cybotechnta: December 2013

ENVIRONMENTAL SCIENCE

DISASTER MANAGEMENT

ENVIRONMENTAL SCIENCE

DISASTER MANAGEMENT

ENVIRONMENTAL SCIENCE &DISASTER MANAGEMENT

MODULES

1. Renewable and Non-renewable Resource

2. Ecosystems

3. Environmental pollution

4. Environmental Hazards & Disasters

OBJECTIVES: Up on completion of this course the student should be able to:

Module - I

1. To identify and understand the vital natural resources that are renewable and nonrenewable, their importance and the problems due to over exploitation.

1.1 Identify important forest resources and their uses – Understand: The problems due to over exploitation of forest resources and the impact due to deforestation with the help case studies – Timber as the main resource fromforest-Its uses - Problems due to cutting of trees – Understand the aftermath ofconstruction of dams and carrying out mining operations in forest area andknow how it affects the forest as a whole and the natural inhabitants, the tribal people in particular.

1.2 Understand water as major natural resource and its importance – Sources ofwater – Surface and sub-surface sources – problems due to over exploitationof water – Identify the causes of flood and draught and the impacts due tothat. Conflicts in precipitation obtained, water availability and water demand.Enumerate the advantages and disadvantages due to dams with specialreference to large dams.

1.3 Identify the major mineral resources and enumerate their uses – Problems dueto mining operation & abandoned mines and the related environmentalimpacts– Issues of overexploitation of mineral wealth – Explanation withtypical case studies expected.

1.4 Understand the basic concept of food chain – mutual dependence – Worldfood scenario - Food crisis at Global level – New threats posed by conversionof agricultural land for non-food production activity – Problems due to overgrazing – Impacts due to agrarian related activity – Effects due to adoption ofmodern agricultural technology – Impacts due to the use of chemical

Fertilizers and pesticides – Causes of water logging & salinity and the effectsdue to that- Discuss these aspects with the help of case studies.

1.5 Enumerate the various conventional and non-conventional sources of energy –Role of non-conventional and alternate energy sources to meet the growingenergy needs of the world – Discuss with the help of case studies.

1.6 Understand land as a resource – Identify the causes for the degradation ofland. Study the manmade and natural causes for land slide, soil erosion anddesertification – Discuss their control measures with case studies.

1.7 Study the individual and collective contributions that can be made for theconservation of natural resources – Discuss the means for an equitable andjudicious utilization of natural resources ensuring its availability for futuregenerations - Develop a life style for achieving sustainable development.4

Module –II

2. Understand what constitutes an ecosystem – The basic components and conceptsof an ecosystem – Its role as the provider of food and habitat.

2.1 Understand the structure and functions of an ecosystem. Understand the roleplayed by the basic components of ecosystem, the producers, the consumersand the decomposers - Importance of each of these components.

2.2 Understand the term ecological succession and the hierarchical order followedin any ecosystem.

2.3 Understand what is meant by a food chain, food web and food pyramid -Importance of food chain – Interdependencies of different components.

2.4 Understand the basic types, characteristic features, structure and functions ofthe Forest ecosystem, Grass land ecosystem, Desert ecosystem and aquaticecosystems (ponds, streams, lakes, rivers, Oceans and estuaries) – Onlyintroduction expected.

Module - III

3. Understand the definition for environmental pollution and the various causes forthat.

3.1 Understand various components of the environment that is subjected topollution - Pollution of air, Water and land – Causes for Marine pollution –Pollution caused by Oil sleek, Noise, Temperature and Nuclear hazards.

3.2 Define the solid waste – Enumerate different constituents of urban andindustrial solid waste – Identify the Sources of solid waste and the type – Illeffects due to different types of solid wastes - Understand the various methodsof solid waste management – Control at the source – composting –incineration – land fill and deep burial methods – suitability, merits and demerits of each method.

3.3 Discuss the role that an individual can play in prevention of pollution andformulate an action plan to implement those measures.

3.4 Conduct case studies on major disasters that caused environmental pollution,identify the causes and suggest mitigation measures to avert such situation inthe past - Conduct case studies on local environment polluting issues –identify the causes and suggest the control measures.

Module –IV

4. Distinguish between hazards and disasters.

4.1 Define Environmental hazards, Environmental disasters, and Environmentalstress - Conceptualize these events and understand how they are inter-related.

4.2 Identify and classify different environmental hazards and the disasters causedby them based on the cause of origination viz. natural cause and manmadecause.4.3 Understand the various causes for occurrence of natural hazards such as flood,draught, volcanic eruption, earth quake, land slide, cyclones, lighting andtsunami. Study their effect on the environment.

4.4 Understand the causes and impact due to manmade hazards and the disastersdue to that – Identify the causes and consequences due to release of toxicchemicals and radioactive substances - Chemical hazards and disasters – casestudies with respect to the disasters occurred at Minimatha, Bhopal andChernobyl.5

4.5 Understand the emerging approaches in disaster management in each of thethree stages of disaster management viz. the pre-disaster stage, the emergencystage and the post disaster stage.

4.6 Understand the different operations that are to be attended in the two phasesof pre disaster stage (preparedness and mitigation operations).

4.7 Understand the need scope of preparedness operations – Method of preparinghazard zoning map – Land use zoning - Methods of predicting and forecasting– Different early warning systems – How to prepare a disaster preparednessplan – Methods of achieving preparedness through Information, education andcommunication (IEC).

4.8 Understand the mitigation measures to be adopted during the pre-disasterstage – Disaster resistant house construction – Population restriction invulnerable areas – Conducting awareness programme.

4.9 Understand various rescue and relief operations to be performed duringemergency stage – Trainings to be imparted for the rescue search and the coordination of operations at regional and national level – Identify theimmediate relief operations to be carried out – Understand various methodsfor carrying out the assessment surveys.

