Oceanography Notes-Test 1 Info PDF

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Professor Goodbred, All of the notes needed for Test #1 ...

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EES-1030: Oceanography Professor Steve Goodbred

1/10 Intro What roles do the oceans play on our planet? -climate stabilization, habitat for living What roles do the oceans play in our society? -food (produces ½ of all food on Earth), tourism (3.5 billion people live close to coastlines), transportation, natural disasters ex. Hurricanes, tsunamis, flooding What roles do humans play in the oceans? -oil drilling (fossil sediments like plankton=petroleum), pollution, overfishing, ● High specific heat (does not change temp very easily), expands when it freezes (why ice is less dense and floats), water takes a lot of energy to evaporate, water vapor has a lot of heat locked in ● Oceans about 3 miles deep, light only penetrates about 100m deep ● ¼ of Earth’s energy is generated by microscopic organisms ex. Plankton ● Coasts=20% of area of oceans, half of food in ocean produced here ● Upwelling zones=1% of area of oceans, half of food in ocean produced here, deep ocean water filled with nutrients are brought to the surface ● Runoff of nutrients from land are what makes coasts so prosperous

1/12 Origins ● ● ● ● ● ●

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Modern universe has origin with Big Bang-14 billion years ago, continuously expanding Earth-4.6 billion years ago, oldest preserved rocks-4 million Galaxies the furthest away from us are moving the fastest All matter began as hydrogen and helium, two lightest elements, fuse primal elements to make other elements Atomic #-number of protons, determines what element is is, atomic massprotons+neutrons, isotope-same element, different number of neutrons Nucleosynthesis: lower weight elements such as carbon, oxygen, and others are a byproduct of fusion reactions in smaller-sized stars, such as our Sun, hydrogen fusion at 10 million degrees C, heavier metals up to iron and nickel are a by-product of fusion reactions in larger stars (5-10x) bigger than our Sun, heaviest elements come from supernovas (explosions of stars when they reach the end of their life cycle) Lighter gases are more abundant because they are more easily and frequently created, rarest elements are formed through supernovas Nebula: clouds of dust and debris, gravitation draws gases to center of the nebula, where temp rises high enough to initiate nuclear fusion (what powers our Sun) Force of gravity=(m1 x m2)/distance2

● Ideal gas law: R=PV/nT, R=ideal gas constant, P=gas pressure, V=volume, n=amount of gas, T=temperature ● Temp very high near the Sun, only elements with high boiling points such as iron can condense there, Mercury=ball of iron ● Further from the Sun, cooler temperatures allow intermediate-mass elements/molecules to condense ex. Water, silicon, oxygen ● Molecules with lowest boiling points accumulated beyond rocky planets to form the large outer planets, which are comprised of gases ● Frozen water has been found on almost every planet in the solar system ● Moons (of outer planets), rings (of outer planet), inner planets (at poles), comets, Pluto are also comprised of frozen water ● Liquid water on Venus (highly acidic), Earth, and Mars ● Density stratification: molten interior maintained as heat was generated through collision of gas, dust, meteors, and gravitation, heavier elements drawn to Earth’s center by gravity, lighter elements stay near the surface, Earth’s core=iron and nickel ● Crust: thin, solid, mostly light elements (aluminum, silicon) ● Mantle: viscoelastic (deformable), composition like crust but enriched in heavy elements (iron, magnesium) ● Outer core: liquid, mostly iron, other heavy elements ● Inner core: solid, mostly iron, other heavy elements ● Earth’s geodynamo: generated by the circulating molten metal of Earth’s outer core, interacting with its rotating solid-metal inner core, electromagnetic field, protects Earth’s outer atmosphere (including the ozone layer) from being stripped away by solar winds ● Ocean crust (5-10km) is thinner than continental crust (20-100 km)=3000m deep, (Atlantic 29%, Indian 21%, Pacific 50%) ● Sub-bottom seismic profiling: used to measure the depth of the oceans by analyzing reflection times, used by oil wellers to find petroleum within the underwater rock layers, goes into the seabed/multiple rock layers ● Great Barrier Reef being buried underneath New Guinea as Australia moves northwards, the reef cannot survive below the Tropic of Capricorn due to cold waters

● Multibeam sonar: seafloor mapping, time and strength of the returned sound signal are recorded to measure depth ● Ocean circulation attracts animals, mineral rich water is brought to the surface which facilitates plant growth, marine animals flood to areas with a wide array of food ● Seafloor mapping with satellites-TOPEX ● Mid-ocean ridges: hydrothermal vents---> rich biological community ● Vent towers (black smokers): rich in metals, high potential for future economic development ● Atoll: as seamount subsides, corals grow upwards

