chemical and physical features of seawater and the world ocean
TRANSCRIPT
![Page 1: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/1.jpg)
Chemical and Physical Features of Seawater and the World Ocean
![Page 2: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/2.jpg)
The “Weather” of the Marine Environment
• Wind• Waves• Tides• Currents• Temperature• Salt
![Page 3: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/3.jpg)
• Where organisms are found in the marine environment is determined by the chemical and physical factors
• To understand the biology of marine organisms, we must know something about the environment in which they live
![Page 4: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/4.jpg)
The Waters of the Ocean
![Page 5: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/5.jpg)
• Marine organisms are mostly made of water• 80% or more by weight in most cases• Jellyfish – 95%• Water makes life possible
![Page 6: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/6.jpg)
The Unique Nature of Pure Water
• All matter is made of atoms• Elements – made of a single kind of element• Molecules – two or more atoms joined together – ex.
Water• Water molecules stick together because of their polarity• These weak bonds are known as hydrogen bonds
![Page 7: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/7.jpg)
• Hydrogen bonds make water different from any other substance on earth
![Page 8: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/8.jpg)
Three States of Matter
• Solid, liquid, gas• Water is the only substance that naturally occurs
in all three states on earth
![Page 9: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/9.jpg)
![Page 10: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/10.jpg)
Special Characteristics of Water
• In liquid water hydrogen bonds hold most of the molecules together in small groups
• Temperature is a reflection of the average speed of the molecules – faster they move the higher the temperature
• When the molecules move fast enough they escape the hydrogen bonds and enter the gaseous phase (evaporation)
![Page 11: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/11.jpg)
• In water vapor the molecules are not held together by hydrogen bonds
• As water cools the molecules pack closer together and take up less space
• Therefore the density of water increases as water cools until it reaches 4oC
• Below 4oC water becomes less dense• Cool seawater will sink since it is denser
![Page 12: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/12.jpg)
• Once water cools hydrogen bonds reform• Ice crystals (solid made of regular patterns of
molecules)• Water molecules are spaced farther apart than in
liquid water making ice less dense than water• Ice will float on top of water – special property
that makes life in the water possible – insulates water below
![Page 13: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/13.jpg)
Heat and Water
• It takes a large amount of heat to melt ice• As heat energy is added and the temperature of
ice rises, the molecules vibrate faster, breaking some of the hydrogen bonds that hold the crystal together
![Page 14: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/14.jpg)
Latent Heat of Melting
• Amount of heat required to melt a substance
![Page 15: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/15.jpg)
Melting Ice
• Once ice begins to melt added heat breaks more hydrogen bonds rather than increasing the speed of molecular motion
• Any heat put in goes into melting the ice, not into raising the temperature
![Page 16: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/16.jpg)
Heat Capacity
• Amount of heat needed to raise a substance’s temperature by a given amount
• How much heat a substance can absorb• Water has one of the highest heat capacities of
any substance
![Page 17: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/17.jpg)
Importance of Water’s High Heat Capacity
• Most marine organisms are not subjected to the rapid and sometimes drastic temperature changes that occur on land
![Page 18: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/18.jpg)
Latent Heat of Evaporation
• The amount of heat energy that is needed to evaporate a substance
• Change from a liquid to a gas• Water absorbs a great deal of heat when it
evaporates
![Page 19: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/19.jpg)
Water as a Solvent
• Universal solvent• Especially good at dissolving salts• Salts are made of combinations of particles that
have opposite electrical charges• The polarity of water allows it to break down the
salts
![Page 20: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/20.jpg)
![Page 21: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/21.jpg)
• Ion – electrically charged particles• Ions have stronger charges than the ends of water
molecules• When a salt enters water the ions break apart and
become surround by water molecules which break there hydrogen bonds to surround the ion
• Ions pull apart or dissociate and the salt dissolves
![Page 22: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/22.jpg)
Seawater
• Characteristics of seawater are due both to the nature of the pure water and to the material dissolved in it
![Page 23: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/23.jpg)
Solids Dissolved in Seawater
