Marine Science test 1

Paleolithic period

Barbed spears/harpoons

Gorge

Neolithic Period

Bone fishhook

net

1st phase (15,000-1000B.C) Polynesians

Micronesia, Melanesia

2nd Phase(15,000-1000 A.D) Polynesians

Fiji, Tunga, Samoa

3rd Phase(A.D 900-1200) Polynesians

Eastern Polynesia (Hawaii, New Zealand, Rapanui

Phoenicians (1200-146 B.C)

Early explorer’s and traders in Mediterranean sea.

Traveled to Europe and Africa

Norse/Vikings (739-1066 B.C)

Shipbuilding and chart-making.

Crossed the North Atlantic ocean, engaged in exploration, trade and colonization.

Zheng He (china) 1371-1433

7 epic voyages 1405-1433 in Western Pacific

One across the Indian Ocean

Fleet >300 ships, up to 130m in length

Prince henry (Portugal) 1394-1460

Most responsible for the great age of European discovery

Sent expeditions along the west coast of Africa to secure trade and colonies

Ferdinand Magellan (Spain) 1480-1521

Exceptional navigator

Discovered Strait of Magellan

One of his ships was first to circumnavigate the Earth – measured circumference of the Earth

Established the length of a degree of latitude.

John Harrison’s Chronometer, 1693 A.D. to 1776 A.D.

First chronometer that kept accurate time at sea

James Cook (UK), 1728 A.D. to 1779 A.D.

Used Harrison’s chronometer to calculate precise longitude at sea

Charted the ocean

Made soundings of depths up to 400m

one of the founders of oceanography

Franklin-Folger Chart, 1769 A.D.

Charted the Gulf Stream current

Encouraged sailing within the current en route to Europe for faster travel

Sir Edward Forbes, 1815 A.D. to 1854 A.D.

Systematic surveys

Co-published “Map of the Distribution of Marine Life” with Alexander Johnston

Azoic Zone (550m+) Hypothesis

Charles Darwin, 1809 A.D. to 1882 A.D.

HMS Beagle naturalist – described, collected and classified organisms from land and sea

Catalyst for theory of evolution by natural selection

Hydrographic surveys • Theory of atoll formation

The Challenger Expedition, 1872 A.D. to 1876 A.D

Comprehensive oceanographic expedition

Deepest sounding taken at 8180m, now known as the Challenger Deep in the Marianas Trench

Oceanography as a modern science is typically dated from the Challenger

Technological advances – 1900 A.D. +

Wind-driven to steam-engine; manual pulling systems to steam winches

During WWII

1. Recording what you see

2. Getting and staying there

3. Visualizing from a distance

How can radiometric dating can be used to determine the age of objects

By measuring the ratio of unstable radioactive "parent" atoms to stable "daughter" atoms produced by radioactive decay.

Half life

Time for ½ of an initial quantity of a radioactive isotope to decay

Geological time

Scale used by scientists based on the history and formation of the Earth

Eon, Era, Period, Epoch

Ecological time

Times scales experienced by living organisms based on natural time periods and cycles

Seconds to Millennia

Earth bulges at

Equator

Earth is nearly

Spherical

Earth

Relatively smooth

Topographic relief is minor compared to size of the planet

Planet’s Equatorial radius ~6,378,000m

Latitude/parallels

Parallel lines/planes perpendicular to axis of Earth

One great circle at equator

Circles of latitude get

smaller closer to the poles

Reference line for latitude

The equator

Latitude degrees

• 0° = Equator

• 90° N = North Pole

90° S = South Pole

• 23½° N and S = Tropic of Cancer and Capricorn, resp.

• 66½° N and S = Arctic and Antarctic Circle, resp.

Measuring latitude

Latitude = angle of elevation above the horizon of a point directly over the pole

• North Star (Polaris) • Southern Cross & Southern Pointers

sextant

an instrument with a graduated arc of 60° and a sighting mechanism, used for measuring the angular distances between objects and especially for taking altitudes in navigation and surveying.

Longitide/meridians

Lines formed at right angles to lines of latitude

• Planes east and west of an arbitrary 0° point • 0°= prime meridian, Royal Naval Obs, Greenwich, England

•

180° = international date line

• Meridians all converge at the poles

Measuring longitude

Need to know time of day and position of sun or stars relative to a longitudinal line

• Set clock to noon when sun is at zenith above reference

• Take clock to new location

• Note time when sun is at zenith at new location

• Earth rotates east at 15° per hour

Reference longitude

Prime meridian

Greenwich Mean Time /Universal Time

Clock set to noon sun’s zenith is above prime meridian

Global Positioning System

A satellite-based navigation network owned by the U.S. Government and operated by the United States Space Force that provides precise location and time data anywhere on Earth

North and East

(+)

South and West

(-)

How much of the surface is covered in water?

