What are the two most important physical factors affecting estuaries?
Salinity and substrate are the two most important physical factors affecting estuaries. 13. Describe how salinity varies from the mouth to the head of an estuary. Salinity in an estuary is closest to the salinity of sea water (35‰) near its mouth—where it is closest to the ocean. Near its head—where it is closest to the river the empties into it—the salinity is much lower. Values might be 10–20‰. Water that is intermediate between salt water and fresh water salinity is brackish. Up river, outside of the tidal influence that brings salt water upstream in the river, the salinity is 0‰ (e.g., it is fresh water). 14. How does salinity vary with depth in an estuary? The higher the salinity of water, the greater its density. High salinity, dense water sinks to the bottom of the estuary, whereas fresher, lower salinity water floats on top. 15. What is a salt wedge? A salt wedge is the dense, high salinity water that flows along the bottom of an estuary. It moves up the estuary, towards its he
