Transcript iv. Bacteria drive the sulfur cycle - Wappingers Central School District

Chapter 5
Ecosystems and the Physical
Environment
Overview of Chapter 5
 Biogeochemical
 Solar
Cycles
Radiation
 The Atmosphere
 The Global Ocean
 Weather and Climate
 Internal Planetary Processes
Biogeochemical Cycles

Matter moves between
ecosystems, biotic & abiotic
environments, and
organisms


Biogeochemical cycling
involves


Unlike energy
Biological, geologic and
chemical interactions
Five major cycles:

Carbon, Nitrogen,
Phosphorus, Sulfur and Water
(hydrologic)
The Carbon Cycle
Carbon Cycle

The global movement of carbon between organisms
and the abiotic environment is known as the carbon
cycle
 1. Carbon is present in the atmosphere as carbon
dioxide(CO2), the ocean as carbonate and bicarbonate
(CO32-, HCO3-) and sedimentary rock as calcium
carbonate (CaCO3)
 2. Proteins, carbohydrates, and other molecules
essential to life contain carbon
 Carbon makes up approximately 0.04% of the
atmosphere as a gas
Carbon Cycle


ii. Carbon primarily cycles through both biotic and abiotic
environments via photosynthesis, cellular respiration and
combustion (CO2)
1. Photosynthesis incorporates carbon from the abiotic
environment (CO2) into the biological compounds of producers
(sugars)
6CO2 + 12H20 + energy

C6H12O6 + 6O2 + 6H2O
2. Producers, consumers and decomposers use sugars as fuel
and return CO2 to the atmosphere in a process called cellular
respiration
C6H12O6 + 6O2 + 6H2O
6CO2 + 12H2O + Energy
Carbon Cycle…
 3.
Carbon present in wood and fossil fuels
(coal, oil, natural gas) is returned to the
atmosphere by the process of combustion
(burning)
 The carbon-silicate cycle (which occurs on a
geological timescale involving millions of years)
returns CO2 to the atmosphere through volcanic
eruptions and both chemical and physical
weathering processes
The Carbon Cycle
The Nitrogen Cycle
Nitrogen Cycle
i. The global circulation of nitrogen between
organisms and the abiotic environment is know
as the nitrogen cycle
1. Atmospheric nitrogen (N2) is so stable that it
must first be broken apart in a series of steps
before it can combine with other elements to
form biological molecules
2. Nitrogen is an essential part of proteins and
nucleic acids (DNA)
3. The atmosphere is 78% nitrogen gas (N2)
Nitrogen Cycle
ii. Five steps of the nitrogen cycle
1. Nitrogen fixation
a. Conversion of gaseous nitrogen (N2) to
ammonia (NH3)
Formula:
N2 + 3H2
2NH3 (Ammonia), which
dissolves to form NH4+ (Ammonium)
Nitrogen Cycle
Nitrogen-fixing bacteria (including cyanobacteria)
fixes nitrogen in soil and aquatic environments
(anaerobic process)
c. Combustion, volcanic action, lightning discharges,
and industrial processes also fix nitrogen
d. Nitrogen-fixing bacteria contain a special enzyme
called Nitrogenase that is used to split atmospheric
nitrogen.
e. Legumes such as alfalfa and beans are planted to
reduce nitrogen loss in soil, since they contain
helpful Rhizobium nitrogen-fixing bacteria which live
inside special nodules on their roots!
b.
Nitrogen Cycle
2. Nitrification
a. Conversion of ammonia (NH3) or ammonium
(NH4+) to nitrate (NO3-)
b. Soil bacteria perform nitrification in a two-step
process (NH3 or NH4+ is converted to nitrite
(NO2-) then to NO3-)
c. Nitrifying bacteria is used in this process
Formula:
NH3 + NH4+
NO2- (nitrite) + NO3- (nitrate)
Nitrogen Cycle
3. Assimilation
a. Plant roots absorb NO3-, NO3 or NO4+ and
assimilate the nitrogen of these molecules into
plant proteins and nucleic acids
b. Animals assimilate nitrogen by consuming
plant tissues (conversion of amino acids to
proteins)
c. This step does not involve bacteria
Formula:
NH3 + NH4+ + NO3-
DNA, Proteins, Amino Acids
The Nitrogen Cycle
Nitrogen Cycle
4. Ammonification – when plants or animals die, or
when animals emit wastes, the nitrogen in the organic
matter re-enters the soil, where it is broken down by
decomposers. This decomposition produces
ammonia!
a. Conversion of biological nitrogen compounds into
NH3 (ammonia) and NH4+ (ammonium)
b. NH3 is released into the abiotic environment
through the decomposition of nitrogen-containing
waste products such as urea and uric acid (birds), as
well as the nitrogen compounds that occur in dead
organisms
c. Ammonifying bacteria is used in this process
Nitrogen Cycle
5. Denitrification
a. Reduction of NO3- to N2
b. Anaerobic denitrifying bacteria reverse the
action of nitrogen-fixing and nitrifying
bacteria
The Phosphorus Cycle
Phosphorous Cycle
i.
Phosphorus cycles from land to sediments in
the ocean and back to land
1.
2.
Phosphorus erodes from rock as inorganic
phosphates and plants absorb it from the soil
Animals obtain phosphorus from their diets, and
decomposers release inorganic phosphate into
the environment
ii. Once in cells, phosphates are incorporated
into biological molecules such as nucleic
acids and ATP (adenosine triphosphate)
iii. This cycle has no biologically important
gaseous compounds, so it is essentially NOT
found in the atmosphere!
Phosphorous Cycle…
 iv.
Phosphorous exists in the hydrosphere
primarily due to absorption and assimilation of
phosphorous by algae & plants in the oceans,
which are then eaten by larger plankton, moves
phosphorous up the food chain into fish, birds,
humans, etc.

