Environmental Science Lesson 3: Biogeochemical Cycles

Flashcards covering the definitions and processes of various biogeochemical cycles (water, nitrogen, oxygen, carbon, phosphorus, and sulfur) as presented in the Cebu Eastern College Environmental Science lecture.

Biogeochemical Cycles

Also known as nutrient cycles, these describe the movement of nutrients and other elements between biotic and abiotic factors.

Gaseous Nutrient Cycle

A cycle where the main source of nutrients are the atmosphere and the oceans; includes nitrogen ($78\%$), oxygen ($21\%$), and carbon dioxide ($0.03\%$).

Sedimentary Nutrient Cycle

A cycle where the main sources are soil, rocks, and minerals; mineral salts come directly from the Earth's crust through weathering.

Residence Time

The certain amount of time a water molecule spends in specific places like oceans, underground, or frozen as ice.

Condensation

A process in the water cycle where water vapor turns into liquid water.

Evaporation

A process in the water cycle where liquid water turns into water vapor.

Transpiration

The process by which plants release water vapor into the atmosphere.

Infiltration

The process by which water on the ground surface enters the soil.

Nitrogen Cycle

The process by which $N_2$ is converted between its various chemical forms through biological and physical processes.

Nitrogen Fixation

The step in the nitrogen cycle that converts $N_2$ to $NH_3/NH_4^+$ or $NO_3^*$.

Nitrification

The step in the nitrogen cycle that converts $NH_3$ to $NO_3$.

Assimilation

The incorporation of $NH_3$ and $NO_3$ into biological tissues.

Ammonification

The process where organic nitrogen compounds are converted to $$NH_3$.

Denitrification

The process where $NO_3$ is converted back into $N_2$.

Oxygen Cycle

A biogeochemical cycle describing the movement of oxygen within the atmosphere (air), the hydrosphere (water), and the lithosphere (land).

Carbon Cycle

The movement of carbon through the Earth between the air, plants, animals, soil, and oceans.

Phosphorus Cycle

The slowest of all major nutrient cycles, moving phosphorus through the land, water, and living things without a gaseous phase traveling through the air.

Phosphine

A very rare phosphorus gas that only forms in special conditions.

Sulfur Cycle

The biogeochemical process through which sulfur moves through the atmosphere, lithosphere, hydrosphere, and biosphere, including a gaseous phase.

Geological Uplift

A process involved in the phosphorus cycle that brings phosphorus from underground or underwater reserves back to the surface.