Chapter 6Chapter 6WaterWater

Oceans and FreshwaterOceans and Freshwater

OceansOceans

71 % of earths surface covered with water71 % of earths surface covered with water97 % of the water is in oceans97 % of the water is in oceansIn fact there is water around all the landIn fact there is water around all the land

Three major oceansThree major oceans–– Atlantic, Pacific, IndianAtlantic, Pacific, Indian

OceanOcean

Smaller, bodies of water almost Smaller, bodies of water almost surrounded by land are called seas.surrounded by land are called seas.Mediterranean Sea, Black Sea, and Arctic Mediterranean Sea, Black Sea, and Arctic Ocean are considered part of the Atlantic Ocean are considered part of the Atlantic OceanOcean

Mediterranean Sea

Black Sea

OceansOceans

Pacific is larger than the Atlantic and Pacific is larger than the Atlantic and Indian combinedIndian combinedAtlantic is second largestAtlantic is second largestPacific is deepest oceanPacific is deepest oceanIndian is second deepestIndian is second deepestOceans have salt waterOceans have salt water

Water CycleWater Cycle

The circulation of water from oceans and The circulation of water from oceans and lakes to the air and back.lakes to the air and back.Sun heats waterSun heats waterWater evaporates from oceanWater evaporates from ocean–– Leaves dissolved salt behindLeaves dissolved salt behind–– Water vapor is fresh waterWater vapor is fresh water

Clouds move the water vaporClouds move the water vapor

Water CycleWater Cycle

Precipitation is falling fresh waterPrecipitation is falling fresh water–– Rain snow, sleet and hailRain snow, sleet and hail

Some water flows back to ocean through Some water flows back to ocean through rivers and streamsrivers and streamsSome seeps into ground to become Some seeps into ground to become groundwatergroundwater

Ocean WaterOcean Water

A mixture of water and dissolved gases A mixture of water and dissolved gases and solidsand solidsWater is HWater is H22OO96% of ocean water96% of ocean water4% dissolved stuff4% dissolved stuffMost elements have been found in ocean Most elements have been found in ocean waterwater

Ocean WaterOcean Water

Sodium chloride most abundantSodium chloride most abundantCommon table saltCommon table saltSalinity Salinity –– the number of grams of salt the number of grams of salt dissolved in 1 kilogram of water.dissolved in 1 kilogram of water.Units are parts per thousand (Units are parts per thousand (pptppt))If you evaporated 1 kilogram of water with If you evaporated 1 kilogram of water with a salinity of 35 a salinity of 35 pptpptYou would have 35 grams of saltsYou would have 35 grams of salts

Ocean WaterOcean Water

Salinity of ocean water varies from place Salinity of ocean water varies from place to placeto placeBetween 33 and 37 Between 33 and 37 pptppt

Ocean WaterOcean Water

Water, 96.50%

Salts, 3.50%

Sodium chloride 27.2 pptMagnesium chloride 3.8 ppt

Magnesium sulfate 1.7 pptCalcium sulfate 1.3 ppt

Potassium sulfate 0.9 pptCalcium carbonate 0.1 ppt

Magnesium bromide 0.1 ppt

SourcesSources

Dissolved materials come from several Dissolved materials come from several sourcessourcesVolcanoes add gases, especially chlorineVolcanoes add gases, especially chlorineErosion adds dissolved saltsErosion adds dissolved salts–– Rain erodes mineralsRain erodes minerals–– Rivers carry them into oceanRivers carry them into ocean–– Source of potassium, sodium and Source of potassium, sodium and

magnesiummagnesium

SourcesSources

Waves dissolve the minerals in the rocks Waves dissolve the minerals in the rocks along the shore.along the shore.

Salinity variesSalinity variesIt is lower where rivers flow into oceansIt is lower where rivers flow into oceans–– Large rivers like the Mississippi and the Large rivers like the Mississippi and the

Amazon have the biggest effectAmazon have the biggest effect–– Lots of freshwater dilutes the salt water.Lots of freshwater dilutes the salt water.

