66 Ecology and Applied Environmental Science
slim thickness of tropical soils. Thus, when tropical soils are not protected
by rich natural vegetation, they become infertile and susceptible to erosion.
The main reservoirs of the carbon cycle and the calculated storages are
the atmosphere, the sea, living organisms, dead organic matter and fossil
fuels. The carbon quantities stored in terrestrial living organisms’ biomass,
as well as those stored in the soil are of the same order of magnitude as the
amount contained in the atmosphere; the carbon quantities stored in fossil
fuels are estimated to be about 4−5 times greater. The greatest carbon quantities are accumulated in carbon rocks, mostly in CaCO 3 that contains a
CO 2 quantity more than 40,000 times greater than that in the atmosphere.
4.3.2.2 Carbon Cycle Perturbations
The carbon cycle has a slow component. Through a series of chemical
reactions and tectonic activity, carbon takes between 100 and 200 million
years to move between rocks, soil, ocean and atmosphere. About 20% of
carbon-containing rock contains carbon from dead organic matter that has
been embedded in layers of mud. Heat and pressure compress the mud and
carbon, forming sedimentary rock such as shale. In special cases, layers
of organic matter become fossil fuel instead of sedimentary rock. During
geological centuries, fossil coal, lignite, petroleum and natural gas were
created by this process. It was a large-scale phenomenon during some of
the geological periods, while at present it continues but is insignificant at
a biosphere level. The carbon from sediments returns slowly to the atmosphere through volcanoes. By burning fossil fuels, human populations emit
per year 100–300 times more carbon dioxide than the volcanoes.
Before the industrial era, carbon’s fast recycling in ecosystems has been
almost perfect and stable. However, in previous geological periods, photosynthesis exceeded respiration in the biosphere, resulting in a decrease of
CO 2 and an increase of O 2 in the atmosphere, and the storage of carbon
in the soil and sediments. Of great importance is also the phenomenon
of dissolved in water CO 2 conversion to CaCO 3 . It is partly due to chemical precipitation, but mostly due to the biological activity of small marine
animals that construct their skeletons with calcium carbonate which, after
their death, is deposited in the bottom’s sediment. Thus, huge sediment
layers of calcium carbonate were created during various geological periods.
The importance of the perturbations of carbon cycle’s fast component
becomes apparent when the history of Earth’s atmosphere is studied. The
atmosphere was not always as it is at present. Initially, large amounts of
hydrogen and light inactive gases were present, which were soon lost,
that is, around 4–5 billion years ago. Next, a reductive atmosphere was
created, containing no oxygen, but mostly gases such as nitrogen, methane,
ammonia, water vapour and carbon dioxide. Some hundred million years
after the
creation of life, oxygen began being produced via the process
slim thickness of tropical soils. Thus, when tropical soils are not protected
by rich natural vegetation, they become infertile and susceptible to erosion.
The main reservoirs of the carbon cycle and the calculated storages are
the atmosphere, the sea, living organisms, dead organic matter and fossil
fuels. The carbon quantities stored in terrestrial living organisms’ biomass,
as well as those stored in the soil are of the same order of magnitude as the
amount contained in the atmosphere; the carbon quantities stored in fossil
fuels are estimated to be about 4−5 times greater. The greatest carbon quantities are accumulated in carbon rocks, mostly in CaCO 3 that contains a
CO 2 quantity more than 40,000 times greater than that in the atmosphere.
4.3.2.2 Carbon Cycle Perturbations
The carbon cycle has a slow component. Through a series of chemical
reactions and tectonic activity, carbon takes between 100 and 200 million
years to move between rocks, soil, ocean and atmosphere. About 20% of
carbon-containing rock contains carbon from dead organic matter that has
been embedded in layers of mud. Heat and pressure compress the mud and
carbon, forming sedimentary rock such as shale. In special cases, layers
of organic matter become fossil fuel instead of sedimentary rock. During
geological centuries, fossil coal, lignite, petroleum and natural gas were
created by this process. It was a large-scale phenomenon during some of
the geological periods, while at present it continues but is insignificant at
a biosphere level. The carbon from sediments returns slowly to the atmosphere through volcanoes. By burning fossil fuels, human populations emit
per year 100–300 times more carbon dioxide than the volcanoes.
Before the industrial era, carbon’s fast recycling in ecosystems has been
almost perfect and stable. However, in previous geological periods, photosynthesis exceeded respiration in the biosphere, resulting in a decrease of
CO 2 and an increase of O 2 in the atmosphere, and the storage of carbon
in the soil and sediments. Of great importance is also the phenomenon
of dissolved in water CO 2 conversion to CaCO 3 . It is partly due to chemical precipitation, but mostly due to the biological activity of small marine
animals that construct their skeletons with calcium carbonate which, after
their death, is deposited in the bottom’s sediment. Thus, huge sediment
layers of calcium carbonate were created during various geological periods.
The importance of the perturbations of carbon cycle’s fast component
becomes apparent when the history of Earth’s atmosphere is studied. The
atmosphere was not always as it is at present. Initially, large amounts of
hydrogen and light inactive gases were present, which were soon lost,
that is, around 4–5 billion years ago. Next, a reductive atmosphere was
created, containing no oxygen, but mostly gases such as nitrogen, methane,
ammonia, water vapour and carbon dioxide. Some hundred million years
after the
creation of life, oxygen began being produced via the process