2. Exploring the Ocean
Since ancient times people have studied the ocean such as waters and ocean floor
It provides food and services, and serves as a route for trade and travel

3. The World’s Oceans
71% of the Earth’s surface is covered by ocean water.
The oceans contain 97% of the earth’s water.
All the oceans and seas are actually one continuous body of water.

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

5. Seas A sea is a part of an ocean that is nearly surrounded by water.
The Mediterranean, Arctic and Black Sea are really part of the Atlantic Ocean.

6. Ocean Floor Makeup
The ocean floor has higher mountains, deeper canyons, and larger flatter plains. Earthquakes occur more often.
The rocks are very different.
The crust is thinner

7. Edges of the Continents
The shoreline is a boundary between where the land and the ocean meet.
The topography of the ocean floor is different from the topography of the continents

8. Continental Margin
The area where the underwater edge of a continent meets the ocean floor is called a continental margin.
A continental margin consists of a continental shelf, a continental slope and a continental rise.

9. Continental shelf
The flat part of a continental margin that is covered by shallow area of the ocean floor that extends outward from the edge of a continents is called a continental shelf.

10. Continental shelf Depth of 130 meters and gets steeper
A continental shelf slopes gently from the shoreline.
The width of the continental shelf varies.
Large mineral, oil and natural gas deposits are found here.

11. Continental Slope

12. Continental Slope The steep edge of the continental shelf
At the edge of the continental shelf, the ocean floor plunges steeply 4 to 5 kilometers.
A continental slope marks the boundary between the crust of the continent and the crust of the ocean floor

13. Continental Rise
Separating a continental slope from the ocean floor is a continental rise.
A continental rise is made of large amount of sediments, rocks, plants and animals.
Sometimes the sediments are carried down the slope in masses of flowing water called turbidity currents, like an underwater avalanche.

14. Abyssal Plain

15. Abyssal Plains
Large, flat areas on the ocean floor are called abyssal plains.
The abyssal plains are larger in the Atlantic and Indian than in the Pacific due to the deposition of sediments by large rivers.
The Pacific Ocean has large cracks that trap sediments and result in smaller abyssal plains.

16. Abyssal Plains
Abyssal plains close to the continent are made of mud, sand and silt.
Farther out on the abyssal plains, some of them contain the remains of tiny organisms that form ooze.
Where ocean life is not abundant, the floor of the ocean is covered with red clay

17. Plates
Pieces of earths crust along with parts of the upper mantle are called plates.
The plates move at an average speed of several centimeters per year-barely faster than your fingernails grow
This is what
shaped the dramatic
features of the ocean,
such as mountains
and trenches

18. Seafloor Spreading
Mid ocean ridge is along boundaries of plates that are moving apart or Diverging adding a new strip of rock to the ocean floor
Magma squeezes up through cracks
Magma hardens
Seafloor spreading is what produced our ocean floor
When plates come together or Converge, one plate sinks under the other

19. Mid Ocean Ridge

20. Mid ocean Ridges
The mid ocean ridges form an almost continuous mountain belt that extends from the Arctic Ocean down through the middle of the Atlantic Ocean around Africa into the Indian Ocean and across the Pacific Ocean , much as the line of stitches winds around a baseball.
In the Atlantic it is called the mid-Atlantic Ridge and in the Pacific, the Pacific-Antarctica Ridge.

21. Formation of Mid ocean Ridges
Mountain ranges on land are formed when the Earth’s crust folds and is squeezed together.
Mid ocean ridges are areas where molten material from deep within the Earth flows up to the surface and cools and forms new crust.
Has 2 parallel chains of mountains separated by valley and trenches

22. Submarine Canyons
In many areas, submarine canyons cut through a continental shelf and slope.
They are deep, V-shaped valleys that have been cut in the rock, possibly by turbidity currents.
The Monterey Submarine Canyon(2000 meters) is deeper than the Grand Canyon.

23. Rifts
Running along the middle of the mid ocean ridges between the rows of parallel mountains are deep crevices or rifts.
Rifts are areas of great earthquake and volcanic activity.

24. Trenches
Trenches are the deepest parts of the ocean found along the edge of the ocean floor.
Is a steep sided canyon in the ocean floor
The Mariana Trench in the Pacific Ocean contains the deepest spot on Earth- the Challenger Deep.

25. Mariana Trench
The Mariana Trench is 2, 542 km (1,580 miles) long (more than five times the length of the Grand Canyon) and 69 km (43 miles) wide
The Challenger Deep is 11,033 meters (36,201 feet), almost 7 miles
If Mount Everest, which is the tallest point on Earth at 8,850 meters (29,035 feet), were set in the Mariana Trench, there would still be 2,183 meters (7,166 feet or about 2 miles) of water left above it.

26. Mariana Trench

27. Properties of Ocean Water
Ocean water is a mixture of gases and solids dissolved in pure water.
Oceanographers believe oceans contain all the natural elements on Earth.
85 of 90 elements have been found in the ocean.

28. 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.

29. Salinity Salinity describes the amount of dissolved salt in the ocean.
Salinity is expressed in parts per thousand.
The average salinity of the ocean is 35 parts per thousand.

30. Sources of Salt in the Ocean
When volcanoes erupt, rock materials and gases, such as chlorine, spew forth.
As rivers, streams and glaciers move over rock and soil, they dissolve salts in them, such as magnesium, sodium and potassium.
As waves pound the shoreline, they dissolve salts from the rocks.

31. Gases in Ocean Water
The most abundant gases in ocean water are nitrogen, carbon dioxide and oxygen.
The amounts of these elements vary with depth. They are more abundant at the ocean’s surface where sunlight causes more plant life.

32. 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.
As a result, fish and other animals can live in deep parts of the ocean.

