Introduction to the OceanIntroduction to the Ocean

Marine BiologyMarine Biology

Introduction to the Introduction to the OceanOcean

• If the Earth were the size of a If the Earth were the size of a basketball, the ocean would be a film basketball, the ocean would be a film of water over its surface. of water over its surface.

• Its average depth is 2.3 miles. Its average depth is 2.3 miles.

The importance of waterThe importance of water

• Water makes up about 80% of most Water makes up about 80% of most marine life. marine life.

• Jellyfish are 95% water!!!!! Jellyfish are 95% water!!!!!

What is water?What is water?

• All matter is made up of tiny particles All matter is made up of tiny particles called called atomsatoms. .

• There are 115 substances that are There are 115 substances that are made up of the same kind of atoms. made up of the same kind of atoms. They are called They are called elementselements. .

• Two or more different atoms can Two or more different atoms can combine into larger particles called combine into larger particles called moleculesmolecules. .

Water is a molecule!!!! Water is a molecule!!!!

• What atoms make up water? What atoms make up water?

• Water molecules are attracted Water molecules are attracted together by weak bonds called together by weak bonds called hydrogen bondshydrogen bonds..

The States of WaterThe States of Water

• Water can be a liquid, solid or a gas. Water can be a liquid, solid or a gas.

• Water is the only substance that Water is the only substance that naturally occurs in all three states on naturally occurs in all three states on Earth. Earth.

How does temperature How does temperature impact water? impact water? • As temperature As temperature increasesincreases, water , water

molecules move molecules move fasterfaster. . • If the water molecule moves fast If the water molecule moves fast

enough it can break free of all the enough it can break free of all the hydrogen bonds.hydrogen bonds.

• If this happens, water goes from the If this happens, water goes from the liquid phase to the gaseous phase in liquid phase to the gaseous phase in a process called a process called evaporationevaporation..

How does temperature How does temperature impact water?impact water?

• As temperature As temperature decreasesdecreases, sea , sea water molecules move slower and water molecules move slower and are packed closer together. are packed closer together.

• What happens to volume? What happens to volume? DECREASES.DECREASES.

• Weight does NOT change. So it gets Weight does NOT change. So it gets more dense. more dense.

DensityDensity

• Remember…Remember…

Density = Density = WeightWeight

VolumeVolume

How about fresh water? How about fresh water?

• As temperature decreases, water As temperature decreases, water becomes more dense…..but only to a becomes more dense…..but only to a temperature of 4 degrees C. temperature of 4 degrees C.

• Below 4 degrees C, water gets less Below 4 degrees C, water gets less dense as it cools. dense as it cools.

• Eventually, hydrogen bonds hold Eventually, hydrogen bonds hold water in a fix 3-D pattern. It is now a water in a fix 3-D pattern. It is now a solid!!!!! solid!!!!!

Why ice floats…Why ice floats…

• Water expands as it freezes!!!! Water expands as it freezes!!!!

• Since the same weight of water Since the same weight of water occupies more volume in ice than occupies more volume in ice than liquid water, ice is liquid water, ice is less denseless dense than than liquid water. liquid water.

• So it floats!So it floats!

Importance of IceImportance of Ice

• Acts as an insulating blanket. Acts as an insulating blanket.

• What would happen if ice sank?What would happen if ice sank?

• Ponds and lakes would freeze from Ponds and lakes would freeze from the bottom up. Good thing this the bottom up. Good thing this doesn’t happen! doesn’t happen!

Heat and WaterHeat and Water

• It takes a lot of heat to melt ice!It takes a lot of heat to melt ice!• Water molecules in ice vibrate but do Water molecules in ice vibrate but do

not move form place to place within not move form place to place within the crystalthe crystal

• Added heat makes the molecules Added heat makes the molecules move faster and faster eventually move faster and faster eventually breaking some of the hydrogen breaking some of the hydrogen bonds – it meltsbonds – it melts

Heat and WaterHeat and Water

• If not for the hydrogen bonds, ice If not for the hydrogen bonds, ice would melt at –90ºC (-130ºF)would melt at –90ºC (-130ºF)

• The amount of heat needed to melt The amount of heat needed to melt a substance is called the a substance is called the latent latent heat of melting.heat of melting.

• Water has a higher latent heat of Water has a higher latent heat of melting than any other commonly melting than any other commonly occurring substance. occurring substance.

Heat and waterHeat and water

• A great deal of heat must be removed to A great deal of heat must be removed to freeze it.freeze it.

