Environmental Studies Lecture Notes PDF

Environmental Studied B.com Asst. Prof : Hemantha kumara v LECTURE NOTES ON ENVIRONMENTAL STUDIES Prepared by...

Environmental Studied B.com Asst. Prof : Hemantha kumara v LECTURE NOTES ON ENVIRONMENTAL STUDIES Prepared by Hemantha kumara v Assistant Professor S.E.T. Degree College , Bangalore - 560079 1 Environmental Studied B.com Asst. Prof : Hemantha kumara v UNIT – I ENVIRONMENT AND ECOSYSTEMS ENVIRONMENTAL STUDIES Introduction: Environment is derived from the French word ―Environ” which mean ―encircle or surround‖ Environmental Studies deals with every issue that affects an organism. So, Environment refers to surroundings which vary from place to place and continent depending upon Physiography, Topography, Climate and the available Natural resources. Since the beginning of the culture, the natural resources such as Soil, Land, Water etc are being over-exploited causing the environment gets polluted or degraded. This has resulted in multi – dimensional environmental crisis like soil erosion, landslides and in turn have created soil pollution, air pollution, water pollution, noise pollution etc. Definition: The sum total of all surroundings of a living organism, including natural forces and other living things, which provide conditions for development and growth. Importance of Environment: 1. Environment is concerned with day – to – day interaction with the surroundings with which human being is closely associated. 2. Environmental Science is related to many branches of Sciences 3. Environment is concerned with the importance of wild life and its protection. 4. Environmental Science explains the significant role of biodiversity in establishing ecological balance. 5. Environmental Science gives information relating to Population growth, Population explosion and impact on Population growth. Environmental Science also gives information about water conservation, watershed management and the importance of water Introduction of Ecology: The term ―Ecology‖ was derived from Greek words viz., Oikes means house or place and logs means a discussion or study. So, ecology is the scientific study of the distribution and the interactions between organisms and their natural environment. The environment (surroundings ) consists of: living organisms ( biotic ) and non-living things ( abiotic ) such as physical components of wind, temperature, rainfall, water, humidity , light, soil etc and chemical components of C,H,N,K,P,S etc..(in-organic components) and carbohydrates, proteins (organic components). Hence, Ecology involves studying the ecosystems. According to George Jackson, an Ecosystem is a natural unit consisting of all plants, animals and micro- organisms in an area functioning together with all of the non-living things. An ecosystem is the smallest unit of biosphere that has all the characteristics to support life. Pond ecosystem, forest ecosystem, desert ecosystem, marine ecosystem, urban ecosystem are some of the examples for ecosystems. An ecosystem varies in sizes from a few square kms to hundreds of square kms. Similarly an ecosystem may be temporary like a fresh pool / agriculture field or permanent like a forest / ocean. 2 Environmental Studied B.com Asst. Prof : Hemantha kumara v Scope of ecosystem: Ecology plays an important role in agriculture crop rotation, weed control (unwanted land); management of grasslands, forestry etc., biological surveys, fishery surveys, conservation of soil, wild life, surveys of water bodies like rivers, lakes; ponds etc... Concept of ecosystem: In an ecosystem, the interaction of life with its environment takes place at many levels. A single bacteria in the soil interacts with water, air around it within a small space while a fish in a river interacts with water and other animals, rivals in a large space. Considering the operational point of view; the biotic and biotic components of an ecosystem are so interlinked such that their separation from each other is practically difficult. So, in an ecosystem both organisms (biotic communities) and a biotic environment (rainfall, temperature, humidity) each influence the properties with other for maintenance of life. Types of Ecosystems: Ecosystem may be natural or artificial. Artificial Ecosystem: These are maintained or created artificially by man. The man tries to control biotic community as well as physico chemical environment. Eg: Artificial pond, urban area development. Natural Ecosystem: It consists of Terrestrial and Aquatic Ecosystems which are maintained naturally. Terrestrial Ecosystem: This ecosystem relates to biotic components living on the land. Vegetation dominates the community and the types of vegetation affect the climate, soil structure & a rapid exchange of O2, water & CO2 Aquatic Ecosystem: This ecosystem relates to biotic community living in water. The types of water (fresh water, saline water, polluted water) dominate and affect the pH of water, depth of water, temperature of water etc. Aquatic ecosystem has been sub-divided into fresh water and saline water based on the quality of water. Sturcture & Function of Ecosystem The two major aspects of an ecosystem are: (1) Structure and (2) Function together they illustrate the organization of an ecosystem. The Structure of an ecosystem consists of: Abiotic structure includes the non-living things of the ecosystem such as physical factors (soil, temperature, light & water) and chemical factors consisting the inorganic compounds (N, C, H, K, P,S) & organic compounds ( carbohydrates, proteins). Biotic structure includes plants, animals & microorganisms present in an ecosystem form the biotic component. These organisms have different nutritional behavior and status in the ecosystem and are known as Autotrophs Producers), Heterotrophy (Consumers) & Micro- consumers (Decomposers) based on how they get their food. Hence, the structure of an ecosystem comprises: (a) The composition of biological community species (plants, animals, microorganisms), their population, life cycles, distribution in space etc. 3 Environmental Studied B.com Asst. Prof : Hemantha kumara v (b) The quantity and distribution of non-living things such as soil; water etc. (c) The range or intensity of conditions like temperature, light, rainfall, humidity, wind & topography plays a major role in the structure of ecosystem. Function of ecosystem means how an ecosystem works/ operates under natural conditions. The rate of biological energy flow ; the rate of nutrient cycles ie Bio- Geo-Chemical cycles and Ecological regulation ( means regulation of organisms by Environment and regulation of Environment by organisms ) plays a major role in the function of an ecosystem 1. Autotrophic components (Producers): Autotrophic means self nourishing. Since these organisms are self nourishing, they are also called producers. Eg: Algae, Green plants, Bacteria of photo synthetic. Green plants prepare their food themselves by making use of CO2 present in the air & water in the presence of sunlight through the process of photosynthesis. CO2 + 2H2O →CH2O + O2 + H2O ( Carbon dioxide ) ( Water )( Carbohydrates ) ( Oxygen ) (Water ) A few micro-organisms which can produce organic matter (nutrients) to some extent through oxidation of certain chemicals in the absence of sunlight known as chemo autotrophs. Eg: In the Ocean depths, where there is no sunlight, chemo-autotrophic bacteria make use of the heat generated by the decay of radioactive elements for preparation of their food. 2. Hetero-trophic components (Consumers): Hetero-trophic means dependent on others for nourishment directly or indirectly upon the utotrophs (producers) for their food. These are of the following types: a. Herbivores (Primary consumers): These animals feed directly on living plants or remains of plants. Eg: Rabbits, Deer‘s, Insects. b. Carnivores (secondary consumers): These carnivores (flesh eating) feed on the herbivores. Eg: Snakes, birds, Lizards, fox. c. Tertiary consumers (or) Tertiary carnivores: These feed on the primary & secondary consumers. Eg: Lions, Tigers. d. Omnivores: These consumers feed on both plants & animals. Eg Human beings, Birds (hawk) 3. Decomposers or Micro consumers: They feed on organic compounds of dead or living plants and animals for their food and energy. They absorb some of the products from decomposed material and release organic compounds (nutrients) making them available to producers. Eg: Bacteria, Fungi, and Flagellates. The decomposers are also called as ―Saprotrophs‖. Food Chain: The transfer of food energy from the producers (plants) through a series of organisms (Herbivores, Carnivores) successively with the repeated activities of eating and being eaten is known as food chain. In an ecosystem(s), one organism is eaten by the second who in turn is eaten by the third and so on... This kind of feeding relationship is called food chain. Examples of food chain: 1. Grass→ Grasshopper→ Frog→ Snake→ Hawk. 2. Grass→ Mouse→ Snake →Hawk. 4 Environmental Studied B.com Asst. Prof : Hemantha kumara v 3. Grass→ Rabbit→ Man. 4. Grass→ Mouse→ Hawk. 5. Plant leaf →Caterpillar →Sparrow →Hawk. Explanation: A caterpillar eats a plant leaf, a sparrow eats the caterpillar, and a hawk eats the sparrow. When they all die, they are all consumed by micro organisms like bacteria (or) fungi which break down the organic matter and convert it into simple inorganic substances that can again be used by the plants. In nature, there are two basic types of food chains viz: 1. Grazing food chain and (2) Detritus food chain Grazing food chain: This food chain starts with green plants (primary producers) and goes to herbivores and on to carnivores. 1. Phytoplankton‘s→ Zooplanktons →Small fish→ Tuna. 2. Phytoplankton‘s→ Zooplanktons→ Fish→ Man. 3. Grass→ Rabbit→ Fox→ Tiger. Detritus food chain: This food chain starts from dead organic matter (dead leaves/ plants / animals) and goes to Herbivores and on to Carnivores and so on….. Leaves or dead plants→ Soil mites→ Insects→ Birds. Dead organic matter→ Bacteria → Insects. Dead leaves → Algae→ Fish→ Man. 5 Environmental Studied B.com Asst. Prof : Hemantha kumara v FOOD WEB:Food web is a net work of food chains where different types of organisms are connected at different trophic levels so that there are a number of options of eating and being eaten at each trophic level. (A trophic level refers to an organism‘s position in the food chain). 