Decomposers then release the inorganic
phosphates back into the seawater.
The Phosphorus Cycle
The Sulfur Cycle
Sulfur Cycle


i. Most sulfur is underground in sedimentary
rocks and minerals or dissolved in the ocean
ii. Sulfur gases enter the atmosphere from
natural sources in both ocean and land


1. Sea spray, forest fires and dust storms deliver
sulfates (SO42-) into the air
2. Volcanoes release both hydrogen sulfide (H2S)
and sulfur oxides (SOx)
Sulfur Cycle

iii. A tiny fraction of global sulfur is present in
living organisms




1. Sulfur is an essential component of proteins
2. Plant roots absorb SO42- and assimilate it by
incorporating the sulfur into plant proteins
Animals assimilate sulfur when they consume
plant proteins and covert them to animal
proteins
iv. Bacteria drive the sulfur cycle
The Sulfur Cycle
The Water (Hydrologic) Cycle
Hydrologic Cycle
The hydrologic cycle is the global circulation of water
for the environment to living organisms and back to
the environment
1. It provides a renewable supply of purified water for
terrestrial organisms
2. the hydrologic cycle results in a balance between
water in the ocean, on the land, and in the
atmosphere
ii. Water moves from the atmosphere to the land and
ocean in the form of precipitation
iii. Water enters the atmosphere by evaporation and
transpiration
i.
i.
The volume of water entering the atmosphere each year is
about 389,500 km3
Hydrologic Cycle…

Water is returned to
the oceans quickly
by runoff of surface
water, or more
slowly by the
processes of
infiltration and
groundwater flow.
Incoming Solar Radiation…
Solar Radiation
 Sun
provides energy for life, powers
biogeochemical cycles, and determines
climate

70% of incoming solar
radiation is absorbed by
atmosphere and earth


Remainder is reflected
Albedo



The reflectance of solar energy
off earth’s surface
Dark colors = low albedo
• Forests and ocean
Light colors = high albedo
• Ice caps
Incoming Solar Radiation (Insolation)

On a typical day, 49%
the Incoming Solar
Radiation reaches
Earth’s surface and is
absorbed by the
ground.
 After Visible Light is
absorbed, the Earth
heats up and reradiates the energy as
Infrared radiation,
which is also called
Terrestrial radiation.
Temperature Changes with Latitude
 Solar

energy does not hit earth uniformly
Due to earth’s spherical shape and tilt
Equator (a)
High concentration
Little Reflection
High Temperature
Closer to Poles (c)
From (a) to (c)
In diagram below
Low concentration
Higher Reflection
Low Temperature
January Global Temperatures
July Global Temperatures…
Temperature Changes with
Season
 Seasons
determined by
earth’s tilt
(23.5°)
 Causes each
hemisphere to
tilt toward the
sun for half the
year

Northern Hemisphere tilts towards the sun
from March 21- September 22 (warm season)
Temperature Changes with Season
On June 21st, the
northern hemisphere
experiences the longest
day of the year (sun is
out the longest), and the
sun is at it’s highest
altitude in the sky
(highest angle of
insolation); This day is
called the summer
solstice!
 Earth is actually further
from the Sun in July than
January…so the ANGLE
of insolation is the main
cause of warmer temps.
In summer!