• Come from the chemical weathering of rocks on land and are carried to the sea by rivers
• Earth’s interior – Hydrothermal vents– Volcanoes
![Page 24: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/24.jpg)
Salt Composition
• Solutes – dissolved materials• 6 ions compose over 99% of the solids dissolved in
seawater• Na and Cl account for 85% of the dissolved solids
in seawater
![Page 25: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/25.jpg)
Salinity
• Total amount of salt dissolved in seawater
• Usually expressed as the number of grams of salt left behind when 1,000 grams of seawater are evaporated
1 = dissolved trace elements
![Page 26: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/26.jpg)
• Ions are good conductors of electricity• Electrical conductivity of seawater therefore
reflects the concentration of dissolved ions• Practical Salinity Units – psu – measurement of
salinity determined from conductivity measurements
![Page 27: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/27.jpg)
Importance of Salinity
• Salinity of water greatly affects the organisms that in it
![Page 28: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/28.jpg)
Rule of Constant Proportions
• Percentage of various ions in seawater remains constant even though the total amount of salt in the water can vary slightly
![Page 29: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/29.jpg)
• Oceans are chemically well mixed and ocean salinity varies almost entirely as a result of the addition or removal of pure water rather than the addition or removal of salt
![Page 30: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/30.jpg)
Addition and Removal of Water
• Water is removed from the ocean primarily by evaporation and to a lesser extent by freezing
• Water is added to the ocean by precipitation
![Page 31: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/31.jpg)
Average Salinity of the Ocean
• 35 ppt (parts per thousand)• Red Sea 40 ppt• Baltic Sea 7 ppt (from river runoff)
![Page 32: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/32.jpg)
Salinity, Temperature and Density
• The saltier the water the denser it is
• The density of seawater therefore depends on its temperature and its salinity
![Page 33: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/33.jpg)
Measuring Temperature and Salinity
• Can be measured by lowering specially designed bottles and thermometers on a wire to the desired depth
• A weight called a messenger is released to slide down the wire, triggering the bottles to snap shut and trap a water sample
![Page 34: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/34.jpg)
Temperature Profile
• A graph that shows the temperature at different depths in the ocean
• Water column – vertical shaft of water
![Page 35: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/35.jpg)
![Page 36: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/36.jpg)
Modern Technology
• Oceanographers usually use electronic sensors to quickly and accurately record salinity, temperature and depth throughout the water column, rather than at certain depths
• CTDs – Conductivity Temperature Depth meters• XBTs – Expendable bathythermographs – measure
temperature
![Page 37: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/37.jpg)
Problem
• Measurements can only be made at one place at one time – difficult to get information over a large area
• Ship had to move to a new place to make more measurements
• Conditions change because of currents or weather• Many ships would help but it is expensive
![Page 38: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/38.jpg)
Part Solution
• Make measurements with automated instruments that are left in the ocean
• Satellites can measure surface conditions
![Page 39: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/39.jpg)
Dissolved Gases
• Gases are dissolved in seawater as well as solid materials
• The 3 most important gases are: oxygen, carbon dioxide and nitrogen
• Found in the atmosphere and dissolve at the sea surface
![Page 40: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/40.jpg)
Gas Exchange
• movement of gases between the atmosphere and the ocean surface
![Page 41: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/41.jpg)
• Gases dissolve better in cold than warm water• Dissolved gas concentrations are higher in polar
waters than in the tropics
![Page 42: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/42.jpg)
![Page 43: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/43.jpg)
Oxygen
• Not very soluble• 0 to 8 milliliters per liter of seawater• On average 4 to 6 ml/L• Air has 210 ml/L
![Page 44: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/44.jpg)
Carbon Dioxide
• More soluble than oxygen because it reacts chemically when it dissolves
• 80% of the dissolved gas in the ocean• .04% in air• Stores more than 50 times as much total CO2 as
the atmosphere
![Page 45: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/45.jpg)
![Page 46: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/46.jpg)
Transparency
• Biologically important property• Sunlight can penetrate into the ocean• Allows for photosynthesis• Not all colors penetrate seawater equally well• Water is most transparent to blue light
![Page 47: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/47.jpg)
