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 non-living 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 models) ecosystem model that consists of flow charts that show the interactions of different compartments of the living and non-living 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, non-linear 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
non-renewable 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 eat 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 eat 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