Post on 01-Jan-2016
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Overview 70.8% Earth covered by ocean Interconnected global or “world ocean” Oceans contain 97.2% of surface water 99% of earth’s biosphere is in the ocean!!
Introduction Oceanography – the
description of the oceansInterdisciplinary○ Geological○ Chemical○ Physical○ Biological
Global Ocean4 principal oceans + plus one
PacificLargest, deepest
AtlanticSecond largest
IndianMainly in Southern Hemisphere
ArcticSmallest, shallowest, ice-coveredOften consider only a “sea”
+ Antarctic or Southern OceanConnects Pacific, Atlantic, and
IndianSouth of about 50o S latitude
The “Seven” Seas Smaller and shallower than oceans Salt water Usually enclosed by land
○ Sargasso Sea defined by surrounding ocean currents
http://www.jimloy.com/biology/sargasso.gif
The “Seven” Seas Before 15th Century:
Red SeaMediterranean SeaPersian GulfBlack SeaAdriatic SeaCaspian SeaIndian Ocean
Current list also includes:North PacificSouth PacificNorth AtlanticSouth AtlanticIndianArcticSouthern
Comparison of elevation and depth
Average depth 3729 m (12,234 ft)
Average elevation of land is 840 m (2756 ft)
Deepest ocean area is Mariana Trench 11,022 m (36,161 ft)
Highest continental mountain Mt. Everest 8850 m (29,935 ft)
History of Oceanography
http://www.divediscover.whoi.edu/history-ocean/index.html
Journey to the bottom of the ocean
Alexander the Great○ Supposedly went down in sealed container in 332 BC
William Bebe - 1934○ Bathyshpere – heavy steel ball with windows○ Went about 923m (3028 ft)
US Navy’s Trieste○ took 3 people down 9906m (32,500 ft!) in Mariana
Trench, heard cracking sound Submersible Alvin
○ Began dives in 1964○ Can go down 4000m (13,120 ft)
Submersible Shinkai○ Japanese submersible that can dive over 21,000ft
James Cameron – 2012 (National Geographic)○ http://www.youtube.com/watch?v=DO6_jKN-1hw&feature=player_embedded
Nature of scientific inquiry Natural phenomena governed by
physical processes Physical processes similar today as
in the past Scientists discover these processes
Make predictions and test themLeads to better understanding and prediction of
future events that rely on natural processes
Scientific method
Observations and questions Develop falsifiable, testable hypotheses
Science can only deal with hypotheses that are testable!
Predictions based on hypotheses Test predictions
Comparative studies Controlled manipulative experiments Field and lab experiments Lot of trial and error! And retesting!
Gather data and analyze results
Accept or reject (falsify) hypothesis Modification of hypotheses
Scientific method
Fig. 1.9
Scientific method Theory
Well-substantiated by large body of dataMany facts, supported by testing of many scientists
“Probably true” versus “absolutely true”○ Always possible that additional data cannot be
fully explained by current theory
○ The public often thinks that scientists really don’t know because of the word “theory”- However, in biology the word theory is a close to a law
as you will come!
Science is continually developing because of new observations and new technology
Formation of Solar System and Earth
• Big Bang formed universe over 15 billion years ago• Earth formed from gases & dust • ~ 4.6 – 5 bya
• How do we know that? Scientists use radiometric dating
Formation of Solar System and Earth
Nebular hypothesisNebular hypothesisNebula = cloud of gases & space dust○Mainly hydrogen and helium
Gravity concentrates material at center of cloud (Sun)
Protoplanets from smaller concentrations of matter (eddies)
Protoearth Larger than Earth today Homogeneous composition Bombarded by meteorites
Moon formed from a chunk of protoearth after collision with large asteroid
Heat from solar radiationInitial atmosphere boiled awayIonized particles (solar wind) swept away
nebular gases
Protoearth Denser materials started to move to
center ○ density stratification (layered Earth)
http://instruct1.cit.cornell.edu/Courses/biog105/pages/demos/106/unit08/media/interior-of-earth.jpg
Earth’s internal structure
Highest density material at center (core)
Lowest density material at surface (crust)
Earth layeredEarth layeredChemical compositionPhysical properties
Chemical composition CrustCrust
Low-density, mainly silicate mineralsOceanic and continental crust
MantleMantleMainly Fe (iron) and Mg
(mangnesium) silicate minerals CoreCore
High-density, mainly Fe and Ni (nickel)
Physical properties Lithosphere Asthenosphere Mesosphere Outer core Inner core
Rock 'behavior' determined by temperature, density and stressranges from brittle to plastic ("deformable") to elastic
Physical properties
• CoreCore• ~ 90% iron with nickel• 5,500-6,600O C (9900-12000O F)
