ENVIRONMENT

DEFINITION
The term environment refers to one’s surroundings. The physical and
biological factors along with their chemical interactions that affect an
organism or a group of organisms. The environment is the biotic and abiotic
surrounding of an organism or population, and consequently includes the
factors that have an influence in their survival, development and evolution.
The environment can vary in scale from microscopic to global in extent.
Examples include the marine environment, the atmospheric environment
and the terrestrial environment. The sum total of all surroundings of a living
organism, including natural forces and other living things, which provide
conditions for development and growth as well as of danger and damage.

Types of Environments
There are two different types of environments:

 Natural Environment
 Man-made/Anthropogenic Environment

Natural Environment
It consists of all components provided by nature and hence can be called as
the natural environment. It is also referred to as the physical environment as
it pertains to the physical requirements of life. These physical or geographic
conditions are not dependent on the existence of humans. Sometimes,
humans have no control over the physical conditions of the environment.

It includes natural resources, the earth’s surface, mountains, plains, land,

water, deserts, storms, cyclones, volcanoes, oceans, climatic factors, and so
on. It is also used to refer to biological situations such as complexities
associated with plants and animals. The sustainability of the natural
resources is known to contribute towards the economy of a country.

Man-Made Environment

This environment is used to refer to the one created by man in order to

regulate and monitor certain environmental conditions. Some address it as a
social-cultural environment. It can further be divided into two types of
environments:
The Inner Environment
It is a social environment and it exists as long as a particular society exists.
It pertains to the regulations, traditions, organizations and institutions. It
involves customs and folkways which is existent in every human group. It is
addressed with names such as non-material culture, social heritage etc. This
heritage is essential for the social life of humans to flourish, it is known to
have an influence on an individual’s life. The altered form of the economic
and physical environment – artificial environment, are seen as two different
aspects of the man-made environment.

The Outer Environment

Through advancement in the field of science and technology, humans have
attempted to alter conditions of their physical environment. This outer
environment is as a result of these modifications which includes modern
infrastructure in cities, our homes and their associated amenities, our modes
of communication and transport, our resorts to conveniences and luxury,
different kinds of industry manufacturing luxurious commodities, electrical
appliances and so on which ultimately aims at civilization and urbanization.

ENVIRONMENTAL SEGMENTS
The environment consists of various segments such as atmosphere,
hydrosphere, lithosphere and biosphere

Atmosphere
The following points highlight the vital role played by atmosphere in the
survival of life in this planet

. • The atmosphere is the protective blanket of gases which is surrounding

the earth. It protects the earth from the hostile environment of outer space.

• It absorbs IR radiations emitted by the sun and reemitted from the earth
and thus controls the temperature of the earth.

• It allows transmission of significant amounts of radiation only in the

regions of 300 – 2500 nm (near UV, Visible, and near IR) and 0.01 – 40
meters (radio waves). i.e it filters tissue damaging UV radiation below 300
nm.

•It acts as a source for CO2 for plant photosynthesis and O2 for respiration.
• It acts as a source for nitrogen for nitrogen fixing bacteria and ammonia
producing plants.
•The atmosphere transports water from ocean to land.

Troposphere
Though the sunlight reaches the Earth’s surface from top to bottom, the
troposphere is primarily heated at the bottom. The Earth’s surface is much
better at absorbing a wide range of solar radiation than the air. When the
parcel of warm air moves upwards, it expands, and when air expands, it
cools. Due to this reason, the base of the troposphere is warmer than its
base because the air on the surface of the Earth absorbs the sun’s energy,
gets heated up, and moves upward, which cools down.
Stratosphere
The Stratosphere lies above the troposphere and extends up to a height of
50 km. This layer is free of clouds and devoid of any weather-related
phenomenon. Due to this, aeroplanes fly in the Stratosphere for a smooth
ride. The Stratosphere also houses the ozone layer that protects us from
the harmful effect of the sun’s rays.
Mesosphere
The temperature in the mesosphere grows colder with the altitude.
T his is
because there are few gas molecules in the mesosphere to absorb the Sun’s
radiation. The only heat source is the stratosphere below. The mesosphere is
extremely cold, especially at the top, dropping to a temperature as low as -
90°C.

Thermosphere
The density of molecules in the thermosphere is very low. One m gas olecule
can go about a distance of 1 km without colliding with another molecule.
Because so little energy is transferred, the air feels freezing. Satellites are
found orbiting in the upper part of the thermosphere.

Exosphere
The exosphere is the final frontier of the Earth’s gaseous envelope. There is
no clear- cut distinction between the Earth’s atmosphere layers and outer
space. The air in the exosphere is constantly but gradually leaking out of the
Earth’s atmos phere into outer space.
Hydrosphere
The hydrosphere is a collective term given to all different forms of water.

It includes all types of water resources such as oceans, seas, rivers, lakes,
streams, reservoirs, glaciers and ground waters.

A hydrosphere is the total amount of water on a planet. The hydrosphere

includes water that is on the surface of the planet, underground, and in the
air. A planet's hydrosphere can be liquid, vapor,or ice.

