Principles of terrestrial ecosystem ecology.pdf

378 Glossary
Chelation. Reversible combination, usually
with high affinity, with a metal ion (e.g., iron,
copper).
Chemical alteration. Chemical changes in dead
organic matter during decomposition.
Chemical weathering. Changes due to chemical
reactions between the materials and the
atmosphere or water.
Chemodenitrification. Abiotic conversion of
nitrite to nitric oxide (NO).
Chemosynthesis. Synthesis of organic matter
fueled by oxidation–reduction reactions
unrelated to photosynthesis.
Chlorofluorocarbon. Organic chemicals containing
chlorine and/or fluorine; gases that
destroy stratospheric ozone.
Chlorophyll. Green pigment involved in light
capture by photosynthesis.
Chloroplast. Organelles that carry out
photosynthesis.
Chronosequence. Sites that are similar to one
another with respect to all state factors
except time since disturbance.
Circadian rhythms. Innate physiological cycles
in organisms that have a period of about
24h.
Clay. Soil particles less than 0.002 mm
diameter.
Climate modes. Relatively stable configurations
of global atmospheric circulation.
Climate system. Interactive system made up of
the atmosphere, hydrosphere, biosphere,
cryosphere, and land surface.
Climatic climax. End point of succession that
is determined only by climate.
Climax. End point of succession where the
structure and rates of ecosystem processes
reach steady state and where resource consumption
by vegetation is balanced by the
rate of resource supply.
Closed system. System in which the internal
transfers of substances are much greater than
inputs and outputs.
Cloud condensation nuclei. Aerosols around
which water vapor condenses to form clouds.
C:N ratio. Ratio of carbon mass to nitrogen
mass.
CO2 compensation point. CO2 concentration
at which net photosynthesis equals zero.
Coarse particulate organic matter. Organic
matter in aquatic ecosystems, including
leaves and wood, that is larger than 1mm
diameter.
Collector. Benthic macroinvertebrate that
feeds on fine organic particles; includes
filtering collectors that consume suspended
particles and gathering collectors that
consume deposited particles.
Co-metabolism. Breakdown of a substrate
by a series of enzymes that are produced by
different microbes.
Community. Group of co-existing organisms in
an ecosystem.
Compensation. Increased growth of some
species in a community, due to release of
resources, in response to reduced growth by
other species.
Compensation point. Temperature, CO 2 concentration
or light level at which net carbon
exchange by a leaf is zero (i.e., photosynthesis
equals respiration).
Competition. Interactions among organisms
that use the same limiting resources
(resource competition) or that harm one
another in the process of seeking a resource
(interference competition).
Complementary resource use. Use of resources
that differ in type, depth, or timing by
co-occurring species.
Conductance. Flux per unit driving force
(e.g., concentration gradient); inverse of
resistance.
Configuration. Spatial arrangement of patches
in a landscape.
Connectivity. Degree of connectedness among
patches in a landscape.
Consortium. Group of genetically unrelated
bacteria, each of which produce only some of
the enzymes required to break down
complex molecules.
Consumer. Organism that meets its energetic
and nutritional needs by eating other living
organisms.
Consumption efficiency. Proportion of the production
at one trophic level that is ingested
by the next tropic level.
Convection. Heat transfer by turbulent movement
of a fluid (e.g., air or water).