Properties of Ocean Water
How did the salt get into the seas? Why is it salty?
Over millions of years, rain, rivers, and streams have washed over rocks containing the compound sodium chloride (salt) and carried it into the seas.
Would the Polar Regions have a higher or lower salinity?
Polar Regions have a higher salinity because ocean water freezes. The salt stays in the water that is not frozen creating a higher salinity.
What are some bodies of water that are warmer and thus have a higher salinity?
Red Sea, Dead Sea, Persian Gulf
Different bodies of water have different amount of salt mixed in, or different ______________.
Salinity
What are 3 properties of ocean water?
Salinity - the amount of salt in water Temperature - how hot or cold it is will depend on the amount of sun that hits the area Chemical composition - the various chemical elements in the water (more than 70)
How is salinity measured?
Salinity is measured by the amount of salt found in 1,000 grams of water (or in 1 liter of water).
Main Thermocline
Temperature decreases rapidly with depth tropical areas - 1,000 meters deep cooler areas - starts at surface
What is the saltiest body of water????
The Dead Sea with a salinity of 300ppt
What determines the temperature of seawater?
The length of time that the sun hits the area as well as the angle of the sun's rays (the more direct the rays of the sun the warmer the temperature).
How is salinity increased in ocean water?
by evaporation or by freezing sea ice
Upper Mixed Layer
+30 degrees C in tropics cools down near polar areas depth - surface to 200 meters deep
What is the average freshwater salinity?
.5 ppt
What is the salinity if there is 1 gram of salt in 1,000 grams of water
1 ppt (part per thousand)
What is the salinity of open ocean water (free from land influences)?
33-36 ppt
What is the average ocean salinity?
35 ppt
How do different sea creatures use different chemicals?
Animals like mussels and crabs use calcium to build their shells. Plankton use silica to build their shells. Sponges and seaweed use iodine.
Why aren't the oceans getting saltier anymore?
Because the salt that gets carried into the oceans sinks to the bottom of the ocean floor and does not dissolve in the water.
Why do tropical areas have warmer surface waters?
Because they get more year-round sun and more direct sun
Why do the polar areas have colder surface waters?
Because they have no sun at all for several months each year and the sun's rays are at very steep angles
How much salt is in the ocean? If you took it out spread it evenly over the Earth's land surface, how much would there be?
Enough to form a layer more than 500 ft. thick (40-story building)
Give examples of what influences the ppt. What makes ppt higher, what makes ppt lower?
Evaporation and freezing sea ice make salinity higher. Rainfall, runoff, and melting ice make salinity lower. Water in warm areas will have higher salinity than water in cold areas. Ocean water along the shores where rivers enter the ocean will have a lower salinity. Water near equator has average salinity (evaporation is offset by rainfall). Water in open water has average salinity.
Will the salinity of water of warmer areas be higher or lower?
The salinity will be higher. Waters in warm areas will have more evaporation. since only fresh water evaporates, the salt stays behind.
Will the salinity of water in cold areas be higher or lower?
The salinity will be lower. Waters in cold areas will have less evaporation. So that means there will be much more fresh water mixed with the salt.
How do mollusks like mussels and clams as well as crustaceans like crabs and lobsters influence the composition of the seawater?
They extract or take out calcium from the sea to build their shells and skeletons
How do plankton influence the composition of the seawater?
They extract or take out silica to build their tiny shells
How do sponges and seaweed influence the composition of the seawater?
They remove iodine from the sea
Will ocean water along the shores where rivers enter the ocean have a higher or lower salinity?
They will have a lower salinity because more fresh water is mixed with the salt.
What is the ocean water like around the equator like?
This water is close to the average (35 ppt) because the evaporation of water is offset by a lot of rainfall
True or False - 500 million years ago, the seas were slightly less salty
True
True or False - Sea life has a strong influence on the composition of the seawater
True
Where are these layers found in the ocean?
Upper Mixed Layer - found anywhere from the surface to 200 meters deep. This layer is deeper in warmer areas. Main Thermocline - found below the upper mixed layer and can go 1,000 meter deep. This layer is deeper in warmer areas and will start at the surface in cooler areas. Deep (Bottom) Water - found below the main thermocline. It starts at the surface in the polar areas.
Deep Bottom Water
always same temperature (-2-5 degrees C) contains most of all seawater 80% of all ocean water In polar areas - all the way to the surface
How is salinity decreased in ocean water?
as a result of rainfall, runoff, or melting ice
What are the common chemical elements found in ocean water?
calcium, magnesium, bicarbonate, silica, and sodium chloride (salt)
Where did the salt in the oceans come from?
land
What does salinity mean?
the amount of salt mixed in a body of water
Ppt stands for parts per thousand. Explain
the amount salt per thousand grams of water. It is how salinity is measured.
What are the 3 layers in the ocean waters?
the upper mixed layer the main thermocline the deep bottom water
