Glossary - Freshwater Ecology: Concepts and Environmental Applications - page 487

Budget, an accounting of the relative magni-
tude of the fluxes between compartments in
an environment
Buffering, the ability of a solution to resist
changes in pH
14 C, a radioactive isotope of carbon often used
as a tracer in ecological studies, particularly
to measure photosynthetic rates
13 C, a stable isotope of carbon used in some
ecological studies; naturally present in the
environment at trace levels relative to the
more abundant 12 C
Caldera, a collapsed volcanic crater; some
calderas contain lakes
Capacity, the amount that a stream can trans-
port when full to the banks
Capillary, involving or resulting from surface
tension
Capillary action, movement of water by capil-
lary forces
Capillary fringe, belt of soil above groundwa-
ter that contains some water drawn up by
capillary action; immediately above the wa-
ter table
Carbonate, CO 3 2 ; an inorganic ion with
carbon
Carbon dioxide, CO 2 , a gas
Carbonic acid, H 2 CO 3 , the form first assumed
by CO 2 when it dissolves in water
Carnivore, animal that eats other animals
Catadromous, fishes that live in freshwater and
spawn in saltwater
Catchment (watershed), surface area drained
by a network of stream channels; although
“watershed” is used synonymously, water-
shed has been defined in European litera-
ture as a line that joins the highest points of
the perimeter of a catchment
Cellulose, complex carbohydrate synthesized
by plants
Certainty, something that rarely happens in
ecology
Chemical diffusion, movement of dissolved ma-
terials in water
Chemoautotrophic, obtains energy from chem-
icals other than organic C
Chemocline, a steep chemical gradient or pyc-

nocline in a lake; often found at the metal-
imnion
Chemolithotrophy, autotrophy with the energy
sources of inorganic chemical bonds and in-
organic substances as electron donors (chemo-
synthesis); also called chemoautotrophy
Chemophobic, repelled by a chemical
Chemotactic, attracted to a chemical
Chlorophyll a, the primary pigment of photo-
synthesis in cyanobacteria and eukaryotic
autotrophs; often used to indicate biomass;
absorbs red and blue light
Chronic, over long periods of time
Chronic toxicity, toxicity with long-term

exposure
Cirque, a bowl formed by glacial action at the
head of a valley; can contain a lake
Clear water, stream water with high trans-
parency, lacking visible suspended material
and brown color; ranging from acidic to
slightly alkaline in pH
Cline, any continuum or gradient
Clinograde, distribution showing a gradient;
often used to describe temperature or oxy-
gen curves
Clinolimnion, part of a lake in which temper-
ature distribution declines exponentially
from the eplimnion to the hypolimnion due
to turbulence
Coarse particulate organic matter (CPOM),
any materials greater than an arbitrary size
of 0.5 mm; includes leaves, wood, and
aquatic organisms
COD 5 , oxygen removed by chemical process
from water in 5 days
Cold monomixis, one annual total circulation
without ice cover; includes cold thereimictic
and warm thereimictic lakes
Cold thereimixis, circulation in summer at ap-
proximately 4°C; cold monomixis that oc-
curs in a polar lake
Collector, an organism that makes its living
collecting fine particles, either by filtering
from the water column or feeding on BPOM
Colloidal particles, particles not settled by
gravity
Combined nitrogen, organic N, nitrate, nitrite,
or ammonium (not N 2 gas)