71%

Total water volume

1.39 x 109 km3

1 km3 = 1.0 x 1012 L

Arctic ocean

14,100,000 km2

Average depth: ~1,205 m

Max depth: ~5,449 m

Mostly ice-covered

Least studied ocean

Indian ocean

73,440,000 km2

Avg depth: ~3,893 m

Max depth: ~7,460 m

Complete enclosure on northern side causes drastic seasonal changes (Monsoons)

Southern ocean

21,960,000 km2

Avg depth: ~3,270 m

Max depth: ~7,432 m

Continuous water connection around Antarctica Shares major boundaries with other oceans**

Noted for severe storm waves High levels of primary productivity

Pacific ocean

165,250,000 km2

Avg depth: ~4,280 m

Max depth: 11,034 m (Mariana Trench)

Relatively small river inputs Most islands, surrounded by volcanic activity

Atlantic ocean

82,440,000 km2

Avg depth: ~3,926 m

Max depth: ~8,380 m

Significant river inputs

Atlantic surface area = 1.6 x land area drained Being enlarged by midAtlantic ridge system

Distribution of water: Surface Area & Depth

Hypsographic curve

Hydraulic cycle

Movement of water among reservoirs

Oceans and sea ice

97.26%

Ice caps and Glaciers

2.11%

Groundwater

0.60%

Freshwater lakes

0.009%

Saline lakes and inland seas

0.008%

Soil moisture

0.005%

Atmosphere

0.0009%

Rivers

0.0001%

Evaporation

80% from oceans

20% from terrestrial sources

Residence time (RT)

Average time a water molecule spends in a given reservoir

RT=Total volume of water in reservoir divided by rate at which water is replaced.

Larger reservoir=

longer residence time

smaller reservoir=

shorter residence time

Crust to the core

Pressure, density and temp increase as you move inward.

Earthquake waves reveal Earth’s structure

Seismic waves

• Generated by earthquakes, volcanic eruption, human made explosions

• Energy released, in the form of vibrations

• Speed depends on chemistry, density and physical state (solid, partially molten, molten)

Body waves

P waves

Compressional

First to arrive

Move through Solid, Liquid, Gas

Surface waves

S waves

Shear

Second to arrive

Travel through Solids

P wave shadow zone

104-140

S wave shadow zone

104-180

Crust depth range

Continental- 0-50km

oceanic- 0-10km

Mantle depth range

2890km

Core depth range

2890-6371km

Crust layer thickness

continental- 40km

oceanic- 7km

Mantle layer thicknes

2866km

core layer thickness

3481km

Crust composition

Continental- Silicates rich in sodium, potassium and aluminum.

Oceanic- Silicates rich in calcium, magnesium and iron.

Mantle composition

Magnesium-iron silicates

Core composition

Iron, nickel

Crust density

Continental- 2.7g/cm cubed

Oceanic- 2.9 g/cm cubed

Mantle density

3.2-5.6g/cm cubed

Core density

9.9-13.1g/cm cubed

Crust temp

Continental- 0-1000 celcius

Oceanic 0-1100 celcius

Mantle temp

1100-3200 c

Core temp

3200-5500c

Atmosphere

gas

Hydrosphere

Liquid

Lithosphere

solid

Depth range- 0-100km oceanic, 0-150 continental

Solid, ridged behavior

Asthenosphere

Soft plastic

Depth-base of lithosphere-350km

Layer thickness- 200 min

Solid cuctile behavior

Mesosphere

Stiff plastic

Depth- 350-2890km

Layer thickness- 2540km

solid, mobile

Outer core

Liquid

Depth- 2890-5150

layer thickness- 2260km

Inner core

Solid

Depth- 5150-6371km

layer thickness- 1221km

Lithosphere

crust and uppermost mantle, fused together

Asthenosphere

denser region just below lithosphere, “plastic”

Mesosphere

solid portion of mantle just below asthenosphere

Isostasy

Buoyant support of lithosphere on top of the “plastic”, deformable asthenosphere – adjusts to maintain equilibrium

Alfred Wegener (1880-1930)

Continental drift

evidence for continental drift

Jigsaw-puzzle continents

Mountain belts line up

Fossil evidence

Climatic evidence

Supercontinent

Pangea

broke up 200-250 mill years ago

Ponthalassa

Single world ocean

No mechanism to explain continental movement

Not accepted by the scientific community

Sea floor survey(1950’s)

Mid-ocean ridge and rise systems

• Rift valley

• Trenches

Physiographic mapping

Revealed mountain ranges throughout the ocean basins

– 2-3 km taller than surrounding ocean floor

– 1000-3000 km wide

– 65,000 km long

Mid-ocean ridge and rise systems

vast underwater mountain chains

Trenches

Narrow and steepsided

– 6,000- 11,000m deep

– Usually seaward of ocean volcano chains and along the edges of continents

Henry hess (1906-1969)

Deep within mantle, large circulation of low-density molten materia

Rising hot mantle caused crust to elevate, forming mid-ocean ridge

Eruption of magma cools and hardens on sea floor

Seafloor diverges at ridge