Temperature Changes with
Season
 Places on
earth receiving
a lower angle
of insolation
will be colder,
while locations
receiving a
higher sun
angle will be
hotter!
Yearly Daylight
Analemma for
Quito, Ecuador
Yearly Daylight
Analemma for
Melbourne,
Australia
Yearly Daylight
Analemma for
Poughkeepsie, NY
The Atmosphere





Invisible layer of gases that
envelopes earth
Content
 21% Oxygen
 78% Nitrogen
 1% Argon, Carbon dioxide,
Neon and Helium
Density decreases with distance
from Earth’s surface!
Pressure decreases with distance
from Earth’s surface!
Our atmosphere shields earth
from high energy radiation
Atmospheric Layers

Troposphere (0-10km)




Where weather occurs
Temperature decreases
with altitude
Highest airplanes fly near
the top of the troposphere
This layer is warming up
due to the trapping of
greenhouse gases
(carbon dioxide mainly)
Atmospheric Layers

Stratosphere (10-45km)



Temperature increases
with altitude- very stable
Ozone layer absorbs UV
radiation, which is why
temperature rises here!
Mesosphere (45-80km)

Temperature decreases
with altitude
Atmospheric Layers
 Thermosphere


Gases in thin air absorb x-rays
and short-wave UV radiation =
very hot
Source of aurora
 Exosphere


(80-500km)
(500km and up)
Outermost layer
Atmosphere continues to thin
until converges with
interplanetary space
Atmospheric Circulation

Near Equator


~30°N&S sinks back to
surface


Warm air rises, cools and
splits to flow towards the
poles
Air moves along surface
back towards equator
This occurs at higher
latitudes as well

Moves heat from equator
to the poles
Surface Winds
 Large
winds due in
part to differences
in pressure caused
by global circulation
of air

High
Low
High
Low
Left side of diagram
High
 Winds
blow from
high to low pressure

Right side of
diagram
Low
High
Coriolis Effect
 Earth’s


Earth rotates from East to West
Deflects wind from straight-line path
 Coriolis



rotation influences direction of wind
Effect
Influence of the earth’s rotation on movement
of air and fluids
Turns them Right in the Northern Hemisphere
Turns them Left in the Southern Hemisphere
Coriolis Effect

Visualize it as a Merry-Go-Round (see below)
Global Ocean Circulation
 Prevailing
winds produce ocean currents and
generate gyres
 Example: the North Atlantic Ocean



Trade winds blow west
Westerlies blow east
Creates a clockwise gyre in the North Atlantic
 Circular
pattern influenced by coriolis effect
Global Ocean Circulation
Westerlies
Trade winds
Position of Landmasses
Large landmasses in
the Northern
Hemisphere help to
dictate ocean
currents and flow
Very little land in
the Southern
Hemisphere
Vertical Mixing of Ocean
Vertical Mixing of Ocean

Warmed water will rise, while colder, more salty water
will sink.
 Creates a global circulation of ocean water
 Wind may blow warm water away from a location,
allowing for upwelling of colder, nutrient-rich waters
from depth.
Ocean Interaction with Atmosphere- ENSO
 El

