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CHAPTER 3SEAWATER: ITS MAKEUP
AND MOVEMENTS
CHAPTER 3SEAWATER: ITS MAKEUP
AND MOVEMENTS
RainRain
SnowSnow
Purest sourcesof water:
1 ~ Snow
2 ~ Rain
Purest sourcesof water:
1 ~ Snow
2 ~ Rain
Most materials expand when heatedand contract when cooled. Most materials expand when heatedand contract when cooled.
Water:
~ contracts until cooled to 39.2° F (4° C)
then~ expands rapidly as it freezes at 32° F (0° C)
and~ increases in volume about 9%
Water:
~ contracts until cooled to 39.2° F (4° C)
then~ expands rapidly as it freezes at 32° F (0° C)
and~ increases in volume about 9%
Without expansion, ice would sink. Water would freeze from the bottom up.Evolution would have been different.
Without expansion, ice would sink. Water would freeze from the bottom up.Evolution would have been different.
Expanding ice floats, serves as an insulation barrier, and holds heat inthe water below.
Expanding ice floats, serves as an insulation barrier, and holds heat inthe water below.
The vast world ocean:
• Enormous heat-controlling thermostat
• Absorbs and loses heat more slowly than land
• Currents transfer heat to other areas
The vast world ocean:
• Enormous heat-controlling thermostat
• Absorbs and loses heat more slowly than land
• Currents transfer heat to other areas
Cape Blanco,
OregonCape Blanco,
Oregon
Rehoboth Bay,Delaware
Rehoboth Bay,Delaware
Gary, IndianaGary, Indiana
~ cooler in summer
~ warmer in winter
~ cooler in summer
~ warmer in winter
Near coasts or Great Lakes, peopleknow that near the water it is: Near coasts or Great Lakes, peopleknow that near the water it is:
Water is not compressible except in theextreme pressure of depth or laboratory.Water is not compressible except in theextreme pressure of depth or laboratory.
It cannot be made smaller in cubic volume.It cannot be made smaller in cubic volume.
Water can “turn over” allowing warmerand colder waters to exchange depths(convection).
Water can also evaporate from thesurface aided by wind and wave action.
Water can “turn over” allowing warmerand colder waters to exchange depths(convection).
Water can also evaporate from thesurface aided by wind and wave action.
Seawater’s ability totransmit light is fundamentallyimportant to lifein the oceans.
Seawater’s ability totransmit light is fundamentallyimportant to lifein the oceans.
Chemically, seawater is very pure, more than 95% water (hydrogen and oxygen). The remaining 5% contains about 80 elements in solution or suspension.
Chemically, seawater is very pure, more than 95% water (hydrogen and oxygen). The remaining 5% contains about 80 elements in solution or suspension.
Seawater ElementsSeawater Elements
5% Other Elements5% Other Elements
95% Hydrogen and Oxygen95% Hydrogen and Oxygen
OO H2H2
Seawater ElementsSeawater Elements
which iscommontablesalt.
which iscommontablesalt.
The 5% not Hydrogen (H) or Oxygen (O)is mostly Sodium (NA) or Chloride (CL),The 5% not Hydrogen (H) or Oxygen (O)is mostly Sodium (NA) or Chloride (CL),
Some parts of the Red Sea in the summer have salinities as high as 41.Some parts of the Red Sea in the summer have salinities as high as 41.
The Great Salt Lake in Utah and the Dead Sea of Israel have salinities of250 and 350 parts per thousand (ppt),the highest salt content on Earth.
The Great Salt Lake in Utah and the Dead Sea of Israel have salinities of250 and 350 parts per thousand (ppt),the highest salt content on Earth.
Every year, 80,000 cubic miles of seawater are drawn off by evaporation and condensation. 24,000 returns tocontinents as rain, sleet, and snow.
Every year, 80,000 cubic miles of seawater are drawn off by evaporation and condensation. 24,000 returns tocontinents as rain, sleet, and snow.
The cycle of evaporation andcondensation that controls thedistribution of the Earth’s wateras it evaporates from bodiesof water, condenses, precipitates,and returns to those bodies ofwater
The cycle of evaporation andcondensation that controls thedistribution of the Earth’s wateras it evaporates from bodiesof water, condenses, precipitates,and returns to those bodies ofwater
Hydrologic CycleHydrologic Cycle(a.k.a. Water Cycle)(a.k.a. Water Cycle)
Plants on land also add to the amount of water vapor entering the air in a process called transpiration.
Plants on land also add to the amount of water vapor entering the air in a process called transpiration.
Today, only magnesium (Mg) and bromine (Br) are taken commerciallyfrom seawater.
A full one-third lighter than aluminum,magnesium is used to manufacturelightweight alloys for airplanes andsatellites.
Bromine is used in the oil/gas drillingindustry and, in combination with otherelements, to manufacture flameretardants.
Today, only magnesium (Mg) and bromine (Br) are taken commerciallyfrom seawater.
A full one-third lighter than aluminum,magnesium is used to manufacturelightweight alloys for airplanes andsatellites.
