oceanography quotations
sarahca8The History of Oceanography
http://ernielb.blogspot.com/2010/10/sailing-ships.html
Humans first went to sea to find food,
for transportation, and
for trade.
Studies of oceanography evolved as people looked to get more out of the ocean
studied fish to find more fish,
analyzed currents to travel faster,
watched the weather to learn how to predict storms…
Early voyages were carried out with little knowledge of geography.
Early explorers include:
Polynesians,
Chinese,
Greeks, and
Vikings
They made remarkable voyages traveling well beyond the boundaries of the known world. They had no maps, no GPS, no idea of what they would find.
WHY did they make these risky voyages?
To find new land,
To discover new food sources,
and to escape war.
The Middle Ages:
The Arabs dominated in the Mediterranean Sea, east Africa, and the Indian Ocean. http://en.wikipedia.org/wiki/File:Map_of_expansion_of_Caliphate.svg
In Europe, the Vikings were the dominant sailors, and were the first Europeans to discover America! Figure 1.8, p. 11.
All Viking colonies in North America and Greenland died out by 1450.
The Age of Discovery: Columbus, Prince Henry, and…
Ferdinand Magellan
The first voyage to circle the globe.
5 ships and 270 men left from Spain in 1519.
1 ship and 34 men returned in 1522,
almost exactly 3 years later.
Even Magellan died during the trip!
Modern Oceanography is considered to have started with the voyages of Captain James Cook (1768 – 1776).
Scientific goals included :
1) studying the position of stars and planets in the southern skies
2) searching for an expected southern continent (Terra Australia) Achievements include:
1) discovered New Zealand, Australia, and many islands
2) described and collected samples of flora and fauna of newly discovered lands
3) sampled seafloor sediments
Cool Fact:
1) his notes and maps were so well constructed that they were still used during WWII
Fate:
1) He was killed in Hawaii during a
dispute with the native population.
Cook
Garrison, Essentials of Oceanography, 2012
James Cook’s voyages of discovery 1768 – 1776.
Figure from Garrison, Oceanography: An Introduction to Marine Science, 2007
The U.S. jumped into ocean exploration - after 10 years of congressional argument over funding the project – with the 1838 – 1842 Exploring Expedition
1) 6 ships
2) supposed to show the flag, scout whale populations, perform scientific exploration and mapping
3) also supposed to test the theory that the Earth was hollow and could be entered through holes located at either the north or south pole.
4) Materials collected formed the beginning of the Smithsonian Museum in Washington, D. C.
Beginning in 1847, American Matthew Maury collected data on ocean currents and wind patterns. The maps prepared using this data were used to speed ocean voyages. This continued the mid-1700’s work of Ben Franklin
Cool Facts: Maury’s maps cut 30 days off the average trip from the East Coast to California, which the ‘49ers appreciated!
The first totally oceanographic voyage was that of the HMS Challenger (1872 – 1876)
(The first where the scientists told the captain where to sail)
Discovered 4717 new species
Collected 472 bottom samples and depth soundings
Proved the existence of life below 1800 feet
Discovered the Marianas Trench (the deepest spot in the ocean)
Collected seawater samples, and salinity and temperature readings throughout all the world’s ocean
Discovered manganese nodules
Published their results in a 50volume report which is still
studied today.
6
Technological advances, especially those driven by military needs during WWII, have given oceanographers the ability to explore the ocean and deep sea floor with much greater speed and vastly increased resolution.
More recent developments in Oceanography!
dusk.geo.orst.edu / pg / fornari.gif
Technologies such as sonar, echo sounding, and seismic profiling => detailed images of the seafloor from the surface.
Sophisticated instrument packages sample and record chemical and physical data through the ocean column.
Techniques such as deep sea drilling plus manned submarines and unmanned deep submersibles => see and sample the deep sea directly, in real time.
http://dusk2.geo.orst.edu/pg/fornari.gif
All of these methods ARE EXPENSIVE!!!
Most research is now done by consortiums or groups of scientists, universities, or countries – for example the Integrated Ocean Drilling Project (once known as DSDP and then JOIDES).
The DSDP Glomar Challenger
(Deep Sea Drilling Project)
The JOIDES Resolution
(Joint Oceanographic Institutions for Deep Earth Sampling)
The IODP R/V Chikyu
(Integrated Ocean Drilling Project)
http://www.iodp.org/ships-platforms/
http://wizzyschool.com/cosmiceducation/coordinates.php#PrimeMeridian
F Y I
Developed by Hipparchus (Greek, 190-120 BCE=Before Common Era)
refined extensively as our knowledge of the world has increased.