On Earth, liquid water exists on the surface in the form of oceans, lakes and
rivers. It also exists below ground—as groundwater, in wells and aquifers.
Water vapor is most visible as clouds and fog.

The frozen part of Earth's hydrosphere is made of ice: glaciers, ice caps and
icebergs. The frozen part of the hydrosphere has its own name, the
cryosphere.

Water moves through the hydrosphere in a cycle. Water collects in clouds,

then falls to Earth in the form of rain or snow. This water collects in rivers,
lakes and oceans. Then it evaporates into the atmosphere to start the cycle
all over again. This is called the water cycle.

Lithosphere

The lithosphere is the solid, outer part of the Earth. The lithosphere includes
the brittle upper portion of the mantle and the crust, the outermost layers of
Earth’s structure. It is bounded by the atmosphere above and the
asthenosphere (another part of the upper mantle) below. The lithosphere is
the most rigid of Earth’s layers. Although the rocks of the lithosphere are still
considered elastic, they are not viscous. The asthenosphere is viscous, and
the lithosphere asthenosphere boundary (LAB) is the point where geologists
and rheologists—scientists who study the
flow of matter—mark the difference in ductility between the two layers of
the upper mantle. Ductility measures a solid material’s ability to deform or
stretch under stress. The lithosphere is far less ductile than the
asthenosphere. The elasticity and ductility of the lithosphere depends on
temperature, stress, and the curvature of the Earth itself.

The lithosphere is also the coolest of Earth’s layers. In fact, some definitions
of the lithosphere stress its ability to conduct heat associated with the
convection taking place in the plastic mantle below the lithosphere.

Biosphere
• The biosphere refers to the realm of living organisms and their interactions
with the environment (VIZ: atmosphere, hydrosphere and lithosphere)

• The biosphere is very large and complex and is divided into smaller units
called ecosystems.

• Plants, animals and microorganisms which live in a definite zone along

with physical factors such as soil, water and air constitute an ecosystem.

• Within each ecosystems there are dynamic inter relationships between

living forms and their physical environment

• These inter relationships manifest as natural cycles.(hydrologic cycle,

oxygen cycle, nitrogen cycle, phosphorous cycle and sulphur cycle),

•The natural cycles operate in a balanced manner providing a continuous

circulation of essential constituents necessary for life and this stabilizes and
sustains the life processes on earth.
Scope of Environmental Science
Environmental science is a multidisciplinary science whose basic aspects
have a direct relevance to every section of the society. Its main aspects are:

•Conservation of nature and natural resources.

•Conservation of biological diversity.

•Control of environmental pollution.

•Stabilization of human population and environment.

•Social issues in relation to development and environment.

• Developmentof non-pollutingrenewable energy system and providing

new dimension to nation’s security.

Importance of Environmental Science

Environment belongs to all the living beings and thus is, important for all.
Each and every body of whatever occupation he or she may have, is affected
by environmental issues like global warming, depletion of ozone layer,
dwindling forest, energy resources, loss of global biodiversity etc.
Environment study deals with the analysis of the processes in water, air,
land, soil and organisms which leads to pollute or degrade environment. It
helps us for establishing standard, for safe, clean and healthy natural
ecosystem. It also deals with important issues like safe and clean drinking
water, hygienic living conditions and clean and fresh air, fertility of land,
healthy food and development. Sustainable environmental law, business
administration, environmental protection, management and environmental
engineering are immerging as new career opportunities for environment
protection and managements.

Need for Public Awareness:

With the ever-increasing development by modern man, large scale degradation of
natural resources have been occurred, the public has to be educated about the
fact that if we are degrading our environment we are actually harming ourselves.
To encourage meaningful public participation and environment, it is necessary to
create awareness about environment pollution and related adverse effects. The
United Nations conference on Environment and Development held in Rio-de-
Janeiro, followed by Earth summit on sustainable Development have high-lighted
the key issues of global environmental concern and have attracted the general
public towards the deteriorating environment. Any Government at its own level
can’t achieve the goal of environment conservation, until the public has a
participatory role in it. Public participatory role is
possible only when the public is awared about the ecological and environmental
issues. In short, if we want to manage on planet earth, we would have to make
the entire population, environmentally educated. The objectives of
environmental awareness should be:

(a) Improving the quality of environment.

(b) Creating an awareness among people on environmental problems and

conservation.

(c) Creating such an atmosphere as people find themselves fit enough to

participate in decision making process of environmental development
programs.
ECOSYSTEM
DEFINITION
In nature, the living organisms (plants, animals and microorganisms) and nonliving
environment (e.g. water, air, soil, etc.) are inseparably interrelated and interact
with each other. No living organism can exist by itself, or without an environment.
Every organism uses energy, nutrients and water from its surrounding environment
in various life activities.

1. The plants obtain the energy directly from the sun, and, in case of animals and
microorganisms, energy is taken from other organisms through feeding on plants, predation,
parasitism and/or decomposition.