Bromine is used in the oil/gas drillingindustry and, in combination with otherelements, to manufacture flameretardants.
Research is constantly under way to develop profitable ways to extract dissolved minerals from the sea.
Research is constantly under way to develop profitable ways to extract dissolved minerals from the sea.
This is the area of oceanography and metallurgy that will undoubtedly expand as continental mineral resources are used up.
This is the area of oceanography and metallurgy that will undoubtedly expand as continental mineral resources are used up.
Upper ocean water temperature variesfrom about 32° F in the polar regionsto a high of 85° F in the Persian Gulf.
Upper ocean water temperature variesfrom about 32° F in the polar regionsto a high of 85° F in the Persian Gulf.
(0° C)(0° C)(-2.2° C)(-2.2° C)
Salt lowers water’s freezing point.
However, in the deep ocean bottom,water stays at a uniform temperatureof about 4 °C (39.2 °F).
Salt lowers water’s freezing point.
However, in the deep ocean bottom,water stays at a uniform temperatureof about 4 °C (39.2 °F).
28° F 32° F
FreshwaterFreshwaterSeawaterSeawater
bathy + thermo + graphbathy + thermo + graphdepth temperature recorddepth temperature record
Bathythermographs, commonly calledBTs, are instruments used to checkwater temperatures at various depths.
Bathythermographs, commonly calledBTs, are instruments used to checkwater temperatures at various depths.
An instrument that makes a recordof the temperature at various depthsin the ocean
An instrument that makes a recordof the temperature at various depthsin the ocean
BathythermographBathythermograph
Navy XBTNavy XBT
Most Navy combatants haveexpendable BTs (XBTs) totake readings.
Most Navy combatants haveexpendable BTs (XBTs) totake readings.
FridtjofNansenFridtjofNansen
NansenBottleNansenBottle
Nansen bottles are metal cylinders withautomatic closing valves on each endthat shut to collect water samples.
Nansen bottles are metal cylinders withautomatic closing valves on each endthat shut to collect water samples.
A waterproof container for takingsamples of ocean water, severalusually being lowered open on aline and each being closed at thedesired depth by the action of afalling weight
A waterproof container for takingsamples of ocean water, severalusually being lowered open on aline and each being closed at thedesired depth by the action of afalling weight
Nansen bottleNansen bottle
When valves close,a mercury columnoutside the bottlecaptures the temperature.
After surfacing the samples,operators can test for salinity, chemical content,and minutemarine life.
When valves close,a mercury columnoutside the bottlecaptures the temperature.
After surfacing the samples,operators can test for salinity, chemical content,and minutemarine life.
NansenBottleNansenBottle
In shallow places, ocean water appears light green, while in deeper water it seems to be blue, gray, or dark green.
In shallow places, ocean water appears light green, while in deeper water it seems to be blue, gray, or dark green.
The Red Sea is sonamed because ofred phytoplanktonin the water.
The Red Sea is sonamed because ofred phytoplanktonin the water.
The Yellow Sea is so named because of the yellow silt carried into it by rivers in northern China.
The Yellow Sea is so named because of the yellow silt carried into it by rivers in northern China.
ULTRAVIOLETULTRAVIOLET
Sunlight consists of a range (spectrum)of different wavelengths of energy.Sunlight consists of a range (spectrum)of different wavelengths of energy.
Radiation with wavelengths
longer than visible light butshorter than radio waves
Radiation with wavelengths
longer than visible light butshorter than radio waves
InfraredInfrared
Radiation with wavelengthsshorter than visible light butlonger than X rays
Radiation with wavelengthsshorter than visible light butlonger than X rays
UltravioletUltraviolet
Spectrum ofRainbowColors
Spectrum ofRainbowColors
Beam ofWhiteLight
Beam ofWhiteLight
PrismPrism
Using a prism will display the visiblespectrum.Using a prism will display the visiblespectrum.
The atmosphere filter keeps out mostof the dangerous ultraviolet rays.The atmosphere filter keeps out mostof the dangerous ultraviolet rays.
Water vapor and carbon dioxide absorbmuch of the infrared rays and blanketthe Earth with life sustaining warmth.
Water vapor and carbon dioxide absorbmuch of the infrared rays and blanketthe Earth with life sustaining warmth.
Water:Water:
~ acts as a filter
~ scatters wavelengths starting at red end
the deeper the water the greater the blue
Below 90 feet:
dark zone of blues, violets, grays, blacks,and nothing else
~ acts as a filter
~ scatters wavelengths starting at red end
the deeper the water the greater the blue
Below 90 feet:
dark zone of blues, violets, grays, blacks,and nothing else
ZoneZone CommentsComments
Lighted
Twilight
Dark
Lighted
Twilight
Dark
3 to 330
260 to 655
Below 655
3 to 330
260 to 655
Below 655
Life in the sea isbountiful
No effective plantproduction
No plants growand animal lifeconsists ofcarnivores anddetritus feeders
Life in the sea isbountiful
No effective plantproduction
No plants growand animal lifeconsists ofcarnivores anddetritus feeders
Depth (in feet)Depth (in feet)
Ocean Light EnvironmentsOcean Light Environments
Waves are caused by any energy source that disturbs the water surface.