• That is why the ocean stays warm well into That is why the ocean stays warm well into November and cool well into May around November and cool well into May around here. here.

• Once ice begins to melt, added heat goes Once ice begins to melt, added heat goes to breaking hydrogen bonds and does not to breaking hydrogen bonds and does not raise the temperature until there is no raise the temperature until there is no more ice left. The temperature remains more ice left. The temperature remains constant at 0º Cconstant at 0º C

Heat and WaterHeat and Water

• Water has a high Water has a high heat capacityheat capacity. . This means that it takes a lot of heat This means that it takes a lot of heat to raise the temperature.to raise the temperature.

• This is great for marine life!!! Why? This is great for marine life!!! Why?

• Most marine organisms are NOT Most marine organisms are NOT subjected to rapid changes in subjected to rapid changes in temperature. temperature.

Car Connection…Car Connection…

• Did you know that water is used in Did you know that water is used in the cooling system of cars because it the cooling system of cars because it can absorb a lot of heat with out can absorb a lot of heat with out greatly increasing in temperature? greatly increasing in temperature?

Water as a SolventWater as a Solvent

Water can dissolve more things Water can dissolve more things than any other naturally occurring than any other naturally occurring substance. That is why it is called the substance. That is why it is called the universal solvent.universal solvent.

Great at dissolving Great at dissolving salts. salts.

• Everyone who has taken in a Everyone who has taken in a mouthful of ocean water while mouthful of ocean water while swimming knows that the ocean is swimming knows that the ocean is really salty!really salty!

What is a salt?What is a salt?

• Salts are made of ions (charged Salts are made of ions (charged particles). particles).

•Example NaCl is made of Na+ and Cl-Example NaCl is made of Na+ and Cl-

• What happens when salt is placed in What happens when salt is placed in water? water?

It dissolves!!!!It dissolves!!!!

Water molecules surround and insulate Water molecules surround and insulate the ions from each other because the + is the ions from each other because the + is attracted to the Oxygen and the – is attracted to the Oxygen and the – is attracted to the Hydrogen of water.attracted to the Hydrogen of water.  

Solute & SolventSolute & Solvent

• Solute- the dissolved material Solute- the dissolved material •Ex. NaClEx. NaCl

• Solvent- What the solute is dissolved Solvent- What the solute is dissolved in. in.

•Ex. WaterEx. Water

Why are the oceans salty?Why are the oceans salty?

Where do the salts come from that Where do the salts come from that are dissolved in seawater? are dissolved in seawater?

1.1. Chemical weathering of rocks. Chemical weathering of rocks.

2.2. Earth’s interior.Earth’s interior. Ex. Released by hydrothermal vents or Ex. Released by hydrothermal vents or

by volcanoes.by volcanoes.

What???? What????

• Most of the salt in the ocean comes Most of the salt in the ocean comes from minerals that were part of the from minerals that were part of the land. When rivers flow over rocks on land. When rivers flow over rocks on land, minerals get dissolved by the land, minerals get dissolved by the river water. These minerals are river water. These minerals are deposited into the oceans as the deposited into the oceans as the rivers flow into the oceans. rivers flow into the oceans.

  Sea Salts include:Sea Salts include:

55% chlorine55% chlorine

30.6% Sodium30.6% Sodium

3.7 % Magnesium3.7 % Magnesium

1.1 % Potassium1.1 % Potassium

7.7 % Sulfate7.7 % Sulfate

1.2% Calcium 1.2% Calcium

0.7 % minor elements0.7 % minor elements

The most common salt…The most common salt…

• About 85% of that salt would be About 85% of that salt would be sodium chloride (NaCl)- ordinary sodium chloride (NaCl)- ordinary table salt. table salt.

Rule of Constant ProportionsRule of Constant Proportions

• States that relative amounts of States that relative amounts of various ions in seawater are always various ions in seawater are always the same. the same.

• Why is that important?Why is that important?

• Because organisms don’t have to Because organisms don’t have to deal with different proportions of deal with different proportions of salts, just varying total salts, just varying total concentrationsconcentrations

What is Salinity?What is Salinity?

• Salinity- is a measure of how much Salinity- is a measure of how much salt is in the water. salt is in the water.

• (Ocean water has a high salinity, (Ocean water has a high salinity, fresh water has a low salinity.)fresh water has a low salinity.)

How is salinity expressed? How is salinity expressed?