4.10 Understand various post disaster operations and their means ofimplementation – The political & administrative aspects – The economicaspects and the environmental aspects6

MODULE 1

Renewable and Non-renewable Resources 1: WHAT ARE NATURAL RESOURCES? Natural resources are materials, which living organisms can take from nature for sustaining their life. Natural resources occur naturally within environments that exist relatively undisturbed by mankind, in a natural form. It is often characterized by amounts of biodiversity and geo-diversity existent in various ecosystems. Exhaustible natural Resources: A natural resource may exist as a separate entity such as fresh water, and air, as well as a living organism such as a fish, or it may exist in an alternate form which must be processed to obtain the resource such as metal ores, oil, and most forms of energy. Inexhaustible Natural Resources: Some Natural resources can be found everywhere such as sunlight and air. There are very few resources that are considered inexhaustible (will not run out in foreseeable future) – these are solar radiation, geothermal energy, and air (though access to clean air may not be). The vast majority of resources are however exhaustible, which means they have a finite quantity, and can be depleted if managed improperly 2: HOW DO YOU CLASSIFY NATURAL RESOURCES BASED ON THEIR ORIGIN? Natural Resources are classified as Biotic and Abiotic on the basis of origin. Biotic – Biotic resources are obtained from the biosphere (living and organic material), such as forests, animals, birds, and fish and the materials that can be obtained from them. Fossil fuels such as coal and petroleum are also included in this category because they are formed from decayed organic matter. Abiotic – Abiotic resources are those that come from non-living, non-organic material. Examples of abiotic resources include land, fresh water, air and heavy metals including ores such as gold, iron, copper, silver, etc. 3: HOW DO YOU CLASSIFY NATURAL RESOURCES BASED ON RENEWABILITY? Renewable resources: Renewable resources are ones that can be replenished naturally. Some of these resources, like sunlight, air, wind, etc., are continuously available. Resources from a human use perspective are classified as renewable only so long as the rate of replenishment/recovery exceeds that of the rate of consumption. Non-renewable resources: Non-renewable resources are resources that form extremely slowly and those that do not naturally form in the environment. Minerals are the most common resource included in this category. By the human perspective, resources are non-renewable when their rate of consumption exceeds the rate of replenishment. eg: fossil fuels. 7

4: DISCUSS THE PROBLEMS ASSOCIATED WITH NATURAL RESOURCES. or 5:WRITE NOTES ON THE DEPLETION OF NATURAL RESOURSES. The depletion of natural resources is a continuing concern for society. Depletion of Natural Resources is associated with social inequity. It could result in losses of ecosystem. It is a major source of social unrest and conflicts in developing nations. The rain forest regions hold most of the Earth's biodiversity. Deforestation and degradation affect 8.5% of the world's forests with 30% of the Earth's surface already cropped. Loss of the world's rainforests could result in a loss of finding more potential life-saving medicines. The depletion of natural resources is caused by mining, petroleum extraction, fishing and forestry. The current practice of Agriculture is another factor causing depletion of natural resources. The depletion of nutrients in the soil due to excessive use of nitrogen causes desertification. 6: WRITE NOTES ON FOREST RESOURCES AND THEIR USES. or 7: DISCUSS THE ECONOMIC IMPORTANCE OF FOREST RESOURCES A forest is an area with a high density of trees. Forests are important components of our environment which contribute significantly to the economic development of the world. The chief products which forests supply is wood which is used as fuel raw materials, new materials for various industries as pulp, paper, board, plywood, timber for furniture items. They also produce minor forest products like canes, gum, resins, dyes, tannins lac, fish etc. In addition forests also shape the soil environment by affecting its composition, structure, chemical properties water contents and play an important role in geochemical cycles of water, carbon, nitrogen, oxygen, phosphorus, sculpture and a number of other elements. Excessive harvesting of forest resources affects the environment of the forest, which leads to the changes in climate, or other elements of the environment. Rapid increase in the deforestation and fossil fuel combustion has been considered to affect largely the forest resources. The major issues of global warming, acid rains and other forms of atmospheric pollution have become the target problems of the global level for it mere survival of the living beings. 8. DISCUSS THE OVER EXPLOITATION OF FORESTS/ DEFORESTATION. Deforestation is the removal of a forest where the land is thereafter converted to a non-forest use. eg: conversion of forestland to farms, ranches, or urban use. About half of the world's original forests had been destroyed during the previous 50 years. The removal of trees without sufficient reforestation has resulted in damage to habitat, biodiversity loss and aridity. It has adverse impacts on bio-sequestration of atmospheric carbon dioxide. Deforested regions typically incur significant adverse soil erosion and frequently degrade into wasteland. Deforestation causes extinction, changes to climatic conditions, desertification, and displacement of populations as observed by current conditions and in the past through the fossil record. 9: WRITE THE VARIOUS USES OF TIMBER or 10: DISCUSS THE VARIOUS USES OF WOOD

Fuel: Wood has a long history of being used as fuel, in rural areas of the world. Hardwood is preferred over softwood because it creates less smoke and burns longer. 8

Construction: Wood has been an important construction material since humans began building shelters, houses and boats. New domestic housing in many parts of the world today is commonly made from timber-framed construction. Furniture and utensils: Wood is used extensively for furniture and also for tool handles and cutlery, such as chopsticks, toothpicks, and other utensils, like the wooden spoon. Engineered wood: Wood can be cut into straight planks and made into wood- flooring. Engineered wood products, glued building products "engineered" for application-specific performance requirements, are often used in construction and industrial applications. In the arts: Wood has long been used as an artistic medium. It has been used to make sculptures and carvings Sports and recreational equipment: Many types of sports equipment are made of wood. eg: cricket bats, baseball bats. 11. HOW DOES THE CONSTRUCTION OF NEW DAMS AFFECT FOREST RESOURCES/ ECOLOGY/ NATURAL INHABITANTS Submergence of forests: The construction of dams result in forest submergence. Roughly four and a half million hectares of forest has been submerged so far! Apart from forests, the reservoir and the dam also affect other ecosystems and various fauna and flora species. Reservoirs also submerge productive agricultural land in the valley. This not only has a social and economic cost but also adversely affects cultivated biodiversity and a host of birds, insects, mammals and reptiles that have adapted to agricultural ecosystems. The variation and reduction in water flow in the river adversely affects water availability downstream, both from surface sources and because of inadequate recharging of groundwater. Degraded catchments, excessive rainfall or over-filling of reservoirs, may make it necessary to suddenly release large quantities of water from the reservoir in order to protect the dam structure. Property losses, of Natural inhabitants/farmers caused by dam construction, are impossible to be compensated for by governments or investors. The homes of local farmers are traditional courtyard houses, will be destroyed, resulting in ‘cultural crisis’. Several ethnic groups and Tribal have grown up and lived in the catchment area for generations, lose their internal harmony.

