1. 1.1.4 and 2.5.4 Thermodynamics nutrient cycles

2. Two basic processes must occur in an ecosystem:
A cycling of chemical elements.
Flow of energy.
Energy flows through systems while materials circulate around systems.

3. Cycling of Chemical Elements
TRANSFERS: normally flow through a system and involve a change in location.
TRANSFORMATIONS: lead to an interaction within a system in the formation of a new end product, or involve a change of state.

4. Groundwater movement (slow) Surface runoff (rapid)
Water “hydrologic” Cycle
Precipitation
to ocean
Evaporation
From
ocean
Surface runoff
(rapid)
Ocean storage
Condensation
Transpiration
Rain clouds
Infiltration and
percolation
from plants
Groundwater movement (slow)
Runoff
Surface runoff (rapid)

5. combustion of wood (for clearing land; or for fuel
Terrestrial carbon Cycle
photosynthesis
aerobic respiration
Terrestrial
rocks
Soil water
(dissolved carbon)
Land food webs
producers, consumers, decomposers, detritivores
Atmosphere
(mainly carbon dioxide)
Peat,
fossil fuels
combustion of wood (for clearing land; or for fuel
sedimentation
volcanic action
death, burial, compaction over geologic time
leaching runoff
weathering

6. nitrogen Cycle Gaseous Nitrogen (N2) In Atmosphere Nitrogen Fixation
NO3 –
in soil
Nitrogen Fixation
by industry for agriculture
Fertilizers
Food Webs On Land
NH3, NH4+
1. Nitrification
bacteria convert NH4+ to nitrate (NO2–)
loss by leaching
uptake by autotrophs
excretion, death, decomposition
bacteria convert to ammonia (NH3+) ; this dissolves to form ammonium (NH4+)
Ammonification
bacteria, fungi convert the residues to NH3 , this dissolves to form NH4+
2. Nitrification
bacteria convert NO2- to nitrate (NO3-)
Denitrification
by bacteria
Nitrogenous Wastes, Remains In Soil
Gaseous Nitrogen (N2)
In Atmosphere
NO2 –
© 2004 Brooks/Cole – Thomson Learning

7. Phosphorous Cycle GUANO FERTILIZER ROCKS LAND FOOD WEBS
DISSOLVED IN OCEAN WATER
MARINE FOOD WEBS
MARINE SEDIMENTS
weathering
agriculture
uptake by autotrophs
death, decomposition
sedimentation
settling out
DISSOLVED IN SOIL WATER, LAKES, RIVERS
uplifting over geolgic time
mining
excretion

8. sulfur Cycle Hydrogen sulfide (H2S) + Water (H2O) Sulfur dioxide (SO2)
and
Sulfur trioxide (SO3)
Dimethyl
(DMS)
Industries
Sulfuric acid
(H2SO4)
Oceans
Ammonia (NH2)
Oxygen (O2)
Ammonium sulfate
[(NH4)2SO4]
Animals
Plants
Sulfate salts
(SO42-)
Decaying
organisms
Sulfur
(S)
Fog and precipitation
(rain, snow)
Aerobic conditions
in soil and water
Anaerobic
conditions in
soil and water
Volcanoes
hot springs
Atmosphere
sulfur Cycle

9. Flow of Energy
Thermodynamics is the study of the energy transformations that occur in a system.
It is the study of the flow of energy through nature.
Within a system energy cannot be re-used.

10. 1st Law of Thermodynamics
States that energy can be transferred and transformed, but it CANNOT be created nor destroyed.
Law of Conservation of Energy.
Energy of the universe is constant.

12. Thermal equilibrium = inputs equal outputs over a long period of time.

13. 2nd Law of Thermodynamics
States that every transformation results in a reduction of the FREE ENERGY (useable energy).
Energy transfers and transformations increase ENTROPY (disorder, randomness or chaos).
Law of Entropy.
Energy always tends to go from a more usable (higher quality) form to a less usable (lower quality) form.
You can’t get something for nothing
No such thing as a free lunch

14. Second Law of Thermodynamics

15. Any conversion is less than 100% efficient and therefore some energy is lost or wasted.
Usually this energy is lost in the form of HEAT (= random energy of molecular movement). We usually summarize it as respiration.
Solar
energy
Waste
heat
Chemical
(photosynthesis)
(food)
Mechanical
(moving,
thinking,
living)

16. Only 25% of chemical “E” stored in gasoline is transformed in to motion of the car and 75% is lost as heat!!

17. Without adding energy to a system, the system will break down .

18. Heat 10
100
1,000
10,000
Usable energy
available at
each tropic level
(in kilocalories)
Producers
(phytoplankton)
Primary
consumers
(zooplankton)
Secondary
(perch)
Tertiary
(human)
Decomposers