for education may be it have mistakes so ignore it

1. Four Major Oceans plus Arctic Ocean and nine or so Seas
Oceans and Coastal ProcessesOceans and Coastal Processes
FlashlightFlashlight
GlobeGlobe

2. Recall Ocean
Depths
depend on the
Plate Tectonic
Province:
(0-150
meters)
~4 km
(less than 3 km)
7 to 11
km
(4-7
miles)

3. Sea Level ChangesSea Level Changes
• Rapid seafloor spreading expands the
mid-ocean ridge displacing water and
raising sea level.
• Sea level slowly drops during Ice Ages
when substantial volumes of ocean water
are locked up in ice sheets.
• Sea Level rises "suddenly" when glaciers
melt

4. Ocean Salinity
• Dissolved “Salts” are ions from weatheringDissolved “Salts” are ions from weathering
• Salinity in surface water averages ~35 partsSalinity in surface water averages ~35 parts
per thousand.per thousand.
• Salinity variation more extreme in coastalSalinity variation more extreme in coastal
waters.waters. River input, evaporation in lagoonsRiver input, evaporation in lagoons
• Salinity and temperature change with depth -Salinity and temperature change with depth -
rapid change salinity (saltiness) at therapid change salinity (saltiness) at the haloclinehalocline..
• Salt water is more dense than fresh waterSalt water is more dense than fresh water
• Ice is less dense than liquid water (so it floats)Ice is less dense than liquid water (so it floats)
• Ice is freshwater, recall most fw in ice capsIce is freshwater, recall most fw in ice caps

5. Ocean TemperaturesOcean Temperatures
• Ocean temperatures of 27Ocean temperatures of 27oo
C are typical ofC are typical of
tropical surfacetropical surface
• Waters and temperatures of 2Waters and temperatures of 2oo
C areC are
typical for deep ocean waters.typical for deep ocean waters.
• Cold water is more dense than warmCold water is more dense than warm
water. It will move under less dense water.water. It will move under less dense water.

6. Salinity varies w/ temperature and
ocean current mixinglow salinity of arctic – isolated low evap cold, freshwater rivers and snow
ocean: 33-37 ppt high 36-37 at +/- 30o,
high evap, low eq 34 trop rain
40 ppt Red Sea

7. Salinity shown in cross-section of ocean in ppt
Southern Hemisphere Summer Saltiest at 23.5S South Latitude
Sun overhead, more evaporation

8. Solar HeatingSolar Heating
• The equator receives 2.5 times more sunlightThe equator receives 2.5 times more sunlight
((insolationinsolation [photons / m[photons / m22
])]),, incoming solarincoming solar
radiation, than the poles.radiation, than the poles.
• Highest average annual ocean surfaceHighest average annual ocean surface
temperatures (~27temperatures (~27oo
C) at equatorC) at equator
• Lowest 0Lowest 0oo
C atC at
high latitudeshigh latitudes
Demo, FlashlightDemo, Flashlight
GlobeGlobe
23.5

10. HeatHeat versusversus TemperatureTemperature
• When heat something, its temperature rises.When heat something, its temperature rises.
• Heat isHeat is thethe total energytotal energy of molecular motion in aof molecular motion in a
substance. Heat energy depends on the speed of thesubstance. Heat energy depends on the speed of the
particles,particles, the number of particlesthe number of particles (the size or mass),(the size or mass),
and the type of particles in an object.and the type of particles in an object.
• Temperature isTemperature is a measure of thea measure of the average energyaverage energy
of molecular motion in a substance. Temperature doesof molecular motion in a substance. Temperature does
not depend on the size or type of object.not depend on the size or type of object.
• For example, the temperature of a small cup of waterFor example, the temperature of a small cup of water
might be the same as the temperature of a large bathtubmight be the same as the temperature of a large bathtub
of water, but the tub of water has more heat because itof water, but the tub of water has more heat because it
has more water and thus more total thermal energy.has more water and thus more total thermal energy.

