Y. M. Svirezhev, A. Block and W. von Bloh
In: W.E. Krumbein, D.M. Paterson and G.A. Zavarzin (eds.), Fossil and Recent Biofilms, A Natural History of Life on Earth, Kluwer Academic Publishers, Dordrecht/ Boston/ London, 415-427 (2003)
Potsdam Institute for Climate Impact Research (PIK),
Telegrafenberg, P.O. Box 60 12 03, D-14412 Potsdam, Germany.
Earth's surface skin can be characterised as the living boundary layer between the
pedosphere and the atmosphere. Via various processes, this highly structured
"bio-film" regulates the accumulation of energy and substances, their transformation and
transportation and, in particular, the exchange of substances between atmosphere and
sub-surface soils. Defining an "active planetary cover" (active planetary surface) as a
dynamical system which directly dominates overall climatic processes and, in turn, is
influenced by the climate, multiple equilibria states are generated which are
determined by using the "virtual biospheres" concept (Svirezhev, 1994). New results
concerning the early stages of Earth's history (2 - 3 aeons ago) are achieved by
regarding only one large and flat continent surrounded by mountains avoiding any
contact to the slightly acid ocean existing at that time: The model-continent is thought
to be covered by shallow water-bodies: epicontinental seas which were ideal niches
for the Cyanobacter microbial mats (CBM) generating an early photosynthetic
ecosphere according to Zavarzin's biosphere approach. In accordance with
thermodynamics calculations this system transforms the atmosphere of juvenile gases
to an atmosphere containing of 1% of CO2 and 8% of O2 during one billion year
forming a hot atmosphere with temperatures ~40 - 50°C and the pressure of
~5 - 8 bar.
After intensive orographic processes the depth of intercontinental seas increases and
the early biosphere of the CBM perishes.
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