Transcript 103-06-HistoryOceanPart1

HISTORY OF OCEANOGRAPHY,
Part 1:
Contributions of the
Ancients to Early Ocean Science
GEOL 1033
Study Lesson 4 in the Study Guide
Outline
•
•
•
•
EARLY History (to ~500 A.D.)
DARK AGES (~5th to ~14th Centuries)
RENAISSANCE (~14th to 16th Centuries)
EARLY OCEAN SCIENCE
EARLY History (to ~500 A.D.)
• Polynesian ancestors
spread from SE Asia
or Indonesia to New
Guinea and the
Philippines by about
20,000 years ago.
(
)
• Mid-Pacific islands
have been colonized
from about 500 B.C.
(
)
• An explosive
dispersion led to
the settlement of
Hawaii about 450-600
A.D.
(
)
EARLY History (to ~500 A.D.)
• Phoenicians:
– Sailed Mediterranean Sea and eastern Atlantic, Indian,
and western Pacific oceans
– 2000 B.C. sailed to Great Britain for tin
– 600 B.C. circled Africa from the Red Sea to Mediterranean in
3 years - not repeated for 2000 y until Portuguese in 15th century
• by ~500 B.C. world considered "round" (spherical) by Greeks
• But, many people still considered the world flat
– Continents were surrounded by oceans
– Oceans were considered limitless
– One could sail too far or "fall off"!
EARLY History (to ~500 A.D.)
• by 400 B.C. tides were somewhat understood
• by 250 B.C., simple early maps of known world,
–
–
–
–
Especially of coastal areas
Contained directions (compass rose)
Some had a distance scale
No modern latitude or longitude
• Babylonians developed 360° concept for a circle
• Egyptians developed:
– Surveying & the necessary mathematics
– Why?
• Recovery from annual floods of the Nile River which enriched the valley soils.
• Improved navigation developed:
– By stars,
– By coastal features
– Pilot books were kept, e.g., James Clavel's "Shogun" novel
• Ptolemy 2nd century A.D. invented latitude & longitude
DARK AGES (~5th to ~14th Centuries)
• Much knowledge lost
• Theological opposition to science
• Irish monks sailed North Atlantic &
visited Iceland (NA?) before Vikings
• Vikings explored North Atlantic
& eastern NA:
– Climate was warmer until ~1 200 A.D.
– Settled Iceland & Greenland
– Lief Ericson explored:
•
•
•
•
Baffin Island
Labrador
Newfoundland ("Vineland")
Nova Scotia(???)
A postage stamp from the
~1200Grenadines
AD
of St. Vincent
Norsedepicting
boat
an early Viking
ocean-going vessel of the
type used by Leif Ericson
(Eriksson) and other
Norwegian sailors on trips to
Iceland, Greenland and North
America.
• Basque & Portuguese also visited North America
– Fished off New England & possibly Newfoundland coasts
DARK AGES (~5th to ~14th Centuries)
• Moslem Arabs sailed widely & traded with India & China
– Acquired magnetic compass from China
– Spread of Moslem power (Near East, North Africa, Spain)
• Crusades (end of 11th to end of 14th centuries)
– Religious wars also had an economic incentive
– A tremendous demand for spices by rising middle class Europe
– Christian Constantinople fell to Arabs in 1453
• Importance of better navigation for improved trade recognized
– Southern Europe acquired magnetic compass from Arabs
– By 1300's, Europeans were sailing and trading by sea widely
• Stimulation from Moslem interference:
–
–
–
–
Controlled land routes for European trade with Far East for ~500 years
Caused European search for southern and western sea routes to East Indies
Resulted in European rediscovery of the American continents
Possibilities for acquiring great wealth was a powerful incentive to fund
marine expeditions westward and exploration of the Americas
RENAISSANCE (~14th to 16th Centuries)
• By ~1500 A.D. many Europeans accepted that Earth was "round"
• Spain & Portugal:
– Became the major European maritime nations
– Led exploration & colonization
• "Age of Discovery" from late 1400's to early 1500's (~1490-1520)