• Salinity is expressed by the amount of salt Salinity is expressed by the amount of salt found in 1000 grams of water. found in 1000 grams of water.

• If we have 1 gram of salt and 1000 grams If we have 1 gram of salt and 1000 grams of water, the salinity is 1 part per of water, the salinity is 1 part per thousand or 1 ppt.thousand or 1 ppt.

• The average ocean salinity is 35 ppt. The average ocean salinity is 35 ppt. (Which means 35 pounds of salt per 1000 (Which means 35 pounds of salt per 1000 pounds of water)pounds of water)

Salt WaterSalt Water• SalinitySalinity

– Expressed in Expressed in PPractical ractical SSalinity alinity UUnits (PSU)nits (PSU)– 1 psu = 1 part per thousand (ppt)1 psu = 1 part per thousand (ppt)– Measured usingMeasured using

•Hydrometer – floats based on densityHydrometer – floats based on density

•Refractometer – Light bends differently in Refractometer – Light bends differently in differrent densitiesdifferrent densities

•Conductivity – more saline = better Conductivity – more saline = better conductivityconductivity

•Titration – Chemical method of measuring Titration – Chemical method of measuring amount of Clamount of Cl-- ions ions

Who discovered average Who discovered average salinity?salinity?

• This average salinity was obtained by This average salinity was obtained by William DittmarWilliam Dittmar in 1884 from in 1884 from chemical analysis of 77 sea water chemical analysis of 77 sea water samples collected from many parts samples collected from many parts of the world during the expedition of of the world during the expedition of the H.M.S. Challenger.the H.M.S. Challenger.

How does ocean salinity and How does ocean salinity and freshwater salinity freshwater salinity compare? compare? • Ocean salinity is around 35 ppt.Ocean salinity is around 35 ppt.

• Freshwater salinity in comparison is Freshwater salinity in comparison is usually less than 0.5 ppt. usually less than 0.5 ppt.

Do all bodies of water have Do all bodies of water have about the same salinity?about the same salinity?• NO!!!!!NO!!!!!

• Different bodies of water have different Different bodies of water have different salinities. Rainfall, evaporation, river runoff salinities. Rainfall, evaporation, river runoff and ice formation cause the variations. and ice formation cause the variations.

• Black sea is diluted by river runoff so its Black sea is diluted by river runoff so its salinity is only 16 ppt. salinity is only 16 ppt.

The oceans continue to get The oceans continue to get saltier due to the following: saltier due to the following:

• 1)1)        erosion of the landerosion of the land

• 2)2)        wearing down of mountainswearing down of mountains

• 3)3)        dissolving action of rain and streamsdissolving action of rain and streams

• 4)4)        Volcanic eruptionsVolcanic eruptions

• 5)5)        Chemical reaction between seawater Chemical reaction between seawater and hot, newly formed volcanic rocks of and hot, newly formed volcanic rocks of spreading zones (mid-oceanic ridges). spreading zones (mid-oceanic ridges).

The Saltiest Sea WaterThe Saltiest Sea Water

• Salts become concentrated in the sea Salts become concentrated in the sea because the sun’s heat vaporizes water because the sun’s heat vaporizes water from the surface of the sea and leaves the from the surface of the sea and leaves the salts behind. salts behind.

• The saltiest water (40 ppt) occurs in the The saltiest water (40 ppt) occurs in the Red Sea and Persian Gulf, where the rates Red Sea and Persian Gulf, where the rates of evaporation are very high. of evaporation are very high.

Not So Salty Sea Water…Not So Salty Sea Water…

• Low salinities occur in polar seas Low salinities occur in polar seas where the salt water is diluted by where the salt water is diluted by melting ice. melting ice.

Salinity, Temperature & Salinity, Temperature & DensityDensity• What affects the density of sea water? What affects the density of sea water?

• Great!!! Temperature but also salinity.Great!!! Temperature but also salinity.

• Temperature has a greater effect on Temperature has a greater effect on ocean water because it is more variable. ocean water because it is more variable.

• Temperature varies from about –2º to Temperature varies from about –2º to +30º C (28º - 86ºF)+30º C (28º - 86ºF)

Dissolved Gases Dissolved Gases • Gases are also dissolved in seawater. Gases are also dissolved in seawater. • The three most important gases in The three most important gases in

the ocean are oxygen, carbon the ocean are oxygen, carbon dioxide, and nitrogen. dioxide, and nitrogen.

