unit 7. concept 2.

geochemical cycles

represent the movement of a particular form of matter through the living and nonliving parts of an ecosystem.

what are the three main geochemical cycles?

Water (Hydrologic), Carbon, Nitrogen

what drives the water cycle?

the sun

precipitation

water falls to Earth as a liquid (usually rain, sleet or snow)

runoff

liquid water that isn’t infiltrated runs along the surface and collects in puddles, lakes, oceans, or other bodies of water.

infiltration

some water seeps from the surface of the Earth to underground aquifers

evaporation

sun heats liquid water to vapor and it rises to the atmosphere

transpiration

water rises back into the atmosphere as water vapor from plants

condensation

water condenses to form clouds before precipitating again

when do organisms release water?

All organisms release water when breaking down food for energy (cellular respiration) C6H12O6 + 6O2 = 6CO2 + 6H2O + ATP

when do organisms take in water

Plants take in water to make sugar (photosynthesis) 6CO2 + 6H2O = C6H12O6 + 6O2

what negative impact do humans have on the water cycle

\-Deforestation: decreased transpiration -Paving/Building/Development: decreased Runoff and increased Infiltration -Pollution

carbon is found in

Macromolecules. Proteins (muscle, skin, etc…) Carbohydrates (food, sugars) Lipids (fats) Nucleic acids (DNA and RNA) Our atmosphere (as CO2) Minerals and rocks Fossil fuels (coal, oil, natural gas) and Organic materials in soil or aquatic sediments

photosynthesis (carbon)

plants capture CO2 from the atmosphere and use it to make sugar

cellular respiration (carbon)

CO2 released into atmosphere as waste from metabolism

consumption

CO2 released into atmosphere as waste from metabolism

combustion

CO2 released into atmosphere from burning

decomposition

decomposers break down carbon from dead organisms, allowing it to be recycled in the soil

fossilization

converts carbon from once-living organisms into a fuel source through intense heat and compression, including natural gas, oil, and coal (fossil fuels)

what living organisms are in the carbon cycle?

Decomposers (like bacteria and fungi) break down dead materials and return the nutrients (like Carbon) to the soil / Photosynthetic organisms (like plants and algae) remove CO2 from the atmosphere and convert it into simple sugars. / Animals, plants and fungi do cellular respiration in order to break down carbon-rich foods for energy

what is the negative human impact of the carbon cycle?

Combustion: when wood or fossil fuels, which contain carbon, are burned causing a major rise of CO2 in the atmosphere

where is nitrogen found?

proteins, nucleic acid, in the atmosphere as N2, etc.

nitrogen fixation

Bacteria (or lightning!) in the soil or water convert nitrogen (from the air or water) into forms that plants can use

decomposition

decomposers like bacteria break dead matter down, returning nitrogen to the soil.

ammonification

Bacteria convert nitrogen from waste (urine and feces) into ammonia.

nitrification

Bacteria convert nitrogen in ammonia into nitrates and nitrites to be absorbed by plants in their roots. This is how nitrogen enters the food chain, and eventually reaches us.

denitrification

bacteria convert nitrogen in ammonia to N2 so it can go back into the atmosphere

what organisms are included in the nitrogen cycle?

Bacteria is most important living organism in converting nitrogen to different forms. Fungi and other decomposers breakdown nitrogen-rich waste and put it in the soil

what is the negative human impact in the nitrogen cycle?

Fertilizers: The use of fertilizers adds WAY too much nitrogen to the soil, creating an imbalance This excess nitrogen can get into groundwater which can be dangerous to drink / Combustion: not as major of an impact on the nitrogen cycle as the carbon cycle, but burning fossil fuels does release excess nitrogen into the atmosphere