12. DISCUSS THE IMPACTS OF MINING OPERATIONS IN FOREST AREA. Impacts of mining and quarrying for construction materials: The soil, stones and sand required for the construction of dams and canals are often mined and quarried from around the dam or canal site. Such extraction can also have ...adverse environmental impacts, especially by aggravating dust pollution, disturbing wildlife and destroying vegetation. The scars and pits that such mining and quarrying leave (sometimes called borrow pits) remain as ecological sores and can also have an adverse impact on the dam and the canals. 13. DISCUSS THE ROLE OF WATER AS A MAJOUR NATURAL RESOURCE. Water resources are sources of water that are useful or potentially useful. Uses of water include agricultural, industrial, household, recreational and environmental activities. Agricultural: 69% of worldwide water use is for irrigation, with 15-35% of irrigation withdrawals being unsustainable. 9

Industrial: It is estimated that 22% of worldwide water is used in industry. Major industrial users include hydroelectric dams, thermoelectric power plants, which use water for cooling, ore and oil refineries, which use water in chemical processes, and manufacturing plants, which use water as a solvent. Household: It is estimated that 8% of worldwide water use is for household purposes, including drinking water, bathing, cooking, sanitation, and gardening Recreation: Recreational water use is usually a very small but growing percentage of total water use. eg: water skiers, nature enthusiasts and swimmers. 14. DISCUSS THE USE AND OVER-USE OF SURFACE AND GROUND WATER. 15. DISCUSS THE VARIOUS SOURCES OF WATER. Rain water: Rain water is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. Surface water: Surface water is water collecting on the ground or in a stream, river, lake, wetland or ocean; it is related to water collecting as groundwater or atmospheric water. It is naturally replenished by precipitation and naturally lost through discharge to evaporation and sub-surface seepage into the ground. Depletion of surface and ground water sources for public consumption (including industrial, commercial, and residential) is caused by over-pumping. Groundwater: Groundwater is water located beneath the earth's surface in soil pore spaces and in the fractures of rock formations. Groundwater is also often withdrawn for agricultural, municipal and industrial use by constructing and operating extraction wells. is a highly useful and often abundant resource. Over-use of Groundwater or overdraft, can cause major problems to human users and to the environment. The most evident problem (as far as human groundwater use is concerned) is a lowering of the water table beyond the reach of existing wells. Wells must consequently be deepened to reach the groundwater. Groundwater is also ecologically important as it sustains rivers, wetlands and lakes. 16. IDENTIFY THE CAUSES OF FLOOD AND DROUGHT Floods: Floods can occur if water accumulates across an impermeable surface (e.g. from rainfall) and cannot rapidly dissipate (i.e. gentle orientation or low evaporation). Floods can be caused by a) storms b) heavy rains from monsoons, hurricanes and tropical depressions, foreign winds and warm rain affecting snow pack. C) unexpected drainage obstructions such as landslides, ice, or debris d) Sudden release from an upstream impoundment created behind a dam, landslide or glacier e) Caused by a significant and unexpected event e.g dam breakage, or as a result of another hazard (eg. volcanic eruption) f) Accidental damage by workmen to tunnels or pipes Drought: A drought is an extended period of months or years when a region notes a deficiency in its water supply whether surface or underground water. Generally, this occurs when a region receives consistently below average rain. Drought can caused by a) deforestation b) global warming c) soil erosion d) Oceanic and atmospheric weather cycles such as the El-Nino e) human activity such as over farming, excessive irrigation. 10

17. DISCUSS THE IMPACTS OF FLOOD AND DRAUGHT Floods: Floods cause physical damage to structures, including bridges, buildings, sewerage systems, roadways, and canals. It contaminates water supplies and the unhygienic conditions spread of water-borne diseases. It destroys Crops and food supplies. Shortage of food crops can be caused due to loss of entire harvest. It destroys transport links, so hard to get emergency aid to those who need it. Floods cause economic hardship due to temporary decline in tourism, rebuilding costs, food shortage leading to price increase, etc. Flooding can be highly traumatic for individuals, in particular where deaths, serious injuries and loss of property occur. Drought: Periods of drought can have significant environmental, agricultural, health, economic and social consequences. Drought can also reduce water quality, because lower water flows reduce dilution of pollutants and increase contamination of remaining water sources. Common consequences of drought include: a) Diminished crop growth or yield productions and carrying capacity for livestock b) Dust bowls, themselves a sign of erosion, which further erode the landscape c) Dust storms, when drought hits an area suffering from desertification and erosion d) Famine due to lack of water for irrigation e) Habitat damage, affecting both terrestrial and aquatic wildlife f) Malnutrition, dehydration and related diseases g) Mass migration, resulting in internal displacement and international refugees h) Reduced electricity production due to reduced water flow through hydroelectric dams i) Shortages of water for industrial users j) Snake migration and increases in snakebites k) Social unrest l) War over natural resources, including water and food m) Wildfires, such as Australian bushfires, are more common during times of drought 18. “FUTURE WARS WILL BE FOR THE CONTROL OF WATER.” SUBSTANTIATE Water’s viability as a commercial resource, which includes fishing, agriculture, manufacturing, recreation and tourism, among other possibilities, can create dispute even when access to potable water is not necessarily an issue. As a resource, some consider water to be as valuable as oil, needed by nearly every industry, and needed nearly every day.Water shortages can completely cripple an industry just as it can cripple a population, and affect developed countries just as they affect countries with less-developed water infrastructure. Because water is so central to agricultural trade, water disputes are common among nations. Countries with greater access to water supplies may fare better from an economic standpoint than those facing crisis, which creates the potential for conflict. The WTO plays more of a role in agriculturally based disputes that are relevant to conflict over specific sources of water. Still, it provides an important framework that shapes the way water will play into future economic disputes. Beyond all, only less than 1% of water resources will be good enough to drink in the near future! 19. DISCUSS THE BENEFITS OF DAMS

