GEO/OC 103Exploring the Deep ….
Today’s Tune“Pirates of the Caribbean”
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Melinda JensenGeosciences Departmental
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“Water World”“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.
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 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 byImprovements in navigation and mapping
Accumulation of data for chartsTemperature, currents
In the United States, Benjamin Franklin (1769-1770) published the first chart of the Gulf Stream
Historical Reviewof Oceanography
(Cont.)
In Britain, James Cook (1768-1779)Constructed charts of coastlines especially for the South Pacific
Secondary discovery the Hawaiian Islands
Historical Reviewof Oceanography
(Cont.)
Historical Reviewof 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 coastlineDeveloped 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
Historical Reviewof 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 Reviewof Oceanography
(Cont.)
C. Wyville Thompson: British explorer Directed the Challenger Expedition (1872-1876)First major scientific expeditionGlobe-encircling voyageChemical, physical, and biological measurements and collections
Disproved Edward Forbes “azoic theory” by collecting sea life from waters as deep as 9000 m
Historical Reviewof Oceanography
(Cont.)
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.
Marine Geophysics
Study of rock structure in the ocean basin, properties of rocks such as magnetism, occurrence of earthquakes.
Dec 26, 20049.0 Eq, Sumatra275,950 killed
Image courtesy of BBC
March 28, 2005 8.7 Eq, Sumatra
290 killed
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 EngineeringDesign and
installation of
oceanographic instrumentati
on and vehicles
Today ocean research is conducted by Today ocean research is conducted by investigators in specialized marine investigators in specialized marine institutions, as well as universities, and state institutions, as well as universities, and state and federal agenciesand federal agencies
The emphasis is on interdisciplinary, The emphasis is on interdisciplinary, process-oriented research and international process-oriented research and international cooperationcooperation
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
Current and Future Oceanographic Research
greater focus on internationalinternational efforts and large scale interdisciplinary expeditions Many scientists Many ships
“remote sensing” “unmanned” platforms
New Technology for Probing the Sea
TOPEX/Poseidon satellite launched in 1992.
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