Chapter 6Chapter 6WaterWater

Oceans and FreshwaterOceans and Freshwater

OceansOceans

71 % of earths surface covered with water71 % of earths surface covered with water

97 % of the water is in oceans97 % of the water is in oceans

In 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 combined

Atlantic is second largestAtlantic is second largest

Pacific is deepest oceanPacific is deepest ocean

Indian is second deepestIndian is second deepest

Oceans 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 water

Water 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 streams

Some 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 solids

Water is HWater is H22OO

96% of ocean water96% of ocean water

4% dissolved stuff4% dissolved stuff

Most elements have been found in ocean Most elements have been found in ocean waterwater

Ocean WaterOcean Water

Sodium chloride most abundantSodium chloride most abundant

Common table saltCommon table salt

Salinity – the number of grams of salt Salinity – the number of grams of salt dissolved in 1 kilogram of water.dissolved in 1 kilogram of water.

Units are parts per thousand (ppt)Units are parts per thousand (ppt)

If you evaporated 1 kilogram of water with If you evaporated 1 kilogram of water with a salinity of 35 ppta salinity of 35 ppt

You 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 place

Between 33 and 37 pptBetween 33 and 37 ppt

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 sourcessources

Volcanoes add gases, especially chlorineVolcanoes add gases, especially chlorine

Erosion 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 freezes- In 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 depthAlot at the surface Alot 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 water

Warm water holds less gases than cold Warm water holds less gases than cold waterwater

Cold water is more dense- sinksCold water is more dense- sinks

In polar region oxygen rich water is carried In polar region oxygen rich water is carried to depthsto depths

Allows 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 thinVaries with seasonsVaries with seasonsThermocline- region below the surface Thermocline- 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 zone-Deep zone- Extremely cold water from Extremely cold water from bottom of thermocline downbottom of thermocline down

Three zones vary in thicknessThree zones vary in thickness

In 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 FloorTopography- the description of the shape Topography- 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 margin

Three 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 floor

Slopes gently from the shorelineSlopes gently from the shoreline

Sediments from land are depositedSediments from land are deposited

Varies in widthVaries in width

Atlantic 200 kmAtlantic 200 km

Siberia 1200 kmSiberia 1200 km

Continental ShelfContinental Shelf

Many minerals and deposits of gas and oilMany minerals and deposits of gas and oil

Claimed by countries as part of their Claimed by countries as part of their boundariesboundaries

Continental SlopeContinental Slope

Floor goes down rapidly- steep slopeFloor goes down rapidly- steep slope

Boundary between continent crust and Boundary between continent crust and ocean crustocean crust

Continental RiseContinental Rise

Slopes more gentlySlopes more gently

Made of sediments that come off the shelfMade of sediments that come off the shelf

Turbidity 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 slopeslope

Caused by turbidity flowsCaused by turbidity flows

Bring deep waterBring deep water close to shore close to shore

Monterrey BayMonterrey Bay

Good fishingGood fishing

The Ocean FloorThe Ocean Floor

The Ocean FloorThe Ocean Floor

Large flat areas are called Large flat areas are called abyssal plainsabyssal plains

Biggest in Atlantic and Indian oceansBiggest in Atlantic and Indian oceans

Because 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 Rivers

Trenches near the edge of continent trap Trenches near the edge of continent trap Pacific sedimentsPacific sediments

Made 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 flat-topped mountains underwater Large flat-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 floor

Near the edge of continentsNear the edge of continents

Deepest is Marianas Trench 11000 m Deepest is Marianas Trench 11000 m deepdeep

Midocean RidgeMidocean Ridge

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 parallel mountain 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°C°C– Shallower than 55 mShallower than 55 mThree types of reefsThree types of reefsFringing reefsFringing reefs around islands but touching around 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 island

Water level rises slowly so corals build up, Water level rises slowly so corals build up, bu valocano starts to sink, making a bu valocano starts to sink, making a barrier reefbarrier reef

When volcano is completely gone- atollWhen volcano is completely gone- atoll

Ocean Life ZonesOcean Life Zones

Ocean life affected byOcean life affected by– Amount of sunlightAmount of sunlight– TemperatureTemperature– Pressure of waterPressure of waterThree major groups of life Three major groups of life Plankton-Plankton- Float near the surface Float 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

Neckton-Neckton- ocean life that swims ocean 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

Benthos-Benthos- live on the ocean floor live 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 environmentsIntertidal zone-Intertidal zone- 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 themAttach themselves to rocks to avoid being Attach themselves to rocks to avoid being washed to seawashed to sea

Ocean Life ZonesOcean Life Zones

Neritic zone-Neritic zone- 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 deep

Low water pressure, fairly constant Low water pressure, fairly constant temperaturetemperature

The most different plants and animalsThe most different plants and animals

Great fishing areasGreat fishing areas

Ends when sulight stops penetratingEnds when sulight stops penetrating

Ocean Life ZonesOcean Life ZonesTwo open ocean zonesTwo open ocean zonesBathyal zone- Begins at continental slope Bathyal zone- Begins at continental slope and goes down 2000 mand goes down 2000 m– Little or no sunlightLittle or no sunlight– Many necktonMany necktonAbyssal 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 measure

High pressure crushes shipsHigh pressure crushes ships

Earliest 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 robotsBathospheres and BathyscaphsBathospheres and 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 water

Of that 85% is ice in glaciers and icecapsOf that 85% is ice in glaciers and icecaps

That water is recycled in the water cycleThat water is recycled in the water cycle

Water evaporates from oceanWater evaporates from ocean

Also evaporates from treesAlso evaporates from trees

And from lakesAnd from lakes

Leaves 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 hailWhen 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 groundwater- which flows back to oceangroundwater- which 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 cold

Over the years snow piles upOver the years snow piles up

Pressure turns it to icePressure turns it to ice

As ice gets thick, it starts to flowAs ice gets thick, it starts to flow

Glaciers 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 glaciers

Flow down the valleysFlow down the valleys

Rocks in the glacier wear Rocks in the glacier wear away the valley wallsaway the valley walls

Make the valley U-shapedMake the valley U-shaped

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 off

Ponds and lakesPonds and lakes

Depressions caused by former glaciers Depressions caused by former glaciers are common places for lakesare common places for lakes

Or where there are blockagesOr where there are blockages

Ponds 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 lakes

Made by damming rivers and streamsMade by damming rivers and streams

Water backs upWater backs up

Used 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 runoffPlants 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 rainsrains

Watershed is the land area that drains into Watershed is the land area that drains into a river or stream a river or stream

Some are huge- like the MississippiSome are huge- like the Mississippi

Are divided by mountain ranges and Are divided by mountain ranges and ridgesridges

WatershedWatershed

GroundwaterGroundwaterWater below the surfaceWater below the surface

More fresh water underground than on the More fresh water underground than on the surfacesurface

Precipitation move down through spaces Precipitation move down through spaces between the rocks and soilbetween the rocks and soil

Spaces are called Spaces are called porespores

PermeablePermeable rock lets water through rock lets water through

– Sandstone- large poresSandstone- large pores

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

Trapped above impermeable rockTrapped above impermeable rock

Reached by digging wellsReached by digging wells

Pollution 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 wellwell

Water 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 tunnels

Especially common in limestoneEspecially common in limestone

Acidic water eats through it easily.Acidic water eats through it easily.