–
–
–
–
Southern European navigators doubled size of their known world
1488 Diaz (Portugal) sailed to southern tip of Africa
1492 Columbus (for Spain) discovered Caribbean area, Bahamas, etc.
1492 Amerigo Vespucci also "discovered America"
• A German cartographer gave his name to the Americas on a map in 1507
– 1497 Vasco Da Gama sailed around southern tip of Africa & up east coast of
Africa in search of a route to India
– 1513 Balboa (Spain) discovers Pacific Oc. by crossing Isthmus of Panama
– 1504 Juan de la Cosa made first depth soundings (depth determinations) at sea
– 1518-1522 Magellan's (Portugal) expedition sailed completely around the
world, proved that Earth was "round," took many depth soundings,
discovered many islands in the Pacific, e. g., Phillipines.
Track of the Magellan Expedition (1519-22)
•
A diagram showing the track of the Magellan expedition, the first
voyage around the world. Magellan himself did not survive the voyage;
only 18 out of 270 sailors managed to return after three years of
voyaging.
RENAISSANCE (~14th to 16th Centuries)
• Mercator (late 1500's):
–
–
–
–
1569 map projection
All straight lines are along a true compass direction
Adopted latitudes & longitudes
1585 included oceanic depth soundings on his maps
• By ~1600:
– Major unknowns were the polar regions:
• Arctic Ocean
• Antarctic Ocean & Continent
– Known that ocean temperature cold below surface
– Known that oceans universally salty
– Henry Hudson's Search for the "Northwest Passage" to the Orient
• Discovered Hudson River (New York City)
• In Canada:
– Explored northeastern North America
– Hudson Bay & Hudson Strait named after him
EARLY OCEAN SCIENCE
• Because colonies were distant, Europeans recognized
further need for better charts & navigation in 1700's
• Motivations were:
–
–
–
–
–
Commerce
Political expansion
Military defense
Safety at sea
Travel, etc.
• Tides:
– Had been related to the phases of the Moon by ancients
– Ship captains & explorers accumulated information on local
• Tides
• Currents
• Water depths of shallow areas
EARLY OCEAN SCIENCE
• Instruments were available for determining latitude
• Chronometer improved in England by late 1700's for determining
longitude accurately (John Harrison's 4th marine time piece)
sextant
astrolabe
Chronometer
EARLY OCEAN SCIENCE - James Cook
•
•
•
•
•
•
•
•
1768 -1780 3 voyages to explore & map Pacific Ocean
1st explorer to make major use of instruments
Often considered the start of scientific oceanography
Used an accurate chronometer to determine longitude
Explored Australia, New Zealand, western N A
Mapped South Pacific, parts of west coast of N A
Rediscovered Hawaiian Islands
Predicted presence of Antarctic
Continent (because of icebergs!)
(Discovered in 1820 by a Russian)
• Ben Franklin urged American
Revolutionary forces to leave
his ship unharmed during the
Revolutionary War (1776-80)
EARLY OCEAN SCIENCE
• Currents charted on old maps for Mediterranean & Arabian seas
• Ben Franklin
–
–
–
–
–
U.S. Postmaster General
Discovered North Atlantic Gulf Stream Current
Used ship's logs of "ship's drift"
Map (1786) suggested faster routes across Atlantic
Improved intercontinental communication,
travel, & trade/commerce
• James Ross' during early 1800's
– First major deep-sea soundings
– Recognized deep-sea life
EARLY OCEAN SCIENCE - Wilkes Expedition to
the Antarctic (1838-1842)
• Wilkes Exploring Expedition (1838-1842)to Antarctica explored
and charted a large section of the east Antarctic coast and
made observations that confirmed this landmass as a continent.
