ENVIRONMENTAL
ENGINEERING
Chemical Engineering department
ENERGY FLOW/ENERGY BUDGET
The movement of energy through ecosystem is called energy flow. It is an
essential part of the ecological process of life support in nature. As stated earlier,
green plants transform solar energy with the help of carbon dioxide and water into
food energy (chemical energy) by photosynthesis. This food energy goes on
transforming when food is taken as energy by other organisms of different trophic
levels. Thus energy flow is related with Food Chain. Almost all the solar energy is
trapped by autotrophic organisms of the first trophic level (green plants). Because
much energy is dissipated, about 90 % of available chemical energy (food energy)
is lost at each stage of transfer from one trophic level to the next higher level.
Energy flow in ecosystem
ENERGY BUDGET
Energy Budget shows a record of the flow of energy through an ecosystem in
each step from one organism to another. The primary productivity of an ecosystem
is defined as the rate at which radiant energy is converted by photosynthetic and
chemosynthetic activity or producer organisms (green plants, for example) to
organic substances. In coastal waters of seas primary production in relation to
biomass shows vertical distribution. It is concentrated in the upper 30 meters or so—
in the clearer but less fertile waters of the open seas the primary production zone
may extend down to 100 metres or more. This is why coastal water appears dark
greenish and the ocean waters blue.
FOOD CHAIN AND FOOD WEB
Food chain means the transfer of food energy from the source in plants
through a series of organisms with the repeated process of eating and being eaten. In
a grassland, grass is eaten by rabbits while rabbits in turn are eaten by foxes. This is
an example of a simple food chain.
This food chain implies the sequence in which food energy is transferred from
producer to consumer or higher trophic level. It has been observed that at each level
of transfer a large proportion, 80-90 %, of the potential energy is lost as heat. Hence
the number of steps or links in a sequence is restricted, usually to four or five. The
shorter the food chain or the nearer is the organism to the beginning of the chain, the
available energy intake is greater. Basically, food chains are of two types:
(i)
Grazing food chain and
(ii)
Detritus food chain.
The grazing food chain starts from green plants and passes through harbivores to
carnivores. On the other hand, the detritus food chain starts from dead organisms
and goes into the micro-organisms and then to detritus feeding organisms and
their predators. The term ‘detritus’ refers to all organic matter involved in the
decomposition of dead organisms.
The energy from the sun is transferred in the form of food from one organism to
another in the ecosystem.
Food chain
Food Web: In complex natural communities the food chains are not found in
isolation. They are all inter-connected with each other since most consumers have
multiple food sources and many species are prey to several predators and parasites.
Such inter-locking food chain is called food web.
Food web in terrestrial ecosystem
ENVIRONMENT STUDIES: IMPORTANCE
The environment studies enlighten us, about the importance of protection and
conservation of our indiscriminate release of pollution into the environment. At
present a great number of environment issues, have grown in size and complexity
day by day, threatening the survival of mankind on earth. We study about these
issues besides and effective suggestions in the Environment Studies. Environment
studies have become significant for the following reasons:
1-Environment Issues Being of International Importance
It has been well recognized that environment issues like global warming and ozone
depletion, acid rain, marine pollution and biodiversity are not merely national issues
but are global issues and hence must be tackled with international efforts and
cooperation.
2. Problems Cropped in the Wake of Development
Development, in its wake gave birth to Urbanization, Industrial Growth,
Transportation Systems, Agriculture and Housing etc. However, it has become
phased out in the developed world. The North, to cleanse their own environment has,
fact fully, managed to move ‘dirty’ factories of South. When the West developed, it
did so perhaps in ignorance of the environmental impact of its activities. Evidently
such a path is neither practicable nor desirable, even if developing world follows
that.
3. Explosively Increase in Pollution
World census reflects that one in every seven persons in this planted lives in India.
Evidently with 16 % of the world's population and only 2.4 % of its land area, there
is a heavy pressure on the natural resources including land. Agricultural experts have
recognized soils health problems like deficiency of micronutrients and organic
matter, soil salinity and damage of soil structure.
4. Need for an Alternative Solution
It is essential, especially for developing countries to find alternative paths to an
alternative goal. We need a goal as under:
 A goal, which ultimately is the true goal of development an environmentally
sound and sustainable development.
 A goal common to all citizens of our earth.
 A goal distant from the developing world in the manner it is from the overconsuming wasteful societies of the “developed” world.
5. Need to Save Humanity from Extinction
It is incumbent upon us to save the humanity from extinction. Consequent to our
activities constricting the environment and depleting the biosphere, in the name of
development.
6. Need for Wise Planning of Development
Our survival and sustenance depend. Resources withdraw, processing and use of the
product have all to by synchronized with the ecological cycles in any plan of
development our actions should be planned ecologically for the sustenance of the
environment and development.