33. Temperature of Ocean Water
Sun is the major source of heat for the ocean.
Motions of the ocean, such as waves and currents, mix the surface water and transfer the heat downward.

34. Surface Zone
The zone where the water is mixed by waves and currents is called the surface zone.
The surface zone extends meters downward.
The temperature remains constant with depth.
Temperature in a surface zone changes due to seasons and locations.

35. Thermocline
The zone of rapid temperature change is called the thermocline.
The thermocline does not occur at a certain depth.
The season and flow of ocean currents alter the depth of the thermocline.
The thermocline exists because warm, surface water does not mix easily with colder, denser water.

36. Deep Zone
The thermocline forms a transition between the surface zone and the deep zone.
The deep zone is an area of extremely cold water that extends from the bottom of the thermocline to depths of 4000 meters or more.
Within the deep zone, temperatures decrease only slightly.
At depths greater than 1500 meters, the temperature is about 4 degrees C.
The three ocean zones are not found in the polar (Arctic and Antarctica) regions since the surface waters are always cold.

37. Seamounts and Guyots
Seamounts are underwater volcanic mountains that rise more than 100 meters above the ocean floor. Most have been found in the Pacific Ocean.
Some seamounts reach above the surface of the water to form islands, like the Azores in the Atlantic and the Hawaiian islands in the Pacific.
Guyots are flat-topped seamounts.

38. Ocean Life Zones Intertidal Zone (Splash Zone)
Neritic Zone (Continental Shelf)
Open Sea Zones
Bathyal Zone (Continental Slope)
Abyssal Zone (Ocean floor)

39. Ocean Life Zones
The plant and animal life in the ocean is affected by several factors.
the amount of sunlight that penetrates the ocean.
the temperature of the ocean water.
Water pressure
The classification of the ocean into life zones is based on the conditions in the ocean. These conditions vary widely.
The classification includes the intertidal zone, the neritic zone and open-ocean zones.

40. Major Groups of Ocean Life
Plants and animals in the ocean are classified into three major groups based on their habits and the depth of the water in which they live.
Plankton
Nekton
Benthos

41. Plankton Plankton float at or near the surface where
sunlight can penetrate.
Most of the plankton are very small, such as algae.
These organisms drift with the currents or tides.
Plankton are the main food for many larger organisms. They account for most of the organisms in the ocean.

42. Nekton
Whales , seals , dolphins, squid, octopus, barracuda and other fish are all nekton.
Nekton are free-swimming organisms that feed on other nekton as well as plankton.
Many have adaptations enabling them to function at depths that have great pressure and no light.

43. Benthos Organisms that live on the ocean floor are benthos.
The forms of these animals include crustaceans and shell fish.
The deep bottom environments are sparsely populated with benthos.
Some benthos are plants that live on the ocean floor in shallow waters where sun can penetrate.

44. Intertidal (Splash) Zone
This region is the most changeable in the ocean.
Anemones, crabs, clams, mussels and plants such as seaweed live here.
They must be
able to exist without
water for periods
of time.
They must be able
to anchor to keep
from being washed out to sea.

45. Estuary An environment along the oceans edge
Is a coastal inlet or bay where fresh water from a river mixes with salty ocean water.
Water is known as brackish.

46. Coastal Wetlands Are habitats found in and around estuaries
Along the US coasts, most wetlands are either mangrove forests or salt marshes.

47. Salt Marshes
Have muddy soil that is rich in nutrients and dominant plant is cord grass
Tide channels running through the grass break up waves, thus protecting organisms from the ocean surf

48. Mangroves Have arching prop roots that anchor the trees to the land
Roots break up wind and waves protecting organisms that live there
Roots also trap sediment so water is rich in nutrients

49. 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.
This zone can support plankton, nekton and benthos.
Marine life is most abundant here.

50. Coral Reefs Can form only in shallow tropical ocean waters
Produce a hard material around their soft bodies
When they die, the hard material is left behind

51. Kelp Forests
Grow in cold neritic waters where the ocean has a rocky floor

52. Open Ocean Zones
There are two open-ocean zones: Bathyal & Abyssal

53. Bathyal (Slope)
The bathyal zone begins at the continental slope and extends down about 2000 meters.
Sunlight cannot penetrate the bottom of this zone and plants do not grow at the bottom.
Many forms of nekton, such as squid, octopus and large whales live in this zone.

54. Abyssal (Ocean Floor) Zone
At a depth of about 2000 meters, the abyssal zone begins.
The abyssal zone extends to a depth of 6000 meters.
This zone covers the large flat plains of the ocean. No sunlight can penetrate and food is scarce. The water pressure is great.
Most of the animals here are small.
Many deep sea fishes produce their own light called bioluminescence.

55. Hydrothermal Vent Located in the deep zone
Is an area in which heated ocean water rises through the cracks of ocean floor
Chemical nutrients in the heated water support unique organisms.

56. 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.
Special thermometers measured the temperature. Samples of water were collected.

57. Present Oceanographers
Today oceanographers have modern instruments.
Underwater cameras provide pictures of the ocean floor. Corers bring up samples of mud and sand from the ocean bottom.
Bathyspheres, bathscaphs and other submersibles are able to dive deep under the surface to explore

58. Mapping the Ocean Floor
One of the most important goals is to map the ocean floor.
This is done by indirect methods such as echo sounding, radar, sonar and seismographic surveys.

59. Echo Soundings All of these methods are based on the same principles.
Energy waves are sent down to the floor are reflected and return to the surface, where they are recorded.
Knowing the speed of sound, 1500 m per second, oceanographers can determine the depth.
The most complete picture was gathered from information from a satellite, the Seasat, launched in 1978

60. Sonar Stands for Sound Navigation and Ranging
Is a system that uses sound waves to calculate the distance to an object