Waves are caused by any energy source that disturbs the water surface.
Any disturbanceto a water surfacewill cause ripples.
Any disturbanceto a water surfacewill cause ripples.
Tsunami waves (huge ripples) can travel thousands of miles across anentire ocean.
Tsunami waves (huge ripples) can travel thousands of miles across anentire ocean.
Wind is the most common cause ofordinary waves. Sailors often callwind-driven waves “sea” or the stateof the sea.
Wind is the most common cause ofordinary waves. Sailors often callwind-driven waves “sea” or the stateof the sea.
Swells:
may indicate an approaching storm
are quite common before hurricanes
Swells:
may indicate an approaching storm
are quite common before hurricanes
A long wave on water thatmoves continuously withoutbreaking
A long wave on water thatmoves continuously withoutbreaking
SwellsSwells
• Wind speed
+ Duration of wind
+ Length of fetch
= determines wave height
• Wind speed
+ Duration of wind
+ Length of fetch
= determines wave height
The distance over which a windblows
The distance traveled by waveswith no obstruction
The distance over which a windblows
The distance traveled by waveswith no obstruction
FetchFetch
Whitecaps begin at about 13 knots of wind.Whitecaps begin at about 13 knots of wind.
12 to 15 foot waves
~ common during a strong storm
12 to 15 foot waves
~ common during a strong storm
25 to 30 foot waves
~ may occur during severe storms or hurricanes
25 to 30 foot waves
~ may occur during severe storms or hurricanes
Wave TerminologyWave Terminology
Wave height(H)
Period past a given point
Period past a given point
Wave Type
Wind
Swell
Tsunami
Wave Type
Wind
Swell
Tsunami
Period
2 to 5 seconds
12 to 15 seconds
10 minutes to 1 hour
Period
2 to 5 seconds
12 to 15 seconds
10 minutes to 1 hour
Waves that break (fall over) when reaching a shallower bottom are called breakers.
Waves that break (fall over) when reaching a shallower bottom are called breakers.
A line of breakers along a shore is asurf, or surf line. A line of breakers along a shore is asurf, or surf line.
The slope of the bottom (gradient)determines the kind of breakers.There are three types.
The slope of the bottom (gradient)determines the kind of breakers.There are three types.
A spilling breaker develops where there is a mild, gradual, almost flat bottom shape. It can be seen advancing as a line of foam.
A spilling breaker develops where there is a mild, gradual, almost flat bottom shape. It can be seen advancing as a line of foam.
A plunging breaker occurs wherethere is a steep bottom slope. Sucha gradient creates huge surfs, like inHawaii, that are the joy of surfers.
A plunging breaker occurs wherethere is a steep bottom slope. Sucha gradient creates huge surfs, like inHawaii, that are the joy of surfers.
A surging breaker occurs where there is a very steep bottom slope with rock formations such as along the coasts of Alaska and much of California.
A surging breaker occurs where there is a very steep bottom slope with rock formations such as along the coasts of Alaska and much of California.
Knowledge of each is crucial to navaland marine amphibious operations.Knowledge of each is crucial to navaland marine amphibious operations.
Sea Waves - Swell - Surf ConditionsSea Waves - Swell - Surf Conditions
On an average beach, a 4-foot surf is considered the “critical” height forsafe amphibious landings.
On an average beach, a 4-foot surf is considered the “critical” height forsafe amphibious landings.
Above that height, boats may broach,To veer or cause to veer broadsideto the wind and waves.
Above that height, boats may broach,To veer or cause to veer broadsideto the wind and waves.
ErosionErosion
Local action of waves, tides, and currents shape coastal landforms.Local action of waves, tides, and currents shape coastal landforms.
ErosionErosion
Rocky OutcroppingRocky Outcropping
White Cliffsof Dover
White Cliffsof DoverWashed Out
BeachWashed Out
Beach
People who have had the misfortune of havinga beach cottage undermined or washed away during gales and hurricanes know what this means.
People who have had the misfortune of havinga beach cottage undermined or washed away during gales and hurricanes know what this means.
Cape Cod, MassachusettsCape Cod, Massachusetts
Waves and currents produced by waves cause most shorelinechange.
The U.S. coastline is eroding about 1 foota year.
Waves and currents produced by waves cause most shorelinechange.
The U.S. coastline is eroding about 1 foota year.
However, in other places like theMississippi River Delta, waves andcurrents build shoreline withsediment accumulation.
However, in other places like theMississippi River Delta, waves andcurrents build shoreline withsediment accumulation.
New Orleans,Louisiana
New Orleans,Louisiana
Carried by wave action, small fragmentsof rock and sand scour away beachesand wear down shoreline.
Carried by wave action, small fragmentsof rock and sand scour away beachesand wear down shoreline.