2. The terrestrial plants obtain water mainly from soil, while animals get it from free standing
water in the environment or from their food.

3. The plants obtain most of their nutrients from the soil or water, while animals get nutrients
from plants or other organisms. Microorganisms are the most versatile, obtaining nutrients
from soil, water, food, or other organisms.

As a result, the organisms interact with one another and with their environment in
a number of ways. These fundamental interactions among organisms and their
non-living/physico-chemical environment constitute an interrelating and
interdependent ever-changing system known as an ecological system or
ecosystem. The ecosystem has been considered as the basic functional unit of
ecology and ecology as study of ecosystems

ECOSYSTEM STRUCTURE
The ecosystem is largely divided into two components - Abiotic and Biotic
components. Ecosystem structure is created due to interaction between abiotic and
biotic components, varying over space and time.

1. Abiotic Components
The abiotic components of an ecosystem refer to the physical environment or the
non-living factors. The organisms cannot live or survive without their abiotic
components. They mainly include i) inorganic substances required by organisms
such as carbon dioxide, water, nitrogen, calcium, phosphorus, etc. that are involved
in material cycles. The amount of these inorganic substances present at any given
time in ecosystem is called as standing state or standing quality of ecosystem. ii)
organic compounds like proteins, carbohydrates, amino acids, lipids, humic
substances and others are synthesized by the biotic counterpart of an ecosystem.
They make biochemical structure of ecosystem. iii) climatic factors including mainly
rain, light, temperature, humidity, wind and air and iv) edaphic and other factors
such as minerals, soil, topography, pH, etc. greatly determine the functions,
distribution, structure, behavior and inter- relationship of organisms in a habitat.

2. Biotic Components
The biotic components of the ecosystems are the living organisms including plants,
animals and microorganisms. Based on their nutritional requirement, i.e. how they
get their food, they are categorized into three groups –
i) Producers are mainly the green plants with chlorophyll which gives them the ability to use
solar energy
to manufacture their own food using simple inorganic abiotic substances, through
the process of
photosynthesis. They are also called as photoautotrophs (photolight, auto-self,
troph-nutrition). This group is mainly constituted by green plants, herbs, shrubs,
trees, phytoplanktons, algae, mosses, etc. There are some chemosynthetic bacteria
(sulphur bacteria) deap beneath in the ocean which can synthesize their food in
absence of sunlight, thus known as chemoautotrophs (chemo-chemical, auto-self,
troph-nutrition).

ii) Consumers lack chlorophyll, so they depend on producers for food. They are also
known as
heterotrophs. They mainly include herbivorous (feed on plants), carnivorous (feed
on other animals),
omnivorous (feed on both plants and animals) and detritivores organisms (feed on
dead parts, waste, remains, etc. of plants and animals,).

iii) Decomposers (saprotrophs) are the microorganisms, bacteria and fungi, which break down
complex dead organic matter into simple inorganic forms, absorb some of the decomposition
products, and release inorganic nutrients that are reused by the producers. All ecosystems
have their own set of producers,
consumers and decomposers which are specific to that ecosystem. The nutritional
relationship among
different biotic components of an ecosystem is shown.
 Nutritional relationship among different biotic components of an ecosyste

Types of Ecosystem
Based on the kind of habitat, there are essentially two types of ecosystems:
Aquatic and Terrestrial
Ecosystem . Any other sub-ecosystem falls under one of these two types-

1. Terrestrial Ecosystem
The ecosystems on land are called as terrestrial ecosystems. They are broadly classed
into:

a) Forest Ecosystem:

They are the ecosystems with an abundance of flora, or plants in relatively small
space. A wide diversity of fauna can also be seen. A small change in this ecosystem
could affect the whole balance and effectively bring down the whole ecosystem.
They are further divided into:
 Tropical rainforest: These contain more diverse biodiversity than ecosystems in any
other region on earth. They receive a mean rainfall of 80 cm for every 400 inches
annually. In these, warm, moisture-laden environments, dense evergreen vegetation
comprising tall trees at different heights are present, with fauna species inhabiting the
forest floor all the way up to canopy.
 Tropical deciduous forest: In these ecosystems, shrubs and dense bushes are found
along with a broad selection of trees. The trees are mainly which shed their leaves
during dry season. The type of forest is found in quite a few parts of the world while a
large variety of fauna and flora are found there.
 Temperate evergreen forest: Those have a few numbers of trees as mosses and
ferns make up for them. Trees have developed needle shaped leaves in order to
minimize transpiration.
 Temperate deciduous forest: The forest is located in the moist temperate places
that have sufficient rainfall. Summers and winters are clearly defined and the trees
 shed the leaves during the winter.
 Taiga: found just before the arctic regions, the taiga is defined by evergreen conifers.
As the temperature is below zero for almost half a year, the remainder of the months, it
buzzes with migratory birds and insects.

b) Desert Ecosystems:

