Midterm 1 Flashcards
The oceans covers
71% of the earths surface
The average depth of the oceans is
3800m
The deepest depth of the oceans is, and was visited by who?
10,994 meters. By two men in 1960 and by James Cameron in 2012
What percentage of all the Living volume of life is in the oceans
more then 90%
light only penetrates to
100m water depth
bio luminescence is
the most common evolutionary trait of life!
What percentage of all goods are transported across the ocean at some point
90%
Oceanography is divided into sub categories
Geological, Chemical, Physical, Biological
Geological
- Structure of the ocean basins
* Sedimentary processes
* Interpretation of the sediment record
Chemical
- Composition of seawater
* Biogeochemical cycles
* Effects of pollutants
Physical
- Motion of the water
* Ocean circulation
* Ocean mixing
Biological
- Ecology of marine organisms
* Fisheries oceanography, sustainability
* Similar to marine biology, however more focus on ecological aspects
Oceanus
Titan son of Gaia, His realm was the Boundary between the living and the dead
Aristotle
- The first marine scientist.
- Meterologica a number of explanations for how the oceans were formed and why they were salty
- Attempted to explain ocean tides
Polynesian voyagers
First true ocean explorers
* Highly skilled navigators using the sun and stars, there patterns on the surface waves, the flight paths of migratory birds, and even the smell of the water
* Originated in the Philippines
* Travelled to New Guinea 30,000 years ago
* Travelled to Hawaii 1500 years ago
Greeks
- By 900-700BC the ancient greeks ventured as far west as at the strait of Gibraltar (750m)
The Principles of Navigation
- Some idea of scale
* Some idea of location
Eratosthenes of Cyrene
- Accurately calculated the Earths circumference
- Also discovered the Earths tilt within a degree, that there are 365 and 1/4 days in the year, and proposed the addition of leap years
Circumference of the earth
Summer solstice Knew the sun was directly overhead in Aswan, Egypt and was 7* off Alexandria. Knew actual distance. = 25,252 miles
Autumn Equinox
Sun is directly over the equator (0*)
Its rays hit all of the earth equally from pole to pole
Winter Solstice
Three months later (one/quarter a year) later
Sun is directly above the Tropic of Capricorn (23.5S)
The Sun no longer rises in the Arctic Circle (above 66.5N)
The start of winter in the Northern Hemisphere
The shortest day of the year
Vernal (Spring) Equinox
Three months later (one/quarter a year) later
Sun is directly over the equator (0*)
Its rays hit all of the earth equally from pole to pole
Start of Spring in the Western Hemisphere
Summer Solstice
Three months later (one/quarter a year) later
Sun is directly above the Tropic of Cancer (23.5N)
First day of summer in the Western Hemisphere
The sun never sets in the Arctic Circle (above 66.5N)
The longest day of the year
Latitude
- Measured along the North-South axis
- Similar to the y-axis in a graph
- 1 Degree of latitude is an exact distance. It is exactly 1/360 the circumference of the Earth
Important Latitudes
- North Pole 90N
* Tropic of Cancer 23.5N
* Equator 0*
* Tropic of Capricorn 23.5*
* South Pole 90*S
Determining ones latitude
Estimate the angle from the horizon to the Sun (or Polaris) at its highest point (noon) and correct for the time of year, In the northern hemisphere only
This method was used as early as 400AD
Cross staff and the Astrolobe
Longitude
- Measured along the East-West axis
- Similar to the x-axis in a graph
- Longitude is a function of time
John Harrison
Reliable method for determining longitude
by calculating the difference in time between your noon and the time at Greenwich (Prime meridian) and then mutlipy by 15* you get your longitude
John Harrison’s chronometer was accurate to within 1/3 of a second
James Cook
In HMS Endeavour followed Transit of Venus. Found and charted New Zealand and Australia Great Barrier Reef, found the cure to scurry. Killed by Hawaiians
Charles Darwin
HMS Beagle in 1831. Mapping expectation
HMS Challenger
Captain George S. Nares. To investigate the physical and biological condition of the great ocean basins, 3 1/2, Sampled over 350 bottom samples. C. WyvilleThomson
Fridtjof Nansen and Frederick Johansen
Cool Guy 😎. First to cross Greenland ice sheet by dogsled. Arctic ice currents. The Fram. Crew of 13 men stuck in ice for nearly 4 years. Came within 400 m of North Pole.