When one part of the wave line developsdrag and changes direction or bends inshallower water this is refraction,critical in amphibious assault landings.
When one part of the wave line developsdrag and changes direction or bends inshallower water this is refraction,critical in amphibious assault landings.
Waves align with bottom contours andconform to general slope of coastline.Waves align with bottom contours andconform to general slope of coastline.
Engineers must account for local waverefraction to take advantage of it whendesigning protective structures.
Engineers must account for local waverefraction to take advantage of it whendesigning protective structures.
Most common harbor protection is abreakwater (line of big rocks) sometimeswith steel-reinforced concrete.
Most common harbor protection is abreakwater (line of big rocks) sometimeswith steel-reinforced concrete.
The protective structure of stone orconcrete; extends from shore intothe water to prevent a beach fromwashing away
A barrier that protects a harbor orshore from the full impact of waves
The protective structure of stone orconcrete; extends from shore intothe water to prevent a beach fromwashing away
A barrier that protects a harbor orshore from the full impact of waves
BreakwaterBreakwater
Another common structure is a groin, walls of stone or wooden pilings builtat right angles to a shoreline.
Another common structure is a groin, walls of stone or wooden pilings builtat right angles to a shoreline.
Cape May, New JerseyCape May, New Jersey
Built in a series of two or more, groinshelp prevent erosion by dammingsediment from longshore currents thatoccur at the immediate shoreline.However, groins may cause additionalerosion in another location.
Built in a series of two or more, groinshelp prevent erosion by dammingsediment from longshore currents thatoccur at the immediate shoreline.However, groins may cause additionalerosion in another location.
Sandbars become navigational hazards.Sandbars become navigational hazards.
Rip currents are strong, seawardmoving currents. They occur whenopposing longshore currents meet.
Rip currents are strong, seawardmoving currents. They occur whenopposing longshore currents meet.
A strong, narrow surface currentthat flows rapidly away from theshore, returning the water carriedlandward by waves
Also called rip tide, tiderip
A strong, narrow surface currentthat flows rapidly away from theshore, returning the water carriedlandward by waves
Also called rip tide, tiderip
Rip CurrentRip Current
Rip current and undertow are not thesame forces.
Undertow is the natural seaward anddownward thrust of a wave as it breaks.
Rip currents occur at the junction ofopposing longshore currents.
Some rip currents move at speeds upto 2 miles an hour.
Rip current and undertow are not thesame forces.
Undertow is the natural seaward anddownward thrust of a wave as it breaks.
Rip currents occur at the junction ofopposing longshore currents.
Some rip currents move at speeds upto 2 miles an hour.
Rip currents:~ rarely over 100 feet wide~ swim parallel to the shore~ don’t panic
Rip currents:~ rarely over 100 feet wide~ swim parallel to the shore~ don’t panic
Ocean currents have profound effectson people, weather, and food cycles.Studying ocean currents can be complex.
Ocean currents have profound effectson people, weather, and food cycles.Studying ocean currents can be complex.
Earth’s atmosphere (winds) andoceans (currents) are linked.Earth’s atmosphere (winds) andoceans (currents) are linked.
Gaspard de Coriolis Gaspard de Coriolis
The Earth’s rotation creates an invisible force called the Coriolis effect. The Earth’s rotation creates an invisible force called the Coriolis effect.
Southern HemisphereSouthern Hemisphere
Northern HemisphereNorthern Hemisphere
Objects deflect tothe left in the Southern Hemisphere
Objects deflect tothe left in the Southern Hemisphere
The apparent deflection of movingobjects relative to an observer on the earthThe apparent deflection of movingobjects relative to an observer on the earth
Objects deflect tothe right in the Northern Hemisphere
Objects deflect tothe right in the Northern Hemisphere
The apparent deflection of particlesin motion with respect to the Earth
Caused by the rotation of the Earth
Appears as a clockwise deflectionthe Northern Hemisphere, counter-clockwise in the SouthernHemisphere
The apparent deflection of particlesin motion with respect to the Earth
Caused by the rotation of the Earth
Appears as a clockwise deflectionthe Northern Hemisphere, counter-clockwise in the SouthernHemisphere
Coriolis EffectCoriolis Effect
Two important factors affect global movement of wind and water:
• Wind acting on water surface• Boundary effects of the continents
Two important factors affect global movement of wind and water:
• Wind acting on water surface• Boundary effects of the continents
The water level of the Sargasso Seais 3 feet higher than along the westcoast of the Atlantic Basin.
The water level of the Sargasso Seais 3 feet higher than along the westcoast of the Atlantic Basin.
Ocean current movement is a result ofconvection and surface wind systems.
Of the two, surface wind has a greaterrole in effecting global water movement.
Surface winds and landmass locationsproduce prevailing wind systems.
Ocean current movement is a result ofconvection and surface wind systems.
Of the two, surface wind has a greaterrole in effecting global water movement.
Surface winds and landmass locationsproduce prevailing wind systems.
