AP Environmental Science Unit 1 - Biogeochemical Cycles

Carbon

Essential element that forms base of all organic matter, including bodies of living organisms, and is key component of fossil fuels

Carbon Dioxide (CO₂)

Compound in atmosphere that is taken in by photosynthetic organisms to make organic molecules, later released back into atmosphere through respiration and decomposition

Photosynthesis

Process where energy from sunlight is used to transform CO₂ from atmosphere into organic matter that fuels food webs

Cellular Respiration

Process where living organisms break down organic compounds to produce usable energy, releasing CO₂ into the atmosphere as by-product

Carbon Cycle

Complex flow of Carbon between inorganic and organic sources within the environment

Carbon Cycle

Continuous flow of Carbon between organic and inorganic Carbon reservoirs / areas where large amounts of Carbon are stored

Biological Carbon Cycle

Occurs through biological process; describes flow of Carboon between atmosphere and earth’s ecosystems

Geological Carbon Cycle

Occurs by geological process; describes much slower flow of Carbon between earth’s nonliving Carbon reservoirs, Carbon moves from rocks on land into oceans via weathering / rainwater runoff

Oceanification

CO₂ enters ocean from atmosphere and forms carbonic acid and bicarbonate ions; increasing acidity

Nitrogen Cycle

Cyclic movement of Nitrogen in different chemical forms between living organisms and the environment

Nitrogen Fixation

Atmospheric Nitrogen gas is fixed or converted into form that can be used by plants / animals

Ammonification

Nitrogen-containing biological molecules may stay in organisms’ tissues or be broken down and released as waste, returning ammonia / ammonium ions to environment

Nitrification

Groups of nitrifying bacteria convert products of ammonification into nitrites (NO₂^-) then nitrates

Denitrification

Denitrifying bacteria convert nitrites/nitrates into N₂ gas, returning N₂ into atmosphere

How does Phosphate move up food chain?

Plants and animals are eaten

Residence Time

Average time that an individual water molecule spends in each of Earth’s major water reservoirs