Desert ecosystems are located in regions that receive low precipitation, generally
less than 25 cm per year. They occupy about 17 percent of land on earth. Some
deserts contain sand dunes, while others feature mostly rock. Due to the extremely
high temperature, low water availability and intense sunlight, vegetation is scarce
or poorly developed, and any animal species, such as insects, reptiles and birds,
must be highly adapted to the dry conditions. The vegetation is mainly shrubs,
bushes, fewgrasses and rare trees. The stems and leaves of the plants are modified
in order to conserve water as much as possible, for example, succulents such as
the spiny leaved cacti.

c) Grassland Ecosystems:

Grassland Ecosystems are typically found in both tropical and temperate regions of
the world. They share the common climactic characteristic of semi-aridity. The area
mainly comprises grasses with a little number of trees and shrubs. A lot of grazing
animals, insectivores and herbivores inhabit the grasslands. The two main types of
grasslands ecosystems are

Savanna: The tropical grasslands are dry seasonally and have few individual trees.
They support a large number of predators and grazers.

Prairies: It is temperate grassland, completely devoid of large shrubs and trees.

Prairies could be categorized as mixed grass, tall grass and short grass prairies.

d) Mountain Ecosystem:

Mountain land provides a scattered and diverse array of habitats where a large
number of animals and plants are found. At the higher altitudes, under harsh
environment, only the treeless alpine vegetation can survive. The animals have
thick fur coats for prevention from cold and hibernation in the winter months.
Lower slopes are commonly covered with coniferous forests.

2. Aquatic Ecosystems:
Aquatic ecosystem is the ecosystem found in a body of water. It encompasses
aquatic flora, fauna and water properties, as well. There are two main types of
aquatic ecosystem – Marine and Freshwater Ecosystem.

a) Marine Ecosystem
Marine ecosystems are the biggest ecosystems, which cover around 71% of earth’s
surface and contain 97% of out planet’s water. Water in marine ecosystems
contains high amounts of dissolved minerals and salts. Various marine ecosystems
include oceanic (a relatively shallow part of oceans which lies on the continental
shelf), profundal (deep or bottom water), benthic bottom substrates, inter-tidal (the
place between low and high tides), estuaries, coral reefs, salt marshes,
hydrothermal vents where chemosynthetic bacteria make up the food base. Many
kinds of organisms live in marine ecosystems: the brown algae, corals,
cephalopods, echinoderms, dinoflagellates, sharks, etc.

b) Freshwater Ecosystem
Contrary to the Marine ecosystems, the freshwater ecosystem covers only 0.8% of
Earth's surface and contains 0.009% of the total water. Three basic kinds of
freshwater ecosystems exist.

i) Lentic - slowmoving or still water like pools, lakes or ponds.

ii) Lotic - fast-moving water such as streams and rivers.

iii) Wetlands - places in which the soil is inundated or saturated for some lengthy period of time.

Natural and Artificial Ecosystems

All above ecosystems are Natural ecosystems as these operate themselves under
natural conditions without any major interference by man. Some ecosystems are
maintained artificially by human beings where, by addition of energy and planned
manipulations, natural balance is disturbed regularly. For example, croplands like
maize, wheat, rice-fields etc. where man tries to control the biotic community as
well as the physico-chemical environment. These are called as Artificial or Man-
engineered ecosystems.
FOOD CHAIN
The transfer of food energy through a sequence of eating and being eaten by the
organisms in an
ecosystem is termed as the food chain. For example, in a grassland ecosystem,
grass fixes the light energy from the sun into chemical energy via synthesis of food
and eaten up by a grasshopper, which in turn is eaten by a frog and the frog itself
is eaten up by a snake. So, grass is food for grasshopper, grasshopper is food for
frog and the frog is food for snake. Thus, grass, grasshopper, frog and snake make
a food chain, through which energy contained in food is transferred from one
organism to another. In a pond ecosystem, the big fishes eat the small fishes which
eat the zooplanktons which in turn consume phytoplanktons. The later fixes the
light energy from the sun into chemical energy. All the organisms, whether live or
dead, are potential food for other organisms. So, essentially there is no waste in an
ecosystem.
Some examples of food chain are as follows:

Grass → Grasshopper → Frog → Snake → Eagle (Grassland Ecosystem) (1)

Tree → Fruit ea.ng Birds (Forest Ecosystem) (2)

→ Eagle

(Forest Ecosystem) (3)

Plant → Deer → Lion

Food Chain in Grassland

ecosystem:
 Phytoplankton → Zooplankton → Small fish → Big fish → Human beings

(Pond Ecosystem) (4)

Therefore, there is a definite sequence of producers and consumers in an

ecosystem and their interactions alongwith population size are expressed together
as trophic structure. The position of organisms along a food chain is referred to as
trophic level and the amount of living matter at each trophic level at a given time is
known as standing crop or standing biomass. All the green plants (primary
producers) belong to first trophic level, plant eaters or herbivores (primary
consumers) belong to second trophic level, carnivores or secondary consumers to
the third trophic level, and other carnivores or tertiary consumers to fourth trophic
level and so on. The top carnivores in the food chain are known as the top
predator.

