Publication Date:
2017-10-06
Description:
ABSTRACT: Salinity is an important environmental control of aerobic methane oxidation, which
reduces the emission of the potent greenhouse gas methane into the atmosphere. The effect of
salinity on methane oxidation is especially severe in river estuaries and adjacent coastal waters,
which are important sources of methane emission and, at the same time, are usually characterized
by pronounced salinity gradients. Using methane oxidation rates determined by a radiotracer
technique as a measure of methanotrophic activity, we tested the effect of immediate and gradual
salinity changes on pure cultures of methanotrophic bacteria, and natural freshwater (Elbe River)
and natural marine (North Sea) methanotrophic populations. According to our results, Methylomonas
sp. and Methylosinus trichosporium are resistant to an increase in salinity, whereas
Methylovulum sp. and Methylobacter luteus are sensitive to such an increase. Natural methanotrophic
populations from freshwater are more resistant to an increase in salinity than those from
marine water are to a decrease in salinity. In contrast to an immediate change of salinity, gradual
change (1.25 PSU d−1) can attenuate salinity stress. Experiments with the natural populations
revealed different reactions to changes in salinity; thus, we assume that the initial composition of
the methanotrophic population, i.e. the ratio of sensitive versus resistant strains, also governs the
community response to salinity stress.Repeated experiments with the natural populations revealed different reactions to changes of salinity; thus we assume that the initial composition of the methanotrophic population, i.e. the ratio of sensitive and resistant strains, also governs the community response to salinity stress.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Permalink