In warm water lots of evaporation makes In warm water lots of evaporation makes the water have higher salinitythe water have higher salinityIn polar regions water freezesIn polar regions water freezes--–– only fresh wateronly fresh water–– leaves the water with higher salinityleaves the water with higher salinity

Dissolved GasesDissolved GasesMost abundant gases are nitrogen, Most abundant gases are nitrogen, oxygen, and carbon dioxideoxygen, and carbon dioxidePlants use carbon dioxide to make foodPlants use carbon dioxide to make foodAnd release oxygenAnd release oxygenFish breathe the dissolved oxygenFish breathe the dissolved oxygenVaries by depthVaries by depthAlotAlot at the surface at the surface –– Mixes with the wavesMixes with the waves–– Sunlight allows plants to existSunlight allows plants to exist

Dissolved GasesDissolved Gases

Varies with temperature of waterVaries with temperature of waterWarm water holds less gases than cold Warm water holds less gases than cold waterwaterCold water is more denseCold water is more dense-- sinkssinksIn polar region oxygen rich water is carried In polar region oxygen rich water is carried to depthsto depthsAllows fish to live in deep waterAllows fish to live in deep water

Ocean TemperatureOcean Temperature

Sun supplies the heatSun supplies the heatWater temperature is highest at surfaceWater temperature is highest at surfaceWaves mixes surface water transfer heat Waves mixes surface water transfer heat downwarddownwardRegion where heat is mixed is called the Region where heat is mixed is called the surface zonesurface zoneIn surface zone temperature is fairly In surface zone temperature is fairly constantconstantSurface zone varies in depthSurface zone varies in depth

Ocean TemperatureOcean TemperatureSurface zone varies by locationSurface zone varies by location–– Caribbean thick Caribbean thick –– Off the coast of Maine thinOff the coast of Maine thin

Varies with seasonsVaries with seasonsThermoclineThermocline-- region below the surface region below the surface zonezoneWater temperature drops with depthWater temperature drops with depthCold deep water doesn’t mix with warm Cold deep water doesn’t mix with warm surface watersurface water

Ocean TemperatureOcean Temperature

Deep zoneDeep zone-- Extremely cold water from Extremely cold water from bottom of bottom of thermoclinethermocline downdownThree zones vary in thicknessThree zones vary in thicknessIn Arctic and Antarctic water is so cold In Arctic and Antarctic water is so cold there is no surface zonethere is no surface zone

The Ocean FloorThe Ocean FloorTopographyTopography-- the description of the shape the description of the shape ocean floor and its featuresocean floor and its featuresOcean floor is different from the Ocean floor is different from the continents.continents.It has higher mountainsIt has higher mountains–– Deeper canyonsDeeper canyons–– Larger, flatter plainsLarger, flatter plains–– Different type of rocks Different type of rocks –– More volcanoesMore volcanoes

Continents EdgeContinents EdgeCalled the continental marginCalled the continental marginThree parts Three parts –– Continental shelfContinental shelf–– Continental slopeContinental slope–– Continental riseContinental rise

Continental ShelfContinental Shelf

More like land than ocean floorMore like land than ocean floorSlopes gently from the shorelineSlopes gently from the shorelineSediments from land are depositedSediments from land are depositedVaries in widthVaries in widthAtlantic 200 kmAtlantic 200 kmSiberia 1200 kmSiberia 1200 km

Continental ShelfContinental Shelf

Many minerals and deposits of gas and oilMany minerals and deposits of gas and oilClaimed by countries as part of their Claimed by countries as part of their boundariesboundaries

Continental SlopeContinental Slope

Floor goes down rapidlyFloor goes down rapidly-- steep slopesteep slopeBoundary between continent crust and Boundary between continent crust and ocean crustocean crust

Continental RiseContinental Rise

Slopes more gentlySlopes more gentlyMade of sediments that come off the shelfMade of sediments that come off the shelfTurbidity flowsTurbidity flows carry sediments down.carry sediments down.Like underwater Like underwater avalanches of avalanches of sediment and sediment and waterwater

