Ecosystem Energy Flow Glossary

The increasing concentration of persistent, non-degradable substances (such as pesticides or heavy metals) in organisms at successively higher trophic levels.

The total mass of living organisms in a given area or at a given trophic level, usually expressed as dry weight per unit area.

The metabolic process by which organisms convert chemical energy in organic molecules to ATP, releasing carbon dioxide and water. This is how energy is lost as heat at each trophic level.

An organism (heterotroph) that obtains energy by eating other organisms. Primary consumers eat producers; secondary consumers eat primary consumers.

An organism, typically bacteria or fungi, that breaks down dead organic material and recycles nutrients back into the ecosystem.

A diagram showing the relative amount of energy available at each trophic level, always tapering upward due to energy loss at each transfer.

A linear sequence showing the transfer of energy from one organism to the next, beginning with a producer and ending with a top predator or decomposer.

A complex network of interconnected food chains in an ecosystem, illustrating the multiple feeding relationships among organisms.

The total rate of energy capture by producers through photosynthesis in an ecosystem, measured in energy per unit area per unit time.

The rate of energy storage by producers after subtracting their own respiratory energy use; NPP = GPP minus plant respiration.

An organism (autotroph) that synthesizes organic molecules from inorganic substances using energy from sunlight (photosynthesis) or chemical reactions (chemosynthesis).

The ecological generalization that roughly 10% of energy at one trophic level is converted to biomass at the next level, with 90% lost as metabolic heat.

An ecological phenomenon where changes at one trophic level cause cascading effects through other levels, often triggered by the addition or removal of top predators.

The feeding position an organism occupies in a food chain or food web, from producers (level 1) through successive consumer levels.