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ecosystem during 50
70 days arrives at stationary regime. It means that the eco-
system of the upwelling zone
-
fluctuations in initial concentrations.
Upper (z = 0) and lower (z = 200 m) boundaries of the ecosystem are charac-
terized by zero gradients for all its elements except for n and d:
'
forgets
'
these
fl
m
3
@
n
=
z¼0
¼ 0
j
;
@
d
=@
z
z¼0
¼ 0
j
;
@
d
=@
z
z¼220
¼
0
j
:
5
;
n
ðu;
l
;
200
;
t
Þ
¼250 mg
=
It is supposed that water covers the distance from the upwelling zone to the
oligotrophy zone in more that 60 days. Figure
4.21
characterizes this evolution
process. It is seen that biomasses of phytoplankton and bacterioplankton reach
maximal levels at 5
10 and 10
15 days, respectively. Small
filtraters are slow in
-
-
their evolution, but large
filtrators are evolved more slowly. Biomass of large
filtrators reaches maximal level only in the 30 day. Existing feedbacks control the
evolution processes for all living ecosystem elements and their biomasses slowly
decrease as a system is moving from the upwelling zone. Flows of nutrient salts that
lift from deep waters through thermocline and vertical turbulence play main role in
this evolution. Ecosystem results quasi-stationary level at 50
60 days characterized
low biomasses of all living elements. Under this situation, stable balance is
achieved between photosynthesis intensity and nutrient salts in
-
fl
ow from deep
layers.
Numerous experimental observations for the ecosystems of the upwelling zones
have veri
ed these model results concerning a dissociation of maximal biomasses
of living elements during ecosystem evolution. Table
4.6
characterizes the precision
of the modeling results. Bacterioplankton biomass proves to be larger in real data. It
is evident that this follows from the failure to take account of allochtonous organic
matter as element of the bacterioplankton food. In general, modeling and obser-
vational results are similar. This conclusion is confirmed by results represented in
Fig.
4.22
where the vertical structure of the ecosystem is given. One can see that
phytoplankton biomass is uniformly big during the
first 5 days in the layer 0
50 m.
-
Fig. 4.21 Integral biomasses
dynamics of living elements
in the water layer 0
200 m
-
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