Earth Science Oceanography “Water World”

Oceanography  “The application of science to the study of phenomena in the oceans”.  Oceanography is a broad Science

4 Disciplines  Geological Oceanography –Structure of the sea floor  Chemical Oceanography –Chemical composition and properties of seawater  Physical Oceanography –Waves, tides, currents  Biological Oceanography –Oceanic life forms

Why Study Oceanography?  Oceans comprise 71% of the Earth’s surface  Oceans contain 97.2% of the water on or near the Earth’s surface  Source of Food  Transportation and Travel  Weather  Shoreline –Interface between land and ocean

CLIMATE

WEATHER

Shoreline – Waves Baby

Food & Marine Life

The 5 Oceans  Pacific Ocean –Largest and deepest ocean –Mariana Trench: 11 km., 36,000 ft.  (Mt. Everest 29,000 ft.)  Atlantic Ocean –About ½ the size of the Pacific  Indian Ocean –Southern hemisphere  Arctic Ocean –¼ as deep, much smaller, sea ice  Southern Ocean –South of 50 deg. South latitude

“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.

Historical Review of Oceanography  Roots traced to ocean exploration.  Describing the oceans

Herodotus (ca 450 BCE) Where is …. ?

Historical Review of 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 ( ) published the first chart of the Gulf Stream Historical Review of Oceanography (Cont.)

 In Britain, James Cook ( ) –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 ( ), 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)

The Voyage of the HMS Beagle Charles Darwin Route of the HMS Beagle

 C. Wyville Thompson: British explorer –Directed the Challenger Expedition ( )  First major scientific expedition  Globe-encircling voyage  Chemical, physical, and biological measurements and collections Historical Review of Oceanography (Cont.)

The Challenger Expedition

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.

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

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