Dams produce a broad range of domestic and economic benefits from a single investment. An additional local benefit is the employment opportunities during the multiple year construction of a reservoir project. Effective management of the world’s water is essential to sustaining the existing and future population of the world. Key purposes and benefits include: a) Water Supply for domestic and industrial use b) Irrigation for agriculture (food supply) c) Flood control d) Inland navigation e) Recreation e) Hydropower: clean, efficient, dependable and renewable form of energy.11

20. DISCUSS THE TERM: MINERAL-RESOURCES AND THEIR USES A 'Mineral Resource' is a concentration of material of intrinsic economic interest in or on the earth's crust in such form, quality and quantity that there are reasonable prospects for eventual economic extraction. These are the natural resources which cannot be renewed. They can be classified into metallic mineral resources and non-metallic mineral resources. The major Mineral Resources that are commonly found in the vast lands of countries play a key role in enhancing the economy. Uses: Minerals are important to our health. We need small amounts of a wide variety of minerals. Minerals found in Tennessee which people need include: calcium, phosphorus, sulfur, copper, fluoride, iron, and zinc. Coal, oil and natural gas provide us with almost all of the energy we use to light, heat and run our world. Minerals are ingredients in almost all of the products we use from fertilizer to plastics. Minerals are common ingredients in pigments. Minerals also play an important role in the processing of materials. 21. WRITE THE DETRIMENTAL EFFECTS OF OVER EXPLOITATION OF MINERALS. Minerals are the natural resources which cannot be renewed. The detrimental effects of over exploitation are. a) Rapid Depletion of High Grade Mineral Deposits: Exploitation of mineral wealth at a rapid rate shall naturally deplete our good quality deposits. When the miners carry on the extraction from increasingly lower and lower grade of deposits which possess a poorer percentage of the metal. Naturally involve a large amount of energy expenditure as well as a large quantity of waste material production. b) Wastage and Dissemination of Mineral Wealth: Extraction of one element usually scatters and wastes a number of other elements, many of which are in short supply. We must try to conserve our resources and also to reduce pollution. c) Pollution of Environment from Mining and Processing Wastes: Mining has created some of the largest 'Environmental disaster' zones in the world. Each step in mining and processing operations produces large quantities of waste materials. d) Pollution Caused by Heavy Energy Requirement of Mining Industry: Every operation related with mining industry need huge amounts of energy. ie. From removing the over-burden to finished products. Naturally, the rates of environmental pollution will be very high. 22: WHY IS CONSERVATION OF MINERAL RESOURCES NECESSARY AND WHAT ARE THE MEASURES TAKEN TO CONSERVE MINERALS? Minerals are important to be conserved because: a. Industry and agriculture depend upon minerals and the substances manufactured from them. b. Workable minerals are in insufficient quantities. (Just one per cent of the earth's crust) c. We are rapidly consuming mineral resources that require millions of years to be renewed. d. The natural rate of replenishment is very small in comparison to the present rates of consumption. e. Mineral resources are finite and non-renewable. f. Mineral deposits in our country will get exhausted in the future.eg. Due to decrease in good quality and they comes from great depths the costs of mineral extraction is increasing.

Measures: Minerals are a non-renewable resource. It takes thousands of years for the formation and concentration of minerals. The rate of formation is much smaller than the rate 12

at which the humans consume these minerals. It is necessary to reduce wastage in the process of mining. Minerals can be conserved in by the following measures: a) · Use of improved technologies to allow use of low grade minerals at low costs b) Using substitutes c) Use of scrap metals d) Recycling of metals is good way in which the mineral resources can be conserved e) they can be used in a judicious manner. 23: DISCUSS THE ENVIRONMENTAL EFFECTS OF EXTRACTING AND USING OF MINERAL RESOURCES. Environmental degradation resulting from mining activity in general can be briefly enumerated as follows:

1. Air pollution with dust and gases due to drilling, blasting, mine haulage and transportation by road, and also from waste heaps;

2. 2. Water pollution when atomic elements and other harmful elements are present in the ore/mineral mine effluents;

3. Modifying water regimes such as surface flow, groundwater availability and lowering down of water table;

4. Soil erosion, soil modification with dust and salt;

5. Noise and vibration problem in the mine and adjoining habitat including wild life;

6. Alteration of the landform;

7. Deforestation affecting flora and fauna; and

8. Spoiling aesthetics with untreated waste dumps.

24: WRITE A CASE STUDY FOR OVER EXTRACTION OF MINERALS. During the 1980s, Papua - New Guinea experienced a proliferation of mining projects. With the third-largest gold reserves in the world, the country has become a magnet for giant multinationals seeking to exploit this rich resource along with extensive silver and copper deposits. The price of copper began falling in the mid-1980s, causing the Papuan government to seek an increase in copper production to maintain income to the nation. Toxic waste from the mines has polluted many areas of the country. Local residents must live with the side effects of mining. Soon after mining began, a drop in the fish population, prawns, lobsters, and bivalves have also declined, and birds that depend on riverine life have also left. The water is no longer safe for bathing, washing clothes, swimming, or drinking. Local residents, have taken to armed resistance to protest the destruction of habitat and to express dissatisfaction with their lack of sharing in the mining benefits. Discontent has led to some violence against the government and mining companies. 25. WRITE A SHORT NOTE ON FOOD RESOURCES.