In the Northern Hemisphere, prevailingwinds are from the northeast from 0° to30°.
In the Northern Hemisphere, prevailingwinds are from the northeast from 0° to30°.
In the Southern Hemisphere, prevailingwinds are from the southeast from 0° to 30°.In the Southern Hemisphere, prevailingwinds are from the southeast from 0° to 30°.
Keep in mind:Winds ~ described by coming from.Currents ~ described by flowing to.
Keep in mind:Winds ~ described by coming from.Currents ~ described by flowing to.
Thus:A colonial sailor using Ben Franklin’smap to catch the Gulf Stream flowing NE,with prevailing winds (SW at 40° N Lat),could have following winds and a speedytrip.
A NE current and a SW wind are headedin the same direction.
Thus:A colonial sailor using Ben Franklin’smap to catch the Gulf Stream flowing NE,with prevailing winds (SW at 40° N Lat),could have following winds and a speedytrip.
A NE current and a SW wind are headedin the same direction.
UnitedStatesUnitedStates
Cuba
Miami
Gulf Stream
Gulf Stream
The most important current affectingthe U.S. and Atlantic seaboardThe most important current affectingthe U.S. and Atlantic seaboard
Warm ocean current of northern Atlantic Ocean off North AmericaOriginates in Caribbean, passes through Straits of Florida, flows northward along southeast United States veers northeastward at Cape Hatteras into Atlantic Ocean and splits to form North Atlantic Drift and Canary Current
Warm ocean current of northern Atlantic Ocean off North AmericaOriginates in Caribbean, passes through Straits of Florida, flows northward along southeast United States veers northeastward at Cape Hatteras into Atlantic Ocean and splits to form North Atlantic Drift and Canary Current
Gulf StreamGulf Stream
An oval 2,000 miles E-W by 1,000 milesN-S, Sargasso Sea forms an oceanicdesert with specially adapted plant life.
An oval 2,000 miles E-W by 1,000 milesN-S, Sargasso Sea forms an oceanicdesert with specially adapted plant life.
Icebergs calving from WesternGreenland Glaciers travel southon the Labrador Current into theNorth Atlantic shipping lanes.
The north traveling Gulf Stream eventually melts them.
Icebergs calving from WesternGreenland Glaciers travel southon the Labrador Current into theNorth Atlantic shipping lanes.
The north traveling Gulf Stream eventually melts them.
The currents of the Gulf Stream andNorth Atlantic Drift warm the regionalclimate more than any other area at similar latitude.
The currents of the Gulf Stream andNorth Atlantic Drift warm the regionalclimate more than any other area at similar latitude.
Late summer and early fall, the southern side of the Sargasso Sea
Winds from West Africa blow overthe warm currents of the Atlantic.
Late summer and early fall, the southern side of the Sargasso Sea
Winds from West Africa blow overthe warm currents of the Atlantic.
Spawning Ground for HurricanesSpawning Ground for Hurricanes
Hurricanes often track the Gulf Streaminto the Caribbean and Gulf of Mexicoor up the East Coast of U.S.
Hurricanes often track the Gulf Streaminto the Caribbean and Gulf of Mexicoor up the East Coast of U.S.
ChinaChina
PhilippinesPhilippines
JapanJapan
IndianOceanIndianOcean South Pacific
OceanSouth PacificOcean
North PacificOceanNorth PacificOcean
KuroshioCurrentKuroshioCurrent
Typhoons are the Pacific equivalentof Atlantic hurricanes, with theWestern Pacific averaging 20 peryear.
Typhoons are the Pacific equivalentof Atlantic hurricanes, with theWestern Pacific averaging 20 peryear.
ChinaChina
JapanJapan
PhilippinesPhilippines
KoreaKorea
Kurosh
io C
urrent
Similar to Atlantic hurricanes, Pacifictyphoons follow the warm currentrunning near land.
Similar to Atlantic hurricanes, Pacifictyphoons follow the warm currentrunning near land.
The warm Kuroshio current meets thecold, south bound Oyashio current andturns East across North Pacific.
Hitting the continent, it becomes theAlaska current traveling North and theCalifornia current moving South.
The warm Kuroshio current meets thecold, south bound Oyashio current andturns East across North Pacific.
Hitting the continent, it becomes theAlaska current traveling North and theCalifornia current moving South.
Winds set major currents in motion withfriction, but a counterforce of gravity andCoriolis effect (higher latitudes) oftencreate opposite motion in deeper water.
Winds set major currents in motion withfriction, but a counterforce of gravity andCoriolis effect (higher latitudes) oftencreate opposite motion in deeper water.
In 1955, Dr. JohnSwallow inventeda floating under-water device (aSwallow buoy) toaid tracking ofdeep current flow.
In 1955, Dr. JohnSwallow inventeda floating under-water device (aSwallow buoy) toaid tracking ofdeep current flow.
Dr. John SwallowDr. John Swallow
Surface current and countercurrentvertical mixing bring rich nutrientsupwards drawing large number of fish.
