WATERWATER

Biologically Important Things Biologically Important Things About WaterAbout Water

9 Major Physical Characteristics9 Major Physical Characteristics

Cohesion and Surface Cohesion and Surface TensionTension

High Latent Heats of High Latent Heats of Vaporization and Vaporization and FusionFusion

High Heat CapacityHigh Heat Capacity Good SolventGood Solvent ViscosityViscosity

Less compressible Less compressible than airthan air

Less dense as a solid Less dense as a solid than as a very cold than as a very cold liquidliquid

Can hold dissolved Can hold dissolved gasesgases

Differentially absorbs Differentially absorbs light wavelengthslight wavelengths

Most of these characteristics Most of these characteristics (the first 5) are based on the (the first 5) are based on the

fact that water is a polar fact that water is a polar moleculemolecule

The Mickey Mouse MoleculeThe Mickey Mouse Molecule

The Water MoleculeThe Water Molecule

Covalent bond

Electron ___

+ +

Hyd

roge

n bo

nd

The Mickey Mouse MoleculeThe Mickey Mouse Molecule

An Atom is made up of three partsAn Atom is made up of three parts The Proton (+ positively charged)The Proton (+ positively charged) The Neutron (no charge)The Neutron (no charge) The proton and neutron make up the The proton and neutron make up the

nucleusnucleus The Electrons (Negatively Charged)The Electrons (Negatively Charged) Bonds form when atoms share electronsBonds form when atoms share electrons

What does polarity mean?What does polarity mean?

The hydrogen atoms are pulled back (form The hydrogen atoms are pulled back (form Mickey’s ears) Mickey’s ears)

This makes the ears slightly positive because This makes the ears slightly positive because the Oxygen molecule has taken the electrons (-) the Oxygen molecule has taken the electrons (-) leaving the protons (+)leaving the protons (+)

The head is slightly negative because it has The head is slightly negative because it has taken on the electrons taken on the electrons

Magnets are polar because one end (pole) is positive and the other end (pole) is negative

Lets Look at Mickey againLets Look at Mickey again

Water molecules are polarWater molecules are polar

Their polarity allows ______to formTheir polarity allows ______to form

CohesionCohesion

means water means water molecules stick molecules stick together together

This causesThis causes

______ _____________ _______

Surface TensionSurface Tension

Water molecules stick together to form a Water molecules stick together to form a “skin”“skin”

So…?So…?Some creatures use this air-water interface Some creatures use this air-water interface

as a niche (e.g. as a niche (e.g. Glaucus)Glaucus)

Wind can impart ______to water to form Wind can impart ______to water to form ______________

Physalia and Glaucus Physalia and Glaucus

Due to surface tension he can float on water and eat jellyfish and

Man ‘o wars

AdhesionAdhesion

Water attracted to Water attracted to other materialsother materials

This is why you have This is why you have to read the ________n to read the ________n a Graduated Cylinder. a Graduated Cylinder.

ViscosityViscosity

The fluid nature of waterThe fluid nature of water Internal friction of water moleculesInternal friction of water molecules Increases with decreasing____________Increases with decreasing____________So…?So…?Planktonic organisms in warm, less viscous Planktonic organisms in warm, less viscous

water have different characteristics than water have different characteristics than those in cold waterthose in cold water

IncompressibiltyIncompressibilty

Water is extremely less compressible than Water is extremely less compressible than air ( you can’t squeeze water that much)air ( you can’t squeeze water that much)

So…?So…?

Organisms in the deep have a higher Organisms in the deep have a higher _______content in their tissues than similar _______content in their tissues than similar organisms at the surfaceorganisms at the surface

Heat CapacityHeat Capacity

Ability to gain or lose a large amount of heat Ability to gain or lose a large amount of heat without ___________ ____________without ___________ ____________

Added energy used to break H bonds – in Added energy used to break H bonds – in other substances, that E increases other substances, that E increases molecular motion and temperaturemolecular motion and temperature

Heat CapacityHeat Capacity

So…?So…? Allows currents to pick up heat and Allows currents to pick up heat and

transfer it around the planet transfer it around the planet

Moderates coastal climatesModerates coastal climatesThat’s why San Francisco is wamer than us now and That’s why San Francisco is wamer than us now and

the news always talks about snow north and west the news always talks about snow north and west of the cityof the city

