AP Environmental Science

Biogeochemical

Nitrification

A two-step process where specialized bacteria convert ammonia (NH₃) first into nitrites (NO₂⁻), and then into nitrates (NO₃⁻), which plants can readily absorb.

Sedimentation

Dead marine organisms can get compacted and added to the formation of sedimentary rock

Percolation

water moves through the soil layer down to recharge ground water

Weathering

the physical and chemical break down of rocks that causes phosphorus to be release

Nitrogen fixation

The process by which certain bacteria and archaea convert atmospheric nitrogen gas (N₂), which is inert and unavailable to most organisms, into ammonia (NH₃) or related compounds that plants can use to synthesize proteins and other vital molecules. This can also occur abiotically through lightning.

Uplift

process that moves rocks from the oceans onto land

Assimilation

uptake of carbon, nitrogen, phosphorus into plants as they grow

Aerobic cellular respiration

release the energy in food by using oxygen and adds carbon dioxide to the atmosphere

Surface runoff

water that doesn’t soak in to the ground but collects and flows into streams and rivers

Precipitation

when water falls from the sky; hail, sleet, snow, rain

Condensation

formation of clouds with the cooling of water vapor

Oceans

major store of carbon dioxide

Aquifer

an underground store of water that can be a source of drinking water

Feeding

how animals get nitrogen

Photosynthesis

removes carbon dioxide from the atmosphere; done by plants and algae

Urine

how animals release/remove nitrogenous waste

Transpiration

water evaporates from the leaves of plants through tiny holes in the leaves called stomata

Denitrification

The process by which denitrifying bacteria convert nitrates (NO₃⁻) in the soil back into nitrogen gas (N₂), releasing it into the atmosphere and completing the nitrogen cycle

Decomposition

break down of dead and decaying material that adds nitrogen and phosphorus into the soil

Ammonification

The decomposition process where bacteria and fungi break down organic nitrogen from dead organisms and waste products, converting it into ammonia (NH₃) or ammonium ions (NH₄⁺) in the soil.

Eutrophication

 an increase in nitrogen and phosphorus in bodies of water that can result in algae blooms and low oxygen (hypoxic) areas

Combustion of fossil fuels

burning of coal to create electricity; adds carbon dioxide to the atmosphere