Human body needs food for various purposes. Food consumed by humans are of different types and a balanced diet is needed for all practical purposes, vitamins, proteins carbohydrates and minerals are primarily obtained from cereals, fruits, vegetables, pulses and spices, milk, butter, meat and eggs all of which obtained from different types of plants and animals. The source of much of the food consumed by man is terrestrial agricultural, which represents the most manipulated of all the non-urban ecosystems. There are two main types of agriculture (1) Crop agriculture in which plant production is harvested for use by man and (2) Animal agricultural where a crop from highly manipulated ecosystem is fed to domesticated animals. Cereals provide carbohydrates for energy requirements: wheat, rice, 13

maize, millets and sorghum. Pulses provide proteins: pea, gram, black gram, green gram, pigeon pea and lentil. Oilseeds provide necessary fats.:soya bean, ground nut, sesame, castor, mustard, linseed and sun flower. Vegetables, spices and fruits provide vitamins and minerals. 26. DISCUSS GREEN REVOLUTION IN INDIA Green Revolution refers to a series of research, development, and technology transfer initiatives, occurring between 1943 and the late 1970s, that increased industrialized agriculture production in India. The initiatives involved the development of high-yielding varieties of cereal grains, expansion of irrigation infrastructure, and distribution of hybridized seeds, synthetic fertilizers, and pesticides to farmers. "Green Revolution" was started by Norman Borlaug in Mexico in 1943. M.S. Swaminathan was the father of green revolution in India. The projects within the Green Revolution spread technologies that had already existed, but had not been widely used outside industrialized nations. These technologies included pesticides, irrigation projects, synthetic nitrogen fertilizer and improved crop varieties developed through the conventional, science-based methods available at the time. Cereal production more than doubled in developing nations between the years 1961–1985. Yields of rice, maize, and wheat increased steadily during that period. 27. DISCUSS THE BASIC CONCEPT OF FOOD CHAIN WITH THE HELP OF AN EXAMPLE. Food chains were first introduced by the African-Arab scientist and philosopher Al-Jahiz in the 9th century. Every living thing needs energy in order to live. A food chain shows how each living thing gets food, and how nutrients and energy are passed from creature to creature. Food chains begin with plant-life, and end with animal-life. A food chain is a linear sequence of links in a food web starting from a trophic species that eats no other species in the web and ends at a trophic species that is eaten by no other species in the web. A food chain consisting of a flower, a frog, a snake and an owl consists of four levels; whereas a food chain consisting of grass, a grasshopper, a rat, a snake and finally a hawk consists of five levels. Producers, such as plants, are organisms that utilize solar energy or heat energy to synthesize starch. All food chains must start with a producer. Consumers are organisms that eat other organisms. All organisms in a food chain, except the first organism, are consumers. Food chain varies in length from three to six or more levels. Food chains are often used in ecological modeling. 28. DISCUSS THE TERM INTERDEPENDENCE IN A FOOD CHAIN

The concept of food chains and food webs relies upon the interdependent relationships among all plants and animals. If the lion becomes extinct, for example, it is taken out of its food chains and the food web. Soon, giraffes will become more populous, eating more and more trees, which will soon become sparse. When those trees become sparse, other organisms dependent upon them will, too. Humans, too, are part of food chains and food webs. People need plants and animals to survive, just as other omnivorous consumers, and certain organisms, such as particular bacteria and domestic animals, need humans to survive. As any other animal, humans are dependent on decomposers to dispose of the dead. However, if one consumer becomes too dominant--using a disproportionate amount of resources--other plants and animals decline in numbers. Humans are a good example of this; as humans dominate the planet's resources, more and more plants and animals may become extinct.14

29: DISCUSS WORLD FOOD CRISIS OR FOOD SECURITY AT THE GLOBAL LEVEL Present scenario: Food prices have hovered near an all-time peak since late 2010 sending tens of millions of people into poverty. Failed crops – often caused by our changing climate – hit food prices hard. So does the rising cost of oil – used to grow, fertilize and transport food. Short-sighted biofuels strategies play a part too – taking food off of people's plates and putting it into car tanks. Humanity face an uncertain future, because all anyone can think about is where their next meal will come from. Food security is the measure of the ability ensure access to essential nutrition. It refers to a household's or country's ability to provide future physical and economic access to sufficient, safe, and nutritious food that fulfills the dietary needs and food preferences of that household for living an active and healthy life. The three facets of food security: food availability, food access, and food use. The various problems affecting food security are. Population growth: Food production in most of the developing countries lag behind their population growth levels. Malnutrition among women and children are very common in third world countries. Forests, agricultural lands and wet lands have been converted as agricultural lands worldwide, arising serious ecological questions. Global water crisis: The water tables are falling in almost every country due to widespread over-pumping using powerful diesel and electric pumps. Poor agricultural practices: Unsustainable agricultural practices like mono-cropping, farming on steep slopes, pesticide and chemical fertilizer usage, row-cropping, and the use of surface irrigation reduce crop yield. Excessive mechanization of agriculture results in excessive soil erosion. Land degradation: Intensive farming often leads to a vicious cycle of exhaustion of soil fertility and decline of agricultural yields. Approximately 40% of the world's agricultural land is seriously degraded. Our fertile soils are being exploited faster than they could recuperate. Land deals/ real estate: Corporations are buying up the rights to millions of hectares of agricultural land in developing countries in an effort to secure their own long-term food supplies as well as real estate; ultimately resulting in decline of agricultural lands. Hybridization, genetic engineering and loss of biodiversity:Inorder to create “high yielding varieties”, local governments and industry have been pushing hybridization which has resulted in several of the indigenous breeds becoming extinct or threatened, resulting in genetic erosion and pollution. Genetically modified seed varieties drastically affect the agro-economy. Climate change: Climate change affects food production directly through changes in agro-ecological conditions and indirectly by affecting growth and distribution of incomes, and thus demand for agricultural produce. 30: DISCUSS THE ENVIRONMENTAL IMPACTS CAUSED BY AGRICULTURE Agriculture imposes external costs upon society through pesticides, nutrient runoff, excessive water usage, and assorted other problems. Depletion of ozone layer and Climate change: The agriculture industry produces large amounts of greenhouse gases detrimental to ozone layer. Chemical fertilizers also contribute a lot to greenhouse gas production and global warming. Agriculture can both mitigate or worsen global warming.15