• Solid inner core and viscous liquid outer core• Differential spin of inner/outer cores Earth's
magnetism
Physical properties• MantleMantle
• Iron and magnesium silicates• 2500O C (4500O F)• Inner mantle -mesosphere
• rigid
• 'Upper' mantle• Asthenosphere - partially molten plastic • Lithosphere – rigid (part of crust)
Physical properties Upper MantleUpper Mantle
AsthenosphereAsthenosphere Plastic – deforms by
flowing High viscosity – able
to flow slowly From 100 km to 700
km (430 miles)
Physical properties Upper Mantle and CrustUpper Mantle and Crust
LithosphereLithosphere “Cool”, rigid, brittle
○ (500O C, 900O F)
Surface (“crust”) fused to uppermost mantle, to about 100 km (62 miles)
Two types of crust Oceanic crustOceanic crust
Underlies ocean basinsIgneous rock basalt
Dark coloredAverage thickness 8 km (5 miles)Relatively higher density○ 3.0 g/cm3
Continental crust – thicker but LESS denseContinental crust – thicker but LESS denseUnderlies continentsIgneous rock – graniteAverage thickness 35 km (22 miles)Lower density○ 2.7 g/cm3
Isostatic adjustment (isostasy) Buoyancy – less dense “floats” higher than
more denseContinental crust “floats” higher than
oceanic crust on plastic asthenosphere
As we will see, when oceanic and continental crust meet, the oceanic crust is forced below the continental crust
Origin of Earth’s atmosphere Partial melting resulted in out-gassingout-gassing
about 4 billion years agoSimilar to gases emitted from volcanoesMainly water vapor (steam)Carbon dioxide, hydrogenOther gases such as methane and
ammoniaLiving organisms had dramatic effect
Origin of Earth’s oceans
Water vapor released by outgassing
Condensed as rain (acidic) Accumulated in ocean basins About 4 billion years ago
Ice Comets may have contributed to ocean waters, but much, much less than outgassing
Origin of Ocean Salinity Rain dissolves rocks
Acidic due to CO2 and H2S gas levels in the atmosphere at that time
Dissolved compounds (ions) accumulate in ocean basins
Ocean salinity based on balance between input and output of ions
Ocean salinity nearly constant over past 4 billion years
Life in oceans Life originated in the oceans
Originated as prokaryotic life Ocean water gave protection against harmful UV rays
from sun (ozone layer was not yet well established) Earliest life forms fossilized bacteria in rocks
about 3.5 billion years old Found in marine rocks
http://www.ucmp.berkeley.edu/bacteria
Fossil cyanobacteria, ~ 850 MYA
Bacteria are microscopic organisms○ How can scientists say they have found
cyanobacteria fossils that are 3.5 billion years old?
○ Mats of cyanobacteria can form stromatolites- Trapped sediment and secreted calcium carbonate
Stanley Miller’s experiment – 1953 Experiment replicated Earth’s early atmospheric conditions
They put molecules/gases that were present, water, exposed UV light, electrical sparks (atmosphere was very dynamic, lightening)
Organic molecules started to form by ultraviolet light, electrical spark (lightning), and mixture of water, carbon dioxide, hydrogen, methane, and ammonia
Organics combined to form more complex molecules○ These molecules are needed for life
http://fig.cox.miami.edu/~cmallery/150/life/Stanley_Miller_large.jpg
Evolution and natural selection – Darwin’s “On the Origin of Species” – 1859
Populations of organisms adapt and change through time evolve Advantageous traits are naturally selectedIndividuals with “better” traits for environment
tend to survive and reproduce better than othersAdvantageous traits passed on to offspring
inherited Produces organisms that…
are adapted to environmentsOrganisms change environments
Types of life forms HeterotrophsHeterotrophs
Most bacteria and animals and fungiMust get energy from others
AutotrophsAutotrophs Chemosynthetic autotrophs
Bacteria that chemosynthesize, fairly recently discovered
Photosynthetic autotrophs Photosynthetic bacteria, algae, and plants○ Chlorophyll captures solar energy
○ produces excess O2 as by-product released
Photosynthesis and respiration
Fig. 1.19
Oxygen Photosynthetic anaerobic bacteria released oxygen
(O2) to atmosphere
About 2 billion years ago, sufficient O2 in atmosphere to oxidize (rust) rocks
Ozone (O3) built up in atmosphereProtects Earth’s surface from ultraviolet solar
radiation
Oxygen and ozone in atmosphere resulted in aerobic organisms to evolve and allowed life to move to land
○ Aerobic organisms (including us) need oxygen for cellular respiration
Age of Earth Radiometric age datingRadiometric age dating
Spontaneous change/decayHalf-lifeCan determine age of rocks and organismshttp://www.youtube.com/watch?v=2io5opwhQMQ
Earth is about 4.6 billion years old
Geologic time scale
MisconceptionsWhat have we learned that make these statements false?