The 19-volume report was a landmark in early American marine
science. (USS Vincennes in Disappointment Bay)
EARLY OCEAN SCIENCE - Ferrel & Maury
• Ferrel (USA) explained (1850) how winds cause surface currents
• Matthew Maury was a U.S. naval captain (major works = 1842-55)
– Made ship drift charts from captains' ship log books
– Charted ocean currents of the world
– His charts resulted in significant reductions in ship travel times during the
era of the fast sailing "clipper ships"
– Using ~800 available deepsea soundings, he published (1854) a bathymetric
map of North Atlantic ocean floor, but Mid-Atlantic Ridge not apparent.
EARLY OCEAN SCIENCE - Marine Biology
• Developed slowly in the pre-1872 era
• Microscopic marine life was being studied
• Edward Forbes
– Studied marine life
– Founded marine ecology
– But, like many people, thought no deep-sea life
• Voyage of the Beagle (late 1831-1836)
– Explored Atlantic, South American
Coasts, Eastern Pacific Ocean and islands
– Naturalist on board was Charles Darwin!
•
•
•
•
•
Copy of 1st geology textbook (Lyell)
Recognized sea-level changes
Developed modern reef atoll theory
Studied biological diversity everywhere
Studied species evolution on islands
EARLY OCEAN SCIENCE - Marine Biology
• 1871 Founding of MBL (Marine Biological Laboratory) at Woods
Hole, Mass.
• Later, WHOI & other marine institutions were also located there
• Marine biology changed with the voyage of HMS Challenger
(British) from December, 1872, to May, 1876.
END OF FILE
•
A diagram showing Eratosthenes' method for calculating the
circumference of the Earth.
He used simple geometric reasoning based
on the assumptions that the Earth is spherical and that the sun is
very far away. (The diagram is not drawn to scale.)
DEVELOPMENT OF MODERN OCEANOGRAPHY
•
A postage stamp from the former German Democratic Republic (East
Germany) depicting Alfred Wegener. Wegener, a German meteorologist,
explorer, and geologist, proposed the theory of continental drift in a
1912 lecture. His suggestion that all the Earth's land masses had
once been part of a single supercontinent, termed Pangaea, was widely
ridiculed at the time. Although Wegener's mechanism for drift -centrifugal forces created by the Earth's rotation -- proved
completely untenable, his writings did set the stage for more modern
investigations and the current general acceptance of sea-floor
spreading and continental drift.
Balboa (Spain) Discovers Pacific Ocean - 1513
•
A postage stamp from the Cook Islands depicting the Spanish
conquistador, Vasco Nunez de Balboa (1475-1517). Balboa, by marching
across the Isthmus of Panama, became the first western explorer to
sight the Pacific Ocean, which he claimed in the name of Spain in
1513. Balboa's discovery led to efforts, by Magellan and others, to
circumnavigate the Americas and sail westward to Asia.
Ferdinand Magellan
•
A postage stamp from Chile depicting the Portuguese navigator
Ferdinand Magellan and one of his vessels. Magellan left Seville in
August of 1519 with five ships and sailed across the Atlantic and
Pacific Oceans as far as the Philippines (where he was killed in
1521). One of his ships managed to return to Spain in 1522 with only
18 of the original 270 crew for 5 ships, completing the first
navigation of the globe; this demonstrated finally that the world was
round and that the 'New World' was separate and far removed from the
East Indies.
Christopher Columbus'3 ships on 1st voyage
•
•
A postage stamps from the Bahamas & Nicaragua
showing a portrait of Christopher Columbus and
the three sailing vessels (the Nina, Pinta, and
Santa Maria) used on his first voyage of
discovery to the "New World" in 1492. It took
considerable courage to embark on an oceanic
voyage in these remarkably small vessels.
Below, a reproduction of the Santa Maria. The
people on board give a sense of scale emphasizing
the remarkably small size of such vessels of
exploration.