Page 26 - Biofuels Refining and Performance

Energy and Its Biological Resources 9

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 par-
ticular 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 remain-
ing the same, the anabolic machineries including the enzymes and coen-
zymes (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 biogeo-
graphical 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.

1.4 Bioenergy
Energy can be derived from living systems in restricted forms only.
Lignocelluloses are burned to get heat, and vegetable oils are often used
for illumination. These may also serve as nutrients for different biotic
species in various forms, i.e., cellulose, starch, and sugars. In other
words, chemically stored energy may be reused in the form of fuel (fire-
wood) or nutrients (food, feed, fodder, etc.). Animals can be employed to
do different mechanical work. Animals directly (fish, meat) or indirectly
(egg, milk) may provide nutrients for others. Use of dried cow dung as