9 terms

Ocean Water Chemistry- Science


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How salty is ocean water?
On an average, one kilogram of ocean water contains about 35 grams of salts - that is 35 parts per thousand, but it can vary from 34 - 37. (3.5%)
How do the temperature and gas content of ocean water vary?
A. The closer to the equator the warmer it is
B. The closer to the surface, the warmer it is
C. Weather conditions affect water temperature.
Gas content:
A. More oxygen at surface than deeper due to closeness to atmosphere and presence of algae
B. More oxygen where there are lots of plants and algae
C. More carbon dioxide where there are lots of animals
60% more carbon dioxide in water than in air
D. More oxygen at poles where water is cooler

Temperature of the ocean varies from place to place. Near the equator, ocean surface temperatures often reach 25 degrees Celsius. The temperature drops as you travel away from the equator. Because warm water is less dense than cold water, warm water forms only a thin layer on the ocean surface. The deeper you descend into the ocean, the colder the water gets. Weather conditions can affect ocean water temperatures.

Carbon dioxide is about 60 times as plentiful in the oceans as in the air. The amount of carbon dioxide in ocean water will vary depending on plant (use carbon dioxide) and animal (produce carbon dioxide) abundance.

Oxygen is scarcer in ocean water than in the air. Its concentration is greater at ocean surface than deeper. Its concentration is greater where there is plentiful algae. Oxygen is more plentiful in colder water, so seawater at polar regions has more oxygen.

There is higher temperatures near surface.
How do conditions in the ocean change with depth?
A. pressure increase as depth increases
B. temperature decreases with depth
C. light decreases with depth
D. salinity of water varies at surface, but remains fairly constant deeper.
Light penetrates to about 200 m. Near the surface, temperature is affected by weather. In the transition zone, the temperature drops rapidly. In the deep zone, water is always extremely cold. Rainfall decreases salinity near the surface, while evaporation increases salinity in the warm, dry areas. Below the surface zone, salinity remains fairly constant throughout the water column. Pressure increases with depth.
How does salinity affect ocean water?
Ocean water does not freeze until the temperature drops to about -1.9o C. Salt water has a higher density than fresh water. Consequently, salt water has greater buoyancy.
How does the temperature of the ocean change with depth?
As you descend through the water column, the water temperature decreases.
How does water pressure change with increasing depth?
Pressure increases continuously with depth in the ocean.
Compare the amount of dissolved oxygen and carbon dioxide in the oceans with the amount of oxygen and carbon dioxide in the air.
There is more carbon dioxide in the ocean than in the air whereas the concentration of oxygen in seawater is lower than in the air.
Why is the ocean salty?
During early Earth history, underwater volcanic eruptions added chemicals to Earth's oceans. Also, evaporation removes only water from the ocean and leaves the minerals behind. When it rains on land, rainwater carries minerals to the sea.
What are some factors that cause differences in the salinity of the ocean?
-Precipitation decreases salinity
-Evaporation increases salinity
-Flow of freshwater (rivers) into ocean
-Freezing increases salinity
-Melting decreases salinity
-Volcanic eruptions increase salinity