1. Grass→ Grasshopper→ Hawk 2. Grass→ Grasshopper→ Lizard→ Hawk 3. Grass→ Rabbit→ Hawk 4. Grass→ Mouse→ Hawk 5. Grass→ Mouse→ Snake→ Hawk ECOLOGICAL PYRAMID: Ecological pyramids were first studied by a British ecologist Charles Eltan (1927). An Ecological Pyramid is a graphical representation consisting varioustrophic levels with producers forming the base and top occupy the carnivores. In an ecological pyramid the huge number of tiny individuals form at the base and a few large individuals occupy the top / apex. This formation is known as ecological pyramid. Hence, all producers (micro & macro plants) belong to the I trophic level; all primary consumers belong to II trophic level and organisms feeding on these consumers belong to the III trophic level and so on. The ecological pyramids are of three types. They are: 1. The pyramid of Numbers (showing population). 2. The pyramid of Biomass (showing total mass of organisms). 3. The pyramid of energy (showing energy flow). 6 Environmental Studied B.com Asst. Prof : Hemantha kumara v 1. The pyramid of Number: It shows the relationships among the producers, herbivores and carnivores at successive trophic levels in terms of their number. Mostly the pyramid of number is straight (or) upright with number of individuals in successive higher trophic levels goes on decreasing from base to apex. The maximum number of individuals occurs at the producers‘ level. They support a small number of herbivores. The herbivores, in turn, support a fewer number of primary carnivores and so on….. Top carnivores are very few in number. For Example: (1) In a grass land ecosystem: Grass→ Grasshoppers→ Frogs→ Snakes→ Peacock / Hawk. (2) In a pond ecosystem: Phytoplankton→ Zooplankton→ Fish→ Crane The pyramids may be inverted in a few cases: A single plant may support the growth of many herbivores and each herbivore in turn provides nutrition to several parasites which support many hyper-parasites. Thus, from the producer towards consumers, there is a reverse position i.e., the number of organisms gradually shows an increase making the pyramid inverted in shape. (3) In a Forest ecosystem: Tree→ Birds / deer →Parasites→ hyper parasites Tree→ Birds→ eagle 7 Environmental Studied B.com Asst. Prof : Hemantha kumara v 2. The Pyramid of Biomass: The amount of organic matter present in environment is called biomass. In pyramids of biomass, the relationship between different trophic levels is mentioned in terms of weight of organisms. The pyramid may be upright for grassland ecosystem and inverted for pond ecosystem. Example: Vegetation produces a biomass of 1000 kg. Out of this 100 kgs of biomass for herbivores, which in turn only 10 kg of biomass for primary carnivores that gives rise 1 kg of biomass for second order carnivores and so on… 1000 kgs 100 kgs 10 kgs 1 kg Vegetation Herbivores primary carnivores Secondary carnivores Hence, a vegetarian diet can support a larger population than a Non – vegetation diet. 3. The pyramid of energy: The amount of energy trapped per unit time and area at different trophic levels of a food chain with producers forming the base and the top carnivores 2 at the apex is 2called pyramid of energy. The energy content is generally expressed as K cal /m / year or KJ / m / year. 2 Large Fish ---126 KJ / m / year 2 Small Fish ---- 840 2 – 126 KJ / m / year Zooplankton ---- 7980 KJ / m / year Phytoplankton (producers) -- 2 - 31080 KJ / m / year Energy flow /Transformation of energy in Ecosystem The movement of energy (or) transfer of energy through a series of organisms in an ecosystem from the external environment and back to the external environment again is known as energy flow. In the universe, the main source of energy is SUN that produces energy in the form of light 8 Environmental Studied B.com Asst. Prof : Hemantha kumara v or solar radiation. Different ecosystems in the world receive variable quantities of solar energy depending upon their location on the globe. The other chief factors that control the amount of solar energy received by an ecosystem are Latitude and Longitude; Slope; Cloud formation; 9 Environmental Studied B.com Asst. Prof : Hemantha kumara v Pollutants in the atmosphere The transformation of energy in an ecosystem begin first with the input of energy from the sun by the process of photosynthesis. Carbon dioxide is combined with Hydrogen (derived from the splitting of water molecules) to produce carbohydrates (CH2O) and the energy is stored in the high energy bonds of Adenosine Tri Phosphate (ATP). Herbivores obtain their energy by consuming plants or plant products, Carnivores eat herbivores and micro-organisms consume the droppings and carcasses (dead bodies). In an ecosystem, the utility of energy is taken place in the following manner: The sun provides heat to maintain the required temperature in which proper Physical andchemical processes can take place. Certain bacteria obtain useful energy by oxidation of a few elements such as sulphur and iron. Bio – Geo-Chemical Cycles: In every ecosystem sunlight or solar radiant energy is accepted by producers (green plants) and the energy doesn‘t recycle through an ecosystem. But nutrients like Carbon; Nitrogen; Oxygen, Hydrogen; Water, Sulphur, Phosphorous etc move in circular paths through biotic and abiotic components and they are known as Bio-geochemical cycles. About forty chemical elements are considered to be essential for living organisms. They are macronutrients of C, H, O, P, K, I, N, S, Mg, Ca etc.. and micro nutrients of Cu, Fe, Co……While all inorganic nutrients have cycles, we focus on the following: WATER CYCLE CARBON CYCLE NITROGEN CYCLE PHOSPHOROUS CYCLE The Water Cycle Or Hydrologic Cycle: Due to the solar heat, water evaporates or water is lost to the atmosphere as vapor from the seas / oceans which is then precipitated back in the form of rain, snow, frost etc.. The evaporation and precipitation continues for ever, and thereby a balance is maintained between the two. This process is known as Hydrologic cycle. 10 Environmental Studied B.com Asst. Prof : Hemantha kumara v Carbon Cycle: All life is based on the element carbon and hence carbon is the main constituent of living organisms.. Carbon may be present in most organic matter from fossil fuels to the complex molecules (DNA & RNA). In fact, the lithosphere is only 0.032% carbon by weight. In comparison, oxygen and silicon make up 45.2% and 29.4% respectively of the earth‘s surface rocks. Plants absorb CO2 during photosynthesis whereas animals emit CO2 during respiration. Animals obtain all their carbon through their food and thus, all carbon in biological systems ultimately comes from plants (autotrophs). The dead bodies of plants and animals as well as the body wastes are decomposed by micro-organisms which release carbon in the form of CO2. Even plant debris if buried a longer time cause for the formation of coal, oil, natural gas and these releases carbon when they burned. Otherwise, the carbon in limestone or other sediments released to the atmosphere when they are subducted (using forces) or undergo chemical reactions. The weathering of rocks also contribute CO2 into the environment. NITROGEN CYCLE: Nitrogen is used by living organisms to produce a number of complex organic molecules like Amino acids; Proteins ; Nucleic acids ; Enzymes; Chlorophyll etc.. The largest reservoir of nitrogen is the atmosphere where it exists as a gas mainly N2. But atmospheric nitrogen is not utilized directly. However, nitrogen gas undergoes many changes in the nitrogen cycle like: Nitrogen Fixation, Ammonification, Nitrification. Nitrogen fixation or conversion of free nitrogen into biologically acceptable form is referred to as Nitrogen Fixation. N2 + 2(O) −electric discharge → 2 NO Nitrogen gas oxygen radical nitrogen oxide In physico chemical process; nitrogen combines with oxygen during lightning or electrical discharges in the clouds and produces different nitrogen oxides (N2O5). These nitrogen oxides get dissolved in rain water and react with mineral compounds to form Nitrates and Nitrogenous compounds on the earth. N2O5 + H2O → 2HNO3 2HNO3 + CaCO3 → Ca (NO3)2 + CO2 + H2O Nitrogen fixation is also carried out by biological process by means of blue – green algae in the oceans. Examples: Rhizobium bacteria fix nitrogen in the roots of Leguminous plants Blue – green algae ( Nostoc, Anabena ) fix Nitrogen. 11 Environmental Studied B.com Asst. Prof : Hemantha kumara v Ammonification: when plants or animals die or release waste, the nitrogen is returned to the soil as ammonia. The bacteria ( nitrite bacteria ) in the soil and in the water which take up ammonia and convert it to Nitrite ( NO2). Another bacteria ( Nitrate bacteria ) take nitriteand convert it to Nitrate (NO3) which can be taken up by plants to continue the cycle. Nitrification means conversion of ammonia into nitrite by some of the bacteri as such as Nitrosmonas, Nitrococcus in oceans and soils. Phosphorus cycle: Phosphorus cycle is the circulation of phosphorous among the rocks, soils, water, and plants and animals of the earth. Human beings and all other organisms must have phosphorus to live. In nature, most phosphorus occurs in phosphate rock, which contains phosphate ions combined with calcium, magnesium, chlorine, and fluorine. It cannot be found in air in the gaseous. This is because phosphorous is usually liquid at normal temperatures pressures. The cycle basically starts out in the earth‘s soil. The soil contains phosphate and when something grows out of the soil it should have phosphate as well. When the plants grow they are consumed by herbivore and omnivore animals. The animal‘s waste or the animal‘s body when it dies becomes detritus. Detritus is non-living organic material. When the detritus goes deep into the soil, detrivores in the soil decompose and become the soil‘s phosphate and the cycle repeats. Phosphorus cycle 12 Environmental Studied B.com Asst. Prof : Hemantha kumara v Biomagnification:  Biomagnification is also known as bioamplification or biological magnification. Increase in the concentration of a pollutant as it passes from one trophic level to the next.  