1. Earth’s Oceans

2. The water on Earth is divided into oceans 1. Pacific Ocean – biggest
The Oceans
The water on Earth is divided into oceans
1. Pacific Ocean – biggest
2. Atlantic Ocean
3. Indian Ocean
4. Arctic Ocean – smallest

4. 4.5 billion years ago there were no oceans on earth.
Origin of the Oceans
4.5 billion years ago there were no oceans on earth.
Volcanoes spewed gases into the air to form the atmosphere

6. Origin of the Oceans
As the Earth began to cool, water vapor began to condense and form rain
This rain filled the deeper levels of the Earth’s surface which created our oceans

8. Composition of the Ocean
Ocean water contains many dissolved salts.
Running water from rivers carries these salts from land to the ocean

9. Composition of the Ocean
When seawater is evaporated, ions combine to from materials called salts.
Sodium and chloride make up most of the ions in seawater.

10. Salinity is a measure of the amount of salts dissolved in seawater.
One kilogram of ocean water contains about 35 g of dissolved salts, or 3.5%

12. Hotter, drier climates typically have a higher salinity
Climate and Salinity
Hotter, drier climates typically have a higher salinity
Cooler, humid climates have a lower salinity

13. The three zones are surface zones, thermocline, and deep zone
Temperature Zones
The temperature of the ocean decreases as the depth increases, the colder the water the more oxygen it can hold.
The three zones are surface zones, thermocline, and deep zone

14. The surface zone is the warm, top layer of the ocean water
Temperature Zones
The surface zone is the warm, top layer of the ocean water
The thermocline is the second layer of the ocean where the temperature drops significantly

15. Temperature Zones
The deep zone is the bottom layer of the ocean where temperature ranges from 1°C to 3°C

17. The water cycle also takes place in the ocean The three parts are
Ocean’s Water Cycle
The water cycle also takes place in the ocean
The three parts are
Evaporation
Condensation
Precipitation

18. The oceans absorb and release heat more slowly than land does
Holding Heat
The oceans ability to absorb and hold heat makes Earth suitable for life
The oceans absorb and release heat more slowly than land does

19. Warm water Circulation
Water at the equator is warmer than other regions
Currents in the ocean move this warm water around the world
This allows coastal lands to have warmer than normal climates

20. Ocean currents are a mass movement, or flow, of ocean water.
An ocean current is like a river within the ocean

21. Ocean currents are a mass movement, or flow, of ocean water.
An ocean current is like a river within the ocean

22. Currents

23. Ocean currents are a mass movement, or flow, of ocean water.
An ocean current is like a river within the ocean

25. Surface currents move water horizontally— parallel to Earth’s surface.
These currents are powered by wind.

26. Surface currents move only the upper few hundred meters of seawater.

27. Origin of Surface Currents
The Coriolis effect is the shifting of winds and surface currents caused by Earth’s rotation.

29. Origin of Surface Currents
Because Earth rotates toward the east, winds curve to the right in the northern hemisphere and to the left in the southern hemisphere.

30. Origin of Surface Currents
The Coriolis effect causes currents north of the equator to turn to the right. Currents south of the equator are turned left.

32. Warm vs. Cold Currents
Currents on the west coasts of continents begin near the poles where the water is colder.

34. Warm vs. Cold Currents
East-coast currents originate near the equator where the water is warmer (Gulf Stream Current)

36. Upwelling
Upwelling is a vertical circulation in the ocean that brings deep, cold water to the ocean surface.

38. Upwelling
This water contains high concentrations of nutrients from organisms that died.

39. Areas of upwelling create important fishing grounds
Nutrients promote primary production and plankton growth, which attracts fish.
Areas of upwelling create important fishing grounds

40. Deep Current
A deep current is a streamlike movement of ocean water far below the surface caused by differences in density

41. The density of seawater increases if salinity increases.
Density Currents
The density of seawater increases if salinity increases.
It also increases when temperature decreases.

42. An important density current begins in Antarctica.
Deep Current
An important density current begins in Antarctica.
As ice forms, seawater freezes, but the salt is left behind in the unfrozen water.

44. This current then slowly makes its way towards the equator
Deep Currents
This salt increases the density of the water until it sinks and forms a deep current
This current then slowly makes its way towards the equator

45. In the North Atlantic Ocean, cold, dense water forms.
Deep Currents
In the North Atlantic Ocean, cold, dense water forms.
These waters sink, forming North Atlantic Deep Water.

