Geoscience Reference
In-Depth Information
For this case, the formula (
4.19
) is reduced to the form:
X
2
b
@
@
z
2
@
b
=@
t ¼ R
b
l
b
b
t
b
b
C
bj
R
j
þ
k
2
@
þ
V
z
w
p
b
=@
z
j
2x
0
n
p
;ðÞ
The rate of the change of the biomass of each element of zooplankton
∂
Z
i
/
∂
7) like in the Eq. (
4.29
) is determined by the level of consumption (ration)
R
Z,i
, food assimilation 1/u
Z,i
, expenditures on energy exchange T
Z,i
= t
Z,i
Z
i
, the rate
of dying-off
t (i =1
-
ʼ
Z,i
= 0.01Z
i
, eating-out of the i-th element by the j-th element with
the coef
cient C
ij
and the age transition of nauplii into copepod of
filtraters and
predators. Thus
R
Z
;
i
t
Z
;
i
þ l
Z
;
i
Z
i
P
,
7
@
Z
i
=@
t ¼
X
m
;
i
þ
1
h
Z
;
i
C
ij
R
Z
;
j
;
i ¼ 1
:
7
j
i
where h
Z,i
= 1
ʩ
m,i
characterizes the age transition of nauplii to another
category of zooplankton. The transition of nauplii Z
2
to copepod of
−
1/u
Z,i
,
filtraters (Z
3
, Z
4
)
takes place with an intensity
g
1
X
m
;
3
¼ Z
2
Z
3
15 Z
3
þ
Z
4
þ
Z
5
þ
Z
6
f
ð
Þ
;
g
1
X
m
;
4
¼ Z
2
Z
4
20 Z
3
þ
Z
4
þ
Z
5
þ
Z
6
f
ð
Þ
;
and for predatory copepod (Z
5
, Z
6
) with an intensity
g
1
X
m
;
4
¼ Z
2
Z
5
15 Z
3
þ
Z
4
þ
Z
5
þ
Z
6
f
ð
Þ
;
g
1
X
m
;
6
¼ Z
2
Z
6
20 Z
3
þ
Z
4
þ
Z
5
þ
Z
6
f
ð
Þ
:
To calculate the ration for the elements of zooplankton by the formula (
4.28
), the
coef
cient
ʽ
is determined from the condition
ʽ
= 0.01/B
min
. When calculating the
coef
cients C
ij
, it is assumed that the food needs refer to various food objects in
proportion to their biomasses taking into account food selectivity. The coef
cients
C
ij
for all elements of the ecosystem are given in Fig.
4.18
.
The daily migrations of zooplankton are simulated by an addition to the daily
ration of the elements Z
j
(j =4
50 m, of some share (k
Z
)of
total food needs of the same elements of the community but in the layer 50
7), located in the layer 0
-
-
200 m.
-
The coef
cient k
Z
is considered to be time-dependent:
0
:
02
þ
0
:
0016t
for
t
50
days,
k
z
¼
0
:
1
for
t
[
50
days
:
Various scenarios both of migration and nutrition of the elements of zooplankton
are possible. Only for certain it is known that some share of the zooplankton elements
from deep layers satisfy their needs for food in the upper layers of the ocean.
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