Small amount in environment → Large concentration at top of food chain. Biomagnification of DDT (Dichlorodiphenyl trichloroethane): DDT sprayed for pest control was in very low concentration, but it‘s concentration increased along the food chain through phytoplanktons to zooplanktons and then to fish which was eatenby the birds. The concentration of DDT was magnified several thousand times in the birds, which caused thinning of shell in the birds eggs causing death of the young ones. It becomes very clear from the above instance that the animals occupying the higher trophic levels are at a greater risk of biomagnifications of toxic chemicals. Human beings consuming milk, eggs and meet are at a higher trophic level. Therefore, we have to stop indiscriminate use of pesticides and heavy metals if we wish to save ourselves from their biologically magnified toxic levels. In order for biomagnification to occur, the pollutant must be: 1. Long-lived 2. Mobile 3. Soluble in fats 13 Environmental Studied B.com Asst. Prof : Hemantha kumara v AQUATIC ECOSYSTEM: Eco system that exists in water is known as aquatic ecosystem. Water is the primary requirement for life in biological community. The aquatic ecosystems range from a small pond to a large ocean. Varying quantities of nutrients are carried from terristrial ( land ) ecosystem by the movement of water and deposited in aquatic ecosystems. The life in aquatic communities is influenced mostly by physical factors like: Water depth Amount of light Temperature Salinity of water Amount of oxygen and Carbondioxide. Aquatic ecosystems are broadly classified into fresh water and marine water ecosystems. In some regions, the marine and fresh water environments overlaps creating ―Estuaries‖. Fresh Water: Eg: lakes, ponds streams, rivers water Marine: Eg: salt lakes, seas, oceans Estuaries: Eg: water bodies mix of fresh & sea I. Ponds & Lake Ecosystems: A pond is a small area of still water, especially is artificial whereas a lake is a large area of water body and the water is natural. The life span of ponds range from a few weeks or months and whereas the life span for lakes depend upon their location, size and depth. Depending upon temperature, the upper part of the lake becomes warm and is called eplimnion and the lower part of the lake becomes cold which is called as hypolimnion. These two zones are separated by thermocline zone which acts as a barrier to exchange of material / nutrients within the pond. During rainy season, entire water body gets same temperature due to mixing of water while in non-rainy season very small amount of mixing occurs by surface waves due to wind blow. The non-living ( abiotic ) components of a pond include Heat; light, pH value of water; organic compounds ( water, CO2, O2, Ca, N, P) and living (biotic) components of Autotrophs or producers ( green plants, bacteria, rooted plants of Trapa, Typha, Sagi Haria ), Consumers ( Herbivores, insects and large fish ) and micro cosumers ( bacteria, fungi). 2. Stream & River Ecosystems: Rivers and streams are flowing fresh water bodies. Out of all natural ecosystems, rivers are the most intensively used ecosystems by man. The organization of river and stream ecosystem include: Abiotic Components: include volume of water, speed of water flow, dissolved oxygen content, temperature etc. The energy flow usually the organic matter which is being imported from adjacent terrestrial ecosystems. Biotic Components: include Producers ( algae, grass, amphibians ); consumers ( leaches, water insects, snails, fishes, crocodiles, reptiles ) and Decomposers ( bacteria, fungi, protozoa). 3. Ocean or Marine Ecosystems: The marine environment is characterized by its high concentration of salts and minerals. The major oceans of the world are Atlantic; Pacific; Indian, Arctic and Antarctic. These are deep and life extends to all its depths. The sea water contains salt o o content in the form of NaCl and rest are Mg, Ca, K. Temperature ranges from 0 to 30 C and pressure of 1 ATM at surface and 1000 ATM at bottom of oceans. The ocean ecosystem consists of the following; Biotic components of Producers (phytoplanktons, marine plants, Ruppia, Zostera, Halophile are true marine angiospers), Consumers of Molluscas, fishes and Decomposers of bacteria and Fungi. 14 Environmental Studied B.com Asst. Prof : Hemantha kumara v Abiotic components include Na, Cl, Mg, Ca, Sulphur, Dissolved oxygen content, light, temperature, pressure variations etc. 4. Estuarine Ecosystem: Estuary is the area at the mouth of the river joins the sea and continents. It has a free connection with the open sea and is thus strongly affected by tidal action. Estuaries are mixed with fresh water from land drainages. River mouth, coastal bay etc are the examples for estuarine ecosystem. Estuaries are one among the naturally fertile in the world. The components of estuarine ecosystem are given below: Abiotic components: Estuaries have their own ecological characteristics. Physical factors such as salinity, temperature, tidal activity etc are variable in estuaries when compared to the sea or ocean. Biotic components include Producers, consumers and Decomposers. Producers: Three major life forms of Autotrophs play a significant role in grass production. They are (c) macrophytes ( sea weeds, sea grass, spartina,Thalassia, marsh grass, nagrove trees ) (d) Phytoplankton and (e) Benthic flora (algae). Consumers include a number of zooplankton, oysters, crabs and some species of fishes capable of surviving in estuarine conditions form primary, secondary, tertiary consumers of the estuarine ecosystem. Decomposers include bacteria and fungi which actively take part in the breaking down the complex and dead organic matter (Fungi of actinomycites ). FOREST ECOSYSTEM Introduction: Forest is a type of terrestrial ( land ) ecosystem. It consists of trees, shrubs or woody vegetation occupying an extensive area of land. Forests are important renewable resources. A different types of forests are seen on this earth. The type of forest depend upon its geographical location and environment factors ( Temperature and moisture ) that influence the kind of vegetation that occur in an area. Types of forests: 1. Savannas: These forests develop where a seasonal rainfall occurs. The grass lands of North Africa are known as savannas. Eg: North Africa, America, Burma & India. 2. Tropical forests: These exits in areas of good rainfall (>200cm per year) with uniform warm temperature. The Soils found in there forests are old, acidic in nature & poor in nutrients. Eg: Amazon rain forest (South America, India). 3. Deciduous forests (or) Temperate forests: Deciduous forests consists of broad leaved trees & occur where rainfall is plenty (750 - 1000 cms per year). Eg: Europe & North-East America. 4. Coniferous forest: These occur in areas with long winters with heavy snowfall. In other words, where moisture is limited & rainfall is low. Herbivores (animals eating plants) & insects exist in these forests. Eg: Moscow. (5) Tundras: These are the large flat Arctic regions of Northern Europe, Asia and North America where no trees grow and where the soil below the surface of the ground is always frozen. The growing season is short and plants grow very slowly. Following are the types of forests present in India: 1. Tropical, forests present in Western Ghats of Maharashtra, Karnataka, Kerala. 2. Deciduous forests present at Dehradun, Eastern Ghats of Andhra Pradesh, Tamil Nadu, M.P. 3. Littoral and swamp forests present at Sunderbans in West Bengal and Andaman islands. 15 Environmental Studied B.com Asst. Prof : Hemantha kumara v 4. Tropical Thorn forests present in New Delhi, Punjab and Gujarat. 5. Mountain wet temperature forests present at Nilgiri and Palani hills. 6. Alpine scrub forests present at Ladakh and Sikkim. The characteristic features of a forest ecosystem are as follows: Abiotic components include inorganic and organic compounds and dead organic debris. Further, the natural light conditions are different in forests due to complex stratification in the vegetation. Biotic components include Producers, consumers and Decomposers. Producers: These are plants and trees and produce the food through photosynthesis. The dominant species of trees are Quercus, Acer, Betula, Thuja, Picea, Abies, Pinus, Cedrus etc. Consumers: The primary consumers are Ants, beetles, leaf hoppers, bugs, spiders, deers, squirrels etc. The secondary consumers are Snakes, birds, lizards, foxes etc are the examples. The tertiary consumers are lion, tiger, hawk etc. Decomposers include micro organisms like bacteria, fungi etc. Consume the dead or decayed bodies. Tropical rain forests are found in the hot and humid regions near the equator: These regions have abundant rainfall ( 2000 – 4500 mm per year ) that occurs almost daily. These forests are found in South and Central America, Western and Central Africa, SE Asia and some islands of the Indian & Pacific Oceans. These rain forests are marked by a variety of tall trees and a dense canopy. The soils are thin and acidic with poor nutrients. A team of Brazilian scientists conducted a research and found that a forest could return as much as 75% of the moisture it received back into atmosphere. Hence, more trees are meant for more rain. Temperate forests are very cold in winter and warm or humid in summer. These forests grow where the annual rainfall is about 750 – 2000 mm per year and are found in Western and Central Europe, Eastern Asia, Eastern America. Soil is rich in temperate forest areas. Oaks, maples, beech, pine trees, ferns, lichens, mosses etc are found in these forests. Temperate forests contain abundant micro – organisms and mammals (squirrels, porcupines, chipmunks, raccoons, hares, deer, foxes, coyotes, bears. Birds like warblers, wood peckers, owls, hawks are seen. Snakes, frogs are also common these forests. Coniferous forests derive the name from the abundance of coniferous trees like spruce, fir, pine, hemlock etc. Coniferous tree produces dry fruits called cones. In coniferous forests, winters are usually long and cold. The soil in these forests is acidic and humus rich. The main animals found in these forests are deer, moose, elk, caribon, mice, hares, squirrels, foxes, bears and birds. Status of Forests in India: Forest Survey of India (FSI) , Dehradun estimated, the country‘s forest cover as 6,76,000 sq km Of this 6,76,000 sq km; 259000 sq km is open forest, 417000 sq km is covered by dense forest and mangroves occupied 4490 sq kms. Madhya Pradesh accounts for the largest forest cover of the country with 77265 sq km followed by Arunachal Pradesh 68045 sq km and Chhattisgarh with 56448 sq km. DESERT ECOSYSTEM: Deserts occur in regions when the annual rainfall is in the range of 250 to 500 mm and evaporation rate is high. Deserts occupy about 30% of land area on the globe. Deserts are found 30 above north and below south of the equator. Deserts are characterized by extremely hot days and cold nights. The largest deserts are found in the interiors of continents where moisture bearing winds do not reach. The desert soils has very little organic matter but rich in minerals. The desert plants have adapted to the dry conditions and conserve water by having few or no leaves. 