Assuming that the wavelength of light remains constant, the intensity influences the rate of photosynthesis, which is why the earlier part of the

forenoon is the most productive, and higher intensity of light energy and higher temperature slow down the photosynthetic rate. Likewise, a cloudy day does not slow down the normal photosynthetic rate of par­ticular species to any observable extent.

Metabolically speaking, reports are insufficient to conclude anything based on this observation, even though the above information itself is very useful and valuable. At the onset of daybreak, the photosynthetic machinery gets into action after a dark rest period and the rate is at its peak; the carbon dioxide tension (partial pressure) at the immediate microenvironment is also higher (it is yet to be established that higher carbon dioxide tension facilitates photosynthesis, though the reverse is true). As the reaction proceeds with time, all other conditions remain­ing the same, the anabolic machineries including the enzymes and coen­zymes (particularly NADP/Co II system) are fully occupied and ATP systems are also fully utilized. ATP production is, in turn, dependent on respiration (oxidative process), which to some extent is competitive with carbon fixation. Geological and geographical factors contribute greatly to ATP productivity.

Let us turn again to the consideration of biogeological and biogeo­graphical distribution on energy. For an energy-based ecosystem, the biosphere may be classified into two major types: terrestrial, and aquatic. These can also be subdivided into eight intraterrestrial types: terrestrial, subterrestrial, epilimnon, mesolimnon, hypolimnon, estuarine, epima — rine, and submarine. What do these have to do with our objective? Natural distribution of flora and fauna largely depend upon the types of microenvironments mentioned above.

At this point, it need not be assumed that the arctic belt, being very cold, is biologically unproductive. The author was surprised to see the existence of almost a minitropical pocket, 66° north latitude and 20° east longitude (Jockmock, Sweden) due to uninterrupted insolation for almost 90 days and prolonged daylight for 60 more days. The flora and fauna have adapted to survival techniques for the cruelty of adverse nature during the long, dark winter months.