• As depth increases more colors are filtered out• Red is the first to be filtered out• Something that is red at the surface looks black or gray at
depth because there is no red light to reflect off them and be seen
• At depths of 1000 m or 3300 ft there is total darkness
![Page 48: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/48.jpg)
![Page 49: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/49.jpg)
![Page 50: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/50.jpg)
![Page 51: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/51.jpg)
Turbidity
• Transparency of water is strongly affected by material that is suspended and dissolved in the water
• Ex. Muddy water, lots of plankton
![Page 52: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/52.jpg)
![Page 53: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/53.jpg)
Pressure
• Factor that changes dramatically with depth• On land – 1 atm of pressure• With each 10m (33 ft) of increased depth another
atmosphere of pressure is added• As the pressure increases the gases are compressed –
limits range of orgs – ex. Swim bladder
![Page 54: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/54.jpg)
![Page 55: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/55.jpg)
Water Density and the Three Layered Ocean
![Page 56: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/56.jpg)
• Much of the three dimensional structure of the sea, especially in relation to depth is controlled by the density of the water
![Page 57: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/57.jpg)
Stability and Overturn
• Densest water sinks so the ocean is usually layered or stratified
• Deep water – cold and dense• Surface water – warm and light
![Page 58: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/58.jpg)
Water Column Stability
• Stable Water Column - Less dense on top, dense on bottom
• Low stability – surface water is only slightly less dense
• Highly stable – large density difference• Unstable – surface water more dense than
bottom water
![Page 59: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/59.jpg)
• Downwelling – when surface water sinks • Overturn – when dense surface water displaces
deeper water• Temperature and density profiles are vertical
straight lines for water columns experiencing overturn
![Page 60: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/60.jpg)
![Page 61: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/61.jpg)
• Overturn usually occurs in temperate and polar regions during the winter when the surface water cools
• The water descends to a depth determined by its density
![Page 62: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/62.jpg)
• The processes that change salinity in the open ocean (precipitation, evaporation and freezing) occur only at the surface
• Temperature changes occur only at the surface
![Page 63: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/63.jpg)
Water Mass
• Once surface water has sunk its properties do not change
• The volume of water has a “fingerprint”, a characteristic combination of temperature and salinity
• Oceanographers can tract the movement or circulation of water masses
![Page 64: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/64.jpg)
Thermohaline Circulation
• Circulation driven by changes in density which in turn is determined by temperature and salinity
• Extend throughout the ocean depths• Important in regulating earth’s climate and chemically
mixing the oceans• Brings dissolved oxygen to the deep sea• Helps determine the abundance of life in the deep sea
![Page 65: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/65.jpg)
The Three-Layered Ocean
![Page 66: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/66.jpg)
Surface Layer
• 100 to 200 m thick (330 to 660 ft)• Mixed by wind, waves and currents• Also known as the mixed layer
![Page 67: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/67.jpg)
Thermocline
• Sudden changes in temperature over small depth intervals
• seasonal
![Page 68: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/68.jpg)
Intermediate Layer
• Below the surface layer of around 1500 m (5000 ft)
• Contains the main thermocline
![Page 69: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/69.jpg)
Main Thermocline
• zone of transition between warm surface water and cold water below
• lies in the intermediate layer• rarely breaks down• feature of the open ocean
![Page 70: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/70.jpg)
Deep and bottom layers
• Below 1,500 m or (5,000 ft)• Uniformly cold
• Typically less than 4oC (39 oF)
![Page 71: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/71.jpg)
Motion in the Ocean
![Page 72: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/72.jpg)
Surface Circulation
• Most intense motion of the ocean occurs at the surface in the form of surface currents and waves
• Driven by wind which is driven by heat from the sun
• Coriolis effect also strongly influences
![Page 73: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/73.jpg)
Coriolis Effect
• Earth is round and rotating so anything that moves over its surface tends to turn a little rather than moving in a single straight line
• Mostly effects winds and ocean currents that move over large distances
![Page 74: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/74.jpg)
![Page 75: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/75.jpg)