11. Water thermal properties 1Water thermal properties 1
• 1. Heat capacity C1. Heat capacity Cpp water very high. Water can storewater very high. Water can store
huge amounts of heat without raising temperature.huge amounts of heat without raising temperature.
The bonds vibrate faster, but the water molecules HThe bonds vibrate faster, but the water molecules H22OO
need not speed up.need not speed up.
•
• CCpp water = 4.2 x Cwater = 4.2 x Cpp airair
Heat Capacity: heat to raise 1 cmHeat Capacity: heat to raise 1 cm33 substance 1substance 1oo
CC
• Ocean heat storage plays a crucial role in controllingOcean heat storage plays a crucial role in controlling
global climate patterns.global climate patterns.
http://hendrix.uoregon.edu/~stanm/phys162s2003/PHYS162/Heat_Capacity.html

12. Water thermal properties 2Water thermal properties 2
• DensityDensity ρρ is mass/unit volumeis mass/unit volume
• Salt water is denser than fresh waterSalt water is denser than fresh water
• Cold water denser than warm water.Cold water denser than warm water.
• Freshwater Ice forms at -2Freshwater Ice forms at -2oo
C fromC from
saltwater. Less dense than Saltwater,saltwater. Less dense than Saltwater,
floatsfloats
• Remaining Seawater is saltier, denserRemaining Seawater is saltier, denser

13. Average Annual Sea-Surface Temperature
~30C Equator, 0C Poles, average temp for a
latitude maintained by currents
Poles should be much colder, but currents carry warm equatorial water poleward

14. Temperature and Currents
• Surface waters (<300 m) warmed by SunSurface waters (<300 m) warmed by Sun
• Currents cause thermal mixing: results inCurrents cause thermal mixing: results in
relatively uniform surface temperature byrelatively uniform surface temperature by
latitude.latitude.
• The impact of current activity on climateThe impact of current activity on climate
diminishes with depthdiminishes with depth

15. Temperature and DepthTemperature and Depth
• Temperatures exceed 20Temperatures exceed 20oo
C over tropicalC over tropical
ocean's surface, 2ocean's surface, 2oo
C below 2,000 m.C below 2,000 m.
• The depth zone in whichThe depth zone in which
temperature decreases rapidly is called thetemperature decreases rapidly is called the
thermoclinethermocline
1000 m
2000 m

16. Continents and ClimateContinents and Climate
• Over two-thirds of Earth’s surface isOver two-thirds of Earth’s surface is
ocean.ocean.
• CurrentsCurrents started by prevailingstarted by prevailing windswinds
• Currents deflected by continent positionsCurrents deflected by continent positions
and Earth’s rotationand Earth’s rotation
• Climates caused by current and windClimates caused by current and wind
circulationcirculation

17. Ocean Currents
• Again, ocean currents started by winds.Again, ocean currents started by winds.
• Winds are ultimately caused by equator toWinds are ultimately caused by equator to
poles insolation (heat from Sun) differencespoles insolation (heat from Sun) differences
• Winds drag surface waters as surface currentsWinds drag surface waters as surface currents
• Winds and currents are influenced by Earth'sWinds and currents are influenced by Earth's
rotation (Coriolis effect).rotation (Coriolis effect).
• Currents influenced by distribution of continentsCurrents influenced by distribution of continents

18. Coriolis Effect
Air masses at rest above the
equator are moving much
faster than air masses at rest
over us in NJ.
Both must rotate once per
day, but the equatorial air
goes much further.

19. Coriolis Effect
Air in Northern Hemisphere
deflects to the right, reverse in Southern H.
Equatorial Air has faster spin as it moves toward poles
it still has it , so it is faster than land below
DEMO: Coriolis Clip

20. Winds Start CurrentsWinds Start Currents
• Air molecules in wind push water moleculesAir molecules in wind push water molecules
3-4% of wind speed.3-4% of wind speed.
• Wind moving nearly parallel to latitude as aWind moving nearly parallel to latitude as a
result of Coriolis deflection.result of Coriolis deflection.
• West-pushed ocean currents form near equator,West-pushed ocean currents form near equator,
east-pushed ocean currents form about 50east-pushed ocean currents form about 50oo
LatitudeLatitude
• Continents deflect or prevent current flowContinents deflect or prevent current flow
• Results in circular current called a gyre.Results in circular current called a gyre.

