Midterm #1 resultsposted early next week

see BlackBoard

Midterm #1 resultsposted early next week

see BlackBoard

Answer Keys for both White and Blue exams will be provided on course website

Scantrons will be returned in labs next week

Answer Keys for both White and Blue exams will be provided on course website

Scantrons will be returned in labs next week

Physical and Chemical Structure of the OceanPhysical and Chemical Structure of the Ocean

Why are the oceans blue?How is sound transmitted in the ocean?

Why is the ocean “layered” in many locations?

How do you keep your beer cool in the tropics?

Why are the oceans blue?How is sound transmitted in the ocean?

Why is the ocean “layered” in many locations?

How do you keep your beer cool in the tropics?

Light Absorption in WaterLight Absorption in Water

Intensity decreases rapidly with depthBlue and green penetrate deepest, giving the ocean its color

Why do objects lose their color with depth?

Why do objects lose their color with depth?

The colors other than blue (and green) are absorbed by the water molecules in the first few meters -- only blue (and green) are reflected

The colors other than blue (and green) are absorbed by the water molecules in the first few meters -- only blue (and green) are reflected

Sound in Sea WaterSound in Sea WaterSound is transmitted better in water Sound is transmitted better in water than it is in airthan it is in airSound velocity in the ocean is about Sound velocity in the ocean is about 1500 m/s, or about 4 times its speed in 1500 m/s, or about 4 times its speed in airairSound velocity increases with pressure Sound velocity increases with pressure and temperatureand temperature

SOFAR Sound ChannelSOFAR Sound Channel

Sound is focused into the SOFAR channel because it is a low velocity region

Sound is transmitted best through this channel -- good for whales and submarines(e.g., “Hunt for Red October”)

Sound is focused into the SOFAR channel because it is a low velocity region

Sound is transmitted best through this channel -- good for whales and submarines(e.g., “Hunt for Red October”)

Heard Island ExperimentHeard Island ExperimentGlobal Warming -- faster velocity??Global Warming -- faster velocity??

Go to Sounds

Go to Sounds

Ocean TemperatureSolar HeatingOcean TemperatureSolar Heating

Uneven heating of Earth’s surface

Release of heat asinfrared radiation

Requires flow ofheat by oceans andatmosphere

Surface circulation

Uneven heating of Earth’s surface

Release of heat asinfrared radiation

Requires flow ofheat by oceans andatmosphere

Surface circulation

Global Heat BudgetGlobal Heat Budgetheat at the Earth's

surface (342 W/m2) is supplied by absorption of ‘short-wave’ solar radiation from the sun.

heat lost from Earth is through long-wave radiation back to space.

heat at the Earth's surface (342 W/m2) is supplied by absorption of ‘short-wave’ solar radiation from the sun.

heat lost from Earth is through long-wave radiation back to space.

The Greenhouse EffectThe Greenhouse Effect

The Atmosphere is transparent to sunlight (ultraviolet [UV] and visible)

Clouds absorb or reflect about halfSunlight heats the Earth’s surface,

which then radiates energy as longer wavelength energy (infrared)

This energy is trapped by the atmospheric gases (CO2, H2O, CH4)

The Atmosphere is transparent to sunlight (ultraviolet [UV] and visible)

Clouds absorb or reflect about halfSunlight heats the Earth’s surface,

which then radiates energy as longer wavelength energy (infrared)

This energy is trapped by the atmospheric gases (CO2, H2O, CH4)

Special Properties of Water

Special Properties of Water

RECALL:Melting and boiling points are very highHighest heat capacity of common liquidsHigh heat of fusion and vaporization

RECALL:Melting and boiling points are very highHighest heat capacity of common liquidsHigh heat of fusion and vaporization

Sea Surface Temperaturesonly 0°-30°C world-wide

Sea Surface Temperaturesonly 0°-30°C world-wide

Land: 50°C to -50°C

Local Annual Heat BudgetsLocal Annual Heat Budgets

Amount of solar energy captured at one location on the Earth varies with season

Amount of solar energy captured at one location on the Earth varies with season

Local Annual Heat BudgetsLocal Annual Heat Budgets

Amount of solar energy captured at one location on the Earth varies with season

Amount of solar energy captured at one location on the Earth varies with season

Where we liveWhere we live

Temperature (vertical profile)Temperature (vertical profile)

