Ecological Imbalance In Nature Essayists
Ecological imbalance and their consequences
Human activities are responsible for the disturbance of balanced system of an environment. Increasing human population produces a strain on the resources and availability of energy and materials, which deplete. The process of urbanization and industrialization, use of chemical fertilizers and pesticides, hasty approaches to the formulation of developmental projects particularly hydro-electric and those on tourism, road, building, mining and disposal of waste materials are the main developmental activities of man.
All these activities introduce many unwanted substances in the environment and disturb the balanced system of the environment. This is known as ecological balance.
The major ecological imbalances are greenhouse effects, depletion of ozone layer and acid rain.
The greenhouse effect refers to circumstances where the short wavelengths of visible light from the sun pass through a transparent medium (i.e. envelope of gases CO, CO2, SO2, etc.) and are absorbed, but the longer wavelength of the infrared radiation from the heated objects are unable to pass through that medium and are trapped causing more heating and a higher resultant temperature.
The causes of greenhouse effect are as follows;
- Due to deforestation.
- Due to population growth, the excessive amount of CO2 is being deposited in the atmosphere through furnaces of power plants, automobiles, factories, etc.
- Industries which are involved in cement production, fertilizers, coal mining, etc. produce harmful greenhouse gas.
- Nitrous oxide is one of the greenhouse gas that is used in fertilizer and contributes to the greenhouse effect.
- It results in the increase in temperature of the earth as a whole causing global warming.
- The rise in temperature result increases in sea level due to the melting of polar caps.
- Warming up of the atmosphere causes natural calamities like flood, hurricanes, and cyclones nearby the oceans.
- Higher atmospheric temperature increase evaporation of water from the farms reducing crop yield.
- Monsoon may even stop altogether or rainfall may be altered.
Depletion of ozone layer
The ozone layer is a deep layer in earth’s atmosphere that contains ozone which is a naturally occurring molecule containing three oxygen atoms. An essential property of ozone molecule is its ability to block solar radiations of wavelengths less than 290 nanometers from reaching Earth’s surface. In this process, it also absorbs ultraviolet radiations that are dangerous for most living beings.
- Chloro Fluro Carbon (CFC) gas released by industry releases chlorine-containing chemicals that react with ozone and causes damage to it.
- Volcanic eruption, burning of large forests and savannahs, jet planes also contribute to the depletion of ozone.
In the stratosphere, the CFCl3 is broken down into chloride atoms in the presence of UV radiation. Each chloride atom reacts with more than 10,000 atoms of O3 converting into O2. Here, produced chlorine atom can destroy other molecules of O3.
- Due to more UV radiations entering, it increases the earth’s temperature that can lead to the failure of rainfall.
- Harmful UV radiations may cause skin cancer.
- Higher UV radiation reduces the photosynthesis thus, reducing the productivity of crops.
- UV radiation results in the number of phytoplankton and zooplanktons and thus, harms fish and other aquatic life.
Acid rain is a rain or any other form of precipitation that is usually acidic, meaning that it have the higher number of hydrogen ions (low pH). Normal or unpolluted rain has a pH of 5.6%, the acidity is due to the presence of CO2 in the air. But acid rain has a pH value of 4 to 4.5 that is due to SO2 and oxides of nitrogen present in it.
Oxides of sulphur and nitrogen (SO2, NO, NO2 ) are the main air pollutants produced mainly by the combustion of fossil fuels for power generation.
In the atmosphere, SO2 and NO2 react with moisture forming respective acids (H2SO4 and HNO3 ) which then dissolving in water vapor in atmosphere fall onto the earth as acid rain. These acidic oxides may even undergo physical and chemical transformations producing toxic agents. About 60% - 70% of acids in the atmosphere are derived by the oxidation and hydrolysis of SO2 and H2S and rest 30% - 40% from various nitrogen compounds and other compounds.
- Acid rain creates particles in the air that can cause respiratory problems.
- It also causes building materials to decay more rapidly and paint more likely to peel.
- Acid rain when mixed into the soil, it dissolves many of the essential nutrients the plant needs.
- Acid rain raises the acidity of water of lake or pond which may destroy the aquatic life.
A textbook of biology 8th edition.
In this article we will discuss about the energy source and ecological imbalance.