A set of imaginary circles around the Earth
projection may make them appear as straight or curved lines.
Latitudes and Longitudes:
http://www.stuffintheair.com/world-map-latitude-longitude.html
Remember,
a circle can be divided into 360 degrees.
A half-circle contains 180 degrees
A quarter circle contains 90 degrees.
A cross-section of the Earth is a circle!
Latitudes
Circles which run east – west
Circles get smaller the closer to the pole one gets
Distance between circles of latitude remain the same
Latitude is measured as the angle between the equator, the center of the Earth, and the point of the Earth’s surface.
a. Latitude of the equator = 0 degrees = 0°
b. The north and south poles have a latitude of 90°
5. Latitudes are given with a suffix to denote hemisphere.
a. N means north of the equator
b. S meanssouth of the equator
6. Maximum Latitude = 90°N or 90 ° S
http://geographyworldonline.com/tutorial/lesson1.html - CHECK THIS WEBSITE OUT!
13
Longitudes
circles which run north – south.
meet at the North and South Poles.
size of a degree of longitude changes
circles stay the same size
0° longitude = the Prime Meridian
Now a line through the Royal Observatory at Greenwich, England.
Has changed position in the past (See the Da Vinci Code)
measured as the angle from the prime meridian, to the center of the Earth, and out to the position at the Earth’s surface.
maximum value =?
180° toward the east and 180° toward the west.
We use a W or an E to indicate which hemisphere we are in.
180° E = 180° W and is approximately the same as the International Date Line
The position of any point on Earth can be given by a latitude followed by a longitude.
Don’t forget the N or S and E or W to show hemisphere.
For example, point A has the position 60° N and 90° W.
BUT… 1° of latitude = about 70 miles on the ground. We need to be more accurate than that! SO…
1° = 60’ (60 minutes)
1’ = 60’’ (60 seconds)
1° = 60 min/deg x 60 sec/min = 3600 seconds
Latitude was/is determined by shooting the stars using a sextant. The angle of the north star above the horizon roughly measures angle of latitude.
http://www.clipperlight.com/howusesextant.html
Do determine longitude, we need to understand the difference between Earth’s:
revolution = time around the sun = a year = 365 ¼ days
rotation = time to spin on axis = a day = 24 hours
http://www.boscobel.k12.wi.us/~schnrich/eath's_revolution.htm
local noon = the time of shortest shadows ≠ 12:00
http://www.eso.org/public/outreach/eduoff/aol/market/collaboration/luneclipse/locnoon.html
To determine longitude, we need to know the difference in time of local noon between a known location and our unknown location.
The change in longitude can be determined by:
1) difference in local noon (hours) x 15° per hour = difference in longitude in degrees.
Why?
1 rotation (day) = 24 hours
1 rotation (day) = 360 degrees, so
360 degrees / 24 hours = 15 degrees / hour
note: (you have to measure time in the same way both times so don’t reset your clock).
2) If local noon happens sooner at your unknown location then you have traveled east
a) for example, local noon at your unknown place happens when it is only 9 am in “known place” time.
3) if local noon happens later at your unknown place then you have gone west.
a) example, local noon at your unknown place happens when it is 3 pm in “known place” time.
http://www.longcamp.com/longitude.html
Example: I measure local noon at my starting position of San Francisco at 12:15 pm. I get on a plane and fly somewhere. The next day, I measure local noon at my new position which occurs at …
3:15 pm San Francisco time = 15:15 (24 hour time)
Longitude difference = (15:15 pm-12:15 pm) hours x 15°/hour
= 3 hours x 15°/hour = 45° difference
Since 15:15 is after 12:15, I have gone west. 122 °W + 45 ° = 167 °W
Formation of the Universe,
The Solar System, and
The Earth!
One popular theory says that the universe began about 13.7 BY (billion years) ago
How?
in a BIG BANG = explosion of pure energy from a single point.
Before the Big Bang there was nothing…
NOT IN BOOK!
Everything was HOT, HOT, HOT right after the BIG BANG – about 10,000,000,000,000,000,000,000,000,000 degrees C! Everything was expanding during this time.
About 300,000 years after the Big Bang, the temperatures had dropped enough for atoms to form. These were mainly hydrogen, with some helium and lithium (the smallest and simplest atoms we know).
After 500 MY, there was enough matter in the universe for the first stars and galaxies to form!
A star = a massive sphere of gas that is hot enough to glow incandescently (like a light bulb). Our star is the Sun.
A galaxy = a huge rotating clump of stars, dust, gas and other interstellar debris. Our galaxy is the Milky Way.
The universe = the totallity of all things that exist.