Science is just a collection of facts just to be memorized. Scientific ideas are absolute and unchanging. Scientists have already studied all the Earth’s systems so there will not
be any new discoveries. All theories are permanent. Science and technology can solve all of our problems. Not everyone can love science and get something out of it. Science always has exact answers. All radioactivity is dangerous. The Earth is younger than ~4.6 billion years old. All rocks are more or less the same. The Earth has always been pretty much the same it is now. There is significant disagreement about Earth’s age among scientists. Evolution has never been observed. Evolution is a theory on the origin of life. Life does not continually change. Fossils are man made.
Ocean Literacy Principles 1.a - The ocean is the dominant physical feature on our planet
Earth—covering approximately 70% of the planet’s surface. There is one ocean with many ocean basins, such as the North Pacific, South Pacific, North Atlantic, South Atlantic, Indian and Arctic.
1.b - An ocean basin’s size, shape and features (islands, trenches, mid-ocean ridges, rift valleys) vary due to the movement of Earth’s lithospheric plates. Earth’s highest peaks, deepest valleys and flattest vast plains are all in the ocean.
1.h - Although the ocean is large, it is finite and resources are limited.
5.a - Ocean life ranges in size from the smallest virus to the largest animal that has lived on Earth, the blue whale.
5.e - The ocean is three-dimensional, offering vast living space and diverse habitats from the surface through the water column to the seafloor. Most of the living space on Earth is in the ocean.
Sunshine State Standards SC.6.N.1.2 - Explain why scientific investigations should be replicable. SC.6.N.1.5 - Recognize that science involves creativity, not just in designing experiments, but also in creating
explanations that fit evidence. SC.6.N.2.2 - Explain that scientific knowledge is durable because it is open to change as new evidence or
interpretations are encountered. SC.6.N.2.3 - Recognize that scientists who make contributions to scientific knowledge come from all kinds of
backgrounds and possess varied talents, interests, and goals. SC.6.N.3.1 - Recognize and explain that a scientific theory is a well-supported and widely accepted explanation of
nature and is not simply a claim posed by an individual. Thus, the use of the term theory in science is very different than how it is used in everyday life.
SC.6.E.7.9 - Describe how the composition and structure of the atmosphere protects life and insulates the planet.
SC.7.N.1.5 - Describe the methods used in the pursuit of a scientific explanation as seen in different fields of science such as biology, geology, and physics.
SC.7.N.1.7 - Explain that scientific knowledge is the result of a great deal of debate and confirmation within the science community.
SC.7.E.6.1 - Describe the layers of the solid Earth, including the lithosphere, the hot convecting mantle, and the dense metallic liquid and solid cores.
SC.7.E.6.4 - Explain and give examples of how physical evidence supports scientific theories that Earth has evolved over geologic time due to natural processes.
SC.7.E.6.5 - Explore the scientific theory of plate tectonics by describing how the movement of Earth's crustal plates causes both slow and rapid changes in Earth's surface, including volcanic eruptions, earthquakes, and mountain building.
SC.8.N.1.3 - Use phrases such as "results support" or "fail to support" in science, understanding that science does not offer conclusive 'proof' of a knowledge claim.
SC.8.N.1.4 - Explain how hypotheses are valuable if they lead to further investigations, even if they turn out not to be supported by the data.
SC.8.N.3.2 - Explain why theories may be modified but are rarely discarded.
Sunshine State Standards (cont) SC.912.N.1.3 Recognize that the strength or usefulness of a scientific claim is evaluated
through scientific argumentation, which depends on critical and logical thinking, and the active consideration of alternative scientific explanations to explain the data presented.
SC.912.N.1.7 Recognize the role of creativity in constructing scientific questions, methods and explanations.
SC.912.N.2.2 Identify which questions can be answered through science and which questions are outside the boundaries of scientific investigation, such as questions addressed by other ways of knowing, such as art, philosophy, and religion.
SC.912.N.2.4 Explain that scientific knowledge is both durable and robust and open to change. Scientific knowledge can change because it is often examined and re-examined by new investigations and scientific argumentation. Because of these frequent examinations, scientific knowledge becomes stronger, leading to its durability.
SC.912.N.3.1 Explain that a scientific theory is the culmination of many scientific investigations drawing together all the current evidence concerning a substantial range of phenomena; thus, a scientific theory represents the most powerful explanation scientists have to offer.
SC.912.E.5.1 Cite evidence used to develop and verify the scientific theory of the Big Bang (also known as the Big Bang Theory) of the origin of the universe.
SC.912.E.5.5 Explain the formation of planetary systems based on our knowledge of our Solar System and apply this knowledge to newly discovered planetary systems.
SC.912.E.6.1 Describe and differentiate the layers of Earth and the interactions among them.
SC.912.E.6.3 Analyze the scientific theory of plate tectonics and identify related major processes and features as a result of moving plates.
SC.912.E.6.5 Describe the geologic development of the present day oceans and identify commonly found features.