Transcript BIOGEOCHEMICAL CYCLES

Biogeochemical
Cycles
EQ: Identify and describe the flow of nutrients in
each biogeochemical cycle.
Explain the impact that humans have on the
biogeochemical cycles.
What does biogeochemical
mean?
• Bio
• Geo
• Chemical
BIOGEOCHEMICAL CYCLES
‘Fundamentals’ of biogeochemical cycles
• All matter cycles...it is neither created nor destroyed...
• As the Earth is essentially a closed system with
respect to matter, we can say that all matter on Earth
cycles .
• Biogeochemical cycles: the movement (or cycling) of
matter through a system
Matter = elements (carbon, nitrogen, oxygen) or molecules
(water)
so the movement of matter (for example carbon) between these
parts of the system is, practically speaking, a biogeochemical
cycle
The Cycling Elements:
macronutrients : required in relatively large amounts
carbon , hydrogen , oxygen , nitrogen , phosphorous
sulfur
other macronutrients:
potassium , calcium , iron , magnesium
micronutrients : required in very small amounts, (but still
necessary)
boron (green plants)
copper (some enzymes)
molybdenum (nitrogen-fixing bacteria)
ATMOSPHERE
LITHOSPHERE
HYDROSPHERE
ECOSPHERE
6 of the most important cycles
are the water, carbon, nitrogen,
sulfur, phosphorus and oxygen.
1.
2.
3.
4.
5.
6.
Water
Carbon
Nitrogen
Phosphorous
Sulfur
Oxygen
I. The Water Cycle
• Evaporation
-Water changes from liquid to gas
• Transpiration
-Water evaporates from the leaves into
the atmosphere.
• Condensation
- Water vapor (gas) turns into liquid
water forming clouds.
• Precipitation
-Water droplets become large
enough to fall to Earth
-Rain, snow, sleet, or hail
• Surface Runoff - Rain, snow, that flows
into streams, rivers, or canals.
HYDROLOGIC CYCLE
Condensation
Rain clouds
Transpiration
Transpiration
from plants
Precipitation to
land
Precipitation
Runoff
Surface runoff
(rapid)
Evaporation
Precipitation
Evaporation
from land
Evaporation
from ocean
Precipitation to
ocean
Surface
runoff
(rapid)
Infiltration and
Percolation
Groundwater movement (slow)
Ocean storage
Effects of Human Activities
on Water Cycle
• We alter the water cycle by:
– Withdrawing large amounts of freshwater.
– Clearing vegetation and eroding soils.
– Polluting surface and underground water.
– Contributing to climate change.
Water Quality Degradation
II. The Carbon Cycle
Where does carbon come from?
Natural Sources
of
Carbon
•Death of plants and animals
•Animal waste
•Atmospheric CO2
•Weathering
•Methane gas from cows
(and other ruminants)
•Aerobic respiration from
terrestrial and aquatic life
Sources of Carbon from
Human Activity
•Burning wood or forests
•Cars, trucks, planes
•Burning fossil fuels
such as coal, oil and
natural gas to produce
heat and energy.
Carbon in Oceans
• Additional carbon is stored in the ocean.
• Many animals pull carbon from water to use in
shells, etc.
• Animals die and carbon substances are deposited at
the bottom of the ocean.
• Oceans contain earth’s largest store of carbon.
Fig. 3-27, pp. 72-73
MARINE CARBON CYCLE
Diffusion between
atmosphere and ocean
Carbon dioxide
dissolved in
ocean water
photosynthesis
Combustion of fossil fuels
aerobic
respiration
Marine food webs
Producers, consumers,
decomposers, detritivores
incorporation
death,
into sediments sedimentation
uplifting over
geologic time
sedimentation
Marine sediments, including
formations with fossil fuels
Figure 4-29a
Page 78
TERRESTRIAL CARBON
CYCLE
Atmosphere
(most carbon is in carbon dioxide)
Combustion
of fossil
fuels
volcanic action
photosynthesis
Terrestrial
rocks
weathering
combustion of wood (for
aerobic
clearing land; or for fuel
respiration
Land food webs
producers,
consumers,
decomposers,
detritivores
Soil water
(dissolved
carbon)
leaching
runoff
death, burial, compaction
over geologic time
sedimentation
Peat,
fossil fuels
Effects of Human Activities
on Carbon Cycle
We alter the carbon
cycle by adding
excess CO2 to the
atmosphere through:
Burning fossil fuels.
Clearing vegetation
faster than it is
replaced.
Figure 3-28
III. The Nitrogen Cycle
• Where does nitrogen come from?
Sources of Nitrogen
•
•
•
•
•
Inorganic fertilizers
Nitrogen Fixation
Animal Residues
Crop residues
Organic fertilizers
Forms of Nitrogen
•
•
•
•
•
•
•
Urea  CO(NH2)2
Ammonia  NH3 (gaseous)
Ammonium  NH4
Nitrate  NO3
Nitrite  NO2
Atmospheric Dinitrogen N2
Organic N
Roles of Nitrogen
• Plants and bacteria use nitrogen in the
form of NH4+ or NO3• It serves as an electron acceptor in
anaerobic environment
• Nitrogen is often the most limiting
nutrient in soil and water.
Nitrogen is a key element for
• amino acids
• nucleic acids (purine, pyrimidine)
• cell wall components of bacteria (NAM).
Effects of Human Activities
on the Nitrogen Cycle
• We alter the nitrogen cycle by:
– Adding gases that contribute to acid rain.
– Adding nitrous oxide to the atmosphere through
farming practices which can warm the
atmosphere and deplete ozone.
– Contaminating ground water from nitrate ions in
inorganic fertilizers.