Latent Heat of VaporizationLatent Heat of Vaporization

Amount of heat energy required to change 1 Amount of heat energy required to change 1 gram of water to ________(or amount of gram of water to ________(or amount of energy removed to change from steam to energy removed to change from steam to water)water)

Is very high for water: 540 cal/gIs very high for water: 540 cal/g

Latent Heat of FusionLatent Heat of Fusion

Amount of heat energy required to change 1 Amount of heat energy required to change 1 gram of ice to water (or the amount of gram of ice to water (or the amount of energy taken out to change water to ice)energy taken out to change water to ice)

Very high for water: __________Very high for water: __________

Latent HeatLatent Heat

So…?So…? If the latent heat of vaporization was lower – If the latent heat of vaporization was lower –

the water on the planet would all evaporate the water on the planet would all evaporate at ________ temperaturesat ________ temperatures

If the latent heat of fusion was lowerIf the latent heat of fusion was lower– the water on the planet would all freeze at the water on the planet would all freeze at

ambient temperaturesambient temperatures The energy assoc. with L.H. of Vap. drives The energy assoc. with L.H. of Vap. drives

the world weather systemthe world weather system

States of WaterStates of Water

Adding HeatAdding Heat

a

bc

d

eLatentHeat offusion

LatentHeat of Vaporization

Increasing amount of added heat

Incr

easi

ng t

empe

ratu

re

Water crystallizes, salts left behindWater crystallizes, salts left behind A progression from ice crystals > pancakes A progression from ice crystals > pancakes

> floes > sheets> floes > sheets

– Icebergs are _________– The Salt is squeezed Icebergs are _________– The Salt is squeezed out out

pancake ice (broken up crusts of ice crystals)

ice bergs

Floes

thicker

Pancakes-Floes - thickening

Floes – with pressure ridges

Floes – and leads

Floes – anchored to the land = fast ice

Shackleton – 1915-1916, stuck in the ice floes

Water’s polarity makes it a good Water’s polarity makes it a good solventsolvent

Dissolving a salt molecule into sodium and chloride ions

Water is less dense as a solid than Water is less dense as a solid than as a very cold liquidas a very cold liquid

Max. density of any phase of water is 4 degrees C Max. density of any phase of water is 4 degrees C (so very cold liquid has highest density)(so very cold liquid has highest density)

Less dense ice floats on more dense waterLess dense ice floats on more dense water Freshwater floats on top of Seawater. Why?Freshwater floats on top of Seawater. Why?

Seawater has Sodium chloride and other minerals to make it more dense than freshwater.

Density and LifeDensity and Life

So…?So…? Organisms aren’t crushed by sinking ice in Organisms aren’t crushed by sinking ice in

the winterthe winter

Water holds dissolved gasesWater holds dissolved gases

Dissolved oxygen (dO)Dissolved oxygen (dO)

- made as by-product of ____________- made as by-product of ____________ - - marine organisms are adapted to pull marine organisms are adapted to pull dO dO out of water ---Ex. Gillsout of water ---Ex. Gills

- colder water holds more dO- colder water holds more dO

- oxygen minimum layer occurs where - oxygen minimum layer occurs where oxygenoxygen consumption is _____and consumption is _____and production is _______production is _______

Oxygen levels in aOxygen levels in a vertical column of water vertical column of water

Surface Layer

IntermediateLayer

Deep Layer

COCO2 2 Origin and FunctionOrigin and Function

Carbon dioxide (COCarbon dioxide (CO22))

-- made as a by-product of respirationmade as a by-product of respiration

-- oceans act as a carbon sink – oceans act as a carbon sink –

absorbing excess COabsorbing excess CO2 2 from the atmosphere from the atmosphere

-- required for photosynthesis required for photosynthesis

-- buffering reaction based on CObuffering reaction based on CO2 2 keeps keeps

ocean pH stableocean pH stable

Buffering Action of COBuffering Action of CO22

Just Know----This just means the COJust Know----This just means the CO22 will help keep will help keep the pH level in the ocean stable the pH level in the ocean stable

Here is the formula but you don’t need it know itHere is the formula but you don’t need it know it

COCO22 + HOH + HOH HH22COCO33

HH22COCO33HH++ + HCO + HCO33--

HCOHCO33-- 2H 2H++ + CO + CO33

2-2-

Light in the OceansLight in the Oceans

Red Light penetrates the leastRed Light penetrates the least

Blue light penetrates the deepestBlue light penetrates the deepest

So…?So…?Color trends of organisms change with depthColor trends of organisms change with depth which means….. which means….. Why be a color no one can see?Why be a color no one can see?