16 Environmental Studied B.com Asst. Prof : Hemantha kumara v Examples: (1) A plant namely Saguaro cactus has a stem that can expand to store water (2) Many desert plants have thorns or toxins to protect themselves from being grazed by animals. (3) Some desert plants have wax – coated leaves that minimize the loss of moisture. (4) Some desert plants have deep roots that reach the ground water. (5) A few desert plants have shallow roots that collect water after any rain and store it in spongy tissues. Desert ecosystem is characterized by scanty flora and fauna. The organisms which with stand the extreme temperatures can survive here. Desert animals are usually small in size and come out during the nights for food. Human impact on deserts: Slow rate of growth of vegetation if topsoil is eroded due to heavy vehicle transportation across the desert. Desert cities, depletion of ground water, land disturbance, pollution from mining, storage of toxic wastes are some of the human activities that cause damage. Abiotic components include temperature, rainfall, soil, water etc plays a major role to control the desert ecosystem. Biotic components include producers ( shrubs, bushes, grasses, a few trees and plants namely Cacti, Acacias, Euphorbias ). Consumers of insects, reptiles, rodents of rats & rabbits; birds, camels which are capable of living under desert conditions. Decomposers include Bacteria, Fungi due to poor vegetation and the less quantity of dead organic matter. A Case study of Desert ecosystem: The Thar desert (the Great Indian Desert) is spread over four states in India Punjab; Haryana; Rajasthan and Gujarat and two states in Pakistan. Thar desert covers an area of about 4,46,000 sq kms. Though the Thar desert is smaller than the Sahara desert in Africa and the Gobi desert in Russia, the Thar desert is most populated in the world with about 13 million people. The average rainfall is between 100 mm and 500 mm. The only river in the region is the Ghaggar which enters Rajasthan from Punjab and dries up in the forest. The Thar desert has no Oasis. Flowering plants like shrubs, grasses, trees (Khejra, Babul, Rohida ); fruit trees ( Ber; Pilu ) are found in Thar desert. Sheep, goats, camels are the common animals found in the Thar desert. In addition, wild ass, black buck deer, hare, red lynx, Jackal, Wild dog etc.. About 23 species of Lizard and 25 species of snakes are found in Thar desert region. part, is gleaning insects. The community provides the habitat—the place where particular plants or animals live. Within the habitat, organisms occupy different niches. 17 Environmental Studied B.com Asst. Prof : Hemantha kumara v UNIT-II NATURAL RESOURCES The word resource means a source of supply. The natural resources include water, air, soil, minerals, coal, forests, crops and wildlife are examples. All the resources are classified based on quantity, quality, re-usability, men‘s activity and availability. Classification of Resource Exhaustible Resources: These resources have limited supply on the earth and liable to be exhausted if used indiscriminately. These resources are of two types. (1) Renewable resources: These resources have the capacity to reappear themselves by quick recycling with a reasonable span of time. Eg: forests, wildlife. (2) Non-renewable resources: Resources that exist in a fixed quantity in earth‘s crust are called non–renewable resources. These resources lack the ability of recycling and replacement. Eg: minerals, fossil fuels etc.. A few mineral resources which occur in the earth‘s crust namely copper, aluminum, mercury, gold etc.., minerals of asbestos, clay and mica are considered as non-renewable resources. Fossil fuels are derived from organic matter that accumulated during hundreds of millions of years of early bio-geological history. There is no way of recycling the energy in fossil fuels. Inexhaustible Resources: These resources are present in unlimited quantity in the nature and they are not likely to be exhausted by human activities. Eg: solar energy, wind power, tidal power, rain fall, atomic energy etc… It is very important to protect and conserve, the natural resources. Natural resources are to be used in a judicious manner so that they cannot be exhausted. It doesn‘t mean that we should stop using them. Natural resources are to be used in such a way that we can make use for future generations. Among the natural resources, Water resources; Mineral resources; Energy resources; Land resources are the major ones to discuss. WATER RESOURCES Hydrologic Cycle: The continuous circulation of water from land, water bodies etc., which joins the atmosphere and finally condenses into the form of precipitation. A part of water is lost by evapo-transpiration and certain portion percolates into the ground to form ground water reservoir and the remaining water flows on the ground as runoff and joins the streams, rivers and finally into sea. This cycle is continuously repeated. Water is the main constituent of hydrosphere & is renewable resource. Water is next to air that man requires for his survival and existence. Water is 18 Environmental Studied B.com Asst. Prof : Hemantha kumara v needed for daily use by organisms, for irrigation, industrial electricity production and domestic use. Hence, water is an important resource in all economic activities ranging from agriculture to industry. The distribution of water resources is not uniform over the earth‘s surface. About 97% of it is salt water in the seas & oceans, 2.6% is trapped in polar ice caps & glaciers. Only 0.4% is available as fresh water. Fresh water occurs mainly in two forms as. 1. Ground water 2. Surface water The distribution of fresh water is geographically uneven varying greatly from country to country & even one region to another region. Uses of water: 1. Domestic use: Water used in the houses for the purposes of drinking, bathing, washing clothes, cooking, sanitary & other needs. The recommended value according to Indian standard specification for domestic use is 135 liters/day 2. Industrial use: Water is required for various industries such as cement, mining, textile, leather industries. 3. Public use: This includes water used for public utility purpose such as watering parks, flushing streets; jails etc. 4. Fire use: Water is used in case of accidents and to prevent the fire issues. 5. Irrigation: To grow crops this is the main sources for food. 6. Other uses: Hydro electric power generation requires water. Effects of over use of ground water: Over use of groundwater has following effects. 1. Lowering of water table: Excessive use of ground water for drinking, irrigation and domestic purposes has resulted in rapid depletion of ground water in various regions leading to lowering of water table & drying of wells. 19 Environmental Studied B.com Asst. Prof : Hemantha kumara v The reasons for shortage of water are: 1. Increase in population, 2. Increasing demand of water for various purposes. 3. Unequal distribution of fresh water. 4. Increasing pollution of water sources cause over exploitation. 2. Ground subsidence: When ground water withdrawal is greater than its recharge rate, the sediments in the aquifer become compacted. This is called ground subsidence which may cause damage of buildings, destroy water supply systems etc. Floods: A Large area of land with water for several days in continuation is called flood. Floods have been regular features of some parts of India & Bangladesh. Floods are caused by both natural as well as human factors. The (i) anthropogenic activities such as deforestation, construction activities, and diversion of river channels cause floods (ii) over-grazing also cause floods. Floods are also caused by various factors such as, climatologically (due to rain), failure of dams (i.e., excessive release of water) and floods could get intensified because of basin characters. Flooding also takes place when the river channels are unable to contain the discharge. Drought: The condition of dryness for prolonged period is called drought due to drop of average rainfall. Drought cause famine and starvation of human & animal population of region concerned. Drought is the most serious physical hazard to agriculture. Shortage of water for even the basic needs is the main problem in the drought areas. Shallow rooted plants don‘t grow. Infiltration wells, construction of dams, water sheds are being taken up in drought prone areas. Clouds seeding techniques, artificial rains etc., are to be implemented. Conflicts over water: Conflict means a situation in which people, groups, countries are involved in a serious argument. Water is an essential resource for sustaining life and environment. The available water resources are under tremendous pressure due to increased demands. Conflicts over sharing of river water between neighboring countries or different states of a country have now become quite common. The conflicts over water are continuing phenomena and leads to wars. Some examples of such conflicts in past & at present are listed below: 1. During Second World War many water dams were bombed. 2. Central dams over YALU River were attacked during Korean War. 3. Water supply systems in North Vietnam were bombed by US in1960‘s during Vietnam War. 4. The construction of Farakka Barrage across Ganga has become a dispute between India and Bangladesh. The Barrage is intended to divert water into river Hoogly to protect Calcutta port. 5. The Cauvery water dispute is between the states of Tamil Nadu and Karnataka. Tamil Nadu is occupying the downstream region of the river wants to use of upstream water whereas the upstream state Karnataka refused to do so. 6. The Sutlej –Yamuna link is the dispute between Punjab & Haryana. 7. The river basin of Fordan and the Nile are the shared water resources for Middle East Countries (Asia; Africa; Europe ). Ethiopia controls 80% of Nile River water whereas Sudan (South Africa) too is trying to divert more water. The sufferer is Egypt. The following statuses have disputes: 20 Environmental Studied B.com Asst. Prof : Hemantha kumara v Rivers Disputing states 1. Yamuna Delhi, Haryana, Rajasthan, Himachal Pradesh, Uttar Pradesh. 2. Narmada Maharashtra, Gujarat, Rajasthan, Madhya Pradesh 3. Krishna Andhra Pradesh, Maharashtra, Tamil Nadu, Karnataka. 4. Godavari Andhra Pradesh, Maharashtra, Orissa, Madhya Pradesh. 5. Cauvery Tamil Nadu, Karnataka Dams benefits & problems : The construction of dams has their own benefits & drawbacks. Excess amount of water flowing in rivers which otherwise Join Sea can be stored as reservoirs by constructing the dams across the rivers. The dam‘s viz., Bhakra-Nangal, Heerakud, Nagarjuna sagar; srisailam etc generate electricity, to supply drinking water. Pandit Jawahar Lal Nehru called these dams as ―THE TEMPLES OF MODERN INDIA‖. Uses: 1. More land can be brought under irrigation. 2. Hydro-Electric power can be generated. 3. Water can be supplied to towns & cities. Disadvantages: 1. Causes change in a climate of region at micro level. 2. Loss of vegetation & soil erosion. 3. Generation of seismic activities due to heavy pressure of water. 4. Blasting operations during construction of dams cause landslides. 