Chapter 1Introduction to Planet

“Earth”

Essentials of Oceanography

7th Edition

Geography of the oceans

Earth’s oceans:

Cover 70.8% of Earth’s surface

Are interconnected (“world ocean”)

Have huge size and volume (as a reservoir, contain 97% of Earth’s water)

The four principal oceans

PacificAtlanticIndianArctic

Plus:Southern or Antarctic Ocean

Figure 1-2

Comparing oceans to the continents

Figure 1-3

Comparing depth of the oceans to elevation on land

Figure 1-4

Early exploration of the oceans

Pacific navigators peopled many remote islands

Figure 1-6

Early exploration of the oceans

Advancements of European navigatorsPhoenicians explored the Mediterranean Sea and beyond

Pytheas developed method to determine latitude

Eratosthenes calculated circumference of Earth

Ptolemy produced map that shows known land surrounded by largely unexplored oceans

Early exploration of the oceans

The Vikings explored the North Atlantic and established many colonies

Figure 1-7

Early exploration of the oceans

During the Age of Discovery, Columbus and Magellan make journeys of exploration

Figure 1-8

Early exploration of the oceans

Voyaging for science began with English navigator and explorer Captain James Cook

Mapped many unknown islandsDetermined outline of the Pacific OceanSampled ocean propertiesModified shipboard diet to eliminate scurvyUsed John Harrison’s chronometer to determine longitude

The scientific method

Figure 1-10

Origin of the Solar System and Earth

Cloud of gas and space dust (nebula) began to contract about 4.6 billion years ago

The Nebular HypothesisFigure 1-12

Origin of the Solar System and Earth

Protoplanets were created from the nebula

Protoearth was initially homogenous:Larger in size than today’s Earth

Had lots of volcanic activity

No continents or oceans

No life

Density stratification

Protoearth experiences density stratificationDensity = how heavy something is for its size

Density stratification causes high density material to sink while low density material rises

High density material = rock material and metals

Low density material = gases

Density stratification creates a layered Earth

Figure 1-13

Origin of the oceans

As a result of density stratification, water for the oceans is outgassed from inside Earth

Figure 1-14

Origin of the atmosphere

Density stratification caused Earth’s early atmosphere (water vapor and carbon dioxide) to be outgassed from inside Earth

The initial atmosphere was rich in hydrogen and helium

Earth’s present atmosphere is rich in nitrogen and oxygen

Photosynthesis releases oxygen to the atmosphere

Figure 1-16

Origin of life on Earth

Stanley Miller’s experiment simulating conditions of an early Earth showed that life probably began in the oceans

Figure 1-15

Major events in Earth’s development

Figure 1F

End of Chapter 1

Essentials of Oceanography

7th Edition