II. DESCRIPTION OF MODEL
REA(:TIQN 4 DA I VING
36
Figure 1. A simplified representation
of the reactions leading to the growth
of phytoplankton . The driv i ng reactions
release free energy whi Ie the driven
reactions consume free energy .
Figure 1 presents the principal biochemical reactions that are to
be described mathematically. The conversion of light and nutrients into
cellular material involves two sets of coupled reactions which are connected by a cycling photosynthetic electron transport system, symbolized
by:
(1)
At coupling site 3-4 the free energy of absorbed quanta reaching reaction centers (reaction 4), drives the separation of charqe between redox pools of electron donors and acceptors (reaction 3).
For the
coupling site 1-2 the free energy released in photosynthetic electron
flow (reaction 2) drives the anabolic reactions of growth (reaction 1),
which may be represented by:
(2)
The series of equations describing the flow of quanta and electrons
through the system shown in Figure 1 are:
J 4
1.3 x 105
J.
ChI a
(3)
l.
J 4
L34 A 3 + L44 A 4'
A4
+40.0
(4)
J 3
L33 A 3 + L 34 A 3 ,
( 5)
J 2
L12 A l + L 22 A 2 ,
Al
-17.5
(6)
J l
LUAI + L 12 A 2 ,
(7)
J 2
J 3 ,
A2
A3
(8) , (S)