21. Example: Generation of
North Pacific Gyre
Maximum
heat from
Sun
Define “Insolation”
= radiation from sunlight
DEMO: globe,
flashlight if not done previously
The major wind cells
Convection

22. Gyre CCW
Gyre CW
Surface Currents
(Influence Climate)
Note Warm Currents not past
S 60o
Latitudes
West pushed flow near equator
East pushed flow near 50 degrees
West pushed flow near equator
East pushed flow near 50 degrees
Winds push currents

23. Western Boundary
Currents
• Winds cause water to pile up along the westernWinds cause water to pile up along the western
subtropical sides of major oceans.subtropical sides of major oceans.
• Generate fast-flowing currentsGenerate fast-flowing currents that redistributethat redistribute
warm tropical waters toward the poles.warm tropical waters toward the poles.
• Gulf Stream, Kuroshio, Brazil currents are “WestGulf Stream, Kuroshio, Brazil currents are “West
Side” marine rivers, relatively narrow (less thanSide” marine rivers, relatively narrow (less than
100 km across) but deep water masses.100 km across) but deep water masses.
• Flow at speeds of 100 to 200 km/day forFlow at speeds of 100 to 200 km/day for
thousands of kilometers, from equator to highthousands of kilometers, from equator to high
latitudeslatitudes

24. Eastern Boundary CurrentEastern Boundary Current
• Eastern boundary currents (Eastern boundary currents ( Canary,Canary,
California, Peru) complete the eastern leg ofCalifornia, Peru) complete the eastern leg of
each gyreeach gyre
• Wider, carry less water, and move more slowly.Wider, carry less water, and move more slowly.
• The Canary current, nearly 1,000 km (625 miles)The Canary current, nearly 1,000 km (625 miles)
wide but very shallowwide but very shallow
• 1/3 water of Gulf Stream and travels at 301/3 water of Gulf Stream and travels at 30
km/daykm/day
• 2/3 continues as cold deep salty current2/3 continues as cold deep salty current

25. North Atlantic Deep Water
(NADW) down here
WIND

26. ThermoHaline
Conveyer Belt AKA
Global Ocean
Conveyer Belt
Evaporation and Ice
formation increases
saltiness and density.
Dense water
sinks
forms NADW
Winds blow
surface
waters west,
forcing deep
water up to
surface
where it
warms
Wallace Broecker
Columbia University
Arc shallowing lifts
cold deep water

27. Shores and Coastal ProcessesShores and Coastal Processes
• Shorelines are places where bodies of waterShorelines are places where bodies of water
meet dry landmeet dry land
• Coasts are landward of ocean shorelinesCoasts are landward of ocean shorelines
• Beach: a narrow strip of land, washed byBeach: a narrow strip of land, washed by
waves or tides .waves or tides .
• Ordinary Waves are caused by WINDOrdinary Waves are caused by WIND
– Waves are produced when wind drag causes theWaves are produced when wind drag causes the
surface water of oceans/lakes to rise and fallsurface water of oceans/lakes to rise and fall
- Waves get refracted on approaching shoreline- Waves get refracted on approaching shoreline

28. Typical CoastTypical Coast

29. Parts of A WaveParts of A Wave
Waves are caused by _____________?
Fetch – length of unobstructed wind
Southern Ocean inc. Straits of Magellan
Dana ‘Two Years Before the Mast’

30. Oscillatory and Translatory MotionOscillatory and Translatory Motion

31. Wave RefractionWave Refraction
Still a small ‘longshore component

32. Longshore Currents (Swash andLongshore Currents (Swash and
Backwash)Backwash)
Longshore current is produced as waves
reflect from coastline. Swash and
backwash

33. Rip CurrentsRip Currents
Sand Bar
Cut in Bar
Rip Currents are produced when storms cut holes in sandbars just offshore.

34. TidesTides
• Daily rise/fall of surfaces of oceans/lakes due
to gravitational pull of the Moon/Sun on the
Earth– also due to force created as Earth spins
on its axis
• Flood tides- elevate sea surface that cause
shoreline to move inland
• Ebb Tides- low sea surface that cause
shoreline to move seaward

35. Tidal BulgesTidal Bulges
Affect of the Sun Much less
Why?
Tides mostly caused by the Moon
A mass in circular motion
accelerates toward the axis
of rotation. This centripetal
acceleration is exerted on
the mass by some other
object,say a string held in
my hand. The mass exerts
an equal and opposite force
on the object, the centrifugal
force.

36. The Effect of Tides On ShorelinesThe Effect of Tides On Shorelines ––
River Hebert in Nova ScotiaRiver Hebert in Nova Scotia
Source: Clyde H. Smith/Peter Arnold, Inc.
Tidal Bore flows upstream

37. Large Tidal ExtremesLarge Tidal Extremes
Source: William E. Ferguson
•Bay of Fundy tides reach16 m (about
53 ft) at the head of the bay. The 12.4
hour period of the twice daily lunar tides
is close to the natural back and forth
sloshing period of the bay.

