584410314-Biogeochemical-Cycles-ppt.ppt. Environmental Science

Environmental Science

1. Biogeochemical CyclesBiogeochemical Cycles

2. Objectives:Objectives:

Identify and describe the flow of nutrients in Identify and describe the flow of nutrients in
each biogeochemical cycle. each biogeochemical cycle.

Explain the impact that humans have on the Explain the impact that humans have on the
biogeochemical cycles.biogeochemical cycles.

3. What Sustains Life on Earth?What Sustains Life on Earth?

Solar energy, Solar energy,
the cycling of the cycling of
matter, and matter, and
gravity sustain gravity sustain
the earth’s life.the earth’s life.
Figure 3-7Figure 3-7

4. Two Secrets of Survival: Two Secrets of Survival:
Energy Flow and Matter RecyclingEnergy Flow and Matter Recycling

An ecosystem An ecosystem
survives by a survives by a
combination of combination of
energy flow and energy flow and
matter recycling.matter recycling.
Figure 3-14Figure 3-14

5. MATTER CYCLING IN MATTER CYCLING IN
ECOSYSTEMSECOSYSTEMS

Nutrient Cycles: Global RecyclingNutrient Cycles: Global Recycling

Global Cycles called biogeochemical cycles, are Global Cycles called biogeochemical cycles, are
cycling of cycling of nutrientsnutrients from the from the abioticabiotic reservoirs reservoirs
to biotic reservoirs. to biotic reservoirs.

NutrientsNutrients are the elements and compounds that are the elements and compounds that
organisms need to live, grow, and reproduce.organisms need to live, grow, and reproduce.

Biogeochemical cycles Biogeochemical cycles move move all all nutrients nutrients
through air, water, soil, rock and living organisms through air, water, soil, rock and living organisms
over millions of years.over millions of years.

6. MATTER CYCLING IN MATTER CYCLING IN
ECOSYSTEMSECOSYSTEMS

Nutrient Cycles: Global RecyclingNutrient Cycles: Global Recycling

Abiotic – nonliving cycles like rock cycle, water Abiotic – nonliving cycles like rock cycle, water
cycle and other chemical cycles.cycle and other chemical cycles.

Biotic – living organism involved cycles like Biotic – living organism involved cycles like
carbon and nitrogen cycle.carbon and nitrogen cycle.

All cycles enable a specific chemical element or All cycles enable a specific chemical element or
nutrient to be taken and reused through various nutrient to be taken and reused through various
forms.forms.

7. What Sustains Life on Earth?What Sustains Life on Earth?
Figure 2Figure 2

8. Closer look at cyclesCloser look at cycles

WATER CYCLEWATER CYCLE

9. Water’s Unique PropertiesWater’s Unique Properties

There are strong forces of attraction between There are strong forces of attraction between
molecules of water.molecules of water.

Water exists as a liquid over a wide Water exists as a liquid over a wide
temperature range. temperature range.

Liquid water changes temperature slowlyLiquid water changes temperature slowly..

It takes a large amount of energy for water to It takes a large amount of energy for water to
evaporate.evaporate.

Liquid water can Liquid water can dissolve a variety of dissolve a variety of
compoundscompounds including rock. including rock.

Water expands when it freezes.Water expands when it freezes.

10. Fig. 3-26, p. 72
Precipitation
Precipitation
Transpiration
Condensation
Evaporation
Ocean storage
Transpiration
from plants
Precipitation
to land
Groundwater movement (slow)
Evaporation
from landEvaporation
from oceanPrecipitation
to ocean
Infiltration and
Percolation
Rain clouds
Runoff
Surface runoff
(rapid)
Surface
runoff
(rapid)

11. Effects of Human Activities Effects of Human Activities
on Water Cycleon Water Cycle

We alter the water cycle by:We alter the water cycle by:

Withdrawing large amounts of freshwater from the Withdrawing large amounts of freshwater from the
ground causing salt water to contaminate reservoir. ground causing salt water to contaminate reservoir.

Withdrawing large amounts Withdrawing large amounts from rivers and from rivers and
streams changes flow of nutrientsstreams changes flow of nutrients

Clearing vegetation causes eroding soils that clogs Clearing vegetation causes eroding soils that clogs
streams.streams.

Polluting surface and underground water.Polluting surface and underground water.

All of this contributes to climate change.All of this contributes to climate change.

12. Carbon Cycles:Carbon Cycles:

One of the most complex cycles on Earth.One of the most complex cycles on Earth.

14. Carbon Cycles:Carbon Cycles:

Carbon just like all other nutrients cycles from Carbon just like all other nutrients cycles from
one reservoir to another through many years.one reservoir to another through many years.
Eg: Carbon enters plants as Eg: Carbon enters plants as COCO
2 2 which is which is
incorporated into organic molecules by a incorporated into organic molecules by a
process called process called photosynthesisphotosynthesis

When organisms respire, a portion of When organisms respire, a portion of
this carbon is returned to the this carbon is returned to the
atmosphere as COatmosphere as CO
2.2.

