tidal wrack Vegetation and debris deposited along the shoreline during high 



tide. 



tide Periodic rising and falling of the oceans resulting from lunar and 



solar tide-producing forces acting upon the rotating earth. 



trophic Pertiiining to the feeding hierarchy, or food web, of a biotic com- 



munity. 



turbidity Condition of water having reduced transparency due to suspended 



materials. 



W 



watershed The land area providing drainage to a stream. 



weir A dam in a waterway over which water flows that sei"ves to regu- 



late water level or to measure flow. 



wetlands Lands or areas containing much soil moisture, such as tidal flats 



or swamps. 



