OUR LIVING, MOVING SEA

SEA WATER COMPOSITION I. Salinity: The amount of solid material dissolved in water A. 1. Seawater is composed of Cl, Na, Ca, Mg, S, K. These elements make up 99% of the dissolved materials in the ocean.

Why is the ocean salty? Clip on: why tell me why? http://videos.howstuffworks.com/discovery/31006-why-tell-me-why-explaining-saltwater-video.htm

Areas of Diverse Salinity C. Variations: 1. Open ocean is between 33-38parts per thousand 2. Brackish water has been diluted with fresh water (estuaries and bays) 3. Hyper saline water is typical of inland bodies of water where evaporation is high and circulation low. (Great Salt Lake 28.0%, Dead Sea 33.0%)

Salty lakes hid deep in the Mediterranean Geoscientists have discovered three lakes of extremely salty brine lying in pockets on the floor of the Mediterranean Sea, south west of the island of Crete. Such Lakes could help explain why the Mediterranean is saltier than typical ocean water. The three brine lakes situated more than 3300 meters below the sea surface were discovered in 1993 and 1994 by a team of European scientists conducting the Mediterranean Ridge Fluid Flow project. MEDRIFF Researchers found the lakes using echo sonar which sends down pulses of sound to probe the seafloor. The boundary between the dense brine fluids and normal seawater above creates a flat lake surface that stands out amid rougher surrounding seafloor. The density contrast prevents the brine from mixing easily with the seawater. Will not be on test

Salty lakes hid deep in the Mediterranean The scientists focused attention on a horseshoe-shpaed lake, called Urania which had an average depth of 80 meters. The chloride content in the Urania brine measured about 5X’s that of Mediterranean seawater. The lakes formed when seawater dissolved deposits of salt-rich rocks along the seafloor. These lakes may explain the Mediterranean’s high salinity. Current theories explain the high salinity to high evaporation rates. Will not be on test

How does salinity affect the density of water Complete the Inquiry Activity from pg. 421 We tried this in class but this was not as accurate as the hydrometer lab on 4.28.11 so ignore the inquiry activity on pg. 421.

Effects of Salinity D. Effects of Salinity 1. Salinity increases density But is not a significant factor in determining density at depth (temperature is more important)

2. Average ocean water has a salinity of 35g/1000ml. The Range is 33-37 ppt 3. Salinity increases temperature at which water boils 4. Temperature is inversely proportional to density Decrease in temp=increase in density Increase in temp=decrease in density

5. Buoyancy changes with changes in salinity (higher=more buoyant, lower=less buoyant) due to density

Salinity and Humans Lack of salt in a diet can produce goiters and associated health issues