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Fig. 1.37 Reserves,
fl
fluxes, and living times of the oxygen in its basic reservoirs
—
endogenic and photosynthetical. Without dwelling upon the respective scientific
discussions and all existing concepts, we shall try to describe the sources of oxygen
in the present biosphere, following numerous studies in this
Now and in the geological past there have been two sources of oxygen
field.
The basic source of atomic oxygen is the photosynthesis of plants, whose
equation has the form:
light
2
H
2
O
+
CO
2
COH
+
H
2
O
+
O
2
chlorophyll
10
9
Photosynthesis produces annually above 50
×
t of oxygen, that is, of an
10
14
% of its supplies in the atmosphere. Hence, we see that only due
to photosynthesis can the oxygen supplies in the atmosphere be totally renewed
during a time period of 300 thousand years. About 80 % of the total amount of
oxygen produced by photosynthesis result from phytoplankton functioning, and
land vegetation communities produce only 20 %.
Global scheme of oxygen cycle in the BCSS was proposed by Krapivin and
Varotsos (2008) that is represented in Fig.
1.38
.
order of 3.3
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