- acid rain
- corrosive rain caused by rainwater falling to the ground through sulfur dioxide gas, turning it into weak sulfuric acid; can damage structures and ecosystems
- analytical model
- ecosystem model that is created with mathematical formulas to predict the effects of environmental disturbances on ecosystem structure and dynamics
- apex consumer
- organism at the top of the food chain
- assimilation
- biomass consumed and assimilated from the previous trophic level after accounting for the energy lost due to incomplete ingestion of food, energy used for respiration, and energy lost as waste
- biogeochemical cycle
- cycling of mineral nutrients through ecosystems and through the nonliving world
- biomagnification
- increasing concentrations of persistent, toxic substances in organisms at each trophic level, from the primary producers to the apex consumers
- biomass
- total weight, at the time of measurement, of living or previously living organisms in a unit area within a trophic level
- chemoautotroph
- organism capable of synthesizing its own food using energy from inorganic molecules
- conceptual model
- (also, compartment model) ecosystem model that consists of flow charts that show the interactions of different compartments of the living and nonliving components of the ecosystem
- dead zone
- area within an ecosystem in lakes and near the mouths of rivers where large areas of ecosystems are depleted of their normal flora and fauna; these zones can be caused by eutrophication, oil spills, dumping of toxic chemicals, and other human activities
- detrital food web
- type of food web in which the primary consumers consist of decomposers; these are often associated with grazing food webs within the same ecosystem
- ecological pyramid
- (also, Eltonian pyramid) graphical representation of different trophic levels in an ecosystem based of organism numbers, biomass, or energy content
- ecosystem
- community of living organisms and their interactions with their abiotic environment
- ecosystem dynamics
- study of the changes in ecosystem structure caused by changes in the environment or internal forces
- equilibrium
- steady state of an ecosystem where all organisms are in balance with their environment and each other
- eutrophication
- process whereby nutrient runoff causes the excess growth of microorganisms, depleting dissolved oxygen levels and killing ecosystem fauna
- fallout
- direct deposit of solid minerals on land or in the ocean from the atmosphere
- food chain
- linear representation of a chain of primary producers, primary consumers, and higher-level consumers used to describe ecosystem structure and dynamics
- food web
- graphic representation of a holistic, nonlinear web of primary producers, primary consumers, and higher-level consumers used to describe ecosystem structure and dynamics
- grazing food web
- type of food web in which the primary producers are either plants on land or phytoplankton in the water; often associated with a detrital food web within the same ecosystem
- gross primary productivity
- rate at which photosynthetic primary producers incorporate energy from the sun
- holistic ecosystem model
- study that attempts to quantify the composition, interactions, and dynamics of entire ecosystems; often limited by economic and logistical difficulties, depending on the ecosystem
- hydrosphere
- area of the Earth where water movement and storage occurs
- mesocosm
- portion of a natural ecosystem to be used for experiments
- microcosm
- re-creation of natural ecosystems entirely in a laboratory environment to be used for experiments
- net consumer productivity
- energy content available to the organisms of the next trophic level
- net primary productivity
- energy that remains in the primary producers after accounting for the organisms’ respiration and heat loss
- net production efficiency (NPE)
- measure of the ability of a trophic level to convert the energy it receives from the previous trophic level into biomass
- nonrenewable resource
- resource, such as fossil fuel, that is either regenerated very slowly or not at all
- primary consumer
- trophic level that obtains its energy from the primary producers of an ecosystem
- primary producer
- trophic level that obtains its energy from sunlight, inorganic chemicals, or dead and/or decaying organic material
- residence time
- measure of the average time an individual water molecule stays in a particular reservoir
- resilience (ecological)
- speed at which an ecosystem recovers equilibrium after being disturbed
- resistance (ecological)
- ability of an ecosystem to remain at equilibrium in spite of disturbances
- secondary consumer
- usually a carnivore that eats primary consumers
- simulation model
- ecosystem model that is created with computer programs to holistically model ecosystems and to predict the effects of environmental disturbances on ecosystem structure and dynamics
- subduction
- movement of one tectonic plate beneath another
- tertiary consumer
- carnivore that eats other carnivores
- trophic level
- position of a species or group of species in a food chain or a food web
- trophic level transfer efficiency (TLTE)
- energy transfer efficiency between two successive trophic levels