Environmental Engineering Reference
In-Depth Information
Macrophyte, large colony of algae visible with-
out magnification, or aquatic plants
Madicolous,
Methylotrophy, bacteria harvesting energy by
oxidizing chemical compounds with methyl
groups
Michaelis-Menten, a relationship used to de-
scribe the influence of nutrient concentra-
tion on uptake rate
Microbenthos, bottom-dwelling microorgan-
isms, including bacteria, small algae, cili-
ates, gastrotrichs, and rotifers
Microbial loop, the part of the food web based
on consumption of bacteria and bacteria-
sized algae, including protozoa, rotifers, and
other microbes; often refers to the flow of
carbon through the microbial community
Microphytobenthos, periphyton
Minerotrophic, a wetland with a high hydro-
logic throughput
Mire, a peat-accumulating wetland (European
definition)
Mixolimnion, upper layer that sometimes
mixes in meromictic lakes
Mixotrophy, capacity to employ both organic
and inorganic carbon sources for nourish-
ment (using both autotrophy and het-
erotrohpy)
Molecular diffusion, diffusion that occurs by
random movement of molecules (Brownian
motion)
Monimolimnion, layer in meromictic lakes un-
der the thermocline
Monod equation, relationship of growth to
concentration of nutrients outside the
organism
Monomictic, a lake that mixes once a year
Moor, a peatland; can be raised or a depres-
sion
Moraine, a wall of material deposited by a
glacier (e.g., when the forward movement
of a glacier is approximately equal to its
backward melting rate a terminal moraine
is deposited); lateral moraines are formed at
the margins of a glacier
Morphometry, shape and size of lakes and their
watersheds, or the shape and size of any
object
Mortality, the number of organisms lost be-
tween each size or age class
Moss, lower plant; a small filamentous
bryophyte
thin sheets of water flowing
over rock
Magnetotaxis, preferential movement toward
north or south magnetic lines
Mainstem, primary flowing section of a river
or stream (as opposed to forks, tributaries,
or other divisions)
Marl, calcareous sediments, primarily soft
Manipulative experiment, all other factors held
constant and factors of interest are varied
Marsh, continuously or usually inundated wet-
land with saturated soils and emergent
vegetation
Mass spectrometer, an instrument used to de-
termine molecular weight of molecules and
elements; used in stable isotope studies and
to identify organic pollutants
Maximum density of water, 1.000 g ml 1 ; oc-
curs at 3.9°C
Meander, a natural feature of flowing water
where S-shaped curves form
MEI, morphoedaphic index to fish production;
TDS (total dissolved solids) of water divided
by the depth of lake; milligrams per liter di-
vided by meters
Meiobenthos, bottom-dwelling organisms
(about 0.05 mm in size)
Meromictic, a lake that is permanently strati-
fied or mixes irregularly
Mesolimnion, see metalimnion
Mesotrophic, moderately productive system
Messenger, a weight that attaches to a line and
can be dropped to trigger sampling devices
Meta-analysis, a statistical technique that tests
the significance of combined results of many
different studies
Metalimnion, the intermediate zone in a strat-
ified lake in which the temperature change
with depth is rapid, below the epilimnion
and above the hypolimnion; also known as
the thermocline or the mesolimnion
Methanogenesis, anoxic bacteria producing
methane
Methanotrophy, oxidizing methane to obtain
energy; a type of methylotrophy
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