Chemical and Physical Structure Chemical and Physical Structure of the Oceansof the Oceans

Light transmissionLight transmission affects life both affects life both directly and indirectly.directly and indirectly.

Most light is absorbed within the top 1 Most light is absorbed within the top 1 meter of the ocean; this contributes to meter of the ocean; this contributes to the warming of the surface layer.the warming of the surface layer.

Light changes with depth.Light changes with depth.– Photic and aphotic zonesPhotic and aphotic zones

Light in the oceanLight in the ocean

Photic Zone- Surface down 100 M depth. Area Where there is Enough light for ____________tooccur

Aphotic Zone- below 100 meters

Not enough light for photosynthesis

V I B G Y O R

Light absorption in the open ocean.

Shorter wavelengths = UV

Longer wavelengths = infrared

Violet OceansViolet Oceans

If our sun radiate more visable violet light If our sun radiate more visable violet light

we would have Violet colored oceanswe would have Violet colored oceans

The color of the oceanThe color of the ocean

Tropical oceanic waters tend to be blue Tropical oceanic waters tend to be blue because in clear water blue wavelengths are because in clear water blue wavelengths are least absorbed and red wavelengths are least absorbed and red wavelengths are strongly absorbed. The blue light is what is strongly absorbed. The blue light is what is left for you to see.left for you to see.

The color of the oceanThe color of the ocean

Coastal waters at mid and high latitudes Coastal waters at mid and high latitudes tend to appear green. This is because tend to appear green. This is because particulate matter, humic (organic) materials particulate matter, humic (organic) materials from land, and marine algae all absorb blue from land, and marine algae all absorb blue light. The Hlight. The H220 absorbs red, so green is left 0 absorbs red, so green is left

for you to see.for you to see.

The angle of the sun’s rays The angle of the sun’s rays and the state of the sea and the state of the sea surface determine how surface determine how much light is reflected and much light is reflected and how much is absorbed.how much is absorbed.– When the sun is overhead When the sun is overhead

only 2% is reflected.only 2% is reflected.– When the sun is at the When the sun is at the

horizon 99% is reflected.horizon 99% is reflected.

Sea state, i.e. waves, Sea state, i.e. waves, increase absorption increase absorption when the sun is low in when the sun is low in the sky and decrease the sky and decrease absorption when the sun absorption when the sun is high in the sky.is high in the sky.

Sun High / Rough Seas = Sun High / Rough Seas = _____ ______ _______________ ______ __________

This is important at high latitudes where the This is important at high latitudes where the sun is always low in the sky but sea conditions sun is always low in the sky but sea conditions are frequently very rough.are frequently very rough.Sun Low / Rough Seas = _____ ______ _______Sun Low / Rough Seas = _____ ______ _______

Refraction of Light in sea waterRefraction of Light in sea water Light is refracted (bent) in sea water.Light is refracted (bent) in sea water.

– This makes objects appear larger.This makes objects appear larger.– This makes the sun always appear higher in the This makes the sun always appear higher in the

sky than it really is, i.e. when you are sky than it really is, i.e. when you are underwater it is always later than you think.underwater it is always later than you think.

PressurePressure

All organisms on earth on under one All organisms on earth on under one atmosphere of pressure 14.7 pounds per atmosphere of pressure 14.7 pounds per square inchsquare inch

For every 10 meters (33ft) you add another For every 10 meters (33ft) you add another Atmosphere of pressure (see chart p.49)Atmosphere of pressure (see chart p.49)

Gases are under the same pressure Gases are under the same pressure

Density is mass per unit volumeDensity is mass per unit volume

Density increases with decreasing Density increases with decreasing temp and with increasing salinitytemp and with increasing salinity

Density gradients lead to vertical Density gradients lead to vertical stratification and thermohaline stratification and thermohaline circulationcirculation

Density

Thermocline and HaloclineThermocline and HaloclineThermocline – The layer of water where there is a big change in _________

Halocline- The layer where there is a big change in_________

Surface layer – Saltier and warmer why?

Sun hits the surface warms the water and water evaporates leaving more salt

PycnoclinePycnocline

Pycnocline – The layer of water where there is the greatest change in _______ _________