Submarine CanyonsSubmarine Canyons

V shaped valleys cut through shelf and V shaped valleys cut through shelf and slopeslopeCaused by turbidity flowsCaused by turbidity flowsBring deep waterBring deep waterclose to shoreclose to shore

Monterrey BayMonterrey BayGood fishingGood fishing

The Ocean FloorThe Ocean Floor

The Ocean FloorThe Ocean Floor

Large flat areas are called Large flat areas are called abyssal plainsabyssal plainsBiggest in Atlantic and Indian oceansBiggest in Atlantic and Indian oceansBecause of sediments from large rivers Because of sediments from large rivers like The Mississippi and Amazon and the like The Mississippi and Amazon and the Ganges and Indus RiversGanges and Indus RiversTrenches near the edge of continent trap Trenches near the edge of continent trap Pacific sedimentsPacific sedimentsMade up of mud silt and clayMade up of mud silt and clay

MountainsMountainsUnderwater mountains are called Underwater mountains are called seamountsseamountsThey are volcanoesThey are volcanoesSome rise above to form islandsSome rise above to form islandsLike Hawaiian islandsLike Hawaiian islandsLarge flatLarge flat--topped mountains underwater topped mountains underwater called called guyotsguyotsWere worn away by waves.Were worn away by waves.Then the ocean level roseThen the ocean level rose

TrenchesTrenches

Deep narrow crevices in the ocean floorDeep narrow crevices in the ocean floorNear the edge of continentsNear the edge of continentsDeepest is Marianas Trench 11000 m Deepest is Marianas Trench 11000 m deepdeep

MidoceanMidocean RidgeRidge

Large underwater ocean rangesLarge underwater ocean rangesMake one continuous chain around the Make one continuous chain around the worldworldFormed when molten liquid comes up and Formed when molten liquid comes up and forms new crustforms new crustConsists of a valley Consists of a valley between two parallelbetween two parallelmountain ranges mountain ranges

Valley is called a Valley is called a rift valleyrift valley

ReefsReefsCoral reefs are limestone made by Coral reefs are limestone made by organisms in shallow warm waterorganisms in shallow warm water–– Warmer than 18Warmer than 18°°CC–– Shallower than 55 mShallower than 55 m

Three types of reefsThree types of reefsFringing reefsFringing reefs around islands but touchingaround islands but touchingBarrier reefsBarrier reefs separated from shore by a separated from shore by a shallow lagoonshallow lagoonAtoll ReefAtoll Reef surrounding a shallow lagoon surrounding a shallow lagoon no islandno island

Coral ReefsCoral Reefs

Charles Darwin was the first to explain Charles Darwin was the first to explain how one changed into another.how one changed into another.Fringing reef forms in shallow water Fringing reef forms in shallow water around volcanic islandaround volcanic islandWater level rises slowly so corals build up, Water level rises slowly so corals build up, bubu valocanovalocano starts to sink, making a starts to sink, making a barrier reefbarrier reefWhen volcano is completely goneWhen volcano is completely gone-- atollatoll

Ocean Life ZonesOcean Life Zones

Ocean life affected byOcean life affected by–– Amount of sunlightAmount of sunlight–– TemperatureTemperature–– Pressure of waterPressure of water

Three major groups of life Three major groups of life PlanktonPlankton-- Float near the surfaceFloat near the surface–– Many types of algaMany types of alga–– Source of food for many life forms.Source of food for many life forms.