1/31/17 (cont.) ● Bikini Atoll-1946 atomic bomb test site ● Continental shelf, shelf break, continental slope, continental rise, abyssal plain (deepest part of the ocean) ● Submarine canyons occurs from turbidity currents (sediment rich waters), graded beddings occurs when turbidity currents come to rest ● Turbidites: large sediment filled currents (can be caused by earthquakes), continental slope fails, can cause tsunami ex. Nova Scotia earthquake in 1929 ● Gas hydrates: bacteria generate gas (methane) which mixes with water and lowers freezing point and creates ice ● Gas release causes a landslide ● Passive margin: faces a divergent plate boundary, not tectonically active, large continental shelf ● Active margin: faces convergent plate boundary, high tectonic activity, narrow continental shelf, steep ● Fall line (creates little water falls which facilitate trade and transportation for cities) is the transition between piedmont (short hills with bright orange/red soil, old coastal plain) and coastal plain ● Hinge line: transition between area going up and area going down

2/2/17 (cont.) ● Accretionary wedge: marine rocks and sediments uplifted during subduction ● Carbonate platforms: biological continents, formation of calcium carbonate from seawater, made of sediments produced by organisms ex. Florida ● Rainwater has a pH of 6 (slightly acidic) from carbon dioxide in the air that dissolves into the rain, slightly acidic rain causes rocks to erode more quickly

Seawater ● Oxygen is missing 2 electrons in the outer valence electron shell, borrows these electrons

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from two hydrogen atoms, electron pairs that are shared with hydrogen are slightly weaker and displaced to one side of the molecule, bent orientation of molecule=dipole (has a positive and negative side) Water molecules bond together by hydrogen bonds which are responsible for high surface tension (cohesion) and capillary action (adhesion) Formation at 104.5 degrees but bond angle must relax to 109 degrees for ice crystals to form, greater bond angle increases the space that molecule takes up therefore decreasing density Water is a universal solvent because it is dipolar, can bond with both cations (positively charged particles) and anions (negatively charged particles) When water changes from liquid to solid, density DECREASES, which is a behavior unique to water Heat capacity: the amount of energy (heat) it takes to raise the temperature of one gram of a material one degree Celsius, water has an usually high specific heat, requires a lot of energy to get water temperature to increase by one degree because of hydrogen bonds (only natural substance with a higher specific heat is liquid ammonia) Sensible heat: gain/loss of heat as reflected by temperature change, 1 calorie/gram/degree centigrade Latent heat: gain/loss of heat associated with a state change Latent heat of melting: solid to liquid (80 calories per gram of water), latent heat of fusion: liquid to solid (-80 calories per gram of water), latent heat of evaporation: liquid to gas (540 calories per gram of water), latent heat of condensation: gas to liquid (-540 calories per gram of water)

2/7/17 Ocean Heat Capacity and Climate ● Water density: temperature and salinity, temp major control on density in warmer waters, salinity dominant control in cold water, waters of diff temp and salinity can have the same density ● Density stratifies the water column into thin surface water (well mixed, receives light), pycnocline: zone of rapid density change (separates surface water and deep ocean and keeps them from mixing), deep ocean (80% of ocean water, relatively homogenous) ● Thermocline: zone of rapid temp change-tropical and temperate regions (huge effect in oceans and lakes), halocline: zone of rapid salinity change (melting glaciers or large rivers responsible for more fresh water) ● Polar waters=no stratification b/c surface water is just as cold as the deeper ocean, lack of stratification allows life to prosper, temperate regions=moderately stratified, tropical regions=highly stratified ● Warm temp=low density, goes to top ● Average temp of deep ocean=4 degrees centigrade (MOST DENSE) ● Light is absorbed quickly into water, particularly long wavelengths (infrared, red, orange,

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yellow), most heat (infrared) is absorbed by the shallowest part of the oceans, 1% of sunlight reaches 100 m depth in pure ocean water Photic zone: depth to which 1% of light penetrates (zone in which photosynthesis can occur) Sound travels faster in water than it does in air, cannot sense direction (1500 m/sec compared to 340 m/s in air) Speed of sound increases with temperature and pressure (faster at ocean surface-warm, and deep ocean-high pressure) Refraction: traps sound in the minimum-velocity zone ex. SOFAR zone=communication line for marine mammals and the Navy

Ocean Chemistry ● Water molecules form hydrogen bonds at edges of salt crystal, ions become dissociated from salt crystal and water surrounds the ions=dissolved state ● Higher concentration of salt in oceans than freshwater (1000x) ● Salt in freshwater from eroded rock, ions added to ocean by river discharge, volcanic eruptions and hydrothermal activity at mid-ocean ridge, removed by biological processes ● Some trace elements are needed for plant photosynthesis ex. Nitrogen, Phosphorus (macro-nutrients), and some trace elements are needed by marine plants and animals in smaller quantities ex. Iron, Zinc, Copper (micro-nutrients), trace elements (iron and silica) ● Freshwater: carbonate, calcium, Seawater: sodium, chloride, calcite, carbonate ● Nitrogen gas is not accessible to marine life as N2, needs to be broken down by specialized bacteria ● Carbon dioxide lowest at the surface, amount increases as you go deeper into the ocean ● Oxygen highest concentration at surface b/c photosynthesizing organisms are there, slightly increases at deeper ocean because of circulation...