Oceanography Chapter 1

Eratosthenes

Greek, lived 276-194 BCE. Determined Earth's circumference within 0.08% accuracy. Invented geography. Used Library of Alexandria extensively for research

Mixotrophs

Have autotrophic and heterotrophic qualities

James Cook

1728-1779; Undertook 3 voyages of discovery, partly to help British maintain maritime superiority. Killed in 'skirmish' with Hawaiians for attempting to kill tribal king over stolen life boats

Matthew F. Maury

1847: Created first wind and current charts of North Atlantic. 1855: Documented the geography of the sea. Considered the first oceanographer. Fought for the Confederacy and invented mines that killed many northerners.

Challenger Expedition

1872-1876; first true oceanographic expedition. Birth of modern oceanography

Earliest form of life on Earth?

3.8 billion year old rock with potential fossil stromatolites (microbial reefs)

First boats

About 40,000 years ago

Hawaii

Colonized between 450 and 600 CE

Charles Darwin

British, 1809-1882. Student at Cambridge; wanted to be minister in the Church of England. Unpaid naturalist on the HMS Beagle 1831-1836. Accurately described coral attol formation. Many other papers including ones on barnacles, volcanic islands, fossils, earthworms. Published On the Origin of Species in 1859, after deliberating over publication for years

Mantle

Chemical layer. thicker (2800 km). Higher density minerals (Fe & Mg)

Core

Chemical layer. thickest (3500 km - center). highest density minerals (Fe & Ni)

Crust

Chemical layer. thin (40-60 km). Low density minerals (silicates, Fe, Si)

Benjamin Franklin

Created first chart of gulf stream in 1769

John Harrison

Discovered a way to determine longitude at sea about 2000 years after latitude was determined

Great Oxidation Event

Evolution caused cyanobacteria to photosynthesize, and thus oxygen to be released into the atmosphere. Oxygen was toxic to other life forms on Earth at the time, so this caused a mass extinction.

Phoenecians

First explored Mediterranean Sea, Red Sea, Indian Ocean (near land) in 2000 BCE

Pacific Islands

First explored/colonized by asians

Heterotrophs

Get organic carbon through feeding on others

Pytheas

Invented a way to measure latitude while at sea in 325 BCE

Pacific Ocean

Largest ocean: covers 1/3 of Earth's surface. Can easily fit all of the continents in it. Deepest ocean: mean depth is 3940 m. Contains deepest point in all oceans: Mariana Trench 11,022 m deep.

Indian Ocean

Mainly located in southern hemisphere. Mean depth: 3840 m. Jason spent 2 months here during December and January last year.

Autotrophs

Make organic carbon for respiration by themselves

Southern Ocean

Meeting of currents called Antarctic Convergence. Really a part of Pacific, Atlantic and Indian Oceans south of 50 degrees latitude. Has unique chemistry, biogeography, which justifies its naming.

Cook's contributions to the scientific knowledge of oceans

Outline of the Pacific Ocean. First systematic measurement of subsurface water temperatures, winds currents and surroundings (depth measurements). Used John Harrison's chronometer to measure longitude. First accurate maps of Earth's surface. Discovered superkraut prevents scurvy.

Lithosphere

Physical layer. Cool, rigid, brittle. Crust, uppermost mantle

Asthenosphere

Physical layer. Warm, plastic (will flow). Uppermost mantle

Polynesia

Remote islands occupied as early as 1100 BCE

Atlantic Ocean

Second largest ocean, 1/2 size of Pacific. Mean depth: 3844 m

Arctic Ocean

Small. 7% of the size of the Pacific ocean. Shallow. 1/4 as deep as other oceans. 1117 m deep. Has a permanent layer of ice

Why do plate tectonics occur?

The lithosphere literally floats on top of the mantle

Isostatic Rebound

The upward movement of crust due to reduced loading. Ex) when ice melts, crust rises due to less weight

Polynesian Navigators

Used movement of stars, seasonal winds, to navigate. Followed flights of birds. Noticed changes in water when close to islands.

Radiometric Dating

Uses decay rate of radioactive elements to daughter elements to determine the age of an object.

Don Walsh & Jacques Piccard

Visited the Mariana Trench in 1960 in submarine known as Trieste (US Navy)

James Cameron

Visited the Mariana Trench in submarine called Deepsea Challenger. Challenger donated to Woods Hole Oceanographic Institute

How were the oceans formed?

Volcanoes outgassed steam (water vapor). Water from comets bombarded the Earth early in its history

Hydrostatic Equilibrium

Where the weight of the columns of rock, at some depth of compensation, is everywhere equal. When plate tectonics are not moving

Isostasy

interplay between buoyancy and gravity. Explains plate tectonics

Outer core

liqiud

Inner core

rigid (due to high pressure)

Mesosphere

rigid (due to high pressure). middle + lower mantle