174 Ecology and Applied Environmental Science
tion of the rain’s pH. Acid rain may appear in areas as far as dozens of kilometres away from the site of emission, due to the air transport of pollutants.
The harmful results of acid rain on ecosystems have been documented by
a great deal of research. It is known that in many areas of the Earth the soil,
due to limestone bedrocks, contains considerable calcium ions that neutralize the increase of acidity through an alkaline reaction. On the rest of the
planet the soil, and by extension the freshwater ecosystems, seem to be more
vulnerable to the increase of acidity. In lakes and rivers of Northern and
Central Europe and Northern America, pH reduction has caused serious
damage to many aquatic organisms (Chapter 8). Acid rain has been considered one of the factors that conduce to the degradation of forests of Central
Europe and Northern America, mainly because of the lowering of the soil’s
pH that it causes. The reduction of soil’s pH can lead to a downsizing of
decomposers’ populations or to the release of trivalent aluminium ions that
are toxic for many terrestrial and aquatic organisms, although they do not
present biological magnification (Chapter 7). Another impact of acid water
is the decrease of photosynthetic ability and the capacity for the renewal of
foliage of trees. Similar damage may be caused to agricultural cultivations.
In coastal marine ecosystems, as for example in the North Sea, the inflow
of N through acid rain is a serious eutrophication factor.
In addition to damage to the ecosystems, acid rain can cause significant material damage. It accelerates the erosion of iron, zinc, copper and
aluminium resulting in serious damage to many human constructions,
especially historical monuments, as well as cars. Especially vulnerable to
SO 2 are building materials containing calcium carbonate that turns to calcium sulphate on the surface, according to the reaction:
H SO CaCO
CaSO H O CO
4
2
3
4
2
2
+
→
+
+
CaSO 4 is partially dissolved in water and as a result the stone surfaces of
buildings and monuments are destroyed. Affected by the SO 2 , the marble
monuments of the Parthenon suffered serious damage in the 1960s and
1970s. Therefore they have had to be protected in special closed spaces
since the 1980s. The measures for SO 2 pollution reduction implemented
since then have prevented aggravation of the problem.
9.3 dEPlEtion oF StratoSPhEric ozonE
A form of pollution that originates on the surface of the Earth but manifests itself on higher stratums of the atmosphere with consequences that
relate to the whole planet is the depletion of the ozone layer (O 3 ) found in
the stratosphere at a height of 20–60 km.
tion of the rain’s pH. Acid rain may appear in areas as far as dozens of kilometres away from the site of emission, due to the air transport of pollutants.
The harmful results of acid rain on ecosystems have been documented by
a great deal of research. It is known that in many areas of the Earth the soil,
due to limestone bedrocks, contains considerable calcium ions that neutralize the increase of acidity through an alkaline reaction. On the rest of the
planet the soil, and by extension the freshwater ecosystems, seem to be more
vulnerable to the increase of acidity. In lakes and rivers of Northern and
Central Europe and Northern America, pH reduction has caused serious
damage to many aquatic organisms (Chapter 8). Acid rain has been considered one of the factors that conduce to the degradation of forests of Central
Europe and Northern America, mainly because of the lowering of the soil’s
pH that it causes. The reduction of soil’s pH can lead to a downsizing of
decomposers’ populations or to the release of trivalent aluminium ions that
are toxic for many terrestrial and aquatic organisms, although they do not
present biological magnification (Chapter 7). Another impact of acid water
is the decrease of photosynthetic ability and the capacity for the renewal of
foliage of trees. Similar damage may be caused to agricultural cultivations.
In coastal marine ecosystems, as for example in the North Sea, the inflow
of N through acid rain is a serious eutrophication factor.
In addition to damage to the ecosystems, acid rain can cause significant material damage. It accelerates the erosion of iron, zinc, copper and
aluminium resulting in serious damage to many human constructions,
especially historical monuments, as well as cars. Especially vulnerable to
SO 2 are building materials containing calcium carbonate that turns to calcium sulphate on the surface, according to the reaction:
H SO CaCO
CaSO H O CO
4
2
3
4
2
2
+
→
+
+
CaSO 4 is partially dissolved in water and as a result the stone surfaces of
buildings and monuments are destroyed. Affected by the SO 2 , the marble
monuments of the Parthenon suffered serious damage in the 1960s and
1970s. Therefore they have had to be protected in special closed spaces
since the 1980s. The measures for SO 2 pollution reduction implemented
since then have prevented aggravation of the problem.
9.3 dEPlEtion oF StratoSPhEric ozonE
A form of pollution that originates on the surface of the Earth but manifests itself on higher stratums of the atmosphere with consequences that
relate to the whole planet is the depletion of the ozone layer (O 3 ) found in
the stratosphere at a height of 20–60 km.