• These gases are found in the These gases are found in the atmosphere. atmosphere.

• They are dissolved in seawater at the They are dissolved in seawater at the surface. surface.

Dissolved GasesDissolved Gases

• Sometimes, gases are released from Sometimes, gases are released from the surface into the atmosphere. the surface into the atmosphere.

• This is called This is called gas exchangegas exchange..

How does temperature impact How does temperature impact the ability for gases to the ability for gases to dissolve?dissolve?

• Gases dissolve better in cold water. Gases dissolve better in cold water.

• Whereas, most solids dissolve better Whereas, most solids dissolve better at warmer temperatures. at warmer temperatures.

Animals can impact the Animals can impact the amount of gases in amount of gases in seawater.seawater.• Animals use up oxygen in respiration. Animals use up oxygen in respiration.

TransparencyTransparency• Sea water is transparent. Sea water is transparent. • Sunlight can penetrate into the ocean. Sunlight can penetrate into the ocean. • This is very important for plants. Why?This is very important for plants. Why?• Turbidity is measured with a secchi disk. Turbidity is measured with a secchi disk. • Water transparency depends on how much Water transparency depends on how much

and what kind of material is suspended and what kind of material is suspended and dissolved in the water. and dissolved in the water.

TransparencyTransparency

• Ex. Muddy water reduces Ex. Muddy water reduces transparency.transparency.

• Ex. Large quantities of plant life Ex. Large quantities of plant life reduces transparency. reduces transparency.

• Water near the coasts is generally not Water near the coasts is generally not as clear as that of the open ocean. as clear as that of the open ocean.

• Remember!!! Rivers bring runoff. Remember!!! Rivers bring runoff.

ROY G BIVROY G BIV• Sunlight contains all the colors of the Sunlight contains all the colors of the

visible spectrum. visible spectrum. • Not all colors of light penetrate Not all colors of light penetrate

seawater equally. seawater equally. • Different colors of light penetrate to Different colors of light penetrate to

different depths in the ocean. different depths in the ocean. • Blue light penetrates the deepest. Blue light penetrates the deepest. • Red light the least. Red light the least.

Light In WaterLight In Water

Photic ZonePhotic Zone

• The upper regions of the ocean The upper regions of the ocean where photosynthesis occurs. where photosynthesis occurs.

• Depth of photic zone is determined Depth of photic zone is determined by how rapidly light is absorbed. by how rapidly light is absorbed.

What were those What were those substances that diminish substances that diminish light penetration?light penetration?

• Dissolved substancesDissolved substances

• Suspended materialSuspended material

• Plankton populationsPlankton populations

ThermoclineThermocline

• A subsurface zone of rapid A subsurface zone of rapid temperature change. temperature change.

• The layer between the The layer between the

mixed layer at the surface mixed layer at the surface

and the deep water layer. and the deep water layer.

• Temperature changes rapidly from the Temperature changes rapidly from the mixed layer to the deep water layer.mixed layer to the deep water layer.

                          

PycnoclinePycnocline

• A LAYER of rapid A LAYER of rapid

Change in water Change in water

density with depth.density with depth.

PressurePressure

• Organisms on land are under 1 atm of Organisms on land are under 1 atm of pressure at sea level. pressure at sea level.

• Marine organisms are under the Marine organisms are under the weight of the water above them + weight of the water above them + atmosphere. atmosphere.

• Water is heavier than air. Water is heavier than air.

• Therefore, marine organisms are Therefore, marine organisms are under MORE pressure. under MORE pressure.

PressurePressure

• Pressure INCREASES with DEPTHPressure INCREASES with DEPTH

• With every 10m (or 33 feet) of With every 10m (or 33 feet) of increased depth, another increased depth, another atmosphere of pressure is added. atmosphere of pressure is added.

Gases Gases

• As pressure increases, gases are As pressure increases, gases are compressed. compressed.

• Gas filled structures inside organisms Gas filled structures inside organisms like air bladders, lungs shrink or like air bladders, lungs shrink or collapse. collapse.

• Limits depth range of many Limits depth range of many organisms. organisms.