5. Sedimentation & silting of reservoirs. MINERAL RESOURCES Minerals are naturally occuring inorganic, crystalline, solid having a definite chemical composition with a certain physical properties or a substance that is naturally present in the earth and is not formed from animal or vegetable matter. In any country, the growth and development of industry depends on the availability and quality of deposits of minerals of economic importance. Mineral resources can be classified under three main types. They are metallic, nonmetallic and atomic minerals. Metallic minerals include native elements such as gold and silver ; haematite and magnetite (iron) ; Cuprite ( copper) ; Laterite ( aluminum) and non- metallic minerals include sand ( quartz ), garnet ; steatite (talc); muscovite ( mica ) whereas atomic minerals include Pitchblende (Uranium, Thorium ). The geological processes are caused for the formation of the minerals over million of years ago in the earth‘s crust. Minerals are generally localized in occurrence and the deposits are very sporadic in distribution. Mineral resources are non renewable and the mineral /ore is extracted by the process of mining. Much risk is involved in mining process because of high temperature, pressure variations, fire hazards and lack of ventilation in mines. Minerals are used in a large number of ways for domestic, industrial, commercial sectors etc… Generation of energy by using coal ( lignite / anthracite ) ; uranium, gold, silver, platinum, diamond are used in jewellery. Copper, aluminum etc are used ascables for transmission of power. Some of the minerals are used in ayurvedam as medicine. Gold is reputed to strengthen the heart muscle and increase energy and stamina. By placing a piece of gold (devoid of stones) into 1000 ml of water and boiling it until reduced to 500 ml. Historical dose used gold ash of 10 mcg/day or gold water of 1 tsp 3x/day. Silver is a very important healing substance due to its cooling and antiseptic properties. It is most useful for treating Vata 21 Environmental Studied B.com Asst. Prof : Hemantha kumara v and Pitta especially conditions involving weakness, and some of chronic fevers. It is also used for gastritis, inflammatory of the intestines. Historical dose used silver ash of 10-30 mcg/day or silver water of 1 tsp 3x/day. Copper was used to treat conditions of excess kapha (primarily) and vata (secondarily). Historical dose used: copper ash: 10-30 mcg/day or copper water: 1 tsp 3x/day Environmental effects: Mineral extraction and processing in mines involves a negative impact on environment. Mining process involves removal of over burden of soil, ore extraction & transportation, crushing & grinding of ore, water treatment of ore, storage of waste material As a result of these activities cause air pollution, noise pollution, water pollution, loss of habitat of wildlife, concentration of toxic substances in tailing ponds and spreading of dust. People working in mines often suffer from serious respiratory system and skin diseases. Mining often causes ground subsidence which results in tilting of buildings, cracks in houses, buckling of roads, bending of rail tracks etc. Exploration process before a mining involves, geochemical, geophysical surveys drilling activities which causes for air pollution, noise pollution etc.. In addition, disturbance of all vegetation ( flora ) and fauna ( animals ) from that a region. Remedial measures: Atmospheric pollution due to mining and associated activities can be minimized by planning and using dust extractors, by optimizing the blast design, maintenance of roads and sprinkling of water for easy movement of dumpers, by using eco generators ( sound proof ), proper maintenance of equipment and the machines not only minimize the air pollution but also the noise generation. case studies of mineral resources 1) Aravalli hills in Rajasthan: The Aravallis hills spread across Haryana, Rajasthan and Gujarat and control the climate and drainage system of the region. Mining activity is being taken in this region due to immense mineral wealth ( Talc, marble, granite ). Rajasthan state alone has 9700 industrial units connected with mining and 90% of forest has been depleted over the past 20 years. When the mining activity reached below the under ground water level, a cone of depression was formed in the surrounding areas and ultimately bore wells, dug wells, dried up and affected agriculture in a massive level. Several studies have pointed out that the natural drainage system and the ground water table of the entire region have been badly affected. Pollution levels have also increased. Lung diseases, silicosis were attacked by the laborers. In November 2002, the Supreme Court imposed a blanket ban on mining activities in the Aravalli hills. The court ruling closed all 9700 units. The environmentalists have alleged that mining has affected the water, forest and the land. 2) Uranium mining in Nalgonda: The Uranium Corporation of India proposed to mine Uranium from the deposits of Lambapur and Peddagattu villages of Nalgonda dist. Processing unit was proposed at Mallapur village in Nalgonda dist by offering employment opportunities. But experts didn‘t propose mining activity because of possible contamination of water. The proposed mines are just 1 km away from human habitation and 10 km from Nagarjuna sagar dam and 4 km away from Akkampalli reservoir, which is a source for drinking water. 3) Gold mining in Europe: Potassium Cyanide is used during the process of gold treatment. In 2000, the Baia Mare Gold mine in Romania ( Europe ), released 80 million litres of less concentrated cyanide into the Tisza river. The cyanide flowed 500 km via Hungary and Serbia cities caused for diseases. 22 Environmental Studied B.com Asst. Prof : Hemantha kumara v 4) A Gold and Copper project of Tedi Island in New Guinea released 1000 cubic meters of less concentrated cyanide into a river and affected the cultureand lifestyle of Guinea people. LAND RESOURCES Land is the major part of the lithosphere. Land is made up of soils / rocks and are considered as very important resources of earth. Land plays a major role for growth of crops, vegetation, forests etc., Soils are formed due to disintegration of rocks by various physical processes like change in temperature, pressure, blowing wind and flow of water. The top layer of soil consistsof mixtures of Humus (dead leaves & plants), some of the living organisms and Inorganic components which supply nutrients to the soil. Soil fertility depends on inorganic matter, organic matter, water, air and a variety of micro-organisms viz., bacteria, fungi, which help in the decomposition of organic matter and regeneration of nutrients. Distribution of land resources The utilization of land distribution in India as under: Agriculture land 43.60 % Pastures 14.60 % Waste lands but cultivable 12.20 % Forests 10.70 % Barren land 8.40 % Urban land 5.30 % Unavailable information on lands 5.20 % Total 100.00 % Types of Indian Soils Different types of soils are identified by taking into account the geographical extent, physical and chemical properties for the purpose of agriculture, nutritional factors. (a) Alluvial soils: This is generally alkaline and best soil for agricuture. Alluvial soils are derived from debris brought by the floods or rivers or by tidal waves. Eg: North Indian Plains; Indo– Gangetic Plain; Ganga and Brahmaputra Plains … (b) Black soils: Black soils are predominantly with clay and sandy loams. These soils are found in the regions of AP (Krishna and Tungabhadra basins) , Maharashtra ( Deccan Traps ) and Madhya Pradesh. (c) Red soils: The red colour is due to the presence of high proportion of iron component and characterized by low water retention capacity. Red soils are found in Andhra Pradesh, Tamil Nadu and parts of Bihar, Orissa and Western Ghats of Karnataka.. (d) Laterite soils: These soils are rich in hydroxides of Ferrous and aluminum. At low elevation areas, the laterite soils are suitable for paddy cultivation whereas at higher elevations, they are suitable for coffee, tea, rubber etc., Western Ghats, Northern part of Eastern Ghats, North of Bangalore and West of Hyderabad are examples for laterite soils. (e) Mountain soils: These are stony. Mountain soils are formed due to dislodgement of rocks due to landslides and occur over altitudes between 2000 to 3000 mts. Eg: Aravallis and East of Himalayas. Mountain soils are favour for growth of vegetation / forest. 23 Environmental Studied B.com Asst. Prof : Hemantha kumara v (f) Desert soils: These soils cover the parts of areas of Rajasthan and Kutch where the annual rainfall is less than 50 cms per annum. (g) Saline soils: Presence of salt and water retention make the soils unsuitable for agriculture. Eg: Arid (no rain ) and Semi arid ( partly rain ) regions of northern plains and Maharashtra. Soil erosion and causes for soil erosion The top layer of the earth is called as soil. Soil erosion occurs due to deforestation, overgrazing, industrialization; desertification etc. Deforestation: Mining, industrial, urban development etc causes deforestation and leads to exposure of the land to wind and rains causing soil erosion. Cutting trees leads to deforestation which in turn loss of organic matter in the soils. Overgrazing: When sufficient amount of grass is available for the organisms usually the entire land /area may be subjected to exhaust and the land is exposed without grass and ultimately the land expose to wind/rain causing soil erosion.. Industrialization: Different processes carried out by industries and mining operations cause soil pollution which leads to degradation of land. Desertification: The process of conversion of productive lands to unproductive lands is called desertification. This occurs due to loss of top layer of soil by erosion. Erosion of top layer results in loss of water holding capacity and finally converted in to unproductive areas. Land degradation and control of land degradation Land degradation can be defined as any change in the land that alter its conditions or reduces its quality. Land degradation occurs due to both natural disasters like volcanic eruptions, earthquakes, heavy rains, fire etc or human induced activities. The other causes of land degradation consists of wind blow, salinity of water, water logging, soil acidity, loss of flora and fauna. Desertification is land degradation occurring in the arid, semi-arid regions of the world. These dry lands cover about 40% of the earth‘s surface and puts at risk more than 1 billion people who are dependent on these lands for survival. Land clearing and deforestation; Mining activity in forest areas; urban conversion; bringing more land under cultivation; soil pollution ; loss of organic matter in the soils; alkalinization of soils; salinity of water etc leads to land degradation. Severe land degradation affects in decreasing the mineral wealth and economic development of nations. The methods that are followed for the prevention of land degradation are called soil conservation methods. Some of the popular methods are; (a) Contour farming: The land is prepared with alternate furrows (a long narrow cut in the ground ) and ridges at the same level. The water is caught and held in furrows and stores which reduces run off and erosion. (b) Mulching: Stems of maize, cotton, tobacco etc are used as a mulch (decay of leaves) to reduce soil moisture, evaporation. (c) Crop rotation: Growing same crop year after year depletes the nutrients and land becomes unproductive. This is overcome by changing the crops and cultivating legumes (plants like peas, beans) after a regular crop. (d) Strip cropping: It consists of planting crops in rows or strips along contours to check flow of water. (e) Agrostological methods: Korean grass, Mexican grasses are grown as erosion – resisting plants. 