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.