Water pollution: Excessive fertilization and manure application to cropland cause nutrient runoff and leaching from agricultural land. These nutrients contribute algal booms resulting in fish kills, loss of biodiversity and water contamination. Pesticides: Pesticides may cause acute and delayed health effects in workers who are exposed.Pesticide use raises a number of environmental concerns. Pesticides are one of the majour causes of water pollution and contributes of soil contamination.Apart from these, soil erosion, land degradation, deforestation and endangered wildlife and loss of genetic diversity are very important environmental impacts of agriculture. 31. DISCUSS THE EFFECTS OF OVERGRAZING Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, or by overpopulations of native or non-native wild animals.Overgrazing reduces the usefulness, productivity, and biodiversity of the land and is one cause of desertification and erosion. Overgrazing is also seen as a cause of the spread of invasive species of non-native plants and weeds.Overgrazing is used as the canonical example of the tragedy of the commons. Sustainable grassland production is based on grass and grassland management, land management, animal management, and livestock marketing. Grazing management, with sustainable agriculture and agro-ecology practices, is the foundation of grassland-based livestock production since it affects both animal and plant health and productivity 32: WHAT ALL ARE THE MAIN CAUSES OF LANDSLIDING?

The causes of landslides are usually related to instabilities in slopes. It is usually possible to identify one or more landslide causes and one landslide trigger. The difference between these two concepts is subtle but important. The landslide causes are the reasons that a landslide occurred in that location and at that time. Landslide causes are listed in the following table, and include geological factors,morphological factors, physical factors and factors associated with human activity.

Geological causes

• Weathered Materials

• Sheared materials

• Jointed or fissured materials

• Adversely orientated discontinuities

• Permeability contrasts

• Material contrasts

• Rainfall and snow fall

• Earthquakes

Morphological causes

• Slope angle

• Uplift

• Rebound

• Fluvial erosion

• Wave erosion

• Glacial erosion

• Erosion of lateral margins

• Subterranean erosion

• Slope loading

• Vegetation change

• Erosion

Physical causes

• Intense rainfall

• Rapid snow melt

• Prolonged precipitation

• Rapid drawdown

• Earthquake

• Volcanic eruption

• Thawing

• Freeze-thaw

• Ground water changes

• Soil pore water pressure

• Surface runoff

• Seismic activity

• Soil erosion

Human causes

• Excavation

• Loading

• Draw-down

• Land use change

• Water management

• Mining

• Quarrying

• Vibration

• Water leakage

• Deforestation

• Land use pattern

• Pollution

33: HOW COULD BE THE HUMAN ACTIVITIES PLAY SOME ROLE IN LAND SLIDING?

Human economic activities play an important role in the formation of landslides. The denudation of the forest on mountain slope fields exposes the slope, and accelerates the processing of the weathering of the rock on the mountain slope. This contributes to the risk of 17

landslides, also helps landslides to worsen further. In addition, overgrazing causes the soil on the slope to become trampled. Irrational farming technologies, for example, plowing in a lengthwise direction down the slope, accelerate a loss of substances on the slopes that are eroded by weathering. These practices continue to deteriorate the mountain slopes and make these slopes the source regions of landslides. With the development of the economy and the sports in mountainous regions, the risk of landslides increases. In the past, the human factors contributing to landslides were mainly attributed to the denudation of the forest and the irrational farming technologies. Nowadays, the factors of industrial production also play a role. Industrial factors include the irrational piling of the waste rock and the mullock of mines, the damage to the slope caused by road building and open-air striping mining. The explosion of open-air mining destroys the local balance and all kinds of industrial facilities and sites to be built, accelerating the formation of landslides. 34: WHAT ARE THE CAUSES OF SOIL EROSION? There is no particular soil erosion cause which can be singled out and assumed as the main cause of soil erosion. The process has many underlying factors, some induced by nature and some by humans.Human Induced Causes of Soil Erosion Human exploitation of nature is perhaps the most hazardous cause of soil erosion, which has increased over the last decade. Human activities, such as faulty farming systems, deforestation caused by overgrazing, clearance of land for agricultural purposes and construction, dam construction and diversion of the natural course of river, and mining activities are just a few among the various human activities which have either directly or indirectly weakened the topmost layer of the planet, thus making it vulnerable to excessive wearing away by the various agents of erosion. For instance, tree roots help in holding the soil together, and therefore depletion of vegetation cover is bound to make soil vulnerable to erosion by running water. Natural Causes of Soil Erosion Gradient of Slope:Gradient of the slope is an important factor when it comes to soil erosion. In fact, erosion and gradient have a direct relationship. The steeper the gradient, higher is the rate of erosion and vice versa. This factor plays an important role in water erosion, glacial erosion, and gravitational erosion. Soil Properties:The vulnerability of a piece of land to soil erosion depends on the physical and chemical properties of the soil as well. Different types of soil have different physical and chemical properties. The texture, structure, water retention capability, etc. play an important role in determining whether the soil is susceptible to erosion by various agents of erosion or not. This factor is common in all the above mentioned types of erosion. Water Flow:Hydrological cycle, especially the surface flow as well as underground flow also play a major role in soil erosion.Variation in the velocity and type of the flow determine the gradient of soil erosion. This is the major factor when it comes to water erosion, and sometimes even in case of glacial erosion.

