Geoscience Reference
In-Depth Information
Figure 10-13.
Restoration of Marmor Broen (Marble Bridge) in the historic royal district of central Copenhagen,
Denmark. This restoration was undertaken because decades of exposure to urban and industrial pollution had
caused the stone to decay badly. Stone from the original quarry in eastern Germany was imported in order to carry
out an authentic restoration. A. Bridge during restoration with heavily damaged stones, B. Master stonemason
i nishes new stone sculptures, C. Completed bridge restoration with a mix of new and old stones. Photos by J.S.
Aber and S.W. Aber.
electricity and greatly improved pollution con-
trols (Fig. 10-14). Already by the mid-1990s the
i rst signs of bog recovery were evident (Karo-
feld 1996), and bog renewal has continued with
the spread of mosses, increased number of
Sphagnum
species, decreased radial growth of
Scots pine, lower contents of heavy metals in
mosses, and decrease in pH (Paal et al. 2009).
Sphagnum
mosses reappeared i rst on hum-
mocks and pool banks, places that depend solely
on atmospheric precipitation, and once estab-
lished the mosses released acids that further
lowered water pH. This self-recovery process has
been most remarkable and relatively quick. Still,
the most damaged sites have not yet reached the
status of intact bogs, and air pollution remains a
problem close to the largest power plants.
10.4 Human experiment
Homo sapiens
are conducting a global experi-
ment involving immense use of fossil fuels, vast
land conversions, and intense water consump-
tion in order to support and raise the living
standard for a rapidly growing human popula-
tion, which has now reached seven billion
people (US Census Bureau 2010). The experi-
ment is uncontrolled; in other words, no stand-
ard procedures or protocols are in place.
Measurements of processes and results are
insufi cient to monitor the progress of the
experiment, and our theoretical understanding
of the various biogeochemical cycles is incom-
plete. Most decisions for this experiment are
made for immediate individual survival, gain or
