These model descriptions enable the above quantum yields Φfl(z) and Φph(z) to be estimated Epacadostat from the three main environmental parameters governing phytoplankton growth in the sea: basin trophicity, assumed to be

the surface concentration of chlorophyll a, Ca(0); the light conditions in the sea, the index of which are values of the irradiance PAR(z) at various depths; and the temperature temp(z) at different depths. These models are based on empirical material collected in the surface layer of waters, i.e. from the surface down to a depth of ca 60 m. This is equivalent to the water masses in roughly half the euphotic zone in basins with Ca(0) < 1 mg m−3, and almost the whole of the euphotic zone or even transgressing it in other basins. The measurements were carried out in basins of different trophicity and at temperatures ranging from ca 5°C to ca 30°C. We can therefore assume that the relationships are practically universal: to a good approximation they quantitatively describe the processes of photosynthesis and the natural fluorescence

of phytoplankton in any ocean or sea basin. The modelling of the yields of heat processes presented in this work is based on the same principles as the above models of fluorescence and photosynthesis. The appropriately modified assumptions of this modelling are as follows: • Assumption 1: The model quantum yields of the heat production ΦH(z) at particular

see more depths in the sea are complementary to the unity of the sum of the quantum yields of photosynthesis Φph(z) and fluorescence Φfl(z), as emerges from equation (1). The set of equations, derived from assumptions 1–4, describing the models of the dependences of the quantum yield of heat production in the sea on environmental factors, is given in Table 1. where Ca(0) – total chlorophyll a concentration in the surface water layer [mg m− 3], The mathematical description of the relationship between the quantum yields of processes of the deactivation of phytoplankton pigment excitation energy Thymidine kinase and environmental factors, presented in this paper (see (2), (3) and (4) and Table 1), enables their variability under different conditions in the water column to be tracked down to a depth of ca 60 m. On this basis Figure 1 illustrates the dependences of the quantum yields of all three sets of processes by which excited states in the molecules of all phytoplankton pigments are dissipated on the PAR irradiance in different trophic types of water. Apart from the dependence of the yield ΦH ( Figure 1b), the figure also shows the dependence of the quantum yield of fluorescence Φfl ( Figure 1a) and the quantum yield of photosynthesis Φph ( Figure 1c). In order to compare the strongly differentiated ranges of variability of these three yields, their values are presented on a logarithmic scale.