Surface current and countercurrentvertical mixing bring rich nutrientsupwards drawing large number of fish.
Distinct layers influence underwatersound transmission, important in undersea warfare.
Distinct layers influence underwatersound transmission, important in undersea warfare.
The MoonThe Moon
Our closest neighborOur closest neighbor
A weaker but much closer influence, theMoon’s gravitational pull is the main forceacting on the world’s oceans cycling therise and fall of ocean tides.
A weaker but much closer influence, theMoon’s gravitational pull is the main forceacting on the world’s oceans cycling therise and fall of ocean tides.
The periodic variation in the surfacelevel of the oceans and of bays,gulfs, inlets, and estuaries, causedby gravitational attraction of theMoon and Sun, and occurring aboutevery 12 hours
The periodic variation in the surfacelevel of the oceans and of bays,gulfs, inlets, and estuaries, causedby gravitational attraction of theMoon and Sun, and occurring aboutevery 12 hours
TideTide
MoonMoon
PlutoPluto
EarthEarth
The pull of gravity is very small for smallobjects, but enormous for a planet, moonor star.
The pull of gravity is very small for smallobjects, but enormous for a planet, moonor star.
Gravity alignment and centrifugal force interact to create variable bulges in the Earth’s oceans.Gravity alignment and centrifugal force interact to create variable bulges in the Earth’s oceans.
The Sun causestides also, but with only abouttwo-fifths of the Moon’s effect.
The Sun causestides also, but with only abouttwo-fifths of the Moon’s effect.
As the Earth rotates, the new and full moons produce the high and low ranges of tides because the Moon and Sun are working together. These tides are called spring tides.
As the Earth rotates, the new and full moons produce the high and low ranges of tides because the Moon and Sun are working together. These tides are called spring tides.
Exceptionally high and low tidesthat occur at the time of the newmoon or the full moon when theSun, Moon, and Earth areapproximately aligned
Exceptionally high and low tidesthat occur at the time of the newmoon or the full moon when theSun, Moon, and Earth areapproximately aligned
Spring TideSpring Tide
As the Moon orbits the Earth, halfway between the spring tides (Moon aligns with Sun) are the neap tides when the gravitational pulls are not working together. These are tides of minimal differences.
As the Moon orbits the Earth, halfway between the spring tides (Moon aligns with Sun) are the neap tides when the gravitational pulls are not working together. These are tides of minimal differences.
Tide that occurs when the differencebetween high and low tide is least;the lowest level of high tide
Neap tides comes twice a month inthe first and third quarters of theMoon.
Tide that occurs when the differencebetween high and low tide is least;the lowest level of high tide
Neap tides comes twice a month inthe first and third quarters of theMoon.
Neap TideNeap Tide
The ebb of a tide is the fall of thetide, that is, the moving of the tideaway from the shore.
The ebb of a tide is the fall of thetide, that is, the moving of the tideaway from the shore.
Receding or outgoing tide
The period between high waterand the succeeding low water
Receding or outgoing tide
The period between high waterand the succeeding low water
Ebb TideEbb Tide
The flood of the tide is the rise of thetide, or the flowing of the tide towardthe shore to its highest point.
The flood of the tide is the rise of thetide, or the flowing of the tide towardthe shore to its highest point.
Incoming or rising tide
The period between low waterand the succeeding high water
Incoming or rising tide
The period between low waterand the succeeding high water
Flood TideFlood Tide
High tides occur twice a day (every 12hours 25 minutes) in most parts of theworld - a high tide nearest the Moonand a lower high tide on the oppositeside of the Earth.
High tides occur twice a day (every 12hours 25 minutes) in most parts of theworld - a high tide nearest the Moonand a lower high tide on the oppositeside of the Earth.
The Earth and Moon are not in a fixed position relative to each other.
For any location on Earth to be directly opposite the Moon again, it takes 24hours and 50 minutes.
Therefore, high tides are 12 hours25 minutes apart.
The Earth and Moon are not in a fixed position relative to each other.
For any location on Earth to be directly opposite the Moon again, it takes 24hours and 50 minutes.
Therefore, high tides are 12 hours25 minutes apart.
Tidal flows are critical for ship personnel.
They impact:
~ slack or tension in mooring lines
~ harbor and channel navigation
~ boat runs and schedules
Tidal flows are critical for ship personnel.
They impact:
~ slack or tension in mooring lines
~ harbor and channel navigation
~ boat runs and schedules
Tides in mid-ocean are measurableonly with scientific instruments.Tides in mid-ocean are measurableonly with scientific instruments.
Boston(12 feet ±)Boston(12 feet ±)
Bay ofFundy(50 feet +)
Bay ofFundy(50 feet +)
Norfolk(<6 feet)Norfolk(<6 feet)
Tidal ranges varyfrom location tolocation. In somecases, especiallyin high northernlatitudes, rangesare extreme.
Tidal ranges varyfrom location tolocation. In somecases, especiallyin high northernlatitudes, rangesare extreme.