Winds and CurrentsWinds and Currents

• WindsWinds– Coriolis effectCoriolis effect

•a point rotating at the equator moves faster a point rotating at the equator moves faster than a point at a higher latitudethan a point at a higher latitude

•path of air mass appears to curve relative to path of air mass appears to curve relative to the earth’s surface—to the right in the the earth’s surface—to the right in the Northern Hemisphere, left in the SouthernNorthern Hemisphere, left in the Southern

Winds and CurrentsWinds and Currents

• Ocean currentsOcean currents– surface currentssurface currents

•driven mainly by trade winds (easterlies and driven mainly by trade winds (easterlies and westerlies) in each hemispherewesterlies) in each hemisphere

•Coriolis effectCoriolis effect– currents deflected to the right of the prevailing currents deflected to the right of the prevailing

wind direction in the Northern Hemisphere, to the wind direction in the Northern Hemisphere, to the left in the Southern Hemisphereleft in the Southern Hemisphere

•gyres—water flow in a circular pattern gyres—water flow in a circular pattern around the edge of an ocean basinaround the edge of an ocean basin

Winds and CurrentsWinds and Currents

– currents below the surfacecurrents below the surface•energy transferred from winds to surface energy transferred from winds to surface

water is transferred to deeper waterwater is transferred to deeper water

•deeper-water currents are deflected by the deeper-water currents are deflected by the Coriolis effect, down to about 100 mCoriolis effect, down to about 100 m

•friction causes loss of energy, so each layer friction causes loss of energy, so each layer moves at an angle to and more slowly than moves at an angle to and more slowly than the layer above, creating an Ekman spiralthe layer above, creating an Ekman spiral

•Ekman transport—net movement of water to Ekman transport—net movement of water to the 100-m depththe 100-m depth

WavesWaves• Wave formationWave formation

– wave = a flow of energy or motion, not a wave = a flow of energy or motion, not a flow of waterflow of water

– generating force—a force that disturbs generating force—a force that disturbs the water’s surfacethe water’s surface•most common = windmost common = wind•also geological events, falling objects, shipsalso geological events, falling objects, ships

– restoring force—the force that causes the restoring force—the force that causes the water to return to the undisturbed levelwater to return to the undisturbed level•= surface tension for capillary waves= surface tension for capillary waves•= gravity for gravity waves= gravity for gravity waves

WavesWaves

WavesWaves• tsunamistsunamis

– Shallow water waves – wavelength is more Shallow water waves – wavelength is more than 1/20 depththan 1/20 depth

– seismic sea waves are formed by seismic sea waves are formed by earthquakes or landslidesearthquakes or landslides

– tsunamis have long wavelengths, long tsunamis have long wavelengths, long periods and low heightperiods and low height

– compression of the wave’s energy into a compression of the wave’s energy into a smaller volume upon approaching a coast pr smaller volume upon approaching a coast pr island causes a dramatic increase in heightisland causes a dramatic increase in height

– CoriolisCoriolis

TidesTides• Why tides occurWhy tides occur

– tides result from the gravitational pull of the tides result from the gravitational pull of the moon and the sunmoon and the sun

– though smaller, the moon is closer to earth, so though smaller, the moon is closer to earth, so its gravitational pull is greaterits gravitational pull is greater

– water moves toward the moon, forming a bulge water moves toward the moon, forming a bulge at the point directly under itat the point directly under it

– the centrifugal force opposite the moon forms the centrifugal force opposite the moon forms another bulgeanother bulge

– areas of low water form between bulgesareas of low water form between bulges

TidesTides

• Spring and neap tidesSpring and neap tides– during spring tides, the times of highest during spring tides, the times of highest

and lowest tides, the earth, moon and sun and lowest tides, the earth, moon and sun are in a line, combining the pull of the sun are in a line, combining the pull of the sun and moonand moon

– when the sun and moon are at right when the sun and moon are at right angles, the sun’s pull offsets the moon’s, angles, the sun’s pull offsets the moon’s, resulting in neap tides, which have the resulting in neap tides, which have the smallest change between high and low tidesmallest change between high and low tide

TidesTides

• Tidal rangeTidal range– diurnal tide—one high tide and one low tide each diurnal tide—one high tide and one low tide each

dayday– semidiurnal tide—two high tides and two low semidiurnal tide—two high tides and two low

tides each day (most common)tides each day (most common)•mixed semidiurnal tide—high and low tides are at mixed semidiurnal tide—high and low tides are at

different levelsdifferent levels

•tide ranges from high water to low watertide ranges from high water to low water

•flood tides are rising; ebb tides are fallingflood tides are rising; ebb tides are falling

•tidal currents are associated with tidal cycletidal currents are associated with tidal cycle

•slack water occurs during the change of tidesslack water occurs during the change of tides

TidesTides