Chapter 2

History of Ocean

Exploration

Key Ideas

Earliest direct evidence for voyaging was from the Mediterranean. There may well have been intentional or unintentional ocean travel previous to that time.

The origins of marine science lie in voyaging – traveling on the ocean for a purpose, which varied form one culture and time to another. Technological advances made during voyaging and later marine exploration led to the rise of scientific oceanography.

Earth’s shape and circumference were accurately estimated around 230 B.C. at the Library of Alexandria, Egypt. The use of latitude and longitude for positioning and navigation also began there.

Polynesian adventurers were the first to perfect methods of sustained, long-distance, open-ocean travel. Possibly as early as 900 BCE, but surely by 300 AD

The first systematic voyages of oceanic exploration were undertaken by the Chinese in the fifteenth century.

Key Ideas Continued…

Christopher Columbus did not discover North America, and he did not sail

around the world.

Captain James Cook, Royal Navy, was perhaps the first ocean observer careful enough to be considered a marine scientist.

The Challenger expedition was the first purely scientific voyage of oceanic exploration.

Polar Studies greatly advanced marine science at the beginning of the

twentieth century.

Nearly all research is conducted not by individuals but by teams of specialists working in large, nationally funded oceanographic or military institutions.

Satellites are increasingly important tools of oceanographic research.

Understanding the Ocean Began with

Voyaging for Trade and Exploration

Our word ocean is derived from oceanus, a Latin root of the word okeanos originally named by the early Greek seafarers. Thought to be an immense river.

Voyaging on water was important to many early civilizations. The Egyptians, Cretans, and Phoenicians were all skilled sailors.

Cartographers, or chart makers, recorded information about locations and landmarks and currents. Today, charts are detailed graphic representations of water and water-related information.

The Library at Alexandria, in Egypt, was founded in the third century B.C. This

library stored information on every area of human endeavor. . http://en.wikipedia.org/wiki/Library_of_Alexandria

Eratosthenes of Cyrene was the second librarian at Alexandria. He was the first to calculate the circumference of Earth. He also invented a system of longitude and latitude.

The principles of celestial navigation were invented at the Library at Alexandria.

Eratosthenes Accurately Calculated the Size

and Shape of Earth

A diagram showing Eratosthenes’s technique for calculating the circumference of Earth.

As described in the text, he used simple geometric reasoning based on the assumptions that Earth is spherical and that the sun is very far away. Using this method, he was able to discover the circumference of

Earth to within about 8% of its true value.

Latitude and Longitude

Diagrams showing the calculation of lines of latitude and longitude.

Latitude is calculated by

measuring the angle

between the north Star,

Polaris and the horizon.

Longitude is more

difficult to measure.

John Harrison’s clock.

He won ₤20,000 in 1728 for solving this technologic problem. Earlier clocks

used pendulums. How does knowing an accurate calculation of the time help

you figure out where you are? The Earth rotates 360° every 24 hours. Hint:

What time is it in New York City? How far (in °) is it to NYC?

A third century B.C. chart showing the system of latitude and longitude developed by Eratosthenes.

Oceania Seafarers Colonized

Distant Islands(Right) The Polynesian triangle.

Ancestors of the Polynesians spread from Southeast Asia or Indonesia to New Guinea and the Philippines by about 20,000 years ago. The mid-Pacific islands have been colonized for about 2,500 years, but the explosive dispersion that led to the settlement of Hawaii occurred about A.D. 450-600.

The Polynesian colonization's are an example of knowledge of oceans and marine science used to colonize a vast number of islands.

Polynesian Navigation

http://www.imachination.net/next100/brainstorm/polynesia.html

The Vikings

The Chinese Undertook Organized Voyages of Discovery

Chinese navigators set out in the early 1400s to explore the Indian Ocean,Indonesia, Africa and the Atlantic. Their ships were laden with giftsdesigned to show China’s wealth and degree of civilization! The Chineseinvented:

The central rudder

Water-tight compartments

Sails on multiple masts

marine compass

The Age of Discovery

Europeans explored the world by sea during the Renaissance.

Henry the Navigator – Explorers under his patronage compiled detailed charts and explored the west coast of Africa.

Christopher Columbus – Although he never saw the mainland of North America, his stories inspired other explorers to follow.

Ferdinand Magellan – Although Magellan died en route, the small surviving portion of his crew circumnavigated the globe.

European Age of Discovery

Voyaging Combined with Science to

Advance Ocean Studies

James Cook, a commander in the British Royal Navy, is credited

with leading voyages that greatly contributed to scientific

oceanography. Some of the accomplishments of James Cook and his

scientists include:

– Verification of calculations of planetary orbits

– Charting of New Zealand and the Great Barrier Reef, Tonga and Easter Islands

– Initiation of friendly relations with many native populations

– Sampling marine life, land plants and animals

– Recording data concerning the ocean floor and geological formations

Cook’s 3 Voyages

Benjamin Franklin and the Gulf Stream

Voyaging Combined with Science

• The United States Exploring Expeditionlaunched in 1838 was a naval and scientific expedition.

• The HMS Beagle, on which Charles Darwin served as a naturalist, voyaged to South America and some Pacific Islands.

“In the light of the fate of Stokes and the suicide of his own uncle, FitzRoy was concerned about the lonely position of a captain at that time. His attempts to get a friend to accompany him fell through, and he asked his friend and superior, Captain Francis Beaufort, to seek a gentleman passenger who would act as a companion as well as having opportunities as a naturalist. This led to Charles Darwin joining the voyage.”

http://en.wikipedia.org/wiki/HMS_Beagle

The British Challenger expedition of 1872-1876 was the first oceanic expedition dedicated to

scientific research.

Advances in oceanic exploration in the twentieth century?

– Polar Exploration – explorers reached both the North and South poles in the twentieth century. Scandinavians very important in early oceanography and meteorlogy.

– The Meteor Expedition – the first expedition to use modern optical and electronic equipment for oceanographic investigation

– The Atlantis – investigations by scientists on this research vessel confirmed the presence of the Mid-Atlantic Ridge.

– The Trieste – a blimp-like bathyscape which descended into the Challenger Deep area of the Mariana Trench

– Glomar Challenger – ocean floor samples (mud and rock) obtained by scientists on this drilling ship provided confirming evidence for seafloor spreading and plate tectonics.

New Ships for New Tasks

Ocean drilling (sediment and rock), water sampling (Temperature, Salinity, chemistry, etc), Echo sounders, side scan radar, submersibles, Remotely Operated Vehicles (ROVs) and now satellites in space (TOPEX, SeaWifs etc)

Oceanographic Institutions Arose to

Oversee Complex Research Projects

Three of the most prominent oceanographic institutions in the United States:

– Woods Hole Oceanographic Institution

– Scripps Institution of Oceanography

– Lamont-Doherty Earth Observatory of Columbia University