What is Oceanography?
Study of the oceans
Beach to the deep sea
Covers ~70% of the earth’s surface
Requires an understanding of the atmosphere to the core of the earth
Oceans hold 97% of the water on the earth
Oceanography
Interdisciplinary Science:
- Geology
- Geophysics
- Physics
- Chemistry
- Meteorology/climatology
- Biology
Oceanography
Relatively new science
- Know more about the surface of Mars than the seafloor
- The oceans are all interconnected and form a single continuous body of seawater
The Oceans
4 principal oceans plus 1
Pacific Ocean- largest, covers over one third of the earth’s surface
Deepest of the Oceans- average depth is 3940 m.
Atlantic Ocean- half the size of the Pacific
Indian Ocean- slightly smaller than the Atlantic
The Oceans
Arctic Ocean- 7% the size of the Pacific ocean, has a permanent layer of sea ice
Southern ocean- near Antarctica, is really portions of the Pacific, Atlantic and Indian Oceans below 50o south latitude
History of Oceanography
Peopling of the Pacific islands- How did they travel so far?
Pheonicians investigated the Mediterranean Sea, Red Sea and the Indian Ocean in 2000BC. They circumnavigated Africa in 590 BC
Vikings had excellent ships and colonized Iceland and discovered Greenland in 981.
History of Oceanography
Earliest voyages:
- Establish trade routes
- Chart (and claim) new lands
- Wealth
= voyages of discovery
History of Oceanography
Voyages of discovery:
Magellan (Portuguese, sailed for Spain)
searching for ocean trade route to the Orient
Circumnavigated the globe
1519-1522- Magellan killed in Philippines in 1521
- Sir Francis Drake (English)
- First captain to circumnavigate the globe
- 1577-1580
- West coast of US and Canada
- Treasures and trade
Cook’s Expeditions
~1770- several trips
- Claimed territory for Britain
- Mostly an explorer, but
- Scientific goals:
Charted the Pacific
Studied natural history and humankind
Search for southern continent
1st to circumnavigate at high latitudes (71° S, never saw Antarctica)
Search for northern passage
Depth soundings to 400m
Killed in Hawaii 1779
History of Oceanography
Maury (US Navy) 1840’s
- Compiled data on winds and currents
- The Physical Geography of the Seas
- Redesigned depth sounding techniques (baling twine)
- Mapped North Atlantic seafloor (mid Atlantic Ridge)
Charles Darwin and the HMS Beagle
1831 sailed on the Beagle to South America
Produced structure and distribution of coral reefs
His observations on the morphology of coral reefs in the Pacific resulted in the insightful theory of their geological development that remains the accepted explanation today
Scientific Expeditions
First expedition devoted to marine science
= HMS Challenger (1872-1874) led by Charles Wyville Thomson
Charge- explore the "conditions of the deep sea throughout all of the great ocean basin"
HMS Challenger Expedition
1872 - 1876
Highlights:
- 500 deep soundings (steel cable)
- deepest = Mariana Trench
(8 km)
4500 new species
Sediment distributions
Disproved idea that there was no life >500 m (no light/high pressure)
Temperature/salinity/currents
50 volumes of results
New Technology
WWII Innovations:
Echo sounders
Gravity measurements
Seismic studies
Magnetic studies
Largely funded by the Office of Naval Research
Modern Scientific Questions
Ocean circulation- climate
Ocean/atmosphere gas exchange
Biological and inorganic resources
Interactions between ocean cruse and seawater
Energy sources
Modern Techniques
Satellite data
Submersible (Alvin, Jason)
Deep sea drilling (Ocean Drilling Program
TOPEX/Poseidon
Glomar Challenger
Deep Sea Drilling Program
Alvin Deep Diving Submersible
Joides Resolution
Ocean Drilling Program