Cycles in an Ecosystem

Water, Carbon, and Nitrogen

Carbon, Nitrogen, and Carbon, Nitrogen, and WaterWater

• Each is essential to living things.Each is essential to living things.

• Why do we need each one?Why do we need each one?

The Water CycleThe Water Cycle

• Earth is considered the WATER Earth is considered the WATER planet.planet.

• Water covers about 70% of its Water covers about 70% of its surface.surface.– Also our bodies are about 65% waterAlso our bodies are about 65% water

•We can’t live without it. We can’t live without it.

WaterWater

• Earth’s water supply is finiteEarth’s water supply is finite

– The same amount of water that is here The same amount of water that is here now is the same amount of when the now is the same amount of when the dinosaurs roamed the earth.dinosaurs roamed the earth.

OceansOceans

They are the GREATEST reservoirs of They are the GREATEST reservoirs of water on the planet.water on the planet.

What happens??What happens??

• Energy from the sunlight, Energy from the sunlight, – water evaporates, from surface water, water evaporates, from surface water, – rises into the atmosphere as a gas rises into the atmosphere as a gas

called called water vapor.water vapor.

• In the atmosphereIn the atmosphere– Water vapor cools Water vapor cools – Condenses into a liquid Condenses into a liquid – Formation of cloud DropletsFormation of cloud Droplets

What happens ContinuedWhat happens Continued

• Cloud droplets: If they continue to growCloud droplets: If they continue to grow– They become precipitationThey become precipitation

• Which returns to earthWhich returns to earth– Often falling directly back into the ocean Often falling directly back into the ocean

or surface wateror surface water– Or on land where it seeps directly into soil Or on land where it seeps directly into soil

or washes over the surface and enters or washes over the surface and enters bodies of water, as a runoff.bodies of water, as a runoff.

Water RunoffWater Runoff

The Carbon CycleThe Carbon Cycle

• Once you understand the water cycle the carbon cycle is relatively simple.

• Carbon is considered the building block of life.

Uses for CarbonUses for Carbon

• Essential for DNA, proteins, fats, carbs and many more substances

• Used for food and gives energy which living things need.

• Carbon is a form of carbon dioxide=greenhouse gas (maintains heat).

Where carbon is found.Where carbon is found.

• The ocean

• Atmosphere

• Rocks– When carbon leaves these reservoirs, it

cycles through the environment in several CONNECTED ways.

In ONE Part of the CYCLEIn ONE Part of the CYCLE

• Carbon moves between the atmosphere, ocean, and living things.– Plants use carbon dioxide in photosynthesis

to make sugars and other organic chemicals.– Consumers eat both plants and animals that

eat plants via food web = intake of Carbon.– Respiration releases Carbon into Atmosphere.– The decomposition of living organisms

releases CO2 in the soil, water, and air.

In ANOTHER Part of the C. CycleIn ANOTHER Part of the C. Cycle

• In book:– Shells of marine animals (contain carbon), fall

to the bottom of the ocean– The decompose the shells pile up and are

covered by sediment--- over long periods of time turn to rock.

– Millions of years go by seafloor becomes dry land---Erosion dissolves carbon containing minerals

– Returning Carbon into the atmosphere.

Third Pathway:Third Pathway: Burning of Fossil Fuels Burning of Fossil Fuels

• Oil and Natural gas form from the remains of dead organisms (CO2 and H2)– Covered by layers of sediment

• Compaction and Chemical changes take place

• Turns into Petroleum. (Millions of yrs later)

• When we burn Oil and Gas it is releasing Carbon back in the atmosphere again.

ProblemsProblems

• People are altering because of Deforestation and Burning of Fossil Fuels.– Increase in CO2 in the air

• Might be one of the causes of global warming

Nitrogen CycleNitrogen Cycle

A major component of Amino Acids (proteins)A major component of Amino Acids (proteins) Major chemical of the atmosphere (78%)Major chemical of the atmosphere (78%) Paradox: Nitrogen by itself is not useable by Paradox: Nitrogen by itself is not useable by

most organisms.most organisms. Must be “fixed” to be useful to biological Must be “fixed” to be useful to biological

formsforms NH3, NO2, or NO3NH3, NO2, or NO3

Fixations: Nitrogen combines with Fixations: Nitrogen combines with Oxygen=NitrateOxygen=Nitrate

High Energy= Lightning N2 with High Energy= Lightning N2 with H1O=Ammonia Nitrate Produced (usable)H1O=Ammonia Nitrate Produced (usable)

Biological Fixation: Microbe MediationBiological Fixation: Microbe Mediation Bacteria that live in roots of legume plants.Bacteria that live in roots of legume plants.

Clover, peas, soybeans, and alfalfa.Clover, peas, soybeans, and alfalfa. Bacteria converts gas N2 to ammonia-> nitrate.Bacteria converts gas N2 to ammonia-> nitrate.

Plants=Nitrogen Cycle ComponentPlants=Nitrogen Cycle Component

Plants use ammonia, nitrate, and absorbed Plants use ammonia, nitrate, and absorbed nutrients from the soil to make proteins.nutrients from the soil to make proteins.

How do we get it?How do we get it?

We eat the plants .. This is the only way we We eat the plants .. This is the only way we can get Nitrogen!!can get Nitrogen!!

Nitrogen can also move through and Nitrogen can also move through and ecosystem by trophic levels just like Carbon.ecosystem by trophic levels just like Carbon.

The last step in cycleThe last step in cycle

Decomposition: bacteria break down organic Decomposition: bacteria break down organic compounds (such as proteins) into simple N2 compounds (such as proteins) into simple N2 containing compoundscontaining compounds

Denitrifying bacteria in soil act on ammonia , Denitrifying bacteria in soil act on ammonia , simplifying into H2 and N2.simplifying into H2 and N2.

Which then releases N2 gas back into soil and Which then releases N2 gas back into soil and atmosphere. atmosphere.

Problems:Problems:

Humans: Burning of F.Fuels and using N2 Humans: Burning of F.Fuels and using N2 fertilizers.fertilizers.

Responsible for : Acid rain, pollution in water Responsible for : Acid rain, pollution in water systems in agricultural areas, and formation of systems in agricultural areas, and formation of algae blooms.algae blooms.

Rob bodies of water of O2. Rob bodies of water of O2.