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Glossary
coarse stream substrate: Cobble- to boulder- (tennis-ball-to-car size; 64 to
4000 mm) size substrate.
critical load: A quantitative estimate of an exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur according to present
knowledge.
decomposition: The microbially mediated reaction that converts solid or
dissolved organic matter into its constituents (also called decay or
mineralization).
dissolved inorganic carbon: The sum of dissolved (measured after filtration)
carbonic acid, bicarbonate, and carbonate in a water sample.
dissolved organic carbon: Organic (derived from the breakdown of plant
or animal material) carbon that is dissolved or unfilterable (0.45-μm
pore size) in a water sample.
drainage lake: A lake that has a permanent surface water inlet and outlet.
ecosystem: The interactive system formed from all living organisms and
their abiotic (physical and chemical) environment within a given
area. Ecosystems cover a hierarchy of spatial scales and can make
up the entire globe, biomes at the continental scale, or small, wellcircumscribed systems such as a small pond.
epilimnion: The layer of water in a thermally stratified lake that lies above the
thermocline, is circulating, and remains perpetually warm.
episodic acidification: The short-term decrease of acid-neutralizing capacity
from a lake or stream. This process has a timescale of hours to weeks
and is usually associated with hydrological events.
EPT Index: Index of taxonomic richness of three insect orders
(Ephemeroptera-Plecoptera-Tricoptera).
eutrophication: The process whereby a body of water becomes overenriched
in nutrients, resulting in increased productivity (of algae or aquatic
plants) and sometimes also decreased dissolved oxygen levels.
evapotranspiration: The process by which water is returned to the air
through direct evaporation or transpiration by vegetation.
fine/sand stream substrate: Stream substrate not gritty (silt/clay/muck
< 0.06-mm diameter) to gritty (up to ladybug size; 2-mm diameter)
substrate.
glide: Water moving slowly along stream channel, with a smooth, unbroken
surface; low turbulence.
Gran analysis: A mathematical procedure used to determine the equivalence
points of a titration curve for acid-neutralizing capacity.
gravel stream substrate: Fine-to-coarse gravel (ladybug to tennis ball size;
2- to 64-mm diameter) size substrate.
groundwater: Water in a saturated zone within soil or rock.
Glossary
coarse stream substrate: Cobble- to boulder- (tennis-ball-to-car size; 64 to
4000 mm) size substrate.
critical load: A quantitative estimate of an exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur according to present
knowledge.
decomposition: The microbially mediated reaction that converts solid or
dissolved organic matter into its constituents (also called decay or
mineralization).
dissolved inorganic carbon: The sum of dissolved (measured after filtration)
carbonic acid, bicarbonate, and carbonate in a water sample.
dissolved organic carbon: Organic (derived from the breakdown of plant
or animal material) carbon that is dissolved or unfilterable (0.45-μm
pore size) in a water sample.
drainage lake: A lake that has a permanent surface water inlet and outlet.
ecosystem: The interactive system formed from all living organisms and
their abiotic (physical and chemical) environment within a given
area. Ecosystems cover a hierarchy of spatial scales and can make
up the entire globe, biomes at the continental scale, or small, wellcircumscribed systems such as a small pond.
epilimnion: The layer of water in a thermally stratified lake that lies above the
thermocline, is circulating, and remains perpetually warm.
episodic acidification: The short-term decrease of acid-neutralizing capacity
from a lake or stream. This process has a timescale of hours to weeks
and is usually associated with hydrological events.
EPT Index: Index of taxonomic richness of three insect orders
(Ephemeroptera-Plecoptera-Tricoptera).
eutrophication: The process whereby a body of water becomes overenriched
in nutrients, resulting in increased productivity (of algae or aquatic
plants) and sometimes also decreased dissolved oxygen levels.
evapotranspiration: The process by which water is returned to the air
through direct evaporation or transpiration by vegetation.
fine/sand stream substrate: Stream substrate not gritty (silt/clay/muck
< 0.06-mm diameter) to gritty (up to ladybug size; 2-mm diameter)
substrate.
glide: Water moving slowly along stream channel, with a smooth, unbroken
surface; low turbulence.
Gran analysis: A mathematical procedure used to determine the equivalence
points of a titration curve for acid-neutralizing capacity.
gravel stream substrate: Fine-to-coarse gravel (ladybug to tennis ball size;
2- to 64-mm diameter) size substrate.
groundwater: Water in a saturated zone within soil or rock.