15. Carbon Reservoir pools: Where Carbon Reservoir pools: Where
Carbon is storedCarbon is stored

Organic molecules – in living and dead Organic molecules – in living and dead
organisms. organisms.

Carbon Dioxide (COCarbon Dioxide (CO22) in atmosphere. ) in atmosphere.

Organic matter in soil.Organic matter in soil.

Fossil fuels Fossil fuels and sedimentary rock like and sedimentary rock like
limestone.limestone.

COCO22 in ocean/water bodies. in ocean/water bodies.

Calcium carbonate Calcium carbonate in the shells of in the shells of
marine organisms.marine organisms.

16. Effects of Human Activities Effects of Human Activities
on Carbon Cycleon Carbon Cycle
We alter the carbon We alter the carbon
cycle by adding cycle by adding
excess COexcess CO
22 to the to the
atmosphere through:atmosphere through:

Burning fossil fuels.Burning fossil fuels.

Clearing vegetation Clearing vegetation
faster than it is faster than it is
replaced.replaced.

Just Just BreathingBreathing
Figure 3-28Figure 3-28

17. The Nitrogen CycleThe Nitrogen Cycle

Nitrogen is the Nitrogen is the second largest second largest nutrient cycle nutrient cycle
on the planet, second only to carbon.on the planet, second only to carbon.

20. Effects of Human Activities Effects of Human Activities
on the Nitrogen Cycleon the Nitrogen Cycle

We alter the nitrogen cycle by:We alter the nitrogen cycle by:

Adding gases to Adding gases to atmosphereatmosphere that contribute to that contribute to
acid rain.acid rain.

Adding nitrous oxide to the atmosphere through Adding nitrous oxide to the atmosphere through
farming practices farming practices which can warm the which can warm the
atmosphere and atmosphere and deplete ozonedeplete ozone..

Contaminating Contaminating ground water ground water from nitrate ions in from nitrate ions in
inorganic fertilizers.inorganic fertilizers.

Releasing nitrogen into the troposphere through Releasing nitrogen into the troposphere through
deforestation.deforestation.

21. Effects of Human Activities Effects of Human Activities
on the Nitrogen Cycleon the Nitrogen Cycle

Human activities such Human activities such
as as production and production and
use of fertilizers use of fertilizers now now
“fix” (put into “fix” (put into
environment) more environment) more
nitrogen than nitrogen than all all
natural sources natural sources
combined.combined.
Figure 3-30Figure 3-30

22. Phosphorous CyclePhosphorous Cycle

Phosphorous Cycle has been greatly affected Phosphorous Cycle has been greatly affected
by human activity in the last 100 years.by human activity in the last 100 years.

23. Fig. 3-31, p. 77
Dissolved
in Ocean
Water
Marine Sediments Rocks
uplifting over
geologic time
settling out
weathering
sedimentation
Land
Food
Webs
Dissolved
in Soil Water,
Lakes, Rivers
death,
decomposition
uptake by
autotrophs
agriculture
leaching, runoff
uptake by
autotrophs
excretion
death,
decomposition
mining Fertilizer
weathering
Guano
Marine
Food
Webs

24. Effects of Human Activities Effects of Human Activities
on the Phosphorous Cycleon the Phosphorous Cycle

We remove large amounts of phosphate from We remove large amounts of phosphate from
the earth to make fertilizer.the earth to make fertilizer.

We reduce phosphorous in tropical soils We reduce phosphorous in tropical soils
by clearing forests.by clearing forests.

We add excess phosphates to aquatic We add excess phosphates to aquatic
systems from systems from runoffrunoff of animal wastes and of animal wastes and
fertilizers.fertilizers.

25. Fig. 3-32, p. 78
Hydrogen sulfide
Sulfur
Sulfate salts
Decaying matter
Animals
Plants
Ocean
Industries
Volcano
Hydrogen sulfide
Oxygen
Dimethyl
sulfide
Ammonium
sulfate
Ammonia
Acidic fog and
precipitation
Sulfuric acid
Water
Sulfur
trioxide
Sulfur dioxide
Metallic
sulfide
deposits

26. Effects of Human Activities Effects of Human Activities
on the Sulfur Cycleon the Sulfur Cycle

We add sulfur dioxide to the atmosphere by:We add sulfur dioxide to the atmosphere by:

Burning coal and oilBurning coal and oil

Refining sulfur containing petroleum.Refining sulfur containing petroleum.

Convert sulfur-containing metallic ores into free Convert sulfur-containing metallic ores into free
metals such as copper, lead, and zinc releasing metals such as copper, lead, and zinc releasing
sulfur dioxide into the environment.sulfur dioxide into the environment.