GEO/OC 103Exploring the Deep ….

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Melinda JensenGeosciences Departmental

Office104 Wilkinson Hall

melinda.jensen@oregonstate.edu

737-1238

“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 land surface was 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.

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 Reviewof Oceanography

Roots traced to ocean exploration.

Describing the oceans

Historical Reviewof Oceanography

The 18th century was marked by–Improvements in navigation and mapping

–Accumulation of data for charts

Temperature, currents

In the United States, Benjamin Franklin (1769-1770) published the first chart of the Gulf Stream

In Britain, James Cook (1768-1779)–Constructed charts of coastlines especially for the South Pacific

–Secondary discovery the Hawaiian Islands

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

Edward Forbes: British naturalist (1815-1854)– Proposed the hypothesis that no life (azoic) existed in the oceans below 550 m

– “Deserts in the ocean”

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”

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 Challeng

er Expediti

on

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.

Study of rock structure within an ocean basin,

properties of rocks such as magnetism, occurrence of

earthquakes.

Geological Oceanography

(Marine Geophysics)

Dec 26, 20049.0 Eq, Sumatra275,950 killed

Image courtesy of BBC

September 29, 20096:48 a.m. local time, M8.19 deaths in Tonga, 149 in Samoa, 39 in

American SamoaDeadliest in history, $150 million damage

September 29, 20096:48 a.m. local time, M8.19 deaths in Tonga, 149 in Samoa, 39 in

American SamoaDeadliest in history, $150 million damage

Sandwell & Smith Estimated Bathymetry, v. 12.1, ve = 6

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, Marine

Ecology)

Organisms that live in the oceans and their relationships

to the environment.

Ocean Engineering

Design and installation

of oceanographic instrumentati

on and vehicles

Research at Research at specialized marine specialized marine institutionsinstitutions, as well as , as well as universities, and state and universities, and state and federal agenciesfederal agencies

Emphasis on interdisciplinary, Emphasis on interdisciplinary, processprocess-oriented research and -oriented research and international cooperationinternational cooperation

Modern Oceanography (Cont.)

19031903www.sio.ucsd.eduwww.sio.ucsd.edu

19301930www.whoi.eduwww.whoi.edu

19491949www.ldeo.columbia.eduwww.ldeo.columbia.edu

Woods Hole Oceanographic InstitutionWoods Hole, MA

Scripps Institution of OceanographyUC-San Diego

Technologies for Probing the Sea

Current and Future Oceanographic Research

greater focus on internationalinternational efforts and large scale interdisciplinary expeditions– Many scientists– Many ships

“remote sensing” “unmanned” platforms

National Polar-orbiting Operational Environment Satellite System (NPOESS), a next-generation platform for weather and climate.

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

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