Source of Energy:
As referred to, sun is the only source of energy to our planet earth. The solar energy is released in form of invisible ultra-violet light and infra-red light, and visible light. Most of the ultra-violet light is absorbed by ozone layer in the upper atmosphere and most of the infra-red light having longer wavelengths are absorbed by atmospheric gases and some are reflected back in the environment.
Visible light constitutes nearly 50 per cent of solar energy; a part of it is reflected by clouds and dust particles, and a part is absorbed by the atmosphere (Fig. 12.19). In fact, sun radiates energy of nearly 1026 Joules/second but the earth gets only a fraction of it.
On the top of the atmosphere, the earth receives energy equal to 173 x 1015 Joules/second; of this about one-third is reflected back into the space by the atmosphere.
However, whatever amount of energy from the sun rEcology, eaches the earth in form of light and heat regulates the climatic phenomena on this planet. The green plants trap only a very small fraction (nearly one per cent) of available solar energy during the process of photosynthesis. Green plants trap light energy with the help of the pigment chlorophyll and convert it in chemical energy.
Thus, the energy trapped by green plants, i.e., autotrophs is utilised then in synthesizing organic compounds during the process of photosynthesis. The green plants, thus, are the only organisms which can trap and fix solar energy and can manufacture food used by them as well as by other organisms; hence, these are called producers.
The rate at which organic compounds are synthesized in a green plant or a population of green plants is called gross primary productivity (GPP). GPP gives us an idea of the proportion of assimilation of light energy into living matter of the plant. The organic compounds synthesized by plants are used as a source of energy for their body building, storage and various catabolic activities.
The total stored energy in form of organic matter (which is not used by the producer itself) is called net primary productivity (NPP). Exactly in the manner as a single plant contributes to the gross primary productivity and net primary productivity, all autotrophs in a community contribute to community productivity.
It has been mentioned earlier that all heterotrophs depend upon autotrophs (producers) directly or indirectly for food. So, by consuming autotrophs, heterotrophs consume organic matter from them. Energy, thus, enters the ecosystem through photosynthesis and passes through the different trophic levels. In other words, flow of energy takes place from the sun to autotrophs to heterotrophs.
The food consumed by heterotrophs is utilized in their maintenance and for storage too. If there is more storage than consumption, the biomass of the population would be higher at the end of a time period than at the beginning. So, this rate of increase in the biomass of heterotrophs is referred to as secondary productivity.
There occurs a continuous loss of energy all along the path when it is transferred from producer to a consumer and from consumer to the next consumer at the higher trophic level. For this, Lindemann (1942) formulated a concept called 10 per cent law.
To explain, when plants (producers) are eaten by a herbivore (primary consumer), about 10 per cent of energy in the food is fixed in herbivore’s body and when a carnivore (secondary consumer) eats up the herbivore, only about 10 per cent of energy in food is fixed in carnivore’s body.
Therefore, the second level consumer gain in energy is only 0.01 per cent of the net productivity of a plant (producer). This clearly shows that there is a loss of energy at each trophic level. So, the longer the food chain, the minimum is the energy available to the last member of the chain. It is, therefore, there are usually four or five steps in natural food chains.
The flow of energy is, however, unidirectional.
Ecological studies suggest that there exists an ecological balance between various constituents of abiotic and biotic components in the biosphere. For example, the various biogeochemical cycles operate in nature without any interruption and the abiotic as well as biotic components including producers, consumers and decomposers are significant.
If producers be destroyed carbon from atmospheric carbon dioxide cannot move to organic compounds in living organism and if consumers and decomposers be destroyed the organic compounds will accumulate resulting into locking up of carbon and further not available for cycling.
However, when all organisms of an area are studied, it becomes evident that in spite of different types of competitions and struggles between them, they co-operate each other on many ways or they seem to be interdependent. This dependence is called ecological balance. It is very necessary for the continuity of ecosystems and, hence, the biosphere.
However, man being a dominant organism of most ecosystems controls and modifies environment more extensively than any other organism. In fact, there have been significant changes in the natural environments due to man’s intervention and his rapid progress in colonization, urbanization, industrialization, agriculture, transportation and technology.
Thus, deforestation has provided land for agriculture and rural inhabitation, rural land has been converted into urban settlements and open spaces are fast vanishing.
All these have resulted into a mass-scale destruction of flora and fauna which has become detrimental to ecological balance. If, this balance is disturbed for long, it is bound to create a number of crises to the biological world including our lives. Hence, considering this importance, a number of ways are being adopted by government and private agencies so that ecological balance could be maintained.