Sandworm, Yellow-bellied Ribbon Worm, Pacific Sand Lance, Surf Smelt, Glaucous-winged Gull, Ring-billed Gull, Greater Yellowlegs, Least Sandpiper, Northwestern Crow, Black Brant and Great Blue Heron.


Animals associated with subtidal (deeper than the intertidal zone) sandy habitat are: Sea Lemon nudibranch, Blackeyed Hermit Crab, Speckled Sanddab, Giant Sea Cucumber and Leather Sea Star.


























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