1. Ecology-Nutrient Cycles

2. Geochemical Cycles
Movement of a particular form of matter through the living & nonliving parts of an ecosystem
Closed system
Law of conservation of mass
Used over & over again in continuous cycle
Organisms are important part of cycle

3. Geochemical Cycles Matter in systems always transferred & transformed
Matter gets cycled in & out of ecosystems:
Carbon
Nitrogen
Water

4. Carbon Major component of living organisms (macromolecules) Found in:
Proteins, carbohydrates, lipids, nucleic acids
Found in:
Atmosphere
Minerals, rocks
Fossil fuels (natural gas, petroleum, coal)
Organic materials (soil, aquatic sediments)

5. Carbon Cycle Photosynthesis: Respiration: Decomposition:
Organisms take in CO2 from atmosphere  simple sugars (glucose)
Respiration:
Organisms break down glucose  carbon released into atmosphere as CO2
Decomposition:
Organisms die
Decomposers break down carbon compounds
Enrich soil/sediments
Released into atmosphere as CO2

6. Carbon Cycle Conversion of biochemical compounds:
Organisms store carbon  macromolecules
Example:
Animals eat plants & animals
some compounds used for energy
others converted to compounds suited for predators body
others released into atmosphere (methane, other gases)

7. Carbon Cycle Other methods of releasing stored carbon: Combustion:
wood or fossil fuels burned, CO2 released
Weathering of carbonate rocks:
Bones/shells fall to bottom of bodies of water
Incorporated into sedimentary rocks (calcium carbonate)
When weather & decompose, carbon released into ocean, eventually into atmosphere

10. The Carbon Cycle Linked to the flow of energy.
Atmospheric CO2 - carbon dioxide
Carbon taken in by plants (enters the living portion of the carbon cycle) through photosynthesis.
Heterotrophic Nutrition - animals eat plants
Organisms release CO2 through cellular respiration.
Fossil Fuels (coal, oil, natural gas)
stored carbon left over from bodies of plants and animals that died millions of years ago
Combustion – burn fossil fuels – releases CO2 back into the atmosphere
Decomposition – carbon from carbohydrates in organisms (converted into fats, oils, etc.) is released into the soil or air after an organism dies – some can form deposits of fossil fuels

11. Nitrogen Component of amino acids Needed to build proteins Found in
atmosphere as elemental nitrogen (N2)-gas
Living organisms (proteins & nucleic acids)
Organic materials (soil/sediments)

12. Atmospheric nitrogen (N2) makes up nearly 78%-80% of air.
Organisms can not use it in that form.
Lightning and bacteria convert nitrogen into usable forms

13. Nitrogen Cycle Nitrogen-fixation: Intake of nitrogen into organisms:
Nitrogen fixing bacteria
found in soil, root nodules of plants, or aquatic ecosystems
convert N2 (found in air or dissolved in water) into forms available for use by plants
Intake of nitrogen into organisms:
Plants take in nitrogen through roots = assimilation or absorption
Ammonia or nitrate
Nitrogen enters food chain

14. Nitrogen Cycle Decomposition: Organism dies or animal waste
Decomposers return nitrogen to soil
Denitrification:
Denitrifying bacteria
break down nitrogen compounds in soil
Release N2 into atmosphere

15. 15

16. The Nitrogen Cycle
Nitrogen – needed by organisms (DNA, amino acids/proteins…)
1. Nitrogen Gas(N2) - 79% of air, BUT not usable by plants
Part I: Nitrogen Fixation – making nitrogen gas (N2) into nitrogen that plants can use (ammonia, nitrates)
2. N2—lightning  nitrates (dissolved in rain)
3. N2—heat/pressure  fertilizer
9. N2—bacteria  ammonia
Part II: Food Web
4, 5. Absorption of nitrogen by Plants – make amino acids / protein
6. Nutrition - Animals eat plants – nitrogen moves through food web
7. DECAY excretions/dead stuff— bacteria  ammonia
Part III: 8. Denitrification
Nitrates — bacteria  nitrogen gas

17. Water Necessary substance for life Found in: Atmosphere
On surface of Earth
Underground
In living organisms
Evaporation, transpiration, condensation, precipitation

18. Hydrologic cycle (water cycle)
Driven by Sun’s heat energy
Causes water to evaporate from bodies of water & organisms

19. Hydrologic cycle Intake of water into organisms: Transpiration:
Use it to perform life functions
Photosynthesis
Transport of nutrients
Transpiration:
Plants release water back into atmosphere
Evaporative loss of water from plants

20. Hydrologic cycle Respiration: Elimination:
Metabolizing food for energy produces water as a by-product
Elimination:
Need water to assist with elimination of waste

23. The Water Cycle It’s driven by the sun condensation: gas to liquid
precipitation: water falls to the earth’s surface
Runoff
groundwater
transpiration: “Plant Sweat” water evaporating from the leaves of plants
respiration: organisms give off water vapor
evaporation: liquid to gas
How humans affect the water cycle:
When forests are cut down, the water cycle is disrupted and less moisture is returned to the atmosphere.