Cycles in an Ecosystem Water, Carbon, and Nitrogen

Carbon, Nitrogen, and Water 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 Cycle Earth is considered the WATER planet. Earth is considered the WATER planet. Water covers about 70% of its surface. Water covers about 70% of its surface. –Also our bodies are about 65% water We can’t live without it. We can’t live without it.

Water Earth’s water supply is finite Earth’s water supply is finite –The same amount of water that is here now is the same amount of when the dinosaurs roamed the earth.

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

What happens?? Energy from the sunlight, Energy from the sunlight, –water evaporates, from surface water, –rises into the atmosphere as a gas called water vapor. In the atmosphere In the atmosphere –Water vapor cools –Condenses into a liquid –Formation of cloud Droplets

What happens Continued Cloud droplets: If they continue to grow Cloud droplets: If they continue to grow –They become precipitation Which returns to earth Which returns to earth –Often falling directly back into the ocean or surface water –Or on land where it seeps directly into soil or washes over the surface and enters bodies of water, as a runoff.

Water Runoff

The Carbon Cycle Once you understand the water cycle the carbon cycle is relatively simple. Carbon is considered the building block of life.

Uses 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. The ocean Atmosphere Rocks –When carbon leaves these reservoirs, it cycles through the environment in several CONNECTED ways.

In 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. 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: 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.

Problems 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 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 most organisms. Paradox: Nitrogen by itself is not useable by most organisms. Must be “fixed” to be useful to biological forms Must be “fixed” to be useful to biological forms NH3, NO2, or NO3 NH3, NO2, or NO3

Fixations: Nitrogen combines with Oxygen=Nitrate High Energy= Lightning N2 with H1O=Ammonia Nitrate Produced (usable) High Energy= Lightning N2 with H1O=Ammonia Nitrate Produced (usable) Biological Fixation: Microbe Mediation Biological 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 Component Plants use ammonia, nitrate, and absorbed nutrients from the soil to make proteins. Plants use ammonia, nitrate, and absorbed nutrients from the soil to make proteins.

How do we get it? We eat the plants.. This is the only way we can get Nitrogen!! We eat the plants.. This is the only way we can get Nitrogen!! Nitrogen can also move through and ecosystem by trophic levels just like Carbon. Nitrogen can also move through and ecosystem by trophic levels just like Carbon.

The last step in cycle Decomposition: bacteria break down organic compounds (such as proteins) into simple N2 containing compounds Decomposition: bacteria break down organic compounds (such as proteins) into simple N2 containing compounds Denitrifying bacteria in soil act on ammonia, simplifying into H2 and N2. Denitrifying bacteria in soil act on ammonia, simplifying into H2 and N2. Which then releases N2 gas back into soil and atmosphere. Which then releases N2 gas back into soil and atmosphere.

Problems: Humans: Burning of F.Fuels and using N2 fertilizers. Humans: Burning of F.Fuels and using N2 fertilizers. Responsible for : Acid rain, pollution in water systems in agricultural areas, and formation of algae blooms. Responsible for : Acid rain, pollution in water systems in agricultural areas, and formation of algae blooms. Rob bodies of water of O2. Rob bodies of water of O2.