What is Oceanography?

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Melinda Peterson

Geosciences Departmental Office

104 Wilkinson Hall petersom@geo.oregonstate.edu

737-1238

“Earth is a unique planet, possibly one of the few in the galaxy that has water.

Nearly 71% of it’s surface is ocean.

From space, Earth is brilliantly blue, white in places with clouds and ice, sometimes swirling with storms.

“Water World”

At it’s surface the ocean is in constant motion with powerful currents that stretch for thousands of miles and towering waves.

Beneath the ocean’s surface lie hidden mountain ranges, vast trenches tens of thousands of feet deep, immense hot springs, and huge volcanoes spewing molten rock in massive eruptions.”

-- T. Garrison

Chapter 1

“Just the Facts…”

 Over 97% of the water on the Earth is in the ocean.

 The average depth of the ocean is about

4000 meters .

 The Mariana Trench is 11,022 m deep, the deepest spot on the planet.

– 8 tons per sq. in.

– Mt. Everest is “only” ~8667 m above sea level

“Just the Facts…”

 Mauna Kea on the Big Island of Hawaii, measures ~10,600 m from the ocean floor, making it the tallest mountain on the planet (surpassing even Mt. Everest).

If the Earth’s contours were leveled to a smooth ball, the ocean would cover it to a depth of 2686 m.

“Just the Facts…”

 The ocean contains some 5 trillion tons of salts

– If dried and spread evenly, that mass would cover the entire planet to a depth of 45 m.

 On a planetary scale the ocean is insignificant.

– Its average depth is a tiny fraction of the

Earth’s radius.

– The blue ink representing the ocean on a paper globe is proportionally thicker .

Why Study the Ocean?

 Major influence on weather and climate

 Source of food, energy, medical drugs

 Transportation

 Military significance

 Recreational resource

 Major influence on the health of the planet

 Culture and history

Historical Review of Oceanography

 Roots traced to ocean exploration .

 Describing the oceans

Historical Review of Oceanography

 The 18th century was marked by

– Improvements in navigation and mapping

– Accumulation of data for charts

 Temperature, currents

Historical Review of Oceanography

(Cont.)

 In the United States, Benjamin Franklin

(1769-1770) published the first chart of the Gulf Stream

Historical Review of Oceanography

(Cont.)

 In Britain, James Cook (1768-1779)

– Constructed charts of coastlines especially for the South Pacific

– Secondary discovery the Hawaiian

Islands

Historical Review of Oceanography

(Cont.)

 In the 19th century curiosity about the oceans increased and voyages for scientific purposes were initiated

 Charles Darwin : British naturalist

– Voyage of the Beagle (1831-1836), studied geology and biology of the South American coastline

 Developed theory of organic evolution based on natural selection

 Published On the Origin of the Species

(1859)

$1200!

The Voyage of the HMS

Beagle

Charles Darwin

Route of the HMS Beagle

Historical Review of Oceanography

(Cont.)

 Edward Forbes : British naturalist (1815-

1854)

– Proposed the hypothesis that no life (azoic) existed in the oceans below 550 m

Historical Review of Oceanography

(Cont.)

 Matthew Fontaine Maury : U.S. naval officer

– Compiled information on winds and currents

– Published The Physical Geography of the

Sea (1855)

– “Father of physical oceanography”

Historical Review of Oceanography

(Cont.)

 C. Wyville Thompson: British explorer

– Directed the Challenger Expedition (1872-1876)

 First major scientific expedition

 Globe-encircling voyage

 Chemical, physical, and biological measurements and collections

Disproved Edward Forbes “azoic theory” by collecting sea life from waters as deep as 9000 m

The

Challenger

Expedition

Modern Oceanography

 Major interdisciplinary expeditions e.g., the Meteor

Expedition: German (1925-1927)

– Bottom topography

– Vertical profiles of salinity, temperature, oxygen

 Subsequent growth, World War II, urgent need for information on the physical structure of the oceans

What is Oceanography Today?

Geological Oceanography

(Marine Geology)

Study of rocks and sediments & processes responsible for their formation.

Marine Geophysics

Study of rock structure in the ocean basin, properties of rocks such as magnetism, occurrence of earthquakes.

Image courtesy of BBC

Dec 26, 2004

9.0 Eq, Sumatra

275,950 killed

290 killed

March 28, 2005

8.7 Eq, Sumatra

Image courtesy of USGS

Physical Oceanography

How and why ocean currents flow, air-sea interactions such as the generation of waves by the wind.

Chemical Oceanography

Composition of sea water and the processes controlling and altering its composition, including marine pollution .

Biological Oceanography

(Marine Biology)

Organisms that live in the oceans and their relationships to the environment.

Ocean Engineering

Design and installation of oceanographic instrumentation and vehicles

Modern Oceanography

(Cont.)

Today ocean research is conducted by investigators in specialized marine institutions , as well as universities, and state and federal agencies

The emphasis is on interdisciplinary, process -oriented research and international cooperation

1903 www.sio.ucsd.edu

1930 www.whoi.edu

1949 www.ldeo.columbia.edu

Scripps Institution of Oceanography

UC-San Diego

Woods Hole Oceanographic Institution

Woods Hole, MA

Current and Future

Oceanographic Research

 greater focus on international efforts and large scale interdisciplinary expeditions

– Many scientists

– Many ships

“remote sensing”

“unmanned” platforms

New Technology for Probing the Sea

Seasat-A, the first oceanographic satellite, was launched in 1978.

TOPEX/Poseidon satellite launched in 1992.

Summary:

What is Oceanography?

 Broad science focused on the oceans

– Geology/geophysics, chemistry, physics, biology, engineering

 Highly interdisciplinary

 Also highly collaborative

We are still exploring (!) but …

 Feeds also into ocean policy, management, and conservation

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