Types of Food Chains

Food chains are of two basic types:

1. Grazing Food chain

The grazing food chain is the major food chain dominantly occurring in
ecosystems. As obvious from the name, it starts from the green plants, the
major source of energy for this chain is taken from the sun as plants carry
out the process of photosynthesis in presence of sunlight. The green

Plants are the primary

producer and eaten up by herbivores, are eaten up by
which in turn
 carnivores. This food chain doesn’t consist of microbes or other
decomposers; it is carried out by the macroscopic organisms. Examples are:
Plant → Deer → Tiger (Forest Ecosystem)
Grass → Insect → Sparrow → Snake → Hawk (Grassland Ecosystem)

1. Detritus Food Chain

The detritus food chain starts from the dead organic matter such as dead
bodies of animals or fallen leaves, which are eaten by microorganisms and
then followed by detritus feeding organisms (detritivores) and their
predators. This food chain has the remains of detritus as the major source
ofenergy, and this process gets completed by the subsoil organisms,
which can either be
macroscopic or microscopic. Thus, these food chains are less dependent on
direct solar energy.
Unlike the grazing food chain, detritus food chain produces a large amount
of energy to the
atmosphere. This type of food chain ensures maximum utilization and
minimum wastage of the available material. It is useful in fixation of
inorganic nutrients and utilizing up to the maximum. For example, the food
chain operating in the decomposing accumulated litter in a temperate forest
ecosystem is a detritus food chain.

Leaf Litter → Bacteria → Protozoa → Small fish → Big fish

Detritus Food Chain

Food Webs
In nature, the food chains never exist as isolated linear sequence; rather they are
interconnected to form a
network called food web. Therefore, a food web can be defined as a network
of food chains
interconnected to each other so that a number of options of eating and being eaten
are available at each trophic level. It was Charles Elton who presented the notion of
food web what he referred to as food cycle (Krebs 2009). In 1927, he recognized
that the length of these food chains was mostly limited to 4 or 5 links and the food
chains were not isolated, but hooked together into food webs. Food web is the real
depiction and illustration of the feeding relationships amongst species in a
community.

It offers an important tool for investigating the ecological interactions that define
energy flows and
predator-prey relationship (Cain et al. 2008). Fig. 5.4 shows a simplified food web in a
desert ecosystem.
this food web, grasshoppers feed on plants; scorpions feed on grasshoppers; kit
foxes prey on scorpions. In addition, the predators of a scorpion in a desert
ecosystem might be a golden eagle, an owl, a roadrunner, or a fox. The analysis of
food web is important to understand ecosystem dynamics.

A simple six-member food web for representative desert grassland.

Types of Food webs
Food webs illustrate the links or connections among species in an ecosystem, but
these connections may differ in their importance in terms of energy flow and
dynamics of species populations. Some trophic relationships are more important
than others in dictating how energy flows through ecosystems. Some connections
are more influential on species population change.
Based on how the species influence one another in a community, American
zoologist, Robert Paine (1980) proposed three types of food webs.
1. Connectedness webs: These food webs depict feeding linkage among species in a
food web. These are also called as topological food webs. These depict only the presence or
absence of a trophic interaction. They, however, do not show the strength of the interaction,
nor any change in trophic relationships. For the above reasons, topological food webs are
sometimes referred to as static food web.
2. Energy flow webs: These quantify energy flow from one species to another. The
connections between populations are quantified on the basis of flux of energy between a
resource and its consumer. In these food webs, the thickness of an arrow reflects the strength
of the relationship.
3. Functional webs (or interaction food webs) : These food webs represent the
importance of each species in maintaining the integrity of a community and reflect influence
on the growth rate of other species populations.
ECOLOGICAL PYRAMIDS
Ecological pyramids are the way to show the structure of ecosystems, the term was first
described by Charles Elton in 1920s in the pioneering studies of ecosystem. In his studies, he
noted that larger organisms higher in food chains were less abundant than smaller ones in
lower trophic levels. Ecological pyramids show the relative amounts of various parameters
(such as number of organisms, energy, and biomass) across trophic levels. They can also be
called as trophic pyramids or energy pyramids. A graphical representation of trophic
structure and function of an ecosystem, starting with producers at the base and
successive trophic levels forming the apex is called as an ecological pyramid.

TYPES OF ECOLOGICAL PYRAMIDS:

1) Pyramid of Numbers, in which individuals at each successive trophic level are counted
per unit area and their numbers are plotted in the form of pyramids.
2) Pyramid of Biomass, in which the total biomass existing at each of the successive
trophic levels is measured in terms of dry weight or caloric value, per unit area and
plotted.
3) Pyramid of Energy, in which energy flow per unit time at each of the successive
trophic levels is measured and plotted. It is also called as pyramids of productivity.
 Pyramid of Numbers in Grassland Ecosystem (Upright)

DEFINITION OF BALANCE IN AN ECOSYSTEM:

A balanced ecosystem signifies a habitat which is sustainable. It consists of animals,
plants, microorganisms and more which depend on each other and their
surroundings.