C. Wyville Thomson
Coined the term oceanography in its present sense
Ronald Nansen
Found the Northwest passage
Remotely Operated Vehicles (ROV)
ROPOS: Remotley operated Platform for Ocean Science
Autonomous Underwater Vehicles (AUV)
The Big Bang
- Occurred 13.8 Billion years ago
* The massive explosion sent matter hurtling out in all directions
Georges Lemaitre
Proposed the idea of the big bang in in 1927
Doppler effect:
As light travels towards us, the wave lengths being emitted will be compressed out will causing it to be blue shifted
As light travels away from us, the wave lengths being emitted will be stretched out will causing it to be red shifted
Visible wavelength spectrum
Purple= 400 Green = 500 Yellow= 600 Red= 700
edward Hubble
- Found supporting evidence for the Big band theory
* Distant galaxies in all directions are flying away from us, at speeds proportional to their distance
A million years after the Big Bang
cool down, particles, clouds, stars, heavier particles, supernovas, nebulas, planetesimals, protoplanets, planets
Giant-impact hypothesis
hot, then A large planetesimals collied into earth, losing some mantel, caused earths tilt and to cool down and speed up rotation
iron catastrophe
- Molten material began to cool down
- Heavier elements like iron sank into the earths core
- Lighter elements rose to the surface
not unique to earth, did not occur on the moon
50 Million Years After the Earth Formed
Origin of Earths water
- 4 billion years ago the earth had its oceans, * The outgassing theory: * Volcanic activity would have released water vapour onto the surface
* The collision with the moon would have blown away any atmosphere the earth had therefore cooling the earth
Differentiation by chemical characteristics
Crust: 0-80km
* Continental crust: Granite, lighter
* Oceanic crust: Basalt, heavier, contains more metals
Mantle: 80km-2900km
* Similar in chemical composition to oceanic crust
* More magnesium and iron
Core:
* iron
Differentiation by their physical characteristics
- Lithosphere: 0-100km
* Lithos means stone
* Crust and outer most part of mantel- Asthenosphere: 100-300km
- Asthenes means soft
- Not strictly a liquid but no a solid either
- Deforms under stress
- Lithosphere literally floats on top of it
- Mesosphere: 300- 2900km
- Mesos means middle
- Rigid due to extreme pressure
- Outer core:
- Extremely dense liquid
- 5500 degrees Celsius
- Inner core:
- More pressure there solid
- 6000 degrees
- Asthenosphere: 100-300km
The magnetic field
protects the Earth from the solar wind
Iron core
The Aurora Borealis
arise from the solar wind plunging into Earth’s atmosphere
Solar system
Our solar system formed 4.55 billion years ago.
Crust
a thin rigid outer layer rich in Silicates 6-80km
Continental crust is thicker and composed primarily of granite 40km
Oceanic crust is thinner and composed primarily of basalt, high density 8km
Mantel
contains more iron and magnesium than the crust. 80km-2900km
Silicates
Contain silica, oxygen and one or more metals.
* Two main groups
Mafic silicates: contain heavier metals like magnesium and iron. (Basalt )
Felsic silicates: contain lighter metals like aluminum and potassium. (Granite)
Asthenosphere
- is a plastic layer that flows when deformed.
* 300-500km
Lithosphere
- is the rigid outer layer.
- It includes the crust and upper mantle.
- 1-100km
Mesosphere
- is the more rigid, less fluid part of the middle and lower mantle.
- Largest physical property
heat energy to the Earth:
- Compaction as the Earth coalesced;
- Bombardment by meteors and planetesimals;
- Radioactive decay
- Solar radiation
Three basic types of heat flow
Conduction: is heat passing through a substance, without any movement of the substance.
Convection: is the flow of heat caused by the movement of a heated substance.
Radiation: is the flow of heat through space with no direct contact with another object.
Heat
is thermal energy transferred from a hotter system that is in contact with a cooler system.
Density
- Density of a substance is equal to its mass divided by its volume.
- Density has units of kg m-3
- Density determines buoyancy
Isostasy
- The lithosphere, which is rigid, floats on the asthenosphere, which is plastic and can flow.
Principle that lithosphere rides at a state of gravitational equilibrium on the asthenosphere is called isostasy
The weight of a unit area of lithosphere equals its density times its thickness.
P waves,
also known as primary or compression waves, move back and forth in the direction of wave motion.
* First ones to arrive after an earthquake (primary)
* Faster
* Able to transmit energy through fluids
S waves,
also known as secondary or shear waves, move from side to side, perpendicular to the direction of wave motion.
