chapter 8 michael slemp. octopus is cephalopod mollusc octopuses have two eyes 8 arms with suction...
TRANSCRIPT
Chapter 8
Michael Slemp
*Marine Biology
Octopus• Is cephalopod mollusc• Octopuses have two eyes • 8 arms with suction cups• Hard beak in the mouth• Octopuses have no internal or external skeleton • One of the most intelligent
of all invertebrates• To defend themselves, they release ink (melanin = same as your
hair and eye color), use camouflage and arm autonomy (detaching of arm)
• All octopuses are venomous• Short life expectancy (6months-5 years). Die shortly after
reproduction • They have 3 hearts ( 2 pumps blood thru gills and 1 thru body)• They eat crabs, other molluscs (clams), fish, other cephalopods
What is AIR (atmosphere)? Gase
sNitrogen 78 %Oxygen 21 %Argon 1%Carbon Dioxide 0.03%All other gasses 0.01%
See pie chart in your book page 8-4
Water vapor
Aerosol
Water vapors are invisible. The
reason clouds are white is because the water have condensed
Aerosol is liquid and
solid particles suspended in air (like dust, pollen, ash)
Water vapor and aerosol makes about
4% of air)
Atmospheric layers
Troposphere: from sea level up to 15,000 meters (49,200 feet)Contains most of the air. Air compresses under its own weight = higher air
pressure
Stratosphere: up to 50,000 meters (164,000 feet)Has the most ozone!
Mesosphere: up to 100,000 meters (360,800 feet)
Thermosphere: beyond 110,000 meters (360,800 feet) into space
What is ozone?• Gas composed of 3 oxygen atoms (O3)
• Normally oxygen molecule has 2 oxygen atoms (O2)
• Extra oxygen in ozone causes instability and increased reactivity
• Ozone is mostly in stratosphere and absorbs the UV light (radiation from sun)
• Ozone protect us. If there would be no ozone, the UV light would kill the life on our planet
• In 1974, scientist came out with theory that ozone interacts with CFCs (chemical found in aerosols and air conditions)
• Reaction of ozone with CFCs can cause ozone hole and effect life on planet Earth!
Scientists are monitoring the size of the ozone hole existing over Antarctica
How much water vapor is in the air?
That depends on temperature, density and pressure
As temperature increases, pressure increases and density decreases
• Adding water vapor decreases air density even more
• Air is denser than water vapors
• Warm, moist air is less dense than cold air.
• Two air masses of the same temperature can have different densities
• It depends on the amount of water vapor
• Air with more water vapor is less dense
EvaporationAdds water
vapors into the air
CondensationRemoves water vapors from the
air
Saturated airAir in which the rate of
evaporation and the rate of condensation are the
same.The amount of water vapors is unchanged.
What happens when saturated air warms
up?• It becomes
undersaturated.• Evaporation adds
more water vapors into undersaturated air.
What happens when saturated air cools down?
• There is increased condensation • Water vapors are removed from air in
form of rain or snow (if temperature is low enough)
• Initially water droplets or ice crystals are very small and remain suspended in air
• As they collide, they form bigger drops or clusters or ice crystals. This lead to rain or snow
• Rain and snow happens when warm moist air mass collide with cooler air mass
Why is this important?• Air movements redistribute heat around the Earth• Precipitation is our main source of fresh water• All underground water, rivers, lakes get their water from
rain and snow. They return water and nutrients back to the ocean
Earth’s heat balanceSun is the
major energy source for
Earth’s surface
Atmosphere either absorbs or reflects 45%
of sunlight
20% absorbed by clouds and atmosphere
25% reflected by clouds and atmosphere
55% of sun’s energy reaches Earth’s surface
50% is absorbed by
Earth’s surface5% is reflected
by Earth’s surface
20%
25%
50%
5%
Earth’s heat balance
At any time, only half of the Earth’s surface receives sunlight (makes day and night)The energy coming to earth is ultimately lost as heat radiating back into space
What is solar energy?