High TideHigh Tide
Low TideLow Tide
Spring tide at theBay of Fundy oftenexceeds 50 feet.
Spring tide at theBay of Fundy oftenexceeds 50 feet.
Island of Mont-St.-Michel, France
Island of Mont-St.-Michel, France
Mont-St.-Michel is surrounded by 10 milesof sand at low tide, but when the 41-foottide rises, the water moves shoreward at210 feet per minute.
Mont-St.-Michel is surrounded by 10 milesof sand at low tide, but when the 41-foottide rises, the water moves shoreward at210 feet per minute.
The Inchon, Korea harbor encloses its piers with graving basins or docks that hold in the 40-foot tidal waters.
The Inchon, Korea harbor encloses its piers with graving basins or docks that hold in the 40-foot tidal waters.
A tidal phenomenon in which theleading edge of the incoming tideforms a wave (or waves) of waterthat travel up a river against thedirection of the current
As such, it is a true tidal wave (notto be confused with a tsunami).
A tidal phenomenon in which theleading edge of the incoming tideforms a wave (or waves) of waterthat travel up a river against thedirection of the current
As such, it is a true tidal wave (notto be confused with a tsunami).
Tidal BoreTidal Bore
Amazon River in BrazilAmazon River in Brazil
Amazon River
Hangchow (Tsientang) RiverHangchow (Tsientang) River
Fjords in Greenland, Norway, Alaska,and Chile are examples.Fjords in Greenland, Norway, Alaska,and Chile are examples.
Dangerous tidal currents occur inother world locations with big inletsand narrow entrances.
Dangerous tidal currents occur inother world locations with big inletsand narrow entrances.
A long, narrow, deep inlet of the seabetween steep slopesA long, narrow, deep inlet of the seabetween steep slopes
FjordFjord
Currents rushing in fjords at 8 or 10 knots make it too dangerous forboats and ships to attempt passage.
Currents rushing in fjords at 8 or 10 knots make it too dangerous forboats and ships to attempt passage.
Norway
Norway
AlaskaAlaska
GreenlandGreenland
Tidal currentsthrough Great Barrier Reefchannelsreach up to10 knots.
Tidal currentsthrough Great Barrier Reefchannelsreach up to10 knots.
The Frenchbuilt theworld’s firsthighlysuccessfultidal plant onthe mouth ofthe RanceRiver. A damcontainingturbinesspans theestuary.
The Frenchbuilt theworld’s firsthighlysuccessfultidal plant onthe mouth ofthe RanceRiver. A damcontainingturbinesspans theestuary.
Rance RiverRance River
Rance River Rance River
Deben Deben
As the tides rise, they spin the turbinesthat drive banks of generators. Whenthe dam in the basin is full, water isreleased through sluice gates.
As the tides rise, they spin the turbinesthat drive banks of generators. Whenthe dam in the basin is full, water isreleased through sluice gates.
For centuries, the Dutch have reclaimed land from the sea with dikes and pumps.For centuries, the Dutch have reclaimed land from the sea with dikes and pumps.
The largest project was enclosingthe Zuyder Zee.The largest project was enclosingthe Zuyder Zee.
• Generates electricity by tidal flow• Creates freshwater lakes• Protects shoreline from North Sea• Reclaims land from the sea• Creates a coastal highway and connects isolated islands
• Generates electricity by tidal flow• Creates freshwater lakes• Protects shoreline from North Sea• Reclaims land from the sea• Creates a coastal highway and connects isolated islands
• Completed in 1978 across the Rhine, Meuse, and Scheldt Rivers
• Completed in 1978 across the Rhine, Meuse, and Scheldt Rivers
DeltaEstuary Plan
DeltaEstuary Plan
RotterdamRotterdam
NetherlandsNetherlands
Rhine RiverRhine River
GermanyGermany
A.1. FALSE.A.1. FALSE.
Q.1. TRUE or FALSE. Pure water is composed of two (2) atoms of oxygen and one (1) atom of hydrogen.
Q.1. TRUE or FALSE. Pure water is composed of two (2) atoms of oxygen and one (1) atom of hydrogen.
A.2. FALSE.A.2. FALSE.
Q.2. TRUE or FALSE. Plants and animals can live indefinitely without water.
Q.2. TRUE or FALSE. Plants and animals can live indefinitely without water.
A.3. Solid, Liquid, and gasA.3. Solid, Liquid, and gas
Q.3. Name the three forms in which water can exist.Q.3. Name the three forms in which water can exist.
A.4. TRUE.A.4. TRUE.
Q.4. TRUE or FALSE. Water will only exist in the liquid state in a
temperature range from 32 °F to 212 °F at standard sea level pressure.
Q.4. TRUE or FALSE. Water will only exist in the liquid state in a
temperature range from 32 °F to 212 °F at standard sea level pressure.
A.5. Sodium, hydrogen, oxygen, and chlorine
A.5. Sodium, hydrogen, oxygen, and chlorine
Q.5. What are the major components of seawater?
Q.5. What are the major components of seawater?