24 Environmental Studied B.com Asst. Prof : Hemantha kumara v (f) Miscellaneous methods: Construction of bunds, drains, widening of gullies, Afforestation methods prevent the soil erosion. Landslides and man induced land slides Landslides are always exist on this planet and the term land slide is used to describe a wide variety of process that result a downward movement of rocks under gravitational forces. In other words, mass movement of rocks, debris and soil down a slope of land. Landslides are primarily associated with steep slopes. Surface run-off and changes in drainage also cause for landslides. Landslides can also be initiated by rainfall; earthquakes; volcanic activity, changes in groundwater movement or any combination these factors. Debris-flows can travel down a hillside of speeds upto 200 miles per hour (more commonly, 30 – 50 miles per hour) depending on the slope angle, water content, and type of earth and debris in the flow. While landslides are a naturally occurring environmental hazard they have recently increased in frequency in certain areas due to human activities. Building excavations, collapses in mining ( eg : coal mine) causes landslides. However, landslides can be triggered by the human beings by induced changes in the environment. Simply landslides can be explained in three ways: (a) Inherent of rocks (weakness in the structure of a rock ) (b) due to heavy seismic or volcanic activity and (c) due to various environmental conditions. ENERGY RESOURCES The term energy means capacity to do work. Energy can neither be created nor destroyed but transformed from one form to other. Energy is closely related to force. When a force causes an object to move, energy is being transferred from the force to kinetic energy. Energy is present in a number of forms such as mechanical, thermal, chemical, biological energy etc.. Energy production and utilization have become essential to carry out many activities in modern life. Energy is one of the important requirements that a country needs for its economic growth. At the same time, energy production has its impact on environment due to pollution and finally affects the quality of life of people. The energy is used for the following purposes: a) Cooking, heating and lighting b) Transporting people and goods by means of vehicles. c) Manufacturing consumer goods and equipment d) Conversion of fuels into other forms of energy for various use. For Example: (1) Burning coal to produce electrical energy or mechanical energy (2) Chemical to electrical by dry cell batteries (3) Using water in dams to produce electricity through mechanical energy. The power generation capacity in the country has increased from 1400 MW at the end of 1947 to 92,894 MW at the end of 1999 from various sectors comprising as under: Hydro sector 22,438 MW Thermal sector 67,618 MW Nuclear sector 1,870 MW Wind sector 968 MW From all sectors 92,894 MW 25 Environmental Studied B.com Asst. Prof : Hemantha kumara v There are two types of energy sources namely: (1) Renewable energy sources and (2) Non – renewable energy sources. The important renewable energy resources are described below: Solar energy: The energy which is derived from the sun is known as solar energy. It can be used for direct heating or sun‘s heat is converted into electricity. Photo voltaic cells convert direct solar energy into electricity. A number of solar equipments have been developed to utilize sun rays to heat water, to cook food, to pump water and to run certain machines and used for street lighting, railway signals etc. But the major problem with solar energy is that during cloudy weather it is available in less quantity than on sunny days. Hydro-Power energy: Electrical power is generated by hydro-electric projects in which dams are constructed across the river. The kinetic energy of water is converted into mechanical energy by means of turbines and in turn, the mechanical energy is transferred into electrical energy by generators. Hydro power projects lead to several environmental problems like destruction of animal habitats, deforestation, migration of people etc.. Geothermal energy: Geothermal energy found within rock formations. Inside the earth the o temperature rises with depth.The temperature in earth‘s crust is around 4000 C. Geysers (a natural spring that emits hot water) and hot springs are examples for geothermal energy where the steam and hot water come to the surface, in areas where the steam is tapped by drilling. The obtained steam is then used to generate power. Air pollution results in case of geothermal energy where the gases like H2S, NH3, CO2 present in the steam coming out of the geothermal sources. The overall efficiency for power production is low (15%) as compared to fossil fuels (40%). Wind energy: Wind energy is the kinetic energy associated with the movement of atmospheric air. Wind mills convert the wind energy into electrical energy. On an average wind mills can convert 30 – 40 % of available wind energy into electrical energy at a steady wind speed of 8.5 mts / sec. The efficiency of wind mill is increased with the speed of wind and length of rotor blade. The total wind energy potential in India‘s estimate is 25,000 MW of this about 6000 MW is located in Tamil Nadu; 5000 MW in Gujarat and contribute the states of Andhra Pradesh, Maharashtra, Uttar Pradesh and Rajasthan for balance quantity. Merits & demerits of wind energy: 1. It is a non – polluting and environment friendly source of energy. 2. It is a renewable energy available at free of cost 3. Power generation is cheaper with nil recurring expenses. 4.Wind mills are suitable to erect at on shore, remote and rural areas where wind blows with required intensity. 5. Favorable in geographic locations which are away from cities. 6. Wind turbine design, manufacturing, installation is complex due to varying atmospheric conditions. 7. Wind power doesn‘t suitable for large scale generation. Ocean energy: Seas and oceans are large water bodies. Seas absorb solar radiation and a large amount of solar energy is stored in the tides and waves of the ocean. Ocean energy is non – polluting in nature and suitable at a few places only. Energy from seas or oceans is obtained from the following: (1) Ocean Thermal Energy Conversion: The oceans collect and store huge quantities of solar on the surface of the water while the temperature of deep waters is very low. Using this temperature difference it is possible to convert heat into electricity. 26 Environmental Studied B.com Asst. Prof : Hemantha kumara v (2) Tidal energy: Tidal waves of the sea can be used to turn turbine and generate electricity. Asia‘s first tidal power plant of 800 - 1000 MW capacity is proposed to be set up at Kandla in Gulf of Kutch. (3) Wave energy: The wind blowing over water generates waves. A unique property of ocean waves is their ability to travel vast oceanic distances with negligible loss of energy and ultimately arrives the continental margin of that basin. India‘s first wave energy power plant of 150 KW capacity has been commissioned in Thiruvananthapuram, Tamil Nadu. 1 MW wave energy plant is being set up in Andaman and Nicobar islands. (4) Current energy: Theoretically, the ocean water used to generate energy by allowing the water to pass through a series of turbines installed under water. The turbines are to be sealed and are kept at a depth of 10 to 20 mts. A propeller with a dia of 5 mts can generate about 150 MW of power. Bio mass energy: Bio-mass is an organic material from living beings or its residues. It is a renewable source of energy derived from the waste of various human and natural activities. The bio-mass energy sources include Wood, animal manure, sugarcane waste, agriculture crops, house hold waste, roots of plants, garbage etc. The simplest way of using bio-mass energy sources is to allow them to dry out in the sun and burn them. Bio-gas: Bio-gas is a sustainable source of energy by virtue of its production from available natural organic wastes of cattle dung, human excreta, poultry waste, plant leaves, paddy husk etc…. Bio- gas is a mixture of methane (68%), CO2 (31%) and N2 (1%). Methane gas (CH4) is produced by bio-gas plants and this gas is utilized as cooking gas whose calorific value varies from 4400 – 6200 Kilo Calories / cum. Heat value of bio gas can be improved by reducing its CO2 content. Bio-gas production is carried out in an enclosed bio-gas plant made of bricks or steel. Slurry of waste organic matter is fed into the plant through an inlet and gas formed is tapped by an inverted drum. As gas is produced the drum rises and the gas may be drawn through an outlet. Bio-gas is commonly produced from cattle dung in a bio gas plant known as Gobar Gas plant. Bio-gas is a clean, cheap fuel that can be used for lighting purpose, lifting water through small pumps. Non – renewable energy resources include (a) fossil fuels such as coal, crude oil, natural gas and (b) nuclear energy. (a) Fossil fuels: Fossil means the remains of an animal or a plant which have become hard and turned into rock. All these found in earth‘s crust which has been formed in the past by the geological processes. Fossil fuels are solid coal (lignite), liquid (crude oil / petroleum) and gases (natural gas). Coal: Huge quantity of plant materials buried under earth‘s crust and altered by geological process and converted into carbon rich fuel. It is a non – renewable source because it takes a very long period (million of years) for its formation. Coal is extracted by the process of mining and involves accidents due to mine collapse, ground water pollution, accumulation of poisonous material, explosive gases etc cause diseases. CO2 pollution leads to green house effect (global warming). o Crude oil: It is obtained in the form of liquid. The