In all, there are 216 elementary cells in the model, forming a 

 parallelepiped, extended along the equator. The distance between the 

 centers of cells in longitude (X axis) is 1,000 km, in latitude (Y 

 axis)--100 km, in depth (Z axis)--40 m. The system of currents was 

 selected so as to imitate the surface trade current (along the X axis 

 from the coordinate origin) and the Cromwell current, gradually 

 approaching the surface (directed parallel to the X axis, but toward the 

 coordinate origin). In the immediate vicinity of the equator (plane 

 XZ), there is a significant vertical component to the velocity of the 

 flow, leading to ascent of waters to the surface. 



The surface current, directed toward the coordinate origin and 

 flowing parallel to the X axis some 500-600 km to the north of the 

 equator, imitates the equatorial countercurrent, in the area of which we 

 find the convergence zone. The model imitates the outflow of surface 

 waters away from the equator (movement along the Y axis from the 

 coordinate origin) and the corresponding deep countercurrent (parallel 

 to the Y axis toward the coordinate origin). The maximum vertical 

 component of speed of the flow is equal to 5 m/day (0.6 -lO"^ m/s), while 

 the maximum horizontal speed is 50 km/day. The diagram of the currents 

 was selected so that the condition of continuity is maintained for each 

 cell. The model considers the transfer of elements of the currents and 

 the gravitational precipitation of detritus. 



The initial state of the model was assigned in the form of an even 

 distribution of all elements throughout the entire volume analyzed. 

 After 30-40 days of the transient process, the model approached a stable 

 state, in which the flow of biogenic salts toward the bottom surface of 

 the parallelepiped was balanced by precipitation of detritus through 

 this surface. 



The maximum concentration of phytoplankton is created in the area 

 of the maximum intensity of upwelling (coordinate origin). As we move 

 along the X axis (along the equator toward the west), the concentration 

 of phytoplankton decreases, while the maximum itself descends to a depth 

 of 80 m. This result agrees both with observations at sea, and with 

 data obtained in a 2-dimensional model. 



The distribution of biomass of herbivores is characterized by the 

 formation of two areas of concentration: one is located on the equator 

 to the west of the region of intensive upwelling, while the second is 

 extended in the latitudinal direction north of the equator in the 

 convergence zone. It is characteristic that the maximum concentration 

 of phytophages is deeper in the zone of the convergence. 



The area of predominance of carnivores is extended in a broad strip 

 from east to west in the zone of the northern trade current. The 

 maximum concentration of predaceous zooplankton is found at a depth of 

 60-120 m. In the stable state of the model, the carnivores are 

 distributed almost throughout the entire volume down to a depth of 200 

 m, which is less typical of herbivores and not at all typical of 

 phytoplankton. 



340 