46. Intermediate Waters
In the Mediterranean, hot temperatures cause water vapor in the ocean to evaporate which increases the salinity of the water

47. This water is not as dense as the North Atlantic Deep Current
Intermediate Waters
This water is not as dense as the North Atlantic Deep Current
It then forms a middle layer of water called the Mediterranean Intermediate Waters

49. The Ocean Floor

50. Studying the Ocean Floor
Scientists use sonar to determine the oceans depth
The sound moves through the water, bounces off the ocean floor, and returns to the ship

52. Ocean basins are low areas of Earth that are filled with water
The continental shelf is the gradually sloping end of a continent that extends under the ocean to 350 m deep

53. The Ocean Floor
Beyond the shelf, the ocean floor drops more steeply, forming the continental slope.
The continental slope extends from the outer edge of the continental shelf down to the ocean floor.

55. Ocean Basins
Beyond the continental slope lie the trenches, valleys, plains, mountains, and ridges of the ocean basin

56. Ocean Basins
In the deep ocean, sediment, derived mostly from land, settles constantly on the ocean floor.
These deposits fill in valleys and create flat seafloor areas called abyssal plains.

58. Some areas of abyssal plains have small hills and seamounts.
The Ocean Basins
Some areas of abyssal plains have small hills and seamounts.
Seamounts are underwater, inactive volcanic peaks

60. Mid-ocean ridges can be found at the bottom of all ocean basins.
Ridges and Trenches
Mid-ocean ridges can be found at the bottom of all ocean basins.
A mid-ocean ridge is the area in an ocean basin where new ocean floor is formed.

62. Ridges and Trenches
On the ocean floor, subduction zones are marked by deep ocean trenches.

63. Trenches and Ridges
A trench is a long, narrow, steep-sided depression where one plate sinks beneath another.
Marianna Trench in Pacific ocean deepest that we have found “Challenger Deep” 11,000 meters.

65. Pacific Ocean vs. Atlantic Ocean
The Pacific Ocean has a much steeper continental slope.
It has Submarine Canyons caused by Turbidity Currents. These are fast moving currents that move perpendicular to the shoreline that cut into the continental slope to form a canyon.
The Atlantic ocean has more abyssal plains because more rivers empty into into it bringing more sediment

66. Life Zones
Intertidal Zone- found between high and low tide, contains benthos, nekton and plankton.
Neritic Zone- low tide to continental shelf , contains, benthos, nekton and plankton.
Open sea Zone- largest of the zones, over the ocean floor.
a. photosynthetic- surface, contains phytoplankton and zooplankton
b. Bathyal zone- small amount of light reaches here, large nekton swim here, most fishing takes place here, also plankton.
c. Abyssal zone- to see floor, no light, strange creatures make own light.

67. There are three groups of organisms that live in the ocean
Life in the Ocean
There are three groups of organisms that live in the ocean
Plankton
Nekton
Benthos

68. Plankton
Plankton are organisms that float or drift freely near the ocean’s surface
Plankton are divided into phytoplankton (plant-like) and zooplankton (animal-like)

70. Organisms that swim openly in the ocean are called nekton
Nekton include mammals (whales, dolphins) and many types of fish

72. Benthos are organisms that live on or in the ocean floor
These include crabs, starfish and coral

74. The ocean floor is divided into zones based on ecology
Oceanic Zones
The ocean floor is divided into zones based on ecology
The benthic environment is the region near the ocean floor

76. Intertidal zone is located between high and low tides
Benthic Environment
Intertidal zone is located between high and low tides
Sublittoral zone extends to the edge of the continental shelf

77. The abyssal zone is found on the abyssal plain
Benthic Environment
Bathyal zone is located from the continental shelf to the abyssal plane
The abyssal zone is found on the abyssal plain

78. The deepest zone is the hadal zone , found in trenches (abyssal zone)
Benthic Environment
The deepest zone is the hadal zone , found in trenches (abyssal zone)

79. Oceanic Zones
The pelagic environment is the zone near the ocean’s surface and the middle depths (photosynthetic zone)

81. The neritic zone covers the continental shelf
Pelagic Environment
The neritic zone covers the continental shelf
Contains the largest concentration of marine life
Oceanic zone covers the rest of the ocean floor

82. Resources from the Ocean
The ocean offers a vast supply of resources
Food, raw materials, energy and drinkable water are all from the ocean

84. Fishing has become a multi-billion dollar business over the years
Living Resources
Fishing has become a multi-billion dollar business over the years
Because over fishing has become a problem, fish farms have started to flourish

85. Seaweed (kelp) is also harvested from the ocean
Living Resources
Seaweed (kelp) is also harvested from the ocean
Seaweed can be used to thicken foods such as jellies and ice cream

87. Salt can be removed from ocean water by a process called desalination.
As seawater evaporates, salt is left behind.

89. Sea-Floor Minerals
Elements such as sulfur and metals like iron, copper, zinc, and silver can be concentrated in holes and cracks along mid-ocean ridges.