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a rate H
14
¼ O
3
=
T
3
, where T
3
is the lifetime of ozone molecules depending on
atmospheric pollution: T
3
¼ T
3
e
1
B. The lifetime T
3
of the ozone molecules in a
perfect atmosphere averages 50
60 days. Nitrogen oxides participating in the
contrary to H
12
cycle of ozone destruction contribute much to the magnitude of B.
Studies of the history of biospheric evolution reveal a close correlation between
the oxygen production intensity and the development of life on Earth. And although
the expected relative oscillations of the oxygen concentration in the near future do
not exceed 10 %, the considered impacts on the biosphere do not cover all potential
anthropogenic trends, and therefore cannot be considered reliable. Therefore let us
analyze the constituents of possible mechanisms for violation of the natural balance
of oxygen. Naturally, our concern is for not only an increase but also a decrease of
the oxygen content in the atmosphere.
The oxygen cycle is complicated by its ability to take part in a lot of chemical
reactions giving a multitude of epicycles. This fact makes the oxygen cycle suffi-
-
-
ciently stable but hinders an assessment of its stability.
Anthropogenic forcing on numerous epicycles of oxygen manifests itself both
directly through its involvement in other cycles of substances at fuel burning and
production of various materials, and indirectly through environmental pollution and
biospheric destruction. Therefore a parameterization of the anthropogenic impact on
the oxygen balance is realized within other units of the global model. The
ux H
18
taken into account in the scheme in Fig.
1.38
completely covers direst consumption
of oxygen both in industry and in agriculture. Assume H
18
¼ y
1
R
MG
, where R
MG
is
the rate of the natural resourcesexpenditure, and y
1
is the coef
fl
≈
cient (
0.084).
uxes H
15
and H
16
are strongly affected by anthropogenic forcings. Their
variations are caused by discharges of high-temperature industrial sewage con-
taining considerable amounts of oxidizers as well as by the oil-polluted water
bodies. The quantitative characteristics of the change of oxygen dissolved in water
as a function of temperature have been studied comprehensively. The empirical
formula to calculate the concentration of the seawater dissolved oxygen has the
form (Ramad 1981): [O
2
dissolved] = 80/(0.2T
O
−
The
fl
7.1), where [O
2
] is expressed in
mg/
C. The estimates of oxygen solubility in water are well known
(Krapivin and Kondratyev 2002).
The
'
, T
O
in
°
uxes H
9
and H
19
, balancing in natural conditions the oxygen
fluxes into
the water medium, at an anthropogenic forcing increase, as a rule, due to more
active aerobic bacteria and increasing metabolic needs of animals. For instance, a
10
fl
fl
C increase of water temperatureincreases the oxygen expenditure on respiration
of marine animals by a factor of 2.2.
One of the negative manifestations of the anthropogenic impact on the oxygen
cycle is a depletion of the ozone layer, especially marked in the polar regions. There
are various hypotheses on the causes of sharply changing concentrations of ozone,
as well as discussions on the so-called
°
over the Antarctic. The main
cause of all violations is connected with the progressing human activity accom-
panied by the growing volumes of long-lived components emitted to the atmo-
sphere (e.g., freons). The consequences of these violations are very serious, and the
“
ozone hole
”
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