According to Garrison – there are more stars in the Milky Way galaxy than there are grains of sand on the beach, and more galaxies in the universe than stars in our galaxy.
Fate of the Universe
(just for fun, not on test)
The Closed Universe Hypothesis – based on the idea that what goes up must come down, this idea says that the universe will eventually collapse back into a single point due to the pull of gravity, paving the way for another Big Bang.
Open Universe Hypothesis – the energy released during the Big Bang was so huge, it overcomes gravity and the universe expands forever. Eventually, all stars will burn out and drift as dead balls of stone in a cold, lightless and lifeless space
Nothing we need to worry about – it is still many billions of years
in the future!
OR
solar nebula (condensation) theory of star formation
One of several theories of star formation.
A nebula is a cloud of mainly hydrogen and helium gas mixed with cosmic debris.
Lots of mass, so lots of gravity…
Nebula begins to collapse in on itself due to gravity => protostar
Gravitational energy is converted to heat.
once the star reaches a temperature of 18 million degrees, nuclear fusion begins and a star is born.
A solar nebula collapsing, with protostar heating up in the center. http://astrobob.areavoices.com/tag/solar-nebula /
Gas => protostar => star Stars glow but don’t burn!
http://www.atomicarchive.com/Fusion/Fusion1.shtml
Nuclear fusion = heat energy causes 2 or more smaller atoms to merge or fuse together to form a heavier atom.
In glowing stars, hydrogen, lithium and helium atoms are fusing to form heavier atoms such as oxygen, carbon, and nitrogen.
Isotopes of hydrogen
Future Test Question!
The aftermath of a 1054 supernova – nuclear fusion has created heavy elements such as iron, uranium, gold, and others (1999 photo)
http://www.smithsonianmag.com/science-nature/The-Hubble-Space-Telescopes-Finest-Photos.html?c=y&page=3&navigation=next#IMAGES
Eventually stars exhaust or use up their nuclear fuel.
Small stars, like our sun, simply burn out and hang in space as balls of cold rock.
Large stars explode as supernova. These release huge amounts of energy which power nuclear fusion reactions that create the even heavier elements: iron, magnesium, etc.
Recent evidence suggests the heaviest elements, including gold, were produced when two neutron stars(collapsed cores of massive stars) collide and merge. The image below shows an artist’s conception of the moment of collision and is from NASA.
Our solar system is believed to have started from a solar nebula that was spinning due to the impact of a nearby supernova.
But… supernovas add heavier elements too, remember!
Because of the spin, heavier elements moved to the outer part of the cloud.
Figure 1.14, page 17.
There the billions of tiny particles accreted (collided and stuck).
They slowly grew to small planets or planetessimals,
eventually formed our 8 known planets - plus Pluto and the other almost planet - sized bodies.
The solar system was finished when the Sun “turned on” about 4.6 BY ago.
FACT OR THEORY?
Lutgens and Tarbuk, Essentials of Geology, 2011
The asteroid belt (between Mars and Jupiter) is considered a failed planet. This is what the solar system probably looked like during the planet accretion phase.
Garrison, Essential of Oceanography, 2012
http://www.crystalinks.com/asteroidbelt.html
The estimated age of the solar system is based primarily on radiometric dating of meteorites (pieces leftover during planet accretion).
Due to more recent events on Earth, there are no rocks preserved from this time. Our oldest dated rocks so far are only 3.6 BY old!
http://rst.gsfc.nasa.gov/Sect18/Sect18_1.html
- Initially, the earth was a homogeneous (well-stirred)
It was pretty hot due to
Heat left over from accretion,
heat released during radioactive decay
creating smaller elements out of bigger, releasing heat
Impact of meteorites and comets (left-overs of solar system formation)
http://meditationandspiritualgrowth.com/?paged=2
Impact of a Mar-sized body with the Earth about 4.4 BY ago :
Added enough heat to the Earth to cause it to melt completely
Placed enough material into orbit around the Earth to form the moon
the same collision and accretion process that formed the planets
Garrison, Essentials of Oceanography, 2012
34
An artist’s conception of how our Earth looked from the newly forming moon . Garrison, Essentials of Oceanography, 2012.
- Around 4.4 BY ago, the Earth became so hot that it melted completely,
- This allowed density stratification or separation into layers much like oil and vinegar salad dressing.
More on this in a minute!
Fig. 1.11, p. 12
Iron
Lighter
matter and
silicates
http://www.odysea.com/shop/product.php?id=65
The early Sun is believed to have been brighter and hotter than today.
Our first atmosphere (maybe made of hydrogen and helium) was quickly burned away by the extra heat!
http://www.scientificamerican.com/article.cfm?id=jupiter-migration-mars
Earth’s second atmosphere formed from volcanic gasses => a smog-like toxic mixture of ammonia, sulfur, and carbon gases.