A.6. TRUE.A.6. TRUE.
Q.6. TRUE or FALSE. Sound travels faster in water than in air.
Q.6. TRUE or FALSE. Sound travels faster in water than in air.
A.7. SalinityA.7. Salinity
Q.7. What is the term used to describe the dissolved salts in seawater?
Q.7. What is the term used to describe the dissolved salts in seawater?
A.8. FALSE.A.8. FALSE.
Q.8. TRUE or FALSE. The bathythermograph was designed to measure the salinity of the water more accurately.
Q.8. TRUE or FALSE. The bathythermograph was designed to measure the salinity of the water more accurately.
A.9. Nansen bottleA.9. Nansen bottle
Q.9. What is the name of the instrument that captures salt water at depth?
Q.9. What is the name of the instrument that captures salt water at depth?
A.10. The Dead Sea between Israel and Jordan
A.10. The Dead Sea between Israel and Jordan
Q.10. What body of water has the highest salt content of any on Earth?
Q.10. What body of water has the highest salt content of any on Earth?
A.11. The passage of water through a plant from the roots through the vascular system to the atmosphere
A.11. The passage of water through a plant from the roots through the vascular system to the atmosphere
Q.11. What is transpiration?Q.11. What is transpiration?
A.12. Wind speed, duration of the wind, and length of the fetch
A.12. Wind speed, duration of the wind, and length of the fetch
Q.12. What three (3) principal factors does wave height depend?
Q.12. What three (3) principal factors does wave height depend?
A.13. The slope or gradient of the bottom
A.13. The slope or gradient of the bottom
Q.13. As a wave moves ashore, what determines the kind of breaker it will become?
Q.13. As a wave moves ashore, what determines the kind of breaker it will become?
A.14. Walls of stone or wood pilings built at right angles to a shoreline to prevent erosion by longshore currents
A.14. Walls of stone or wood pilings built at right angles to a shoreline to prevent erosion by longshore currents
Q.14. What is a groin, and what is it used for?
Q.14. What is a groin, and what is it used for?
A.15. A swimmer should swim parallel to the shore (across the current) since a rip current is rarely more than 100 feet wide.
A.15. A swimmer should swim parallel to the shore (across the current) since a rip current is rarely more than 100 feet wide.
Q.15. If caught in a rip current, what should a swimmer do?
Q.15. If caught in a rip current, what should a swimmer do?
A.16. The Coriolis Effect is the apparent deflection of a body in motion with respect to the Earth caused by the rotation of the Earth. In the Northern Hemisphere, this is to the right (clockwise direction).
A.16. The Coriolis Effect is the apparent deflection of a body in motion with respect to the Earth caused by the rotation of the Earth. In the Northern Hemisphere, this is to the right (clockwise direction).
Q.16. What is the Coriolis Effect?Q.16. What is the Coriolis Effect?
A.17. GyresA.17. Gyres
Q.17. What do we call the circular system of currents that rotate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere?
Q.17. What do we call the circular system of currents that rotate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere?
A.18. The Gulf StreamA.18. The Gulf Stream
Q.18. What is the most important current affecting the U.S. East Coast?
Q.18. What is the most important current affecting the U.S. East Coast?
A.19. The existence of countercurrents. He found that a strong undercurrent ran counter to the South Equatorial Current in the Pacific existed in the deep ocean.
A.19. The existence of countercurrents. He found that a strong undercurrent ran counter to the South Equatorial Current in the Pacific existed in the deep ocean.
Q.19. What did Townsend Cromwell discover in 1952?
Q.19. What did Townsend Cromwell discover in 1952?
A.20. The MoonA.20. The Moon
Q.20. What is the main cause of the rise and fell (ebb and flow) of the ocean tides?
Q.20. What is the main cause of the rise and fell (ebb and flow) of the ocean tides?
A.21. Spring tidesA.21. Spring tides
Q.21. What do we call tides when they are at their highest and lowest?
Q.21. What do we call tides when they are at their highest and lowest?
A.22. Spring tides occur at new and full moons when the Sun, Earth, and Moon are aligned and the gravitational pull of the Sun and Moon are working together.
A.22. Spring tides occur at new and full moons when the Sun, Earth, and Moon are aligned and the gravitational pull of the Sun and Moon are working together.
Q.22. What phase(s) is the Moon in during the spring tides?
Q.22. What phase(s) is the Moon in during the spring tides?
A.23. Neap tidesA.23. Neap tides
Q.23. What do we call tides whose range is less than average?
Q.23. What do we call tides whose range is less than average?
A.24. 12 hours and 25 minutesA.24. 12 hours and 25 minutes
Q.24. Approximately how long is it between high tides (or low tides)?
Q.24. Approximately how long is it between high tides (or low tides)?
A.25. A tidal boreA.25. A tidal bore
Q.25. What do we call an abrupt rise of tidal water that moves rapidly inland from the mouth of a river estuary?
Q.25. What do we call an abrupt rise of tidal water that moves rapidly inland from the mouth of a river estuary?