• Northern Hemisphere – deflects things to the right
• Southern Hemisphere – deflects things to the left
![Page 76: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/76.jpg)
Winds Patterns
• Winds in our atmosphere are driven by heat energy from the sun
• Most of the solar energy is absorbed near the equator
• Warm air rises at the equator• Air from adjacent areas gets sucked in to replace
the rising equatorial air creating wind
![Page 77: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/77.jpg)
• The wind does not move straight to the equator but are bent by the Coriolis effect – approach at a 45 angle
![Page 78: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/78.jpg)
![Page 79: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/79.jpg)
![Page 80: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/80.jpg)
Trade Winds
• winds near the equator (northeast and the southeast)
• steadiest winds on earth • between 0 and 30 degrees
![Page 81: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/81.jpg)
Westerlies
• driven by solar energy• more variable • between 30 and 60 degrees • move in the opposite direction to the trade winds
![Page 82: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/82.jpg)
Polar Easterlies
• Most variable• Between 60 and 90 degrees
![Page 83: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/83.jpg)
Surface Currents
• The major wind fields of the atmosphere push the sea surface creating currents
• All major surface currents of the open ocean are driven by the wind
![Page 84: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/84.jpg)
• When pushed by the wind the uppermost layer of water begins to move
• The water does not move in the same direction as the wind but at a 45o angle because of the Coriolis effect
• The top layer pushes the water below but at a 45o angle and so on
![Page 85: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/85.jpg)
Ekman Spiral
• Spiral change in the movement in the water column when the water is pushed by the wind
• At a depth of a few hundred meters the wind in not felt at all
• Ekman Layer – upper part of the water column that is affected by the wind
![Page 86: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/86.jpg)
![Page 87: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/87.jpg)
• Ekman transport – taken as a whole the Ekman layer moves at 90o from the wind direction
![Page 88: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/88.jpg)
Consequence of the Coriolis Effect
• Trade winds move towards the equator the equatorial currents that these winds produce move parallel to the equator
![Page 89: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/89.jpg)
Gyres
• Wind driven surface currents combined into huge more less circular systems
• Under the influence of the Coriolis Effect
![Page 90: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/90.jpg)
Transportation of Solar Heat
• Warm currents on the western sides of the gyres carry vast amounts of solar heat from the equator to higher latitudes
• Cold currents flow in opposite direction on the eastern sides
• Ocean currents act as a giant thermostat warming the poles and cooling the tropics
![Page 91: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/91.jpg)
![Page 92: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/92.jpg)
• Large scale fluctuations in current patterns can dramatically effect weather around the world - El Nino
![Page 93: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/93.jpg)
Role of Surface Currents
• Surface water temperatures are higher on the western sides of the oceans where currents carry warm water away from the equator
![Page 94: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/94.jpg)
Waves
![Page 95: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/95.jpg)
Waves
• Wind causes• Most familiar of all ocean phenomena• Affect the organisms that live on the shore
![Page 96: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/96.jpg)
Wave Parts
• Crest – highest part of a wave• Trough – lowest part of a wave• Wave Height – vertical distance between trough
and crest• Wavelength – distance between two successive
crests or troughs• Period – time a waves takes to go by any given
point
![Page 97: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/97.jpg)
![Page 98: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/98.jpg)
Water Movement
• In a wave crest, water moves up and forward• In a wave trough, water moves down and back• On the whole water particles do not go anywhere
at all – just move in circles• Waves carry energy across the surface, not water
![Page 99: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/99.jpg)
![Page 100: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/100.jpg)
Formation of waves
• Begins when the wind starts to blow• The faster and longer the wind blows the larger
the waves get• Fetch – span of open water over which the wind
blows – determines size of waves
![Page 101: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/101.jpg)
![Page 102: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/102.jpg)
Seas
• waves that have sharp peaks and relatively flat wave troughs
![Page 103: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/103.jpg)
Swells
• Waves with smooth rounded crests and troughs• Similar to ideal waves