These ecosystems exhibit resourceful energy and material cycling. It also displays
interconnectedness amid primary producers and predators.

Any balanced ecosystem consists of living as well as non-living organisms who

interact with each other in an environment. The non-living features which are also
called the abiotic features consist of sunlight, temperature, soil, precipitation,
landscape, moisture and more.

Similarly, the living or the biotic features are the plants which are the primary
producers, and herbivores are the primary consumers. Then, comes the secondary
consumers which are carnivores and omnivores. Further, there are detritivores
which consume the decaying organic matter.
Thus, we see how biotic factors depend on the abiotic factors in order to survive.
Similarly, the plants need particular temperature, soil plus moisture for thriving.
Next, animals depend on these plants for food. Therefore, if there is a change or
alteration of any one feature, the balance in an ecosystem gets disturbed.
Impact of Human Activities on Balance in an Ecosystem

Just like any other animal, humans also depend on a balanced ecosystem for a
healthy life. Unfortunately, the activities being carried out by humans is creating a
negative impact on the balance in an ecosystem.

For instance, when humans pollute the abiotic features like water, soil, air and
more. They are degrading the quality of our environment and disrupting the
balance. Similarly, deforestation, land conversion, overfishing, and more impacts
our balanced ecosystem.

However, several good sustainable human activities can restore the lost balance in
an ecosystem. Some of them are the use of biofuels, reforestation, plastic ban,
prevention of burning of fossil fuels and more. So, we must try to adopt practices
which will help in maintaining the balance of our ecosystem rather than degrading
it.

HUMAN ACTIVITIES
With the development of science and technology, man continued to plunder natural
resources and polluted the environment. The craze of progress in industry,
agriculture and transportation has jeopardized the existence of man himself. Today
man equipped with a variety of skills and superior technology has ruined the
natural environment without understanding the rebounding repercussions even on
his own existence.

Instead of sparkling blue and white jewel, the biosphere now seems dull and dark
swirling with clouds of pollutants. Now numerous issues like ecological imbalance,
ozone hole, acid rain, CFC’S and global warming have been raised. We find
warnings everywhere as air unfit for breathing, water unfit for drinking, vegetables
unfit for eating and so on. Some human activities are as below.

FOOD
The need of increased food production as a result of global population explsion led
to manipulation of land resources causing a stress in the natural environment. The
food production and protection technologies are, however so interwoven and
interdependent that it is impossible to visualise a shoot up in crop production
individually. The use of pesticides helped in the eradication of diseases, pests and
in boosting crop production. But the pesticides endangered our life by acutely
affecting man, animals, plants, soil as well as aquatic biota. In a nutshell, if we
continue to rely upon broad spectrum of pesticides for crop production, the
recovery of natural forms of control wil become almost impossible.

SHELTER
Shelters for human living are increasing exponentially with the increasing
population. A good share of land which once was cropland, wetland, forest or fallow
land has been converted to concrete shelters adversely affecting the ecosystem.

ECONOMIC ASPECT
Man, in his pursuit of economic growth is upsetting the environmental equilibrium
and destroying his own life support system. Development in any region be made in
a holistic manner by optimal use of existing and potential resources in the
biosphere for the ultimate improvement of human well being.
SOCIAL SECURITY
Simple reforms of societies, with limited needs have secure and sustainable life
styles. Rapid changes towards a more consumeristic life style and increase in
various types of wastes makes the human life socially insecure.

AGRICULTURE
Modern agricultural techniques which are geared towards bumper crop production
to meet the evergrowing demands of rapidly increasing population are exploring
new agro-technologies to feed the masses. With the extensive use of
agrochemicals, the world is heading towards a complex array of

environmental problems more severe than ever before.

Fertilizer enriched soil can not support microbial flora. Hence there remains poor
humus and less nutrients while the soil can readily become eroded by wind and
water. So the question is: Why fertilizers are used to improve the quality of food
stuffs? Do they harm or benefit the soil?

• It is reported that there is a 30% decline in protein and carbohydrate content when
corn, maize, gram and wheat crops were grown on soils fertilized with NPK fertilizers.

• Potassium fertilizers in soil decreases the valuable nutrient ascorbic acid (vitamin C) and
carotene in vegetables and fruits. Fertilized soil produces bigger sized vegetables and fruits
which are more prone to pest, insects and diseases.

•Excessive use of nitrogenous fertilizers, caled' the miracle drug of farming, lead to
accumulation of nitrate in the soil which are transferred to man through plants. Nitrates,
being highly soluble, go into drinking ground water and become toxic when its concentration
exceeds 90 ppm., In human body these nitrates and nitrites are converted to nitrisoamines
and nitroso compounds which are suspected as agents of stomach cancer.

