1. Coastal Waters and Marginal Seas

2. Salinity
Runoff from rivers does not mix well with coastal waters, so a well developed halocline forms
Though when shallow enough it will mix making it isohaline

3. Temperature
Sea ice forms in high latitudes, while a strong thermocline prevents water to mix in low latitudes
Mixing allows water to bring oxygen from the surface to deeper water
Offshore winds can carry heat in the summer, or take away heat during the winter

4. Coastal geostrophic currents
Geostrophic currents can form as wind blowing parallel to shore piles water up
Gravity then pulls it back towards the ocean
Then as it runs back the coriolis effect takes over and pulls it to the right or left
Even runoff is affected by the coriolis effect

5. Estuaries
Estuary is a partially enclosed body of water in which freshwater runoff dilutes salty ocean water
Most common type is at the mouth of a river
Also most economically important due to being seaports
Experience great variations in temperature and salinity
Classified by both origin and water mixing

6. Origin of estuaries
Coastal plain- formed when sea level rises and flood river valleys
Fjord- formed when valleys carved by glaciers are flooded
U shaped
Moraine- submerged glacial deposit of debris at the mouth of the estuary marks the farthest extent of the glacier

7. Origin of estuaries
Bar built estuary- formed from the opening between a lagoon of a sand bar and the ocean
Tectonic estuary- formed when faulting or folding of rocks creates a lower area where a river flows

8. Water mixing in estuaries
Vertically mixed estuary- the waters are mixed so salinity just increases as one moves toward the ocean
Slightly stratified estuary- Somewhat deeper, like vertically mixed but two water masses can be identified
Water masses separated by a zone of mixing
The flow of low salinity surface water towards the ocean and subsurface high salinity water towards the river is estuarine circulation pattern

9. Water mixing in estuaries
Highly stratified estuary- strong separation between the two water masses
deep estuary
well developed estuarine circulation
strong halocline
Salt wedge estuary-salt water intrude beneath the river
Typical of high output rivers

10. Estuaries and human activities
Colombia river valley
Between Washington and Oregon
Many dams have altered the flow of the river
Salt wedge
Chesapeake Bay estuary
Formed by drowning of Susquehanna river
Slightly stratified
Water can become anoxic due to waters not mixing well

11. Coastal wetlands
Wetlands are in which the water table is close to the surface, so they are saturated most of the time
Very productive and economically beneficial when left alone
Most important types are salt marshes and mangrove swamps
Both periodically covered by ocean water
Both have oxygen poor mud

12. Coastal wetlands
Can filter water very well, .4 acres can filter 2,760,000 liters of water
They are being destroyed
87 mil hectares to 43 mil hectares
Office of Wetland protection created to stop this

13. Lagoons Lagoons lie between sand bars and land Brackish
Salinity is high at the mouth but low at the head of the river feeding it
Can be hyper saline in arid regions

14. Marginal seas
Marginal seas are margins of the ocean semi enclosed isolated bodies of water
Mediterranean sea
Number of seas connected by small necks
Remains of Tethys sea
Contains an underwater ridge called a sill between sicily and Tunisia

15. Mediterranean circulation
Atlantic water flows on the surface to replace water evaporated in the arid eastern end
Water flows into the Atlantic at meters of depth
The water cools to 13*C and 373% salinity as it passes though the Gibraltar
It then goes down to 1000 meters and equalizes wih surrounding water
Mediterranean circulation is where surface water from the ocean replaces evaporated water in the mediterranean

16. Marginal seas Marginal seas of the Atlantic
Mediterranean
Caribbean sea
Gulf of Mexico
Marginal seas of the Pacific
Gulf of California
Bering Sea

17. Marginal Seas Marginal seas of the Atlantic Red sea Arabian sea
Bay of Bengal