Cycles of Matter: Biogeochemical Cycles in Ecosystems

Comprehensive vocabulary flashcards covering the processes, biological components, chemical forms, and anthropogenic impacts across the water, carbon, nitrogen, and phosphorus biogeochemical cycles.

Biogeochemical Cycles

The continuous pathways through which matter circulates repeatedly between living organisms and the abiotic environment via biological, geological, and chemical processes.

Photosynthesis

The biological process in which plants, algae, and certain bacteria absorb atmospheric $CO_2$ to build biomass, forming glucose and other organic molecules.

Cellular Respiration

The metabolic process in which producers and consumers break down food molecules to release energy, returning $CO_2$ to the atmosphere.

Fossil Fuels

Long-term carbon reservoirs such as coal, oil, and natural gas formed when organic matter from dead organisms is buried and compressed over millions of years.

Methane ($CH_4$)

A potent greenhouse gas released through human agricultural and waste activities, including livestock digestion, rice paddies, and decaying organic waste in landfills.

Atmospheric Nitrogen ($N_2$)

A chemically inert gas that makes up approximately $78\%$ of Earth's atmosphere and cannot be directly utilized by most living organisms due to its stable triple chemical bond.

Nitrogen Fixation

The biological or industrial process that converts chemically inert atmospheric $N_2$ gas into biologically usable ammonium ($NH_4^+$).

Legume Root Nodules

Specialized root structures found in plants such as peas, beans, and clover that house mutualistic nitrogen-fixing bacteria.

Nitrification

The biological conversion in the soil where nitrifying bacteria transform ammonium ($NH_4^+$) into nitrites ($NO_2^-$) and subsequently into nitrates ($NO_3^-$).

Ammonification

The phase of the nitrogen cycle where decomposers break down dead biological tissues and excretory waste, releasing nitrogen back into the soil as ammonium ($NH_4^+$).

Denitrification

The ecological process carried out by denitrifying bacteria that converts nitrates ($NO_3^-$) back into gaseous nitrogen ($N_2$), releasing it into the atmosphere.

Haber-Bosch Process

An industrial nitrogen fixation method used to manufacture synthetic chemical fertilizers, which has doubled the amount of reactive nitrogen in the biosphere.

Eutrophication

An ecological disruption occurring when excess nutrient runoff (nitrogen or phosphorus) stimulates explosive algal blooms that deplete dissolved oxygen and suffocate aquatic life.

Weathering

Physical and chemical breakdown processes that gradually release phosphate minerals from exposed rocks into soil and waterways.

Assimilation (Phosphorus)

The uptake of dissolved phosphate ions by plant roots from the soil to synthesize vital biological compounds including DNA, RNA, ATP, and phospholipids.

Phosphorus Cycle Reservoir Characteristic

The unique structural feature of the phosphorus cycle distinguishing it from carbon and nitrogen, characterized by the lack of a significant gaseous or atmospheric phase.

Geological Uplift

A long-term geological mechanism that exposes buried marine sedimentary rock deposits to the surface, restarting terrestrial weathering and nutrient cycling.