 Nitrate in water causes cyanosis (blue jaundice) in children and methemoglobinemia or

blue baby syndrome in infants where nitrite interferes with oxygen carrying capacity of blood.
 Nitrate poisoning in animals have been reported due to consumption of vegetation grown in
nitrate rich soil. According to H.H. Koepf, an eminent soil chemist, modern agriculture can
honestly claim two notable crops-disease and pest but now a third factor (nitrate, nitrite
fertilizers) can be frequently added to soil contaminants.
• Phosphatic fertilizer like DAP (that of P 2O5) is considered detrimental to crop production.
It may lead to Fe, Cu and Zn deficiency in plants. • Cereal crops like jawar, maize and pearl
milet grown onalkaline sail absorb higher amounts of fluorides and responsible for the spread
of fluorosis.
• Excess use offertilizers intensively reduces the ability of plants to fix nitrogen.

Though some pesticides (DDT) are banned, they still show small doses in foods.
Increasedproductivity of crops leads to greater dependency on agrochemicals
creating new problems to be faced in future.
HOUSING
The increase in population increased the demand for housing and dwelling units.
Due to increased human activities, more and more forest land and agricultural
fields are occupied for constructing houses and factories. .

• Housing degraded the land and shrunk the space for other living creatures.

• Ecosystems are destroyed in construction activities.

• Since the land is not available, shallow lakes, ponds and other low lying areas are filled up for
housing.

• Migratory birds that visit these ponds are also affected as they lose a major source of food and
shelter.

• Most severe effect of housing is that any river passing by an urban settlement gets badly
polluted.

INDUSTRY
Industrialisation by man brought an overall change in circumstances accompanying
a society's movement, population and resources from farm production to
manufacturing production and associated services.

• Industries generate a variety of chemicals which are extremely toxic. Industries

manufacturing paper, textile, pesticides etc. release metallic wastes, oils, greases, solvents,
plastics, plasticizers, suspended solids, non-biodegradable materials in the soil.
Consequently these toxicants are transferred to different organisms in their food chain
causing a number of undesirable effects.

• Industrial effluents when discharged through sewage system will poison the biological
purification mechanism of sewage treatment causing several soil and water borne diseases.

• Industrial metallic contaminents (e.g., Hg, Pb, Zn, As, Cd) destroy bacteria and beneficial
micro-organisms in the soil.

• Severe agricultural crop damage is caused by high acidity and alkalinity of the soil
coming from chemical industries.

• Products of industries, such as synthetic fibres, plastics and waste paper when
consigned to incineration, their emissions may contaminate with toxic vapours and
particulates causing air pollution. When discarded plastic materials, textile packagings and
toys of polyvinyl chloride are burnt in soil, they emit highly toxic gases SO2 and NO2 etc.

MINING MAN AND MINING ACTIVITIES

Mining is done to extract minerals (or fossil fuels) from deep deposits in soil by
using surface mining. India is the producer of 84 minerals, the annual value of
which is Rs. 50,000 crores.
Mining has created some of the largest environmental disaster zone in the world.
Six major mines in India causing severe problems are listed below.

(i) Jaduguda uranium mine, Jharkhand. Exposed local people to radioactive hazards.

(ii) Jharia coal mines, Jharkhand. Underground fire leading to land subsidence and forced
displacement of people.
(iii) Sukinda chromite mines, Orissa. Seepage of Cr (VI) into river. Chromium is
highly toxic and carcinogenic.

(iv) Kudremukh iron ore mine, Karnataka. Causes river pollution and threat to biodiversity.

(v) East coast bauxite mine, Orissa. Land encroachment and issue of rehabilitation unsettled.

(vi) North-eastern coal fields, Assam. Very high sulphur contamination of groundwater.

IMPACTS OF MINING
1. Devegetation of landscape. Soil damage during surface mining is inevitable as it leads
to loss of grazing and fertile land, soil erosion, sedimentation, damage to flora and fauna.
Open cast coal mining alone eroded 2,00,000 hectares of fertile land.

2. Subsidence of land. Underground mining causes subsidence of land which results in

tilting of buildings, cracks in houses, buckling of roads and bending of rail tracts.

3. Groundwater contamination. Mining disturbs the natural hydrological cycle. Acid mine
drainage from sulphur bearing minerals leaches toxic metals to ground water.

4. Surface water pollution. Cyanide solution from gold mining severely pollute surface water.

5. Air pollution. Smelting results in emission of particulates, NO, SO2, CO, thereby causing
global warming, acid rain and climatic changes.

6. Dust and noise pollution, is caused during loading, crushing and drilling operations.

7. Ecological damage. Miningleads to erosion of natural biodiversity.

8. Mining displace people from their resource base.

TRANSPORTATION
Transport is a good consumer of both land and energy. Transport consumes 30% of
world's energy (of which 82% is consumed on roads) and produces CO, NO,
particulates and hydrocarbons.

But there is hope of new cleaner transport in future. Several cars now run on
ethanol/petrol mixture and CNG. Use of leaded petrol has curtailed lead emission
by 87%. Auto-emissions have also been cleaned up.
ENVIRONMENTAL IMPACT ASSESSMENT (EIA)

Objective of EIA:

The objective of EIA is to identify, predict and evaluate the economic,

environmental and social impact of development activities and taking
necessary steps as a remedy as part of the overall environmental
management plan (EMP). EIA is widely accepted as a tool to ensure sustained
development with minimal environmental degradation.