Niño-Southern Oscillation (ENSO)
Def: periodic large scale warming of surface waters
of tropical eastern Pacific Ocean
 Alters
ocean and atmospheric circulation
patterns
 Normal conditions- westward blowing
tradewinds keep warmest water in western
Pacific
 ENSO conditions- trade winds weaken and
warm water expands eastward to South
America
ENSO Climate Patterns
El Nino & La Nina Events
• What is an “El Nino” or a “La
Nina”?
– An El Niño/La Nina event is an
oscillation of the ocean-atmosphere
system in the tropical Pacific
having important consequences for
weather around the globe.
– This interaction is sometimes called
ENSO = El Nino/Southern Oscillation
– El Nino & La Nina are the changes
that occur in the ocean sea surface
temperatures
– The “Southern Oscillation” refers to
the atmospheric changes occurring,
specifically the monthly or seasonal
fluctuations in the air pressure
difference between Tahiti and
Darwin, Australia.
El Nino & La Nina
cause major world
wide climate
consequences: (El
Nino Climate
Consequences Shown
Here)
Normal Conditions in the Tropical
Pacific Ocean…
Normal Conditions in the Tropical
Pacific Ocean… • Typically, strong trade winds (from
•
•
both North and South), meet up
and blow ocean water AWAY from
coast of Peru, pushing warm water
toward the western tropical Pacific
(near Australia)
This allows cold water upwelling
off the coast to replace the warm
water that has departed.
Fishing industry benefits greatly,
because cold water upwelling
brings nutrients to supply base of
elaborate food web!
Normal Conditions in the Tropical Pacific Ocean…
El Nino Conditions
• During El Niño, the
trade winds weaken in
the central and
western Pacific leading
to a depression of the
thermocline in the
eastern Pacific
(typically off the coast
of Peru).
El Nino
• The deeper thermocline results in less
upwelling, lack of nutrients, and a loss of
productivity and fish!
• The deeper thermocline impacts climate worldwide!
El Nino Conditions…
Recognizing El Nino…
• El Nino can be identified
•
by monitoring Sea
Surface Temperatures in
the tropical Pacific
ocean, using moored
buoys (see diagram).
Buoys send data
continuously to satellite,
which transmits back to
NOAA computers
NORMAL CONDITIONS
EL NINO CONDITIONS
El Nino
Impacts
La Nina Conditions:
• During La Nina, trade winds strengthen,
thereby more effectively pushing warm surface
water westward, away from the coast of Peru,
and allowing for increased cold water upwelling
off the coast, enhancing the productivity and
fishing habitats.
La Nina Conditions
A look at all three conditions…
Where did the name come from?
• El Niño was originally recognized by fisherman
off the coast of South America as the
appearance of unusually warm water in the
Pacific ocean, occurring near the beginning of
the year.
• El Niño means The Little Boy or Christ child in
Spanish. This name was used for the tendency
of the phenomenon to arrive around Christmas.
• La Niña means The Little Girl.
La Nina
Impacts
…
Animated SST Sequence: ENSO
Most Recent ENSO Index
Weather and Climate
 Weather


The conditions in the atmosphere at a given place
and time
Temperature, precipitation, cloudiness, etc.
 Climate



The average weather conditions that occur in a
place over a period of years
2 most important factors: temperature and
precipitation
Earth as many climates
Rain Shadows
 Mountains
force humid air to rise
 Air cools with altitude, clouds form and
precipitation occurs (windward side)
 Dry air mass moves down opposite
leeward side of mountain
Tornadoes
 Powerful
funnel of air associated with a severe
thunderstorm
 Formation



Mass of cool dry air collides with warm humid air
Produces a strong updraft of spinning air under a
cloud
Spinning funnel becomes tornado when it descends
from cloud
 Wind
velocity= up to 300mph
 Width ranges from 1m to 3.2km
Tropical Cyclone

Giant rotating tropical storms
 Wind >119km per hour
 Formation




Strong winds pick up moisture over warm surface waters
Starts to spin due to Earth’s
rotation
Spin causes upward spiral
of clouds
Damaging on land


High winds
Storm surges
Internal Planetary Processes
 Layers

of the earth
Lithosphere
• Outermost rigid rock layer composed of plates

Asthenosphere
• Uppermost mantle comprised of hot soft rock (rock
behaves “plastically” here)
 Plate
Tectonics- study of the processes by
which the lithospheric plates move over the
asthenosphere
 Plate Boundary- where 2 plates meet

Common site of earthquakes and volcanoes
Plates and Plate Boundaries
Types of Plate Boundaries

Divergent Plate
Boundary-2 plates move
apart

Convergent Plate
Boundary-2 plates move
together (may get
subduction)
Types of Plate Boundaries
 Transform
Plate
Boundary- 2
plates move
horizontally in
opposite, parallel
directions
Earthquakes
 Caused
by the release of accumulated energy
as rocks in the lithosphere suddenly shift or
break


Occur along faults
Energy released as seismic wave
 Focus-
the site where the earthquake originates
below the surface
 Epicenter- located on the earth’s surface,
directly above the focus
 Richter scale and the moment magnitude
scales are used to measure the magnitude
Tsunami
 Giant
undersea wave caused by an earthquake,
volcanic eruption or landslide

Travel > 450mph
 Tsunami

wave may be 1m deep in ocean
Becomes 30.5m high on shore
 Magnitude

9.3 earthquake in Indian Ocean
Triggered tsunami that killed over 230,000 people in
South Asia and Africa