The Vast World OceanThe Vast World Ocean

Chapter 14, Section 1Chapter 14, Section 1

The Blue PlanetThe Blue Planet

• Nearly 71% of Earth’s surface is Nearly 71% of Earth’s surface is covered by the global oceancovered by the global ocean

• It has only been since the late 1800s It has only been since the late 1800s that the ocean became an important that the ocean became an important focus of scientific studiesfocus of scientific studies

• Oceanography –Oceanography – a science that a science that draws on the methods of geology, draws on the methods of geology, chemistry, physics and biology to chemistry, physics and biology to study all aspects of the world oceanstudy all aspects of the world ocean

The Blue PlanetThe Blue Planet

Geography of the OceansGeography of the Oceans• The world ocean can be divided into four The world ocean can be divided into four

main ocean basins – the Pacific Ocean, the main ocean basins – the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, and the Atlantic Ocean, the Indian Ocean, and the Arctic OceanArctic Ocean

• The Pacific Ocean is the largest ocean and The Pacific Ocean is the largest ocean and the largest geographic feature on Earth the largest geographic feature on Earth (deepest at an average depth ~ 3940 m)(deepest at an average depth ~ 3940 m)

• The Atlantic Ocean is about half the size of The Atlantic Ocean is about half the size of the Pacific, and much more narrowthe Pacific, and much more narrow

• The Indian Ocean is slightly smaller than The Indian Ocean is slightly smaller than the Atlantic, but has about the same the Atlantic, but has about the same average depthaverage depth

• The Arctic Ocean is only about 7% the size The Arctic Ocean is only about 7% the size of the Pacific and about ¼ as deep as the of the Pacific and about ¼ as deep as the rest of the oceansrest of the oceans

Geography of the OceansGeography of the Oceans

Concept CheckConcept Check

• What are the four main ocean What are the four main ocean basins?basins?

• Pacific Ocean, Atlantic Ocean, Indian Pacific Ocean, Atlantic Ocean, Indian Ocean, and Arctic OceanOcean, and Arctic Ocean

Mapping the Ocean FloorMapping the Ocean Floor

• If all the water were drained from the If all the water were drained from the oceans, we would see everything from oceans, we would see everything from chains of volcanoes, tall mountain ranges, chains of volcanoes, tall mountain ranges, trenches, and large submarine plateaustrenches, and large submarine plateaus

• The topography of the ocean floor is as The topography of the ocean floor is as diverse as that of continentsdiverse as that of continents

• Bathymetry – the measurement of ocean Bathymetry – the measurement of ocean depths and the charting of the shape or depths and the charting of the shape or topography of the ocean floortopography of the ocean floor

• Today’s technology – particularly sonar, Today’s technology – particularly sonar, satellites, and submersibles – allows satellites, and submersibles – allows scientists to study the ocean floor in a scientists to study the ocean floor in a more efficient and precise manner than more efficient and precise manner than ever beforeever before

Mapping the SeafloorMapping the Seafloor

SonarSonar

• Sonar is an acronym for Sonar is an acronym for sosound und nnavigation avigation aand nd rranginganging

• It works by transmitting sound waves It works by transmitting sound waves toward the ocean bottomtoward the ocean bottom

• A sensitive receiver intercepts the echo A sensitive receiver intercepts the echo reflected from the bottomreflected from the bottom

• Then a clock precisely measures the time Then a clock precisely measures the time interval to fractions of a secondinterval to fractions of a second

• Depth can be calculated from the speed of Depth can be calculated from the speed of sound in water and the time required for sound in water and the time required for the energy pulse to reach the ocean floor the energy pulse to reach the ocean floor and returnand return

SonarSonar

SatellitesSatellites

• We can now measure the shape of the ocean We can now measure the shape of the ocean floor from space with satellites orbiting Earthfloor from space with satellites orbiting Earth

• Gravity attracts water towards regions where Gravity attracts water towards regions where massive ocean floor features occurmassive ocean floor features occur

• This produces relative elevated areas on the This produces relative elevated areas on the ocean surface by mountains and ridges and ocean surface by mountains and ridges and depressions at canyons and trenchesdepressions at canyons and trenches

• Devices on satellites can measure variations in Devices on satellites can measure variations in sea-surface height as small as 3-6 cmsea-surface height as small as 3-6 cm

• Using this data and sonar data, scientists are Using this data and sonar data, scientists are creating detailed maps of the ocean floorcreating detailed maps of the ocean floor

SatellitesSatellites

Concept CheckConcept Check

• How do satellites help us learn about How do satellites help us learn about the shape of the seafloor?the shape of the seafloor?

• Satellites bounce microwaves off the Satellites bounce microwaves off the ocean surface. Outgoing radar pulses ocean surface. Outgoing radar pulses are reflected back to the satellite and are reflected back to the satellite and can be used to detect differences in can be used to detect differences in sea surface height that can be sea surface height that can be correlated to seafloor features.correlated to seafloor features.

SubmersiblesSubmersibles

• Submersible – Submersible – a small underwater a small underwater craft used for deep-sea researchcraft used for deep-sea research

• They are used to collect data about They are used to collect data about areas of the ocean that were areas of the ocean that were previously unreachable by humanspreviously unreachable by humans

• Most submersibles are unmanned Most submersibles are unmanned and operated by computersand operated by computers

SubmersiblesSubmersibles

AssignmentAssignment

• Read Chapter 14, Section 1 (pg. 394-400)Read Chapter 14, Section 1 (pg. 394-400)• Do Chapter 14 Assessment #1-33 (pg. 417-418)Do Chapter 14 Assessment #1-33 (pg. 417-418)

• For Section 1: Do #’s 1-3, 11-14, 24, 25, 29For Section 1: Do #’s 1-3, 11-14, 24, 25, 29