Pass 



Navigable channel through bar, reef, shoal, or between adjacent 



islands. 



Pelagic zone 



Open sea, away from the shore. 



Periphyton 



Attached microscopic organisms growing on the bottom or on other sub- 

 merged substrates. 



Permeable groin 



Groin with openings large enough to permit passage of appreciable quan- 

 tities of littoral drift; see groin. 



Phytovlankton 



Planktonic plant life. 



Pier 



A structure, usually of open construction, extending into the water from 

 the shore. It serves as a landing and mooring place for vessels or for 

 recreational uses. Includes trestles, platforms, and docks. 



Pile 



Long, heavy timber or section of concrete or metal driven or jetted into 

 earth or seabed for support or protection. 



Pile cluster 



Dolphin; group of adjacent piles. 



Pile dike 



Dike construction of piles. 



Pile, sheet 



Pile with generally slender flat cross section, meshed or interlocked 

 with like members to form wall or bulkhead. 



Piling 



Group of piles. 



Pioneer species 



One capable of establishing itself in a barren area. 



Plankton 



Suspended microorganisms with relatively little power of locomotion that 

 drift in water and are and are subject to action of waves or currents. 



Point 



Outer edge of any land area protruding into water, less prominent than 

 cape. 



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