Climate:Climate determines the precipitation levels and wind velocity, which in turn effect soil erosion. More precipitation means more surface flow, and more surface flow means more 18

area vulnerable to erosion by running water. Similarly, if the wind velocity is high, erosion will also be high and eroded material will be carried farther. The climate factor plays an important role in case of wind erosion and water erosion. All the geographical processes occurring on the planet are inter-related, and a slight alteration in one tends to result in a domino effect on ten other processes, which are directly or indirectly related to each other. For instance, if soil cover is depleted vegetation cover will deplete, which will in turn affect the food source for humans. It's high time we understand the geological concept of soil erosion, and initiate soil conservation and erosion control measures. We have already induced major hazards such as climate change and global warming on the planet, adding more would only mean adding to our own woes. 35:WRITE NOTES ON DESERTIFICATION

Desertification is a type of land degradation in which a relatively dry land region becomes increasingly arid, typically losing its bodies of water as well as vegetation and wildlife. It is caused by a variety of factors, such as climate change and human activities. Desertification is a significant global

Ecological andenvironmental problem. Dry-land ecosystems are already very fragile, and can rarely sustain the increased pressures that result from intense population growth. Many of these areas are inappropriately opened to development, when they cannot sustain human settlements. The most common cause of desertification is the over cultivation of desert lands. Over-cultivation causes the nutrients in the soil to be depleted faster than they are restored. Improper irrigation practices result in salinated soils, and depletion of aquifers. Vegetation plays a major role in determining the biological composition of the soil. Studies have shown that, in many environments, the rate of erosion and runoff decreases exponentially with increased vegetation cover.Overgrazing removes this vegetation causing erosion and loss of top-soil. 36: HOW CAN WE PREVENT DESERTIFICATION?

Desertification is recognized as a major threat to biodiversity. Some countries have developed Biodiversity Action Plans to counter its effects, particularly in relation to the protection of endangered flora and fauna19

Reforestation gets at one of the root causes of desertification and isn't just a treatment of the symptoms. Environmental organizations work in places where deforestation and desertification are contributing to extreme poverty. There they focus primarily on educating the local population about the dangers of deforestation and sometimes employ them to grow seedlings, which they transfer to severely deforested areas during the rainy season.

Techniques focus on two aspects:provisioning of water, and fixation and hyper-fertilizing soil.Fixating the soil is often done through the use of shelter belts, woodlots and windbreaks. Windbreaks are made from trees and bushes and are used to reduce soil erosion and evapotranspiration. They were widely encouraged by development agencies from the middle of the 1980s in the Sahel area of Africa.

Some soils (for example, clay), due to lack of water can become consolidated rather than porous (as in the case of sandy soils). Some techniques as zaï or tillage are then used to still allow the planting of crops

Enriching of the soil and restoration of its fertility is often done by plants. Of these, the Leguminous plants which extract nitrogen from the air and fixes it in the soil, and food crops/trees as grains, barley, beans and dates are the most important. Sand fences can also be used to control drifting of soil and sand erosion.

Farmer Managed Natural Regeneration (FMNR) is another technique that has produced successful results for desert reclamation. 37: HOW CAN WE CONSERVE OUR NATURAL RESOURCES? Natural resources are drying up very fast and so need of its conservation has come up. First the problems - population growth and non-sustainable exploitation are two major factors which is the culprit and we need to think about checking both. Population explosion in last few decades has put a lot of pressure on our natural resources and this has led to over exploitation. Sustainable living is a very important idea and should be the basis of our living standards. We need to stop all kind of wastage and try to reuse everything possible. We need to understand natural resources are limited and over exploitation will harm not only us but the coming generation more. 38: SUBSTANTIATE THE ROLE OF AN INDIVIDUAL IN CONSERVING OUR PLANET Recycle and Reuse: Buy recycled. One ton of purchased recycled paper saves 4,000 kW-h of energy, 7,000 gal. of water, and 17 trees. And a tree has the capacity to filter up to 60 lbs. of pollutants from the air. Use old newspapers to protect your garden against frost. Recycle electronics — donate your old wireless phone or computer. Conserve energy and water: Turn off the TV, the faucets, and the lights when not in use. Choose energy and water efficient appliances. Open a window instead of running the AC. Caulk and weatherstrip all your doors and windows. Insulate your walls and ceilings. Use environmentally-friendly cleaning products. Collect rainwater for use during dry months in rain barrels. Learn more about the environment:Read and think about environmental issues. Visit national parks, botanical gardens, or a zoo in your area and learn more about your environment. Get involved: Join a conservation organization. Volunteer your time to pick up trash in a park or teach children about nature. Get involved in tree planting, seed collection, and weed control. Explore all the ways to get involved and choose something that excites you.20

