Ch. 19 The Ocean Basins

Sect. 19.1

Oceanography• The study of the

physical characteristics, chemical composition and life forms of the ocean

• Matthew F. Maury - began early study in 1850’s using records from navy ships

Why Study Oceanography

• To Feed Us - Aquaculture

• To predict weather

• Mineral Resources

Global Ocean

• Covers 3/4 of the earth’s surface (this is the most prominent feature on Earth!)

• contains 97% of all the water on the earth

• Totals 1/800 of Earth’s total volume

• 5 oceans: Pacific, Atlantic, Indian, Arctic and Southern (Antarctic)

• smaller areas of the oceans are called seas

Pacific Ocean

• Largest, Deepest (contains more than ½ the ocean water)

• Has many trenches and few abyssal planes

• Ring of Fire

• Deepest Trench-Mariana Trench

Atlantic• 2’nd largest ocean• Shallowest (avg. depth

3.9km)• Many sea routes

between eastern and western hemispheres

Indian Ocean• 3’rd largest• less than 1/2 the size of

the Pacific• Contains many ridges• Monsoons

Southern Ocean (Antarctic Ocean)• Coldest• Least Salty• Extends from the tip

of Antarctica to 60 degrees South latitude

• Contains largest current

Arctic Ocean

• Smallest• Mostly surrounded by

land• Central part permanently

covered with ice and surrounded by water in summer.

• Completely frozen in winter

Technology in Ocean Exploration

• Drilling Ships

• JOIDES Resolution

• Take Core samples

Submersibles

• Underwater research vessels including the following:

Bathysphere

• One of the first that was linked to the surface with a cable

Bathyscaph• Self-propelled

• Free-moving

• Alvin and Nautile

Alvin

Robotics

• Argo and Jason Jr• Used to discover the

Titanic

Size of Jason Junior

SONAR

• Sound Navigation and Ranging

• consists of a transmitter and receiver

• sound waves are used to map and make profiles of the ocean floor

** Transmitter sends out sound waves @ 1500 m/s

** Sound waves are reflected back to receiver

** The time elapsed gives depth or distance:

Speed = Distance Time

Distance = Speed x time

Time = Distance Speed

……it would it would take take 125 125 yearsyears to to totally map totally map the ocean the ocean floor using floor using sonar…sonar…

…these days we can use satellite altimetry!

• The bumps & dips on the ocean’s surface mimic the topography of the ocean floor.

• SEASAT (and later GEOSAT) circle the earth; their sensitive radar altimeters send data used to create ocean floor maps.