Block diagram of energy flows at the snow -ice-water interface

As a basic scheme for the flow of nutrients in water, the scheme proposed by Krapivin (1996) is accepted, as adjusted to conditions in the Arctic Basin by Legendre and Legendre (1998). It is supposed that the spatial distribution of upwelling zones is given with seasonal variations. Block NUM realizes this scheme regarding the current structure of upwelling regions. 

The dynamic equation for nutrients B6A in the environment, where A = S snow, / ice, W water, is given by 

IJA is the rate of decomposition of detritus in environment A kA is the kinematical coefficient of vertical diffusion is the velocity of nutrient assimilation by the photosynthetic process per unit of phytoplankton production ef is the proportional part of the eth radionuclide that is chemically analogous to B6 A on substrate A H is the rate of input flow of the eth radionuclide 7) is the rate of exchange with the environment p is that part of biomass losses due to exchange that transforms into nutrients (Legendre and Legendre, 1998) and f3v is upwelling velocity. Equation (6.1) is the basic element of block NM. 

Phytoplankton production RpA in environment A is a function of solar radiation Ea, concentration of nutrients nA, temperature TA, phytoplankton biomass pA, and concentration of pollutants A. There are many models that describe the photosynthesis process (Legendre and Legendre, 1998 Legendre and Krapivin, 1992). For the description of this function in the present study, an equation of Michaelis-Menten type is used (block MFB)  

Equation (6.3) adequately fits laboratory data. Relationships (6.4) and (6.5) make the description of phytoplankton production more accurate for critical environmental conditions when the concentration of nutrients and the temperature fluctuate widely. The coefficients of these relationships are defined on the basis of estimates given by Legendre and Legendre (1998). 

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