Ocean Life ZonesOcean Life Zones

NecktonNeckton-- ocean life that swimsocean life that swims–– Fish , whales , squid, octopus etc.Fish , whales , squid, octopus etc.–– Can be predatorsCan be predators–– And avoid being preyAnd avoid being prey

BenthosBenthos-- live on the ocean floorlive on the ocean floor–– Plants where there is sunlightPlants where there is sunlight–– Animals like crab, oyster, star fishAnimals like crab, oyster, star fish

Ocean Life ZonesOcean Life ZonesThree major environmentsThree major environmentsIntertidalIntertidal zonezone-- the region below high and the region below high and low tidelow tideMost challenging for lifeMost challenging for life–– Sometimes underwaterSometimes underwater–– Sometimes dry landSometimes dry land–– Waves breaking on themWaves breaking on them

Attach themselves to rocks to avoid being Attach themselves to rocks to avoid being washed to seawashed to sea

Ocean Life ZonesOcean Life Zones

NeriticNeritic zonezone-- From low tide to the edge of From low tide to the edge of the continental shelf.the continental shelf.About 200 m deepAbout 200 m deepLow water pressure, fairly constant Low water pressure, fairly constant temperaturetemperatureThe most different plants and animalsThe most different plants and animalsGreat fishing areasGreat fishing areasEnds when Ends when sulightsulight stops penetratingstops penetrating

Ocean Life ZonesOcean Life ZonesTwo open ocean zonesTwo open ocean zonesBathyalBathyal zonezone-- Begins at continental slope Begins at continental slope and goes down 2000 mand goes down 2000 m–– Little or no sunlightLittle or no sunlight–– Many Many necktonneckton

Abyssal zoneAbyssal zone–– Little food for animalsLittle food for animals–– Life forms are small and strange lookingLife forms are small and strange looking–– Some produce their own lightSome produce their own light

Mapping the Ocean FloorMapping the Ocean Floor

The deep ocean is difficult to measureThe deep ocean is difficult to measureHigh pressure crushes shipsHigh pressure crushes shipsEarliest method is soundingEarliest method is sounding–– Dropping lines until they hit the bottomDropping lines until they hit the bottom–– Inaccurate and slowInaccurate and slow

Nets to bring ocean water and life upNets to bring ocean water and life up

Modern TechniquesModern Techniques

Instruments like underwater camerasInstruments like underwater camerasUnderwater robotsUnderwater robotsBathospheresBathospheres and Bathyscaphsand BathyscaphsIndirect methods like sonarIndirect methods like sonarSend down sound wavesSend down sound wavesThey hit bottom and bounce upThey hit bottom and bounce upDetect signalDetect signalUse speed of sound to calculate distanceUse speed of sound to calculate distance

FreshwaterFreshwaterOnly 3% of all the waterOnly 3% of all the waterOf that 85% is ice in glaciers and icecapsOf that 85% is ice in glaciers and icecapsThat water is recycled in the water cycleThat water is recycled in the water cycleWater evaporates from oceanWater evaporates from oceanAlso evaporates from treesAlso evaporates from treesAnd from lakesAnd from lakesLeaves the salt behindLeaves the salt behind

Water cycleWater cycle

Next water condensesNext water condenses–– Changes back to liquidChanges back to liquid–– Water must be cooledWater must be cooled–– As it risesAs it rises–– Forms cloudsForms clouds

Water cycleWater cycleNext there is precipitationNext there is precipitation–– There are so many water drops it falls There are so many water drops it falls

out of cloudsout of clouds–– Rain snow sleet and hailRain snow sleet and hail

When it hits the groundWhen it hits the groundSome evaporatesSome evaporatesSome flows back to oceanSome flows back to oceanSome absorbed into ground to become Some absorbed into ground to become groundwatergroundwater-- which flows back to oceanwhich flows back to ocean

Water CycleWater Cycle

Frozen WaterFrozen Water

Glaciers form when more snow falls in Glaciers form when more snow falls in winter than melts in the summer.winter than melts in the summer.Must be coldMust be coldOver the years snow piles upOver the years snow piles upPressure turns it to icePressure turns it to iceAs ice gets thick, it starts to flowAs ice gets thick, it starts to flowGlaciers have 2% of the freshwaterGlaciers have 2% of the freshwater

GlaciersGlaciers

Those that form in Those that form in mountains are called mountains are called valley glaciersvalley glaciersFlow down the valleysFlow down the valleysRocks in the glacier wear Rocks in the glacier wear away the valley wallsaway the valley wallsMake the valley UMake the valley U--shapedshaped

