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