Biogeochemical Cycles Vocabulary Flashcards

Vocabulary flashcards reviewing key processes, reservoirs, and concepts across the Nitrogen, Phosphorus, Carbon/Oxygen, and Hydrological cycles.

Nitrogen fixation

The process where special bacteria convert atmospheric nitrogen gas ($N_2$) into usable forms like ammonia ($NH_3$) or ammonium ($NH_4^+$).

Nitrification

The process in which soil bacteria convert ammonia ($NH_3$) into nitrates.

Assimilation (Nitrogen Cycle)

The process where plants take up nitrates or ammonia from the soil through their roots to build proteins like DNA and RNA.

Ammonification

The process where decomposers break down organic matter after animals die or produce waste, returning nitrogen to the soil as ammonia or ammonium.

Denitrification

The process where specialized bacteria in low oxygen environments convert soil nitrates back into nitrogen gas ($N_2$), releasing it back into the atmosphere.

Main reservoirs of Nitrogen

The atmosphere, ocean (deep), soil, and biomass (living organisms).

Weathering (Phosphorus Cycle)

The process where rain and physical forces break down phosphorus-rich rocks, releasing phosphate into soil and water.

Absorption (Phosphorus Cycle)

The process where plants and fungi absorb dissolved phosphates through their roots.

Food chain transfer (Phosphorus Cycle)

The process where animals eat plants, moving phosphorus through the food web into their tissues, bones, and DNA.

Decomposition (Phosphorus Cycle)

The process where decomposers like bacteria and fungi break down dead organisms and waste, returning inorganic phosphate back to the soil.

Sedimentation

The process where runoff carries phosphorus into oceans and lakes, where it settles into sediments and eventually forms new rocks over long geological periods.

Main reservoirs of Phosphorus

Sedimentary rocks, ocean sediments, soil, and living organisms.

Photosynthesis

The process where plants, algae, and some bacteria take in $CO_2$ and water, using sunlight to make glucose and oxygen as food/energy.

Respiration

The process where animals and plants breathe in oxygen and use it to get energy from food, releasing $CO_2$ back into the atmosphere.

Decomposition (Carbon Cycle)

The process where fungi and bacteria break down dead plants and animals, releasing carbon back into the soil and air while using up oxygen.

Combustion

The burning of materials like wood or fossil fuels, which releases extra $CO_2$ into the atmosphere.

Main reservoirs of Carbon

The lithosphere, ocean, atmosphere, and biosphere.

Evaporation

The process where the sun heats water in oceans, lakes, and rivers, turning liquid water into water vapor that rises into the atmosphere.

Transpiration

The process where plants absorb water through their roots and release it as water vapor through tiny pores in their leaves.

Condensation

The process where water vapor in the air cools and changes back into liquid droplets, forming clouds and fog.

Precipitation

Condensed water falling back to Earth as rain, snow, sleet, or hail.

Infiltration

The process when rain or melted snow soaks into the soil.

Runoff

Water that cannot soak into the ground and flows into oceans and streams.

Main reservoirs of Water

Oceans, groundwater, atmosphere, lakes, rivers, and soil.