Geoscience Reference
In-Depth Information
'Potamalization'
- effects on nutrients
Higher water temperatures
lead to a more rapid
mineralization of organic
matter (leaves, wood) and
thus to eutrophication
effects. As a result, small
streams ('rhithral') will
change character and
resemble larger rivers
('potamal').
Water
temperature
(maximum
monthly values)
The response of
communities is mainly
determined by extremes;
secondary effects (e.g.
oxygen depletion at night
times) are most extreme
in summer.
(x)
x
(x)
Acidification
Increased precipitation
increases acid runoff from
borealic coniferous forests
leading to cascading
acidification effects on
aquatic biota.
pH,
invertebrate-
based acid-
indices
pH-values decrease with
increasing acid deposition.
Since these events are of
short duration,
community based indices
are often better at
reflecting acidification.
x
Increased
macrophyte/algae
growth
Higher water temperatures
and lower discharge
enhance macrophyte and
algae growth. Furthermore,
higher temperatures
increase mineralization
processes and deliver more
nutrients for macrophyte
and algae growth.
Water
temperature
(mean monthly
values),
macrophyte
coverage
Mean monthly
temperatures indicate
overall temperature
increase. Macrophyte
coverage is simple to
record and well correlated
with biomass.
x
x
x
Primary
production
Increase of
respiration rate
The metabolic rates of
bacteria and fungi and the
metabolic rates of
detritivorous species will
rise with increasing
temperatures. The
proportion between
primary production and
respiration will decrease.
Percentage of
collectors in the
invertebrate
community
Collectors gather organic
material. If this food
source increases, the
percentage of collectors
rises to about 40%.
x
x
(x)
Secondary
production and
food webs
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