1. Oceans An Overview

2. How did the oceans form? A long time ago (4.5 billion years) there were no oceans. The Earth was a hot and dry environment. When the volcanoes erupted there was a small portion on moisture that was shot into the sky. Over millions of years as the Earth began to cool the moisture from the sky condensed and fell as rain. This eventually formed the present day oceans

3. Ocean water is salty Salinity: Is the measure of dissolved solids and salts in a liquid. In ocean water there is 35g of solids per 1000g of liquid. Some of the solids are Sodium 30.6% Chlorine 55% Magnesium 7.7% Sulfur 3.7% Calcium 1.2 %

4. Temperature Zones The temperature of ocean water decreases as the depth of water increases There are three zones of ocean water Surface zone Thermocline Deep Zone

5. Surface zone The surface zone is the warm top layer of the ocean. It extends to 300 m below sea level. Sunlight heats the top 100 m of this zone. Currents mix the heated water with the water below

6. Thermocline Is a layer of water extending from 300 m below sea level to about 700 m below sea level. In this zone temperature drops with increasing depth faster than it does in the other two zones.

7. Deep Zone This layer extends from the base of the thermocline to the bottom of the ocean floor. The temperature in this zone averages a chilling 2 degrees Celsius.

8. The Water Cycle Is a cycle that links all of the Earth’s solid, liquid, and gaseous water together. The ocean is very important in the process because nearly all of the Earth’s water supply is found in the oceans.

9. Ocean and heat absorption The ocean absorbs a lot of the heat given off by the sun. It absorbs it at a very slow rate. If this did not occur the average temperature on Earth would fluctuate by 100 degrees Celsius.

10. Ocean Floor The ocean floor is divided into two areas. 1) continental margin: made of continental crust 2) Deep Ocean Basin: made of oceanic crust If you were to think of the ocean as a swimming pool the shallow part would be the continental margin and the deep end would be the oceanic basin

11. Ocean floor terms Continental shelf: Begins at the shore line and slopes gently toward the open ocean. It continues until the ocean floor begins to slope more steeply downward. The depth of the continental shelf can reach 200m

12. Continental Slope Begins at the edge of the continental shelf and continues down to the flattest part of the ocean floor. Depth ranges from 200m to 4000m

13. Continental rise Base of the continental slope, is made of large piles of sediment. The boundary between the continental margin and the deep ocean basin lies underneath the continental rise.

14. Abyssal Plain Is the broad flat portion of deep ocean basin. It is covered by mud and small organisms. The average depth of this section is 4000m.

15. Mid Ocean Ridge Are mountain chains where tectonic plates pull apart. The pulling motion creates cracks in the ocean floor called rift zones. As plates pull apart magma rises to fill the empty space. Heat from either side causes the crust to expand, forming ridges.

16. Rift valley As mountains build up a rift valley forms between them in a rift zone

17. Ocean Trenches Are seemingly bottomless cracks in the deep ocean basin. Ocean trenches form where one tectonic plate is forced underneath a continental plate or another oceanic plate

18. Seamounts Are individual mountains of volcanic material. They form where magma pushes it’s way through the tectonic plates, If seamount builds up past sea level it becomes a volcanic island (Hawaii)

19. How do scientists find out the depth of the ocean floor? By ship a scientist will travel across the entire ocean. During this mission repeated sonar signals are sent down to the ocean floor, then they will bounce back up. A computer record how long it takes each sonar signal to go to the bottom and back and from this a depth is calculated.

20. HW Q 1-4 pg. 341

21. Life in the Ocean There are three main groups of marine life: 1) Plankton 2) Nekton 3) Benthos ** These groups are differentiated according to how they move as well as where they live**

22. The Benthic Environment The benethic environment refers to the ocean floor and all of the organisms that live on it. The deepest zone in the benethic zone is the Hadal zone

23. The Palagic Environment Is the entire volume of water in the ocean and the marine organisms that live above the ocean floor. Two major zones 1) Netric Zone 2) Oceanic Zone

24. Resources from the ocean Fishing is a multi million dollar industry 75 million tons of fish are harvested each year from the ocean With improved technology such as sonar and drift nets fisherman can catch a much greater amount of fish Today the fishing industry realizes not to catch dolphin and other animals so they are taking precautions!!

25. Fish Farming Many types of fish are being caught in nature and then are bred many times to produce fish farms. The benefit of this for the fishing industry is that there is no limitation to the amount of harvest or fishing regulations to deal with.

26. Seaweed Seaweed and algae are being harvested more than others Seaweed is being used a thickeners in food such as jellies and star bucks coffees. Sushi is also growing in popularity. Seaweed consumption is a very large area of growing American consumption Ice cream has seaweed as well!!

27. Tidal Energy Since the ocean is constant in it’s movement it can be used as a source of energy. Wave energy is a clean renewable resource as well. Recently computer programs have been used to determine how much energy a wave carries.

28. Assignment I have listed a few ways that the ocean can be used for it’s resources. Think of 3 additional ways that the ocean can be used as a resource or to accumulate income for a business.