There was little oxygen present at that time!
http://www.greencarreports.com/news/1048506_california-steps-up-gross-polluter-vehicle-retirement-program
Volcanic outgassing and collisions with icy comets are also the source of the water of the Earth’s oceans
Figure 1.15, page 18.
How did we get the oxygen rich atmosphere we have today?
We think that relates to life,
so…
Where did life come from?
http://granitegrok.com/blog/2013/07/a-question-for-martha-fuller-clark-why
Biosynthesis = the formation of new life.
Stanley Miller demonstrates his biosynthesis experiment.
Stanley Miller’s 1953 experiments:
Very large electric current (like lightening) though water containing chemicals similar to those in the early ocean and atmosphere
Created the basic building blocks of life – amino acids, proteins, sugars, etc.
Note Miller did not make new life!
Believed that these organic molecules gradually combined and evolved into primitive life forms somewhat like bacteria.
Questions remain about where this happened – in tide pools, below a thick ice cap, on the deep sea floor, at hot springs?
We also don’t know when, although our earliest fossils show the presence of life by 3.5 BY ago and there is evidence for life 3.85 BY ago. Maybe as early as 4 BY ago?
NO! There is too much oxygen in the atmosphere now! Also, the life that we do have today would scavenge the newly formed organic elements – the amino acids, sugars and proteins, etc – long before they would have time to evolve into life!
Could biosynthesis happen today?
We think…
First life was pretty simple, possibly similar to bacteria recently discovered living in rocks deep below the surface.
These were consumers or heterotrophs = other feeders. They had to find organic matter to “eat.”
Later, producers or autotrophs = self feeders developed, perhaps as organic matter became scarce.
Early autotrophs may have been similar to the chemosynthetic bacteria living around hydrothermal vents on the deep sea floor.
http://www.123rf.com/photo_5528931_8-5x11-flyer-cover-your-cough.html
http://www.ibiblio.org/virtualcell/amazingbiology/oceanography/chemof.htm
Where did all that oxygen come from?
From plants, of course! Beginning about 2.5 BY ago, plant-like autotrophic organisms developed photosynthesis.
- Through photosynthesis, plants convert the sun‘s energy to food and release oxygen as a by-product.
Figures 1.22 and 1.23, page 26 and 27.
Where did all that oxygen come from?
- By about 500 MY ago, there was finally enough oxygen in the atmosphere to allow life to crawl out onto land!
- We also needed to develop an ozone layer before life could exist on land. WHY?
- Ozone in the upper atmosphere blocks UV light (poison to life)
http://chronicle.uchicago.edu/060413/fossils.shtml
Animals (heterotrophic and multicellular) evolved in response to the free oxygen in the atmosphere (and dissolved in the ocean), which they use to break down their food to get energy! Shown, artists conception of early multi-cellular animals. http:// www.astrobio.net/exclusive/3733/skeletons-in-the-pre-cambrian-closet
Of all the planets in our solar system, only the Earth is known to have life. Why? Because it has liquid water!
It is in the ”life zone” – Far enough from the sun to keep the water from boiling, but close enough to keep it from freezing
Our atmosphere acts like a blanket keeping surface temperatures comfortable!
Our rate of rotation is perfectly timed to keep water fluid
You are here
http://www.yecheadquarters.org/catalog2.0.16.html
We use geophysics to learn about the internal structure of the Earth!
geophysics = the study of the earth's physical properties and physical processes acting upon, above, and within the earth.
http://www.magazine.noaa.gov/stories/mag159.htm
gravitational field => The Earth must contain denser material than we see at the surface!
FYI = the pull of gravity is directly proportional to the mass of the objects, so the heavier the Earth, the faster the apple falls!
http:// walrus.wr.usgs.gov/infobank/programs/html/definition/grav.html
magnetic field => The Earth must contain more magnetic material than we see at the surface!
FYI = the strength of the Earth’s magnetic field is proportional to both the type and amount of magnetic material it contains.
http :// www.physics.sjsu.edu/becker/physics51/mag_field.htm
3) Since the early 1900’s, our best source of information comes from seismology = the study of seismic waves traveling through the Earth from earthquakes and large explosions.
http:// geophysics.ou.edu/solid_earth/notes/seismology/seismo_interior/seismo_interior.html
Path of seismic wave through the Earth!
The velocity or speed of a seismic wave depends on: the type of wave, type of rock, pressure (more is faster), and heat (more is slower).
Pressure and heat both increase with depth.