crude oil is heated upto 600 C in the oil refinery and condense the vapours of hydro – carbons. Petrol and other petroleum products are refined fuels from crude oil. Petroleum products are used in large quantities in the manufacture of detergents, plastics, fertilizers, pharmaceuticals, synthetic rubber etc. The transport sector 27 Environmental Studied B.com Asst. Prof : Hemantha kumara v consumes about 40% of diesel; 25% industries and 19% household and rest 16% agriculture and other sectors.. Natural Gas: Gas deposits are trapped from the sedimentary formations by means drilling holes into the rock formations. While burning of natural gas, the emission of CO 2 is less and thus reduces green house effect and global warming. A total of 734 billion cubic mts of gas is estimated as proven reserves. (b) Nuclear Energy or Atomic power: It is the energy which is trapped inside the atom. It is non–renewable source of energy which is released during fission or fusion of certain radioactive elements. The most important advantage of atomic power is the production of an enormous amount of energy from a small quantity of radioactive element. For eg: 1 kg of Uranium liberates energy equivalent to 30000 kgs of coal. Energy released2during nuclear reaction (mass – energy equation as per Albert Einstein‘s formula E = mc ). Nuclear Energy is produced by two Processes namely (1) Nuclear Fission (2) Nuclear Fusion. (1) Nuclear Fission: The nucleus in atoms is split by fast moving neutrons and in turn a tremendous amount of energy in the form of heat, light etc is released by a chain of reactions. Uranium is used as fuel. The energy released slowly in this process is utilized to generate electricity or else released suddenly all at once, results a tremendous explosion as in the case of Atom bomb. (2) Nuclear Fusion: Nuclear energy can be generated by fusion process which involves two hydrogen atoms combine to produce one helium atom. Eg: hydrogen bomb. The disposal of nuclear wastes during mining, fuel production and reactor operation for a long time period resulting in adverse effects on environment. Disposable of nuclear waste is a national and global problem. 28 Environmental Studied B.com Asst. Prof : Hemantha kumara v UNIT – III BIODIVERSITY AND BIOTIC RESOURCES The word biodiversity is a combination of two words: ―biological and diversity‖ and refers to the variety of life on the Earth which includes a large number of living things that exist in a certain area (in the air, on land or in water). The area may be considered as small as heap or as big as whole planet. Hence, Biodiversity means “the existence of a large number of different kinds of animals and plants which make a balanced environment” is called as biodiversity. Biodiversity deals with a large variety of flora and fauna on this earth. Ex: a wide variety of plants and animals are finding in a part of forest. The plant life range from a small herb to a large tree and the animal life vary from a tiny insect to a large mammal in addition to micro-organisms (algae, bacteria and fungi). Biodiversity is usually considered at three different levels: 1. Genetic diversity means the variation of genes within the species. Ex: In human species, genetic variation between an Indian and African and genetic variations within a population. (Ex: Within the Indian population) can be seen. In simple terms, genetic matter dictates whether the persons have blue or brown eyes, brown or black hair and tall or short. Genetic diversity can be identified by using a variety of DNA based and other techniques. One estimate is that there are 1000 crores of different genes distributed across the worlds biota though they do not all make an identical contribution to overall genetic diversity. 2. Species diversity means the richness of species in all ecosystems. It is measured on the basis of number of species in a region. So far 1.75 million species have been described worldwide. Warmer areas tend to support more species than colder ones and wetter areas contain more species than drier ones. Topography and climate of the areas support and control the species of a region. 3. Ecosystem diversity means the study of difference between ecosystem types. Ecosystem diversity is difficult to measure since the boundaries of various sub ecosystems are overlap each other. Ex: for ecosystem diversity is Godavari – Delta ecosystem which consists of grassland ecosystem, river ecosystem, estuarine ecosystem, fresh water aquatic ecosystem, marine water aquatic ecosystem. Importance of biodiversity: Biodiversity performs a number of ecological series for human kind that have economic and aesthetic values. As an example, the contribution of biodiversity to human health is given below: One out of 125 plant species produce a major drug as per Herb Research Foundation. Of the 118 drugs in the US, 74% are based on plants; 18% on fungi; 05% on bacteria and 03% on vertebrates. 80% of the world population relies on traditional plant medicine. Value of biodiversity: The value of biodiversity (in terms of its commercial utility, ecological services, social and aesthetic values) is enormous. There are several ways that biodiversity and its various forms are valuable to humans. We get benefits from organisms in an innumerable ways. Sometimes, one realizes the value of the organism only after it is lost from this Earth. Every year numerous species are lost before we have a chance to know anything about them. 29 Environmental Studied B.com Asst. Prof : Hemantha kumara v The biodiversity value may be classified as follows: 1. Consumptive Value: Biodiversity is an essential requirement for the maintenance of global food supply. The main sources of human food include animals, fish and plant produces. A large number of plants are consumed by human beings as food. A few animal species are consumed by people who come from cattle, pigs, sheep, goats, buffaloes, chickens, ducks, geese and turkey species. Fish: Many fresh water fish can be grown in ponds. Israel and China already get about half of their fish from aqua culture. Drugs & medicines: About 75% of the world‘s population depends upon plants or plant extracts for medicines. The drug Penicillin used as an antibiotic is derived from a fungus called Penicillium. Likewise, Tetracycline from bacteria which is used to cure malaria is obtained from the bark of cinchona tree. Fuel: The fossil fuels like coal, petroleum products and natural gas are the products of biodiversity. 2. Productive Value: Some of the organisms are commercially usable where the product is marketed and sold. The animal products like tusks of elephants; musk from deer, silk from silkworm, wool from sheep or goats; fur of many animals etc all of which are traded in the market. → Calabar bean was tradionally used as a poison in West Africa. →Daisy plants were first used as a lice remedy in the Middle East and this led to the discovery of Pyrethrum. Mosquito coils made from Pyrethrum are sold in the market. → The bacterium Bacillus thuringiensis produces toxic proteins that kill certain insects. → The neem tree has been using in birth control such as parts of neem tree that cause abortion. 3. Social Value: These are the values associated with the social life, religion and spiritual aspects of the people. Many of the plants are considered to be sacred in our country like Tulasi, Mango leaves, Banana leaves. The leaves, fruits, flowers of some of the plants are used in worship. Many animals like cow, snake, bull, peacock also have significant place in spiritual and thus holdspecial importance. Thus, biodiversity has distinct social value, attached with different societies. 4. Ethical Value: The ethical value means that human beings may or may not use a certain species but knowing the very fact that this species exists in nature gives pleasure. Ex: a peculiar species of Pigeon, grey / white bird with short legs is no more on this earth. Similarly, Dodo species is also no more. Human beings are not deriving anything direct from Kangaroo, giraffe but strongly feel that these species should exist in nature. 5. Aesthetic Value: Every one of us would like to visit vast stretches of lands to enjoy the visible life. People from farther areas, spend a lot of time and money to visit wild life areas where they can enjoy the aesthetic value of biodiversity and this type of tourism is known as eco tourism. Eco- tourism is estimated to generate 12 billion dollars of revenue annually that roughly gives the aesthetic value of biodiversity. A study of the impact of environment on the psyche was undertaken by Kaplan and Kaplan (1989) in whom they found that being near nature relieved working stresses while people who worked in closed environment or human made structures experienced much more job stresses and illnesses. 30 Environmental Studied B.com Asst. Prof : Hemantha kumara v India as a mega diversity Nation: India contains a great wealth of biodiversity in the forests, wet lands and marine areas. Hence biodiversity can be observed at all levels ie locally, nationally and globally. India, as a subcontinent representing a major part of South Asia is rich in flora and fauna and hence it is one of the world‘s ―MEGADIVERSITY NATIONS‖. It is estimated that over 75000 species of animals and over 45000 species of plants are found in India. The identified biodiversity in India and world is: Group No of Species in India No of Species in World Mammals 350 4629 Birds 1224 9702 Reptiles 408 6550 Amphibians 197 4522 Fishes 2546 21730 Flowering plants 15000 250000 Biogeographic regions of India: According to wild life Institute of India, the country has 10 distinct biogeographic zones or regions. They are: 1. Trans – Himalayan Zone 2. Himalayan Zone 3. Desert Zone 4. Semi – arid Zone 5. Western Ghats 6. Deccan Zone 7. Gangetic plain Zone 8. NE Indian Zone 9. Coastal Zone 10. Islands around the country. Hot spots of biodiversity: Biologically hot spots are areas that are extremely rich in endemic species of both plant and animals. The world is identified with 34 biodiversity hot spots.The following is the list of identified bio-diversity hot spots of the world: 31 Environmental Studied B.com Asst. Prof : Hemantha kumara v S.No. Location S.No Location 1 Tropical Andes (venezula; Columbia; peru; argentina ) 18 Philliphines 2 Meso America ( central Mexico) 19 Indo-Burma region 3 Caribbean ( West Indies ) 20 Western ghats – Sri Lanka 4 Brazil forest 21 South Central China 5 Western Ecudor (NW of S.America) 22 SW Australia 6 Brazil‘s Cerrado 23 New Caledonia 24 New Zealand 7 Central Chile 8 California Province 25 Polynesia / Micronesia 9 Madagascar 26 The Madrean-pine-Oak Woodland 10 Coastal Forest of Kenya (S Africa) 27 Maputaland-Pondoland-Albany 11 Western African Forests 28 The