GlaciersGlaciers

In polar regions ice builds up in thick In polar regions ice builds up in thick sheetssheetsForm continental glaciersForm continental glaciersCover millions of square kilometersCover millions of square kilometersMove slowly in all directionsMove slowly in all directionsFound in Greenland and AntarcticaFound in Greenland and AntarcticaOne time covered much of AmericaOne time covered much of AmericaIcebergs break off glaciersIcebergs break off glaciers

Standing waterStanding water

Water caught in low places as it runs offWater caught in low places as it runs offPonds and lakesPonds and lakesDepressions caused by former glaciers Depressions caused by former glaciers are common places for lakesare common places for lakesOr where there are blockagesOr where there are blockagesPonds tend to be smaller and shallower Ponds tend to be smaller and shallower than lakesthan lakes

Standing waterStanding water

Reservoirs are artificial lakesReservoirs are artificial lakesMade by damming rivers and streamsMade by damming rivers and streamsWater backs upWater backs upUsed for drinking water, irrigation, Used for drinking water, irrigation, recreation, and electric powerrecreation, and electric power

Running waterRunning water

Precipitation that doesn’t soak in flows into Precipitation that doesn’t soak in flows into rivers and streams is called surface runoffrivers and streams is called surface runoffSome soils soak up more than othersSome soils soak up more than others–– Have more pore spaceHave more pore space–– Empty space between particlesEmpty space between particles–– Less runoffLess runoff

Plants roots absorb waterPlants roots absorb water–– Less runoffLess runoff

Running waterRunning water

More runoff when there has been recent More runoff when there has been recent rainsrainsWatershed is the land area that drains into Watershed is the land area that drains into a river or streama river or streamSome are hugeSome are huge-- like the Mississippilike the MississippiAre divided by mountain ranges and Are divided by mountain ranges and ridgesridges

WatershedWatershed

GroundwaterGroundwaterWater below the surfaceWater below the surfaceMore fresh water underground than on the More fresh water underground than on the surfacesurfacePrecipitation move down through spaces Precipitation move down through spaces between the rocks and soilbetween the rocks and soilSpaces are called Spaces are called poresporesPermeablePermeable rock lets water throughrock lets water through–– SandstoneSandstone-- large poreslarge pores

GroundwaterGroundwaterImpermeableImpermeable rock does not let water rock does not let water throughthrough–– Clay small poresClay small pores

Water moves downward until it reaches an Water moves downward until it reaches an impermeable layerimpermeable layerWater fills up the permeable layers aboveWater fills up the permeable layers aboveWhere water fills is called the Where water fills is called the zone of zone of saturationsaturationWhere pores are filled mostly with air is Where pores are filled mostly with air is called the called the zone of aerationzone of aeration

Water TableWater Table

Boundary between the zones Boundary between the zones Water table is shallow near the oceanWater table is shallow near the ocean–– In the mountains it can be deepIn the mountains it can be deep–– Where it rains a lot, it is shallowWhere it rains a lot, it is shallow–– Where it is dry, it is deepWhere it is dry, it is deep–– Shallower in wet seasonShallower in wet season–– Deeper in dry seasonDeeper in dry season–– Can be lowered by overuseCan be lowered by overuse

AquiferAquifer

A layer of underground water flowing A layer of underground water flowing horizontally through permeable rockhorizontally through permeable rockTrapped above impermeable rockTrapped above impermeable rockReached by digging wellsReached by digging wellsPollution travels through them easilyPollution travels through them easily

Artesian WellArtesian Well

If aquifer trapped between two layers of If aquifer trapped between two layers of impermeable rock, impermeable rock, Pressure builds up and forms an artesian Pressure builds up and forms an artesian wellwellWater flows out of the ground by itself Water flows out of the ground by itself without pumpingwithout pumping

Artesian WellArtesian Well

CavernsCaverns

Water can slowly dissolve underground Water can slowly dissolve underground rock to form open tunnelsrock to form open tunnelsEspecially common in limestoneEspecially common in limestoneAcidic water eats through it Acidic water eats through it easily.easily.