Glossary - Freshwater Ecology: Concepts and Environmental Applications - page 490

Endocrine disrupting compounds, organic com-
pounds that mimic natural metabolic com-
pounds leading to disruption of endocrine
function
Endogenic, endogenous, created or produced
internally; occasionally used instead of
autochthonous
Endorheic, stream or basin that does not drain
to a larger stream or basin (a closed basin)
Endosymbiont, an organism living inside an-
other organism
Entrainment, mixing of part of the hypolimnion
into the epilimnion with high winds
Ephippium, resistant egg case produced by a
cladoceran
Epifluorescent microscopy, microscopy using a
light source from above that excites fluores-
cent molecules and filters the observed light,
rendering the emitted fluorescence visible
Epigean, living in surface water (above the
ground or sediment)
Epilimnion, the surface layer of a stratified lake,
above the metalimnion
Epilithic, growing on rocks
Epipelion, community inhabiting mud surfaces
Epiphytic, growing on a plant or macrophyte
Episammic, growing on sand
Epizooic, growing on an animal
Erosional processes, movement of particles off
land by water or wind
Euphotic zone, the region where light is above
the compensation point, so net photosyn-
thesis is positive
Eutrophic, very productive
Eutrophication,

External loading, supply of nutrients from out-
side the system
Extinction coefficient, same as the absorption
coefficient
Extirpated, locally extinct
Fall mixing, the autumnal period in temperate
lakes after summer stratification breaks down
Fault, a fracture in rock layers where adjacent
layers have moved parallel to the fracture
Fecundity, the number of offspring that repro-
ductive females produce
Fen, like a bog, with peat accumulation but
more input of water from outside
Fermentation, organisms utilizing organic car-
bon in the absence of oxygen
Ferric, iron ion in oxidized state (Fe 3 )
Ferric hydroxide, flocculent precipitate of fer-
ric ions and hydroxyl ions
Ferrous, iron ion in reduced state (Fe 2 )
Fetch, the longest uninterrupted distance on
a lake that wind can move across to
create waves
Fick's law, a mathematical formula describing
the relationship between diffusion flux, dis-
tance, and concentration gradients
Filterers, organisms that sieve small particles
from the water column
Fine particulate organic matter (FPOM), or-
ganic material between 0.45 and 500 m in

diameter
Fixed groundwater,

groundwater trapped

in rocks
Fjord lake, a steep glacial valley containing a
lake (fiord)
Flashy, having repeated, rapid discharge or
floods
Floating attached, macrophytes with floating
leaves that are rooted in the sediments
Floating unattached, free-floating macrophytes
Flood, rising and overflowing of a body of wa-
ter, generally above the banks
Floodplain, a flat region in the bottom of a val-
ley that is, or historically was, influenced by
river flooding
Flow, movement of a fluid; generally a veloc-
ity, but can be used to mean discharge

the process of becoming

eutrophic
Evaporation, to convert into vapor
Evapotranspiration, evaporation plus plant
transpiration
Evenness, a measure of the degree of equal dis-
tribution of numbers of each species in a
community
Exploitation, interaction that harms one species
and helps another
Exploitation competition, competition between
organisms that are using the same resource