Garrison, 2007, Oceangraphy
Seismic waves will change course where the rock type or rock ooziness changes.
=> changes the travel time of waves!
http://www.cyberphysics.co.uk/topics/earth/geophysics/Seismic%20Waves%20Reading.htm
A highly simplified view of how seismic waves bounce around inside the Earth following a large earthquake!
http://faculty.weber.edu/bdattilo/shknbk/Notes/insdearth.htm
Wicander and Monroe, 2008, Essentials of Geology
Use the arrival time of different types of seismic waves to INFER (guess) what the inside of the Earth looks like!
Travel time => velocity =>rock type or behavior
The Earth is an Onion!
No, not really, but it has layers like an onion…
http://www.themedattraction.com/theonionslice.htm
http://roulette404.multiply.com/journal/item/7132/Other_DIMENSIONS_Getting_a_Little_Cosmic
The first model of the Earth was based on changes in rock type!
Remember, this is a theory and is still tested and refined today!
Like Fig. 1.18, page 21.
Layer Name | Sub-layer Name | Depth to Top | Depth to Bottom | Composition |
Crust | Oceanic | 0 Km | 10 Km | Basalt |
Continental | 0 Km | 25 – 50 Km | Granite | |
Mantle | Base of crust | 2,900 Km | Peridotite | |
Core | Outer Core | 2,900 Km | 5,150 Km | Liquid Nickel - Iron |
Inner Core | 5,150 Km | 6,380 Km | Solid Nickel - Iron |
There is also another way to divide up the Earth –
Layers based on material behavior
Chemical or Rock-Type Layers
Physical Property Layering
See figure 1.18 in text
100 km
700 km
Earth Layers Based On Physical Properties
(better for Plate Tectonics)
Layer Name | Depth to Top | Depth to Bottom | Behavior |
Lithosphere | 0 Km | 100 Km | Rigid |
Asthenosphere | 100 Km | 700 Km | Oozy |
Mesosphere (Lower Mantle) | 700 Km | 2,900 Km | More Rigid |
Outer Core | 2,900 Km | 5,150 Km | Fluid |
Inner Core | 5,150 Km | 6380 Km | Rigid |
100 km
700 km
Isostasy = the idea that the outer surface of the Earth is floating buoyantly in the oozy asthenosphere (like an iceberg or a boat floats on water).
Why does
this iceberg
sink deeper than
this iceberg?
FYI: Objects float by displacing or pushing aside a mass of water equal to the mass of the object.
A loaded boat weighs more than an empty one so it has to push more water away and it sinks deeper.
Figure 3.7 in text
Density = how “heavy” something is.
It is a constant for a specific type of material
Density = mass/volume
Density is measured in grams per cubic centimeters = gm/cm3
http://fashionista.com/2011/08/here-is-a-list-of-things-that-are-bigger-than-stella-tennants-waist-on-the-cover-of-vogue-italias-september-issue/bowling-ball/
http://simple.wikipedia.org/wiki/Basketball
http://www.nyu.edu/pages/mathmol/textbook/density.html
http://www.grossmont.edu/judd.curran/outline3.htm
Continental Crust | Ocean | Oceanic Crust | Mantle |
2.8 gm/cm3 | 1.0 gm/cm3 | 3.0 gm/cm3 | 5.5 gm/cm3 |
According to the Theory of Isostasy:
1) every column extending from the surface to the asthenosphere weighs exactly the same
2) Any excess mass at the surface – mountains or heavier crust – must be balanced by a lack of mass at depth
3) So just like heavier boats sink deeper in the ocean, heavier crust sinks deeper into the mantle.
4) So heavy mountains have light weight roots
5) The heavier oceanic crust sinks deeper, leaving room for the light-weight ocean to balance it out.
Isostatic Equilibrium => all pieces of the crust are in balance.
As weight is removed (by erosion or melting glaciers) the crust rises.
As weight is added (mountain building or formation of glaciers), the crust sinks again.
Geologic Time – there are two kinds of time in geology!
Relative time – putting events into their order of occurrence
I am older than my daughter, but younger than my father
in Geology, this is based on fossils, the geometry of the rock layers, and more…
before 1900+, this was all geologists could do
Absolute time – assigning ages in years
my daughter is 18, my father is 80, and I am ?
the absolute ages of rocks is determined using radiometric dating techniques
similar to the carbon 14 dating used in archeology.
The Relative Geologic Time Scale – derived in the 1800s based on relative dating, after many heated debates and the occasional fist fight!
The Absolute Geologic Time Scale adds ages.
Based on radiometric dating = spontaneous decay of one of several specific elements (the parent) to a new element (the daughter). Eg. Uranium 235 to lead 207