Visible light
UV light (ultraviolet
light)
Infrared light
Makes it through the
atmosphere to Earth with
little absorption
Is absorbed mostly in
stratosphere by the ozone
layer
Some is absorbed by carbon
dioxide and water in stratosphere
and troposphere
Earth’s heat balanceSolar Energy is reflected
from various surfaces like • clouds• atmospheric particles• snow • reflective objects on
Earth’s surface
ALBEDO• The measure of amount
of energy something reflects
• Snow has high albedo• Black sand has low
albedo
Yellow = reflection, red = absorptionLeft arrow – snow, right arrow -water
To maintain balance between incoming energy from sun, eventually all energy Earth absorbs reradiates through
various paths back to space as infrared radiation
Unbalanced energy = Earth gets hotter,
less likely we survive!
Greenhouse effect • Important for life on Earth
• Atmosphere, after it absorbed infrared radiation, reradiates a lot of the heat back to Earth’s surface
• Most of the heat is collected in troposphere and stratosphere layers
• Without Greenhouse effect Earth would be on average 35°C (95°F)
The concern is that increased carbon dioxide and other heat-retaining gasses will cause global warming and increase the overall
temperature on Earth!
Uneven Heating• If there would be even heating on earth, there would be little
changes in temperature and no seasons
• But we know that there are seasons and temperature changes
• There are 3 primary factors that cause the Earth to heat unevenly:
1. Earth is spherical2. Earth’s axis of rotation is tilted3. Distance between Earth and sun varies with the time of
the year
Uneven Heating1. Earth is spherical
• Small part of sphere receives perpendicular light rays (mainly in areas around equator)
• Most of the sphere receives slanted light rays
• These slanted rays have same energy but got to cover larger area (means less energy per area unit)
• The farther North and South you go, the more slanted the sunlight reaching the surface
Perpendicular rays
Slanted rays
In order to be perpendicular rays, they would have to come from this direction, which does not happen in
this area!
Uneven Heating2. Earth’s axis of rotation is
tilted• Earth does not spin with its axis perpendicular
to the plane of its orbit• Earth’s orbit inclines 23.5 degrees off• Equator does not always receives perpendicular rays from
the sun• Depending on the time of the year, perpendicular sun rays
fall anywhere between the Tropic of Cancer (23.5° north latitude) and Tropic of Capricorn (23.5° south latitude)
• Longest day of the year for each hemisphere is when the sun is directly overhead at the Tropic line
Uneven Heating2. Earth’s axis of rotation is
tilted• The Amount of sunlight falling
on different parts of Earth changes and creates seasons
• When the Earth is tilted with North Pole toward the sun = there is summer in North hemisphere (and winter in South hemisphere)
• When the Earth is tilted with North Pole away from the sun = there is winter in North hemisphere (and summer in South hemisphere)
Uneven Heating3. Earth’s orbit is not circular
• Earth’s orbit is slightly elliptical• Earth gets more heat when its orbit brings it closer to the sun• Earth is closer to the sun during winter in North hemisphere and
farther away from the sun during summer in North hemisphere• This explains why North hemisphere has warmer winters and
cooler summers than South hemisphere
Uneven Heating Biological Importance
• Based on seasons we can predict migratory patterns
• Gray whales annually migrate to Arctic waters to feed off blooming krill and plankton in summer
• In winter gray whales swim south to breed in warmer waters around the Mexican Baja Peninsula
Uneven Heating Convection
• Convection is vertical movement of currents caused by temperature differences in a fluid (like air)
• On Earth, equator is the “kitchen stove” warming up all the Earth’s air and the poles are the cold parts.
• Equator: air heats up and rises, travels towards the poles
• Poles: Air cools down and sinks, and moves back towards equator where it replaces warm air
• Solar energy absorbed by Earth surface causes a general global pattern of winds moving air between equator and poles
• Sun warms up Earth• Earth warms up air in contact
with it• Warm air is less dense and
raises• High above, warm air cools
down and becomes denser (moves down towards the Earth surface)
• Cold air replaces warm air (and cycle continues creating circular pattern)
Coriolis effect Is the tendency for the path of a moving
object to deflect• To the right on the Northern hemisphere• To the left on the Southern hemisphere
Coriolis effect • Explains why we have winds in all directions, not just from north or
south• Effects also the ocean currents• Is major factor affecting the distribution of the Earth’s heat, nutrients
and many types of life• Is caused by Earth’s rotation• Is greater at higher latitudes• Is zero at equator because the rotational velocity does not change
The wind Recall• Convection causes general circulation pattern that moves air
between the equator and the poles• The Coriolis effect deflect air to the right as it travels (to the left in
the southern hemisphere)• This gives the air circular flow pattern rather than a straight north-
south pattern• It is not as simple as above!