* Secondary because arrive second in an earthquake
* slower
* Do not transmit energy through fluids
Seismic waves
are low-frequency, energetic wave motions generated by earthquakes
P AND S waves
Waves
propagate away from a zone of generation.
transport energy without transporting mass.
perpendicular to the direction of propagation.
can change direction due to lag (refraction).
can propagate in 3 dimensions,
How do we. know our core is liquid iron?
- Both S and P waves are observed in the hemisphere where the quake was generated.
- On the far side of the Earth from the quake, only P waves are observed (because S waves do not transmit through fluids)
Albedo
Reflectivity of the earth surface, life made it less reflective
* During the winter, the planet is highly reflective, high albedo
* During the summer, the planet has a low albedo
Electrical Storms:
Arrise when you have violent updrafts in atmosphere
The Oparin-Haldane hypothesis
- Started with simulated ocean which is hated and partly evaporated
- Evaporated water enter stimulated early earth atmosphere
- Atmosphere was electrified
- Water was cooled and spererated from original water
- Water turned brown because it was rich in organic material (amino acids)
- No life was formed
RNA world hypothesis
- DNA and Proteins are very completcatled things, therefore what if RNA was the pre-curser
- Originally, scientists thought that proteins were the only biological molecules capable of catalysis.
- In the early 1980s, two groups found that RNAs can also act as catalysts.
- This class of catalytic RNAs are known as ribozymes
When did life occur?
may have evolved as early as 4.2 billion years ago, defiantly had life 3.7 billion years ago
Hydrothermal vents and hot springs
Could provide a gradient from high to low energy, allowing organic molecules to survive
Biogenesis
the idea that all living things come from pre-existing living things. One common ancestor
Oparin
Said spontaneous generations occurred at least once but life wiped out the conditions of early earth (Russian)
Haldane
Earths early atmosphere was exposed to a lot of lightning. (British)
Thomas Gold
Life may reside deep beneath the earth in oil wells
Alfred Wegener
Introduced term Pangaea (German)
Abraham Ortelius
First to speculate that South America and Africa were once connected
Edward Suess
Europe and North Africa were once connected but were superheated by ancient ocean ( Tethys). Based on distribution of marine fossils
That fern
Glossopteris
Antonio Sinder-Pellegrin
contentions did drift but due to biblical flood
Sediment thickness
is least on the elevated mid line ridges
is highest near the continents where. the ocean is oldest
Harry Hess
Proposed. that new ocean floor is created at the mid ocean ridge. Spreads outward laterally
remanent magnetism
created when basaltic magma rises from mid ocean ridge and cools, iron aligns itself with the magnetic field. Pink represents normal magnetic orientation, brown represents reversed. Stiped because crust is being pulled laterally at ocean ridge
Convergent plate boundary
two plates collide creating mountains and. deep sea trenches
Transform plate boundary
Occurs at mid ocean ridges, pulled in opposite directions
Types of rocks
- Igneous: Molten material and lava
- Metamorphic rocks: High pressures
- Sedimentary rocks: Bits of other rocks
- Most abundant
Glomar challenger
Spy ship disguised as a science ship
The Chikyuis
- the latest, greatest drill ship devoted to science
- Japanese ship
- 7km below the sea bed
Terrigenic sediment
is produced by the break down of rocks on land
* Most abundant type * Tend to get trapped by the continents
Biogenic sediment
is produced by organisms.
* Most of the seafloor is biogenetic
Hydrogenic sediment
is produced in place by chemical reactions in seawater or within the upper sediment
Volcanogenic sediments
are produced from the ejecta of volcanic eruptions.
Cosmogenic sediments
are produced from cosmic debris that constantly bombards the Earth.
- Physical weathering
- Physical weathering breaks big chunks of rock into little chunks of rock without changing the chemical composition.
* Water expands by 10 percent when it freezes
* Higher latitudes
- Chemical weathering
- Chemical weathering breaks down rock by chemical alteration
* Chemical weathering occurs because water and carbon dioxide combine to make carbonic acid
* Carbonic acid eats away at rocks, and the dissolved byproducts wash out to sea.
Ooze
Rich in biogenic debris (greater than 30% by weight)
can be calcareous or siliceous
Oozes can be classified according to the dominant group within them, e.g. a radiolarian ooze.
Coccolithophores
produce CaCO3shells. Sheed plats called coccoliths
Two other important CaCO3 producing groups
Foraminifera and pteropodsare
opal producing groups
Radiolarians, Diatoms, Silicoflagellates
