| A | B |
|---|
| Acid Precipitation | Rain, snow, or fog that is more acidic than pH 5.6. |
| Autotroph | An organism that obtains food molecules without eating other organisms or substances derived from other organisms. |
| Biogeochemical cycles | Any of the various nutrient circuits, which involve both biotic and abiotic components of ecosystems. |
| Biological magnification | A trophic process in which retained substances becomes more concentrated with each link in the food chain. |
| Biomass | The dry weight of organic matter comprising a group of organisms in a particular habitat. |
| Detritus | Dead organic matter. |
| Ecosystems | All the organisms in a given area as well as the abiotic factors with which they interact. |
| Greenhouse effect | The warming of planet Earth due to the atmospheric accumulation of CO2. |
| Gross primary production (GPP) | The total primary production of an ecosystem. |
| Heterotroph | An organism that obtains organic food molecules by eating other organisms or their by-products. |
| Net primary production (NPP) | The gross primary production of an ecosystem minus the energy used by the producers for respiration. |
| Nitrogen fixation | The assimilation of atmospheric nitrogen by certain prokaryotes into nitrogenous compounds that can be directly used by plants. |
| Primary production | The amount of light energy converted to chemical energy (organic compounds) by autotrophs in an ecosystem during a given time period. |
| Trophic level | Any of the severl levels of a food chain, whose species are based on their main nutritional source. |
