412
activity. A part of the ejected products is launched verti-
cally and dispersed by a plume, and another part moves
as ground-hugging flows due to the lateral expan-
sion of gases, which wreack very destructive effects.
Simultaneously, the maar enlarges as a result of circular
collapses of the bedrock.
Magnetic susceptibility measurement of volumic induced
magnetization in a sediment linked with its grain size and
content in magnetic material.
Marvelous extra-ordinary natural lake event or behavior,
difficult to explain with contemporary knowledge and
worth to be reported.
Mass wasting deposit a general term for a deposit result-
ing from the dislodgement and downslope transport of
material under the direct application of gravitational body
stresses.
Meromictic a lake that undergoes incomplete mixing of its
waters during periods of circulation. Most often consists
of a free circulating upper fresh water layer (mixolim-
nion) and a stagnant, often anoxic, bottom water layer
(monolimnion).
Meromixis A lake or a pond is considered as meromictic
when it is composed of a monimolimnion.
Marvelous extra-ordinary natural lake event or behavior,
difficult to explain and worth to be reported.
Mesological in this case mean objective and measurable
environmental data.
Metagenomics culture-independent methods where the
genetic material (metagenomes) recovered directly from
environmental samples is used to characterize microbial
communities thriving in a particular ecosystem.
Methanogenesis The production of methane by bacteria or
other living organisms.
Methylotrophy The consumption of C1 compounds (i.e.,
methanol, methylamine, methane).
Microbial biogeography study of the distribution of micro-
bial species with a special focus on the existence of geo-
graphic barriers and endemic species.
Microbial food web refers to the combined trophic interac-
tions among microbes which included dissolved organic
matter, prokaryotes, and both photosynthetic and hetero-
trophic protists (such as ciliates and flagellates) in aquatic
environments.
Microbial loop Trophic pathway in the microbial food
web where dissolved organic carbon (DOC) is returned
to higher trophic levels via its incorporation into bacte-
rial biomass, and then coupled with the classic food chain
formed by phytoplankton-zooplankton-nekton.
Microcosm An experimental tool that brings a small part of
the natural environment under controlled conditions.
Misbehavior deviation of a normal lake functioning per-
ceived by local witness. Applicable to diverse state of lake
degassing.
Misericords inferior part of wooden credences in church
choir, carved with figurative or non- figurative represen-
tations. In Besse church the exceptional misericords are
interpreted to be related to Pavin misbehavior and its
damages on populations.
Mitomycin C Antibiotic produced by the soil actinomycete
Streptomyces caespitosu. It is a DNA cross-linker and
a DNA-alkylating agent leading to mispairing of bases,
DNA strand breakage, and cross-linking of complimen-
tary strands which prevents DNA synthesis. In aquatic
virology, mitomycin C is used to activate prophages.
Mixolimnion The upper layer of a meromictic lake, charac-
terized by mixing events.
Mixotrophic An organism capable of existing as either/both
an autotroph or/and heterotroph.
Molecular diffusion Molecular diffusion is caused by the
agitation of water molecules in the water column due to
temperature and not by a mean advective transport or
turbulence.
Molecular diversity Diversity based on the composition of
one or several molecular markers. These markers could be
nucleic acids, proteins, carbohydrates, metabolites... The
molecular diversity is studied by sequencing.
Monimolimnion the lower, dense stratum of a meromictic
lake that does not mix with the waters above.
Monooxygenase One of a group of enzymes that catal-
yses the incorporation of one hydroxyl group into
substrates.
Moraine a mount, ridge, or other distinct accumulation
of unsorted, unstratified glacial drift, predominantly till,
deposited chiefly by direct action of glacier ice.
Multibeam bathymetric measurement measurement of
the lake’s topography (bottom and slope) using depth
sounding from an echosounder (sonar) mounted beneath
a boat.
Nanoalgivore Algivorous organisms with a size between 2
and 20 μm.
Nanophytoplankton A phytoplanktonic organism with a
size between 2 and 20 μm.
Nanoplanktonic A planktonic organism with a size between
2 and 20 μm.
Nutrients dissolved nitrogen, phosphorus and silica neces-
sary for algal production in waters.
ONEMA French National Agency for Water and Aquatic
Environments.
Oligonucleotide probes Short sequence of nucleotides that
are synthesized to match a specific region of DNA or
RNA then used as a molecular probe to detect the specific
DNA or RNA sequence.
Oligotrophic state of a lake in which algal production is low
Onlap description of the termination of a stratigraphic hori-
zon (or seismic reflection) whereby the horizon termi-
nates against the margins of a depositional basin.Glossary