![Page 104: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/104.jpg)
Surf
• Waves that becomes so high and steep as it approaches the shoreline that it breaks
• Waves become closer together
• Energy is released on the shoreline when the wave breaks
![Page 105: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/105.jpg)
Tsunamis
• Deadly waves• Japanese word for “harbor wave”• Produced by earthquakes, landslides, volcanoes,
and other disturbances of the sea floor• Tidal waves – properly called – seismic sea
waves
![Page 106: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/106.jpg)
• Long fast moving waves• Wavelengths of 240 km (150 mi)• Travel 700 km/hr (435 mi/hr) – as fast as a jet
plane• Open ocean – not very high – 1 m
![Page 107: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/107.jpg)
Warning
• Worldwide network of seismic monitoring stations that provide instant notice of an earthquake or other seismic disturbance
• System has saved lives but is far from perfect• Can’t predict which earthquakes produce killer tsunamis • Also many people in developing countries do not get the
warnings
![Page 108: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/108.jpg)
Tides
![Page 109: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/109.jpg)
Tides
• Dominant influence on near shore sea life• Expose and submerge organisms on the shore• Drive the circulation of bays and estuaries• Triggers spawning
![Page 110: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/110.jpg)
Causes of the Tides
• Caused by the gravitational pull of the moon and sun by rotations of the earth moon and sun
• Earth and the moon rotate around a common point (their combined center of mass)
• This rotation produces a centrifugal force
![Page 111: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/111.jpg)
• The centrifugal force just balances the gravitational attraction between earth and the moon
• The centrifugal force and the moon’s gravity are not in perfect balance everywhere on earth’s surface
![Page 112: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/112.jpg)
• On the side nearest the moon, the moon’s gravity is stronger and pulls the water toward the moon
• On the side away from the moon the centrifugal force dominates and pushes the water away from the moon
![Page 113: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/113.jpg)
• If earth were completely covered with water, the water would form two bulges on opposite sides of the planet
• Water would be deep under the bulges and shallower away from the bulges
![Page 114: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/114.jpg)
• Earth is spinning like a top on its own axis• As it does this any given point would be under the
bulge and then away from the bulge• High tide occurs when a point is under a bulge
and low tide occurs when it is away from a bulge
![Page 115: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/115.jpg)
• The earth rotates on its axis every 24 hours so a point will have two high tides and two low tides
• The moon advances on it orbit each day so a full tidal cycle takes 24 hours and 50 minutes
![Page 116: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/116.jpg)
![Page 117: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/117.jpg)
![Page 118: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/118.jpg)
The Sun’s Bulge
• Sun produces a bulge like the moon but is it smaller
• When the sun and the moon are in line there bulges add up and when they are at right angle to one another they cancel each other out
![Page 119: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/119.jpg)
Tidal Range
• Difference in water level between successive high and low tides
![Page 120: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/120.jpg)
Spring Tide
• When the sun and moon bulge add together• High high tides and low low tides• Named because they seem to surge up like
spring water• Occur when there is a full or new moon
![Page 121: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/121.jpg)
Neap Tide
• Occur when sun and moon are at right angles to one another
• Moon is in the 1st and 3rd quarters• Average tides• Low high tide and a high low tide
![Page 122: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/122.jpg)
![Page 123: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/123.jpg)
Variations in Tides
• Tides vary from place to place depending on the location and on the shape and depth of the basin
![Page 124: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/124.jpg)
Bay of Fundy, Canada
![Page 125: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/125.jpg)
![Page 126: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/126.jpg)
![Page 127: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/127.jpg)
![Page 128: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/128.jpg)
Tide Terms
• Semidiurnal tides – two high and two low tides• Mixed semidiurnal tides- successive high tides of
different height• Diurnal Tides – one high and one low -
uncommon
![Page 129: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/129.jpg)
Tide Tables
• Give the predicted time and height of high and low tides
• Very accurate
![Page 130: Chemical and Physical Features of Seawater and the World Ocean](https://reader036.vdocuments.mx/reader036/viewer/2022062300/56649dc85503460f94abddcc/html5/thumbnails/130.jpg)
The End