Oceans Introduction Chapter 23 Section 1

The global ocean covers 71% of the Earth’s surface.

The ocean contains more than 97% of the Earth’s surface water.

There are five major oceans. They are all connected.

Pacific Ocean: Largest and Deepest Average depth is 4.3 km.

Atlantic Ocean: Second Largest. Average depth = 3.9 km.

Indian Ocean Third largest. Average depth = 3.9 km.

Southern Ocean Extends from the coast of Antarctica up to 60 degrees South latitude.

Arctic Ocean is smallest and often covered with ice.

Seas are smaller than oceans, and often surrounded by land.

Modern Oceanography An American naval officer named Matthew F. Maury used records from navy ships to learn about ocean currents, winds, depths and weather conditions. He wrote a book in 1855.

The British ship HMS Challenger collected data for 1000 days.

Scientists on the HMS Challenger Measured water temperatures, and collected samples of water, sediments and organisms.

Modern Drilling Ships JOIDES Resolution CHIKYU is Japanese.

SONAR = SOund Navigation And Ranging The ship gives off sound waves and measures how long it takes for them to come back.

Natural Sonar Whales Bats

Uses of SONAR Sonar was used to detect submarines in World War II. It is now used to measure and map the depths of the ocean.

Submersibles are underwater vessels. Bathysphere - attached Bathyscaph –free moving

Submersibles may be manned or robotic. Some are remote controlled.

Depth Facts A typical US navy submarine can dive to approximately 250 m. The Titanic wreck is about 3800 m deep.

The deepest part of the ocean is Challenger Deep. 11,035 m deep (about 7 miles) Only four people have been to the bottom.

Two trips to Challenger Deep 1960 – bathyscaph Trieste – stayed 20 min, too murky for photographs. 2012 - Deepsea Challenger – can stay 6 hours, lots of photos, Imax movie & samples.