• Wind patterns exists in small regions called atmospheric circulation cells
• Atmospheric circulation cells are six distinct air masses (3 in each hemisphere) with individual airflow patterns
The wind – 1. Hadley cells • Most important atmospheric circulation
cell• They lie between the equator and 30
degree north or south latitude• Warm air rises at the equator and moves
northward due to convection• Air does not make it all the way to the
north pole• By the time it reaches 30°N it becomes
dense enough from cooling and moisture loss to sink
• Most of the air descends and flows back to the equator, deflecting to the right (westward) as it flows
• This causes trade winds (flow westward between equator and 30° latitude
• Trade winds are what brought ships to Europe and America centuries ago
The wind – 2. Ferrel cells • Between approximately 30-60
degree latitude• These cells exist because some of
the wind that descends from Hadley cells does not turn toward the equator
• They continue towards the poles shifting to the right or left (depends on the hemisphere)
• The airflow forms the westerlies (because they are from the west) and blows towards the east
• The vertical circulation in Ferrel cells is opposite of what you would expect from convention because it is “sandwiched” between the Hadley cells and the Polar cells
The wind – 3.Polar cells • These lie between approximately 60
degrees and the pole• Airflow in the polar cell is similar to
the Hadley cell• Warm air at 60 degree rises and
flows towards the pole, where it cools, descends, and flows back to the equator
• Coriolis effect deflects it, so that the prevailing polar winds go to the west
• The south –flowing cold air from the polar cells affects the air flowing north and eastward in the Ferrell cells.
• Two air masses do not easily mix due to the different densities and temperatures.
• Polar cell air rises and heads northward again from convection, and causes the Ferrell cell air to deflect upward
INTERTROPICAL CONVERGENCE ZONES• This is where the trade winds meet from both hemispheres
• 30 degrees north and south latitude• Trade winds rise in this region• Vertical movement of air in ITCZ transports large amounts of heat
and moisture• Water vapor condenses in the rising and cooling air, and
rainstorms form.• Some of the world’s wettest climates are in the ITCZ• Surface winds are weak• Sailors call this area doldrums because they could be stranded
there without winds• ITCZ influences climates and weather, and the seasons and
landmasses affect the ITCZ
INTERTROPICAL CONVERGENCE ZONES• This is the reason why there is a difference between the
geographical equator and the meteorological equator (ITCZ)• Geographical equator is 0 degrees latitude• ITCZ is an imaginary line marking the temperature equilibriums
between the hemispheres that shift North and south with seasonal changes.
• It shifts because land has lower heat capacity than water, and there is more land mass in the northern hemisphere.
• Not a straight line due to the landmass affects its location• The ITCZ equator is important because atmospheric circulation is
approximate symmetrical on either side of it• 30 degree latitude leads to high evaporation and little rain fall• Most of the earth’s desert are at this latitude• There is a higher salinity around 30 degree latitude• More water is evaporated that returns to the
ocean making a higher salinity concentration
Monsoons• Seasonal wind pattern changes
caused by heating or cooling on the continents
• Causes summers with significant rainfall and winters with very little
• Results when air warmed by a hot landmass rises
• Warm, moist air from the ocean flows in to replace it; this in turns also rise
• Cools, which causes rain• When winter comes the cycle is
reversed• Wind reverses and land has very
little rain• Common in India and southeast
Asia
Cyclones• Large rotation storm systems of low pressure air
with converging wind at the center• Also called typhoon or hurricanes• Two types: extra tropical and tropical
Cyclones - Tropical• From within a single atmospheric cell• Form in low latitudes• Experience explosive growth because
of extremely rapid transport of heat and moisture into the atmosphere from the surface of the warm, tropical ocean
• They quickly dissipate once they hit land due to the loss of heat
• Cyclones move tremendous amounts of heat from the tropics to higher latitudes very quickly
• One cyclone can release about as much energy as the USA uses in an entire year
• This redistribution of heat is important to life on earth
Cyclones - ExtratropicalForm in higher latitudeForms as an area of low air pressure intensifies Occurs between the westbound polar winds and eastbound westerliesThese do not become hurricanes or typhoons They do cause hurricane strength winds, huge ocean waves rain and snow outside the tropics