Eastern Afromontane 12 Cape Province ( S. Africa ) 29 The Horn of Africa 13 Karoo ( Australia ) 30 The Irano-Anatolian Mediterranean Basin 14 ( surroundings of Europe, Asia; The Mountains of Central Asia 31 Africa; Algeria; Libya; Egypt) 15 Caucasus 32 Eastern Himalaya 16 Sunda land 33 Japan 17 Wallacea 34 East Melanesian Islands Hot spots in India: Among 34 hot spots of world three found in India extending into neighbouring countries viz., 1) The Western Ghats – Sri Lanka region and 2) The Indo – Burma 3) Eastern Himalayas (The Eastern Himalayas form a distinct region which comprises Nepal, Bhutan; Sikkim and states of Northern India). Major threats to the Biodiversity: Biodiversity is threatened by anthropogenic activities in many ways (by destruction of forests, over – hunting conversion of wet lands & grass lands into industrialization; mining of minerals / rocks; pollution; constructions of roads; tourism business; exploitation of timber resources etc.. ) to eliminate millions of species. Habitat loss is the major cause of species extinction. Habitat loss may be qualitative and quantitative losses: Qualitative losses involve a change in the structure, function or composition of the habitat. Ex: If a paper industry discharging chemicals into a waterway system and polluting / poisoning the water, thus there has been a qualitative loss. Quantitative losses are measured by looking at a previously mapped area and determining how much of the habitat area no longer present is. Ex: If a wet land is paved over, then there has been a quantitative loss of wet land. Diseases; the spread of non – native species threatens many local species with extinction (Ex: Dodo); climate changes (threatens to force species and ecosystems to migrate towards favorable areas) etc disturb and cause the elimination of species.. 32 Environmental Studied B.com Asst. Prof : Hemantha kumara v th largest country in the world and Asia‘s second India as a mega diversity nation: India is the 7 largest nation with an area of 32,87,263 sq km. It has a land frontier of 15,200 kms and a coast line of 7516 km. India‘s northern frontier‘s are Tibet; China; Nepal and Bhutan. In the North West, India borders on Pakistan; in the Northeast China and in the East, Burma. The southern peninsula extends into Indian Ocean; Bay of Bengal lying to the Southeast and the Arabian Sea to the Southwest. For administrative purposes India is divided into 28 states and 7 union territories. Physically the country is divided into four relatively well defined regions: a) Himalayan region b) The Gangetic river plains or Indo-Gangetic plains. c) The southern ( Deccan ) Plateau and d) The islands of Lakshadweep, Andaman and Nicobar. The Himalayas in the North include the highest peaks in the world. The highest mountains are: a) Khanchen Junga ( 8586 mts ) which is located in Sikkim; b) Pir Panjal ( 3,600 – 4,600 mts ) in Kashmir; c) Dhaula dhar in Himachal Pradesh and d) Siwaliks ( 900 – 1500 mts ) in the Indo – Gangetic plains. The northern plains of India stretch from Assam in the East to the Punjab in the West covering a distance of 2400 kms. Some of the largest rivers in India including the Ganges, Ghaghara, Brahmaputra and Yamuna flows across this region. Thar desert which is located at the western extremity of Indian part of the plains in the states of Rajasthan. Observations show that the biodiversity is far richer in NE Himalayan range compared to Northwest range. The following factors play a major role in the classification of biogeographical / biodiversity: Climate: The climate of India is dominated by the Asiatic monsoon, mostly by southwest rains between June and October and drier winds from the North between December and February. From March to May the climate is dry and hot.. Wet Lands: India has a rich variety of wetland habitats. The total area of wetlands excluding rivers in India is 5,82,86,000 hectares. Chilka lake (orissa ) and Keoladeo National Park ( Bhartpur in Rajasthan ) have been designated under the convention of wetlands of International importance. The country‘s wet lands are generally differentiated by region into 8 categories: 1. The reservoirs of the Deccan Plateau in south 2. the vast saline expanses of Rajasthan and Gujarat 3. Fresh water lakes and reservoirs from Gujarat eastwards. 4. The delta wet lands and lagoons of India‘s east coast. 5. The fresh water marshes of Gangetic plain 6. The Flood plain of Brahmaputra 7. The marshes and swamps in the hills of NE India and Himalayan foot hills and the lakes and rivers of the mountain region of Kashmir and Ladakh and 8. Wet lands of the island areas of Andaman & Nicobars. Forests: The panorama of Indian forests ranges from evergreen tropical rain forests in the Andaman and Nicobar Islands; the Western Ghats to alpine forests in the Himalayas to the North. 33 Environmental Studied B.com Asst. Prof : Hemantha kumara v The country has also several types of forests viz., 34 Environmental Studied B.com Asst. Prof : Hemantha kumara v a) Semi – ever green rain forests b) Deciduous forests c) Thorn forests d) Pine forests e) Tropical forests (Andaman & Nicobar Islands; the Western Ghats) f) Rain forests ( Orissa ) g) Western Ghats monsoon forests contain rosewood, Malabar, teak. h) Tropical evergreen rain forests and tropical monsoon forests (Andaman & Nicobar) Marine Environment: The coastal waters of India are extremely rich in fishing grounds. In 1981, it was estimated that there were approximately 1,80,000 non – mechanized boats carrying out fishing activities in these waters. At the same time, there were about 20,000 mechanized boats operating mainly out of ports in the states of Maharashtra, Kerala, Gujarat, Tamil Nadu and Karnataka. Indian coral reefs have a wide range of resources which are of commercial value. Exploitation of corals, coral debris is widespread on the Gulf of Mannar and Gulf of Kutch. Ornamental shells and pearls are the important reef industry. Other marine areas are including sea grass and prawns. Five species of marine turtle occur in Indian waters. 1. Green turtle 2. Logger head 3. Olive Ridley 4. Hawksbill 5. Leather back. Conservation of Biodiversity: In order to maintain and conserve biodiversity, the Ministry of Environment and Forests, Govt of India has already taken several steps to manage wildlife, the objectives of which are: 1. Maintenance of a number of species in protected areas such as National Parks, Sanctuaries. 2. To improve the biosphere reserves 3. Implement strict restrictions of export of rare plants and animals 4. Educate the public on these through the Govt agencies and NGO‘s. Conservation of biodiversity can be carried out in two ways, as shown: Conservation is the protection, preservation, management, or restoration of wildlife and natural resources such as forests and water. Through the conservation of biodiversity and the survival of many species and habitats which are threatened due to human activities can be ensured. There is an urgent need, not only to manage and conserve the biotic wealth, but also restore the degraded ecosystems. 35 Environmental Studied B.com Asst. Prof : Hemantha kumara v In-situ Conservation: In-situ conservation is on site conservation or the conservation of genetic resources in natural populations of plant or animal species, such as forest genetic resources in natural populations of tree species. It is the process of protecting an endangered plant or animal species in its natural habitat, either by protecting or cleaning up the habitat itself, or by defending the species from predators. In India following types of natural habitats are being maintained: 1. National parks 2. Wildlife sanctuaries 3. Biosphere reserves INDIA has over 600 protected areas, which includes over 90 national parks, over 500 animal sanctuaries and 15 biosphere reserves Table. List of some major Biosphere Reserves of India: Area (in S.No. Name State Established km2) 1. Nanda Devi Uttarakhand 1982 5,860.69 2. Manas Assam 1990 2837 Gulf of 3. Mannar Tamil Nadu 1980 10,500 Andaman and 4. Great Nicobar 1989 885 Nicobar 36 Environmental Studied B.com Asst. Prof : Hemantha kumara v Islands Madhya 5. Panchmarhi Pradesh 1999 4,926.28 Advantages of in-situ conservation: 1. The flora and fauna live in natural habitats without human interference. 2. The life cycles of the organisms and their evolution progresses in a natural way. 3. In-situ conservation provides the required green cover and its associated benefits to our environment. 4. It is less expensive and easy to manage. 5. The interests of the indigenous people are also protected. Ex-Situ Conservation: Ex-situ conservation is the preservation of components of biological diversity outside their natural habitats. This involves conservation of genetic resources, as well as wild and cultivated or species, and draws on a diverse body of techniques and facilities. Such strategies include establishment of botanical gardens, zoos, conservation strands and gene, pollen seed, seedling, tissue culture and DNA banks. Gene bank: Genetic variability also is preserved by gene bank under normal growing conditions. These are cold storages where germ plam are kept under controlled temperature and humidity for storage; this is an important way of preserving the genetic resources. Cryopreservation: This is the newest application of technology for preservation of biotic parts. This type of conservation is done at very low temperature (196°C) in liquid nitrogen. The metabolic activities of the organisms are suspended under low temperature, which are later used for research purposes. 37 Environmental Studied B.com Asst. Prof : Hemantha kumara v Botanical gardens: A botanical garden is a place where flowers, fruits and vegetables are grown. The botanical gardens provide beauty and calm environment. Most of them have started keeping exotic plants for educational and research purposes Advantages of ex-situ preservation: 1. It is useful for declining population of species. 2. Endangered animals on the verge of extinction are successfully breeded. 3. Threatened species are breeded in captivity and then released in the natural habitats. 4. Ex-situ centres offer the possibilities of observing wild animals, which is otherwise not possible. 5. It is extremely useful for conducting research and scientific work on different species. National biodiversity Act: The Act covers conservation, use of biological resources and associated knowledge occurring in India for commercial or research purposes or for the purposes of bio-survey and bio-utilisation. It provides a framework for access to biological resources and sharing the benefits arising out of such access and use. The Act also includes in its ambit the transfer of research results and application for intellectual property