Seasonalchanges in temperature profile

Temperature (vertical profile)Temperature (vertical profile)

Cool drinks go here

Thermocline

Temperatures with DepthTemperatures with Depth

Thermocline -- sharp temperature change

Thermocline -- sharp temperature change

Evaporation - PrecipitationEvaporation - Precipitation

Over the oceans, evaporation exceeds precipitation

The balance is restored by rain over the continents, returning water via rivers

Over the oceans, evaporation exceeds precipitation

The balance is restored by rain over the continents, returning water via rivers

Evaporation vs Precipitation

Evaporation vs Precipitation

Climate BeltsClimate Belts

Ocean Surface SalinityOcean Surface Salinity

Salinity VariationsSalinity Variations

Salinity VariationsSalinity Variations

Surface salinity follows evaporation-precipitation pattern

Atlantic Ocean is generally more salty than Pacific Ocean, in spite of river input -- why??

Surface salinity follows evaporation-precipitation pattern

Atlantic Ocean is generally more salty than Pacific Ocean, in spite of river input -- why??

Isthmus of PanamaIsthmus of Panama

Net transfer offresh waterfrom Atlanticto Pacific

Net transfer offresh waterfrom Atlanticto Pacific

Salinity of Rivers and Ocean Water

Can’t just concentrate river water to get seawater

How do we explain this observation?

Rivers

Ocean

Concept of Residence Time

Each element removed from ocean in different ways

And at different rates

e.g. Cl- vs. SiO2

Residence Time

Flux has units of mass per unit time

Reservoir has units of mass

R/F has units of time

Density of Sea Water(Where does Oregon’s seawater

plot?)

Density of Sea Water(Where does Oregon’s seawater

plot?)

Density of Sea Water(Where does Oregon’s seawater

plot?)

Density of Sea Water(Where does Oregon’s seawater

plot?)

Bottom Water

Oregon’s ocean

Density Rules!Density Rules!

Where does the Ocean’s Deepest Water Come

From?

Where does the Ocean’s Deepest Water Come

From?The densest seawater is COLD and

SALTYThis is formed at high latitudes in the

North and South Atlantic: North Atlantic Deep Water (NADW) Antarctic Bottom Water (AABW)

Could dense seawater form in the tropics?

(evaporation!)

The densest seawater is COLD and SALTY

This is formed at high latitudes in the North and South Atlantic: North Atlantic Deep Water (NADW) Antarctic Bottom Water (AABW)

Could dense seawater form in the tropics?

(evaporation!)

Dissolved Gases in the OceanDissolved Gases in the Ocean

Important Gases in the OceanImportant Gases in the Ocean

Oxygen -- Respiration, Decomposition

CO2 -- Photosynthesis, CaCO3

Nitrogen -- Nutrient for growth (NO3)Methane -- a product of

decomposition

Oxygen -- Respiration, Decomposition

CO2 -- Photosynthesis, CaCO3

Nitrogen -- Nutrient for growth (NO3)Methane -- a product of

decomposition

Photosynthesis and Respiration

Photosynthesis and Respiration

Biology interacts with the ChemistryBiology interacts with the Chemistry

Dissolved OxygenDissolved Oxygen

Biochemical RecyclingBiochemical Recycling

Summary: Biochemical Cycles

Summary: Biochemical Cycles

Elements enter oceans through riversGases enter oceans thru air-sea boundaryBiology alters distribution of elements

(“nutrients”) and gasesOcean circulates nutrients to surface, but

only in a few places (called “upwelling”)Interaction of physics, chemistry and

biology => geological record (sediments)

Elements enter oceans through riversGases enter oceans thru air-sea boundaryBiology alters distribution of elements

(“nutrients”) and gasesOcean circulates nutrients to surface, but

only in a few places (called “upwelling”)Interaction of physics, chemistry and

biology => geological record (sediments)