38. Rising Tide at Bay of FundyRising Tide at Bay of Fundy
Source: William E. Ferguson
Maximum

39. Coastal Erosion (Crashing Surf)Coastal Erosion (Crashing Surf)
Wave erosion occurs whenWave erosion occurs when
deep water waves hit the shoredeep water waves hit the shore
with full force. Air and waterwith full force. Air and water
are forced into cracks at highare forced into cracks at high
pressurepressure

40. Crashing Surf, Oregon CoastCrashing Surf, Oregon Coast
Source: Criag Tuttle/The Stock Market
Fast Erosion

41. Erosional Coastal LandformsErosional Coastal Landforms
Submerged Shallow
Area Bends Waves

42. Erosional Coastal LandformsErosional Coastal Landforms

43. Sea Caves on Cape Kildare, Prince Edward Island, Canada)Sea Caves on Cape Kildare, Prince Edward Island, Canada)
Source: John Elk/Bruce Coleman

44. Deposition of A TomboloDeposition of A Tombolo

45. A Tombolo Landward of A Sea StackA Tombolo Landward of A Sea Stack –– Big Sur,Big Sur,
CaliforniaCalifornia
Source: Cliff Wassmann

46. Coastal ProtectionCoastal Protection
• Riprap/Seawall- protects shore lines
• Breakwaters – Stabilize beaches
• Jettys – Keep inlets clear

47. Beach-Protection StructuresBeach-Protection Structures -- RiprapRiprap
Source: Jack Dermid /Photo Researchers, Inc.

48. Beach-Protection StructuresBeach-Protection Structures ––
Seawall Along the Gulf Coast of LouisianaSeawall Along the Gulf Coast of Louisiana
Source: Martin Miller

49. BreakwatersBreakwaters

50. Breakwaters off Cape May, NewBreakwaters off Cape May, New
JerseyJersey
Source: John S. Shelton

51. JettiesJetties

52. Jetty in Miami Beach, FloridaJetty in Miami Beach, Florida
Source: Townsend P. Dickinson

53. Components of A Typical BeachComponents of A Typical Beach
•A beach is a dynamic narrow
segment of coast washed by
waves/tides and covered with
sediments
•Foreshore is the area
between low tide and high
tide
•Backshore is the area
between high tide and sea
cliff or inland vegetation
line
•Beach face is the
steepest part of Foreshore
•Berm is a horizontal

54. Transport and DepositionalTransport and Depositional
FeaturesFeatures
• Recall Longshore Drift sand moved by
LSC
• Spit is a finger-like ridge of sand deposited
where Longshore drift encounters deeper
water
• Hook is a curved spit
• Baymouth is a spit that covers the access
to a bay – fills with sediment

55. Deposition Spits, Hooks, and BaymouthDeposition Spits, Hooks, and Baymouth
BarsBars

56. Organic CoastsOrganic Coasts
• Fringing Reef- initially surround land, grow
seaward
• Barrier Reef- separated from coast by a
lagoon
• Atoll- circular structure from great depth that
encloses shallow lagoon
• Mangroves

57. Evolution of Coral AtollsEvolution of Coral Atolls
Remember Guyots?Remember Guyots?
Charles Darwin coral larvae are planktonic

58. Wake Island, a Coral AtollWake Island, a Coral Atoll
Source: William E. Ferguson

59. Typical Mangrove Coast,Typical Mangrove Coast,
FloridaFlorida
Source: S. J. Krasemann/Peter Arnold, Inc.
“Make your own island”

60. Steep ShoreSteep Shore
Source: William Boyce/Corbis
Steep Cliffs may occur at new Divergence (Red Sea)
or near a Trench (Oregon Coast)
Headlands, benches, sea arches, stacks, tombolos
All other things
being the same,
steep cliffs
easier to erode
than gentle
slope
Define Active MarginDefine Active Margin

61. Island Arcs protect coastlineIsland Arcs protect coastline
allow deltas to formallow deltas to form
Source: Tom Van Sant / Geoshere Project
Santa Monica/Science Photo Library
Thailand Cambodia
Laos
(Chao Phraya River)
Sumatra,
Indonesia
Delta Protected from
Typhoons and Tsunamis
December 26, 04
Tsunami

62. Passive MarginPassive Margin
coast far from plate marginscoast far from plate margins
Define Passive Margin

63. Active Margins
coasts close to plate boundaries