– Releasing nitrogen into the troposphere through
deforestation.
Effects of Human Activities
on the Nitrogen Cycle
• Human activities
such as
production of
fertilizers now fix
more nitrogen
than all natural
sources
combined.
Figure 3-30
IV. The Phosphorous Cycle
IMPORTANCE OF
PHOSPHOROUS CYCLE
• 1.Phosphorous is an essential nutrient of both plants and
animals.
• 2. It is part of DNA molecules which carry genetic
information.
• 3. It is part of ATP and ADP) that store chemical
energy for use by organisms in cellular respiration.
• 4. Forms phospholipids in cell membranes of plants
and animal cells.
• 5. Forms bones, teeth, and shells of animals as calcium
phosphate compounds.
PHOSPHOROUS CYCLE
mining
excretion
FERTILIZER
GUANO
agriculture
uptake by
autotrophs
MARINE
FOOD
WEBS
weathering
DISSOLVED
IN OCEAN
WATER
uptake by
autotrophs
leaching, runoff
DISSOLVED IN
SOIL WATER,
LAKES, RIVERS
death,
decomposition
sedimentation
death,
decomposition
weathering
settling out
uplifting over
geologic time
MARINE SEDIMENTS
ROCKS
LAND
FOOD
WEBS
HUMAN IMPACTS TO
PHOSPHOROUS CYCLE
1. Humans mine LARGE quantities of phosphate rock to use in
commercial fertilizers and detergents. Phosphorous is NOT
found as a gas, only as a solid in the earth’s crust. It takes
millions to hundreds of millions of years to replenish.
2. Phosphorous is held in the tissue of the trees and vegetation, not
in the soil and as we deforest the land, we remove the ability for
phosphorous to replenish globally in ecosystems.
3. Cultural eutrophication – ad excess phosphate to aquatic
ecosystems in runoff of animal wastes from livestock feedlots,
runoff of commercial phosphate fertilizers fro cropland, and
discharge of municipal sewage.
Effects of Human Activities
on the Phosphorous Cycle
• We remove large amounts of phosphate from
the earth to make fertilizer.
• We reduce phosphorous in tropical soils by
clearing forests.
• We add excess phosphates to aquatic
systems from runoff of animal wastes and
fertilizers.
V. The Sulfur Cycle
IMPORTANCE OF SULFUR
CYCLE
1. Sulfur is a component of most proteins and some vitamins.
2. Sulfate ions (SO4 2- ) dissolved in water are common in
plant tissue. They are part of sulfur-containing amino
acids that are the building blocks for proteins.
3. Sulfur bonds give the three dimensional structure of amino
acids.
4. Many animals, including humans, depend on plants for
sulfur-containing amino acids.
SULFUR CYCLE
Water
Sulfur trioxide
Acidic fog and
precipitation
Sulfuric acid
Ammonia
Oxygen
Sulfur dioxide
Ammonium
sulfate
Hydrogen
sulfide
Plants
Volcano
Dimethyl
sulfide
Industries
Animals
Ocean
Sulfate salts
Metallic
sulfide
deposits
Decaying
matter
Sulfur
Hydrogen
sulfide
Effects of Human Activities
on the Sulfur Cycle
• We add sulfur dioxide to the atmosphere by:
– Burning coal and oil
– Refining sulfur containing petroleum.
– Convert sulfur-containing metallic ores into free
metals such as copper, lead, and zinc releasing
sulfur dioxide into the environment.
VI. The Oxygen Cycle
The Oxygen cycle
PHOTOSYNTHESIS
Photosynthesis: occurs within the chloroplasts of green plants.
The photosynthetic membranes are arranged in flattened sacs
called the thylakoids.
6CO2 + 12H2O
C6H12O6 + 6O2 + 6H2O
light
(reactants)
Function: Chemical energy
Storage for cell use
(products)
CELLULAR RESPIRATION
Cellular Respiration occurs
in light simultaneously with
photosynthesis. It occurs in
the cytoplasm and
mitochondria.
It is the reverse reaction of
photosynthesis.
Function = chemical energy
release
C6H12O6 + 6O2 + 6H2O
chemical energy
6CO2 + 12H2O+
CULTURAL
EUTROPHICATION
Cultural Eutrophication &
Anoxia
• Eutrophication: natural process; over
1000’s of years, lakes fill in with
sediment, become marshes then dry
land
• Cultural Eutrophication: same
process, but speeded enormously by
loading with “limiting nutrients”
(typically P, sometimes N)
ROCK CYCLE
HUMAN IMPACTS ON THE
ROCK CYCLE
• 1. Humans are excavating minerals and removing
rock material. It takes millions of years for rock
to form.
• 2. Humans remove sediments for building
materials. This removes sediments that may form
sedimentary rocks in the future.
• 3. Humans are filling in wetlands (peatlands),
area that will form future coal beds.
1. Which part of the atmosphere is the ozone layer right above?
A. Stratosphere B. Troposphere C. Mesosphere D. Thermosphere
2. How long does it take rock formations to form?
A. 1,000 years B. 10,000 years C. 100,000 years D. 1,000,000 years E.
10,000,000 years
3. What is cultural eutrophication good for?
A. Fish B. Dissolved Oxygen in the lake C. algae D. clear lake
Works Cited
1. http://science.pppst.com/carboncycle.html
2. westernreservepublicmedia.org/earthmotion3/image
s/Carbon_Cycle.ppt
3. clima-dods.ictp.it/d3/annalisa/ocean_sv/lecture1.ppt
4. www.geology.wmich.edu/Koretsky/envs2150/Pcycl
e_1.ppt