First Environmental Legislation. The first comprehensive environmental

legislation in United States came into force on 1st January 1970 in the form of
National Environmental Policy Act (NEPA). In India, the Central Ministry of
Environment and Forests issued a Notification on 27th January, 1994 making EIA
statutory for 29 specified activities falling under sectors such as industries,
mining, irrigation, power, transport etc.

This Notification was amended on 4th May, 1994 and the amended version
includes a self explanatory note detailing the procedure for obtaining
environmental clearance, technical information, documents required to be
submitted for getting environmental clearance from the Ministry of Environment
and Forests.

Key Elements of ElA Process:

• First step in ElA process is to determine whether the project falls within the
Jurisdiction of the relevant Acts.

•Whether the project is likely to create any environmental disruption?

• If so, an EIA is undertaken and the Environmental Impact Statement (EIS) is prepared.

• Decision is t a k e n to accept or reject the project.

Participants in ElA Process:

The following persons/groups/agencies are involved.

1. Proponent. Government or Private agency which initiates the project.

2. Decision maker. Designated individual or group.

3. Assessor. Agency responsible for the preparation ofEIS.

4. Reviewer. Individual/Agency/Board.

5. Expert advisers, Media and Public, Environmental organisations etc.

Design of ElA:
Important aspects that should be considered for the design of an EIA process are
listed below.

• Project design and construction.

• Project operation.

• Site characteristics.

• Possible environmental impacts.

• Socio-economic and socio-political factors.

• Availability of the information and resources.

Importance of ElA
• It is the Government policy that any industrial project has to obtain EIA clearance
from the Ministry of Environment before approval by the Planning Commission.

• EIA is a potentially useful component of good environmental management.

SUSTAINABLE DEVELOPMENT
The World Commission on Environment and Development (the Brundtland
Commission) in its report to the United Nations in 1987 defined sustainable
development as meeting the needs of the present without compromising the
ability of future generation to meet their own needs.

Agenda 21, adopted during the United Nations Conference on Environ- ment
and Development (UNCED) called Earth Summit held in Rio de Janeiro in
Brazil in 1992 is a blue print on how to make development socially,
economically and environmentally sustainable.

For sustainability to occur, technological advances in process control,

product design and monitoring are essential for efficient use of resources

while simultaneously abating pollution. The ultimate objective is the quest

for zero emissions from the industrial processes.

Important Components of Sustainable Development.

• Population stabilisation.

• Conservation of biodiversity.
• Air, water, soil pollution prevention and control.
• Renewable energy resources.
• Renovation, recycling and reuse of wastes.
• Environmental education and awareness at all levels.

Sustainability is thus effecting a balance between stability, equity and diversity.

Sustainable Environmental Programmes

The new strategies are :

Pollution Prevention

It is a multimedia management approach to pollution to front-end r e d u c t i o

n of pollutants in waste streams by strictly controlling industrial processes.
Pollution prevention also eliminates transfer of pollutants from one media to
another because pollutants are not generated in the first place. Raw materials
are used more efficiently and also the costs of waste disposal and clean-up are
avoided.

Design of Environment

While synthesizing a chemical substance, all the scientific, environmental and

economic impacts should be incorporated to ensure environmentally benign
synthesis.

Future challenge is to switch over from the present pollution control policy and
Government regulations to a new more realistic pollution prevention policy
based on source reduction, recycling and reuse of wastes.

Industrial Ecology

Industrial ecology is based upon an analogy of industrial systems to natural

ecological systems achieving sustainability. An industrial complex established
in Kalundborg, Denmark provides an excellent example of industrial ecology
concept.

Green Chemistry

Green chemistry is the use of chemistry for sustainable development and

pollution prevention by environmentally-conscious design of chemical products
and processes that eliminate the use or generation of hazardous substances.
Basic principles of Green Chemistry involve-

• Prevention of chemical waste.

• Designing less hazardous, safer chemicals, solvents and auxiliaries. • Designing energy
efficient synthetic routes.
• Using renewable feed stocks.
• Producing innocuous degradation products.
Preventive Environmental Management (PEM)

PEM involves elimination of wastes and pollutants at their source rather than at
the end-of-the pipe stage. The principles of PEM are as follows.
• Prevention ofpollution at source.
• Recycling and treatment in a safe manner.
• Disposal, a last resort, should be done in an environmentally benign manner.

Government Efforts to Attain Sustainability

Governments, political forces at international, national and local levels have a
pivotal role in achieving the goal of sustainability.
• Agenda 21 is a blue print to achieve sustainable development.
• European Union in 1992 adopted its fifth Environmental Action, Programme called
Towards Sustainability.
• In 1999, the Amsterdam Treaty enshrined sustainable development as one of the
core programmes of the European Union.
• In June 2001, the Gothenburg European Council" adopted the Commission’s
Sustainable Development Strategy.