1. Oceans
“Quite possibly the best PowerPoint about Oceans you will ever see!” - PPTA

2. The Blue Planet 71% of the Earth’s surface is covered by water.
The oceans contain 97% of the earth’s water.
All the oceans and seas are actually one continuous body of water.

3. Origins of the Oceans
The collision of large asteroids and the bombardment of meteorites formed the Earth some 4.6 billion years ago.
Asteroids and meteorites are composed of about 0.5% water.

4. How were the oceans formed?
When Earth was still a young planet, many active volcanoes existed. As they erupted, lava, ash, and gases were released from deep within the Earth.
One of these
gases was water
vapor.

5. Formation of Oceans
Over millions of years, the water vapor cooled enough to condense and form clouds. Then torrential rains began to fall from the clouds.
Eventually, much of the land was covered by the water that formed.

6. Studying the Ocean Floor
In 1872, the first expedition to explore the ocean began when the Challenger sailed from England.
Scientists used wire to measure the ocean depth.
Scientists aboard used nets to collect animals and plants from the ocean floor.

7. Oceans
The oceans are the Atlantic, Pacific, Indian, Arctic, and Southern.
The Pacific Ocean is the largest ocean.
The area of the Pacific Ocean are greater than the Atlantic and Indian combined.

8. Major Elements in the Ocean
Ocean water is 96% pure water.
Chlorine (1.9) and sodium (1.1) make up the next largest concentration of elements.
Sodium chloride is table salt.

9. Salinity Salinity describes the amount of dissolved salt in the ocean.
The average salinity of ocean is 35 parts per thousand.
Saline water is more dense than freshwater, contributing to density currents.

10. Temperature of Ocean Water
Warm water holds less dissolved gas than cold water.
When ocean water is cold, like in polar regions, it sinks and carries oxygen rich water to the ocean depths. (Also contributing to density currents)
As a result, fish and other animals can live in deep parts of the ocean.

11. Thermocline
The zone of rapid temperature change is called the thermocline.
The thermocline exists because warm, surface water does not mix easily with colder, denser water.

12. Ocean Ecosystems
The classification of the ocean into ecosystems is based on the conditions in the ocean (pressure, temperature, salinity).

13. Neritic (Shelf) Zone
This zone extends to a depth of 200 meters and receives plenty of sunlight.
The water pressure is low and the temperature is constant.
Salinity is high
Marine life is most abundant here.

14. Bathyal (Slope) Zone
The Bathyal zone begins at the thermocline and extends down to about 2000 meters.
Sunlight can’t penetrate this zone (cold) so plants do not grow.
Low salinity.
Nekton such as squid and octopus live in this zone.

15. Abyssal (Ocean Floor) Zone
The abyssal zone extends from 2000 m to a depth of 6000 m.
Slightly colder than the Bathyal zone and food is scarce.
The water pressure is extreme so most of the animals here are small.
Some make their own light.

16. Waves
A wave in water is a rhythmic movement that carries energy through the water.
Waves are primarily caused by winds blowing on top of the water.

17. Tides
Throughout a day, the water level at the ocean’s edge changes. This rise and fall in sea level is called a tide.
Tides are created by the gravitational attraction of Earth  Moon and Earth  Sun.

18. Tides
Spring Tides (higher than normal), are produced when the sun, Earth and moon line up.
Neap tides (lower than normal), are produced when the sun, Earth and moon are at right angles.

19. Movement of Water Water moves in streams called currents.
Also called a gyre.
Currents are caused by two factors: wind patterns and differences in water density.

20. Upwellings
Cold water sinks to the ocean floor and begins to flow. As currents come close to land, the ocean floor forces these cold currents upward.
At the same time, surface winds move the warm surface water away. The upwellings carry nutrient rich water from the ocean floor that results in feeding grounds near the coast.

21. El Niño
El Niño is an abnormal climate event that occurs every 2-7 years in the Pacific Ocean, causing changes in the winds, currents, and weather patterns.

22. El Niño El Niño interrupts the pattern of upwelling.
Without the nutrients from upwelling, fish and other organisms cannot find food resulting in large fish kills.
Weather patterns are disturbed because of the lack of cold water being uplifted.