126 ENVIRONMENTAL SCIENCE
(2) Again 21 per cent of this energy, or 23 gcal/cm^2 /yr (show on the bottom as respiration)
is consumed in metabolic reactions of autotrophs for their growth, development,
maintenance and reproduction.
(3) 15 gcl/cm^2 /yr are consumed by herbivores that graze of feed on autographs-this
figure amounts to 17 per cent of net autotroph production.
(4) Decomposition is 3 gcal/cm^2 /yr which amount to be 3, 4 per cent of net production.
(5) The remainder of the plant material, 70 gcal/cm^2 /yr of 79.5 per cent production, is
not utilised. It becomes part of the accumulating sediments. Apparently much more
energy is available for herbivory than is consumed.
We may conclude the following conclusions
(1) Various pathways of loss are equivalent to and account for total energy capture of
the autotrophs i.e. gross production.
(2) The three upper ‘fates’ i.e. decomposition, herbivory and not utilized collectively are
equivalent to net production.
(3) Of the total energy which is incorporated at the herbivory level, i.e. 15/ gcal/cm2yr,
30 percent of 4.5 gcal/cm^2 /yr is used in metabolic reactions.
(4) In this way more energy is lost via respiration by herbivores (30 percent) than by
autotrophs (21 percent),
(5) Considerble energy is available for the carnivores, namely 10.5 gcal/cm^2 /yr
or 70-per cent. It is not entirely utilized, merely 3.0 gcal/cm^2 /or 28.6 per cent
of net production passes to the carnivores. This utilization of resources is
evidently more efficient than the one, which occurs at autotroph-herbivore
transfer level.
(6) At the carnivore level the consumption in metabolic activity is about percent of the
carnivores energy intake.
(7) The remainder becomes part of the un-utilized sediments;
(1) There is Noe-way Street along which energy moves (unidirectional flow of energy.
(a) The energy that is captured by the autotrophs does not revert back to solar
input.
(b) The energy which passes does not pass back to the autotrophs. It moves
progressively through the various trophic levels. As such, it is no longer
available to the previous level. Since there is one-way flow of energy, the
system would collapse in case the primary source, the sun, were cut off.
(2) Secondly, progressive decrease in energy level is seen at each trophic level. This
decrease is accounted as under:
(i) By the energy dissipated as heat in metabolic activities.
(ii) Measured here as respiration coupled with unutilized energy.
Below is a figure after Epodum (1963).