Sandy mud Beach



Inside the protected inlets of South Puget Sound and other locations, wind waves and tidal currents are much reduced.  As a result sediments from streams or rivers along with cliff erosion will remain in the area resulting in wide beaches with a mixture of mud and sand.  Depending on the ratio of mud to sand, as well as the percentage of gravel, the beach will be home to a different assemblage of animals and plants.


Frye Cove County Park in Totten Inlet is an example of a mud dominated beach (see photograph).  The upper intertidal zone is characterized by cobbles and muddy sand mixed with gravel.  However the expansive flat beyond is composed of sandy/mud that hosts a variety of worms and other organisms.   Some of those organisms are only present if rocks lie on the surface.  Most of the seaweeds need a hard surface to attach to while the High Cockscomb Prickleback lives along the underside of the rock where moisture occurs at low tide.  If that surface is untreated wood you may find Gribbles and Teredos burrowing into it.


Sandy mud substrate is ideal for preserving the evidence of creatures from the uplands that will invade the beach when the tide recedes.  See a discussion of those animals HERE.


Other organisms that can be found in this low current, low wave setting are:  Colonial Diatom, Green String Lettuce, Sea Lettuce, Rockweed, Nori, Red String Seaweed, PickleweedMoonglow Anemone, Light-edged Ribbon Worm, Thread Sludgeworm, Polyclad Flatworm, Jointed-tube Worm, Spaghetti Worm, Sandworm, Pile Worm Bentnose Clam, Littleneck clam, Manila clam, Butter clam, Geoduck clam, Horse clam, Moon Snail,  Bay Mussel, Pacific Oyster, Frilled Dogwinkle,, Marine Pill Bug, Cumacean, Ghost Shrimp, Graceful Crab, Red Rock Crab, Mud-flat Crab, Hairy Hermit Crab, Ostracod, Arrow Goby, Pacific Staghorn Sculpin, Plainfin midshipman, ring-billed Gull, Glaucous-winged Gull, Least Sandpiper, Northwestern Crow, American Wigeon and Great Blue Heron.

























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