Interaction of Climate Change and Acid Deposition - Climate Change Impacts on Freshwater Ecosystems - page 173

90

eq l -1 ) ANC ( µ CLe MFR

85

80

SOH

75

SOH

70

WTH

65

60

WTH

55

50

1900 1950 2000 2050 2100 2050 2100

Year Year

50

CLe MFR

45

SOH

40

SOH

35

Base saturation (%)

30

WTH

WTH

25

20

1900 1950 2000

Year

2050 2100 2050 2100

Year

Figure 7.15 Temporal development of the median of lake water ANC (top) and the
catchment soil base saturation (bottom) for the 163 Finnish study catchments under the
two emission scenarios (current legislation CLe: left panel and maximum feasible
reduction MFR: right panel) and two forest harvest (biomass energy) scenarios (stem-
only harvest SOH and whole-tree harvest WTH). (From Aherne et al . 2008b.)

Effects on aquatic biota

Acid deposition affects aquatic biota because the water becomes toxic with too
high concentrations of inorganic Al and H + . Climate change interacts with acid
deposition by affecting the concentrations of these toxic chemical components.
But in addition, climate change can have direct effects on aquatic biota. A good
example is the dependence of salmon migration on water temperature and
discharge.
Hardekopf et al . (2008) have made one of the few studies of the interactions
of acid deposition and climate change on aquatic biota. Theirs was a modelling
study of a small catchment and stream in the Czech Republic. They found that
under scenarios of future warmer climate, the recovery of benthic invertebrates
in the stream will still be hampered by continued release of sulphate (and acid)
from the soil.