39: ENUMERATE THE STATEMENT “NATURAL RESOURSES FOR OUR FUTURE” Use a little, save a little. The question facing nonrenewable resources is: How much do we use today to satisfy our wants and needs, and how much do we save for future wants and needs? Each drop of oil, every cubic inch of natural gas, and any molecule of iron used today imposes an opportunity cost on humans of the future. We get it and they don't. For efficiency's sake, we need to make sure that the value we get from today's use is equal to the opportunity cost on the future – Conserve. If we pursue the option of intense conservation, saving as much as we can today, then future will certainly have more resources available. Is this, however, a wise choice? Historically, each generation has been better off (higher living standard) that the previous one. Technological advances are largely responsible for this. As such, by conserving, we're probably sacrificing needlessly. We may conserve gasoline for cars that will never be built, replaced instead with something far superior. A Whimper, Not a Bang: When we use nonrenewable resources today, their prices (that is, values) will tend to rise into the future. With smaller supplies, future generations will value what's left more dearly. As such, they (the future folk) are naturally going to conserve. They're going to direct what's left to their own highest valued uses. They'll also seek out alternatives to their limited supplies. Let the Sun shine in. We don't need to concern ourselves over the use of perpetual resources. It matters not how much we use today, because more will be waiting tomorrow. In fact, from an efficiency view, we should make the most use of any and all available perpetual resources. When we don't use perpetual resources, we're missing out a valuable opportunity that has absolutely no cost. Let me reiterate that point. Using perpetual resources -- especially the sun's energy -- imposes no opportunity cost on future generations. This is as close as we can get to a free good. Use, but don't abuse. Renewable resources can be used like perpetual resources, to a point. Renewable resources have what we can call a "rate of regeneration," that is, the natural rate of growth. So long as the rate we use renewable resources is less than this rate of regeneration, we're in good shape. We'll never exhaust the supply or cause extinction. For example, if 10,000 trout in a stream have a natural 5 percent growth rate, then we can catch 500 each year without reducing the total below 10,000. Moreover, if a new seedling is planted each time a mature tree is chopped down, then our forests will continue into perpetuity. Problems, of course, result when our use outpaces regeneration. Thoughts on Future Value: On the supply side, the most obvious source of value is the quantity of nonrenewable resources available. All things considered, if the supply is less, the value is likely to be higher. We naturally tend to value stuff more when we have less of it. This alone would make future, diminished supplies of nonrenewable resources more valuable. On the demand side, the value of nonrenewable resources springs from two related items. First, resources are more valuable when they produce more valuable (consumer satisfying) goods. Oil is valuable today, because it's used to power our beloved and exceedingly valuable cars. Future supplies of oil would be less valuable it future people didn't value cars as greatly. Second, resources are more or less valuable depending on the availability of alternatives used to produce valuable goods. A tank full of oil is much less valuable if we have another source of car fuel.21

Module II ECOSYSTEMS 1: WRITEA SHORT NOTE ON AN ECOSYSTEM

An ecosystem is a community of living organisms (plants, animals and microbes) in conjunction with then-on-living components of their environment (things like air, water and mineral soil), interacting as a system. .These components are regarded as linked together through nutrient cycles and energy flows.As ecosystems are defined by the network of interactions among organisms, and between organisms and their environment,they can come in any size but usually encompass specific, limited spaces[ (although some scientists say that the entire planet is an ecosystem)

Energy, water, nitrogen and soil minerals are other essential abiotic components of an ecosystem. The energy that flows through ecosystems is obtained primarily from the sun. It generally enters the system throughphotosynthesis, a process that also captures carbon from the atmosphere. By feeding on plants and on one another, animals play an important role in the movement of matter and energy through the system. They also influence the quantity of plant and microbial biomass present. By breaking down dead organic matter,decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be readily used by plants and other microbes. 2: DESCRIBE THE VARIOUS FACTORS AFFECTING AN ECOSYSTEM

Ecosystems are controlled both by external and internal factors. External factors such as climate, the parent material which forms the soil and topography, control the overall structure of an ecosystem and the way things work within it, but are not themselves influenced by the ecosystem. Other external factors include time and potential biota. Ecosystems are dynamic entities—invariably, they are subject to periodic disturbances and are in the process of recovering from some past disturbance. Ecosystems in similar environments that are located in different parts of the world can end up doing things very differently simply because they have different pools of species present. The introduction of non-native species can cause substantial shifts in ecosystem function. Internal factors not only control ecosystem processes but are also controlled by them and are often subject to feedback loops. While the resource inputs are generally controlled by external processes like climate and parent material, the availability of these resources within the ecosystem is controlled by internal factors like decomposition, root competition or shading. Other internal factors include disturbance, succession and the types of species present. Although humans exist and operate within ecosystems, their cumulative effects are large enough to influence external factors like climate. 3: HOW BIODIVERSITY AFFECTS THE FUNCTIONING OF AN ECOSYSTEM?

Ecosystem processes are broad generalizations that actually take place through the actions of individual organisms. The nature of the organisms—the species, functional groups and trophic levels to which they belong—dictates the sorts of actions these individuals are capable of carrying out, and the relative efficiency with which they do so. Thus, ecosystem processes are driven by the number of species in an ecosystem, the exact nature of each individual species, and the relative abundance organisms within these species.Biodiversity plays an important role in ecosystem functioning. 22

Ecological theory suggests that in order to coexist, species must have some level of limiting similarity—they must be different from one another in some fundamental way, otherwise one species would competitively exclude the other. Despite this, the cumulative effect of additional species in an ecosystem is not linear—additional species may enhance nitrogen retention, for example, but beyond some level of species richness, additional species may have little additive effect.The addition (or loss) of species which are ecologically similar to those already present in an ecosystem tends to only have a small effect on ecosystem function. Ecologically distinct species, on the other hand, have a much larger effect. Similarly, dominant species have a large impact on ecosystem function, while rare species tend to have a small effect. Keystone species tend to have an effect on ecosystem function that is disproportionate to their abundance in an ecosystem. So,in such a way diversity play some major role in the overall functioning of an ecosystem. 4: SUBSTANTIATE THE ROLE OF ECOSYSTEM AS GOODS AND SERVICES Ecosystems provide a variety of goods and services upon which people depend. Ecosystem goods include the "tangible, material products" of ecosystem processes—food, construction material, medicinal plants—in addition to less tangible items like tourism and recreation, and genes from wild plants and animals that can be used to improve domestic species. Ecosystem services, on the other hand, are generally "improvements in the condition or location of things of value".These include things like the maintenance of hydrological cycles, cleaning air and water, the maintenance of oxygen in the atmosphere, crop pollination and even things like beauty, inspiration and opportunities for research. While ecosystem goods have traditionally been recognized as being the basis for things of economic value, ecosystem services tend to be taken for granted. 5: DESCRIBE BRIEFLY THE CONCEPT OF FOOD WEB

A food web (or food cycle) depicts feeding connections (what eats what) in an ecological community and hence is also referred to as a consumer-resource system. Ecologists can broadly lump all life forms into one of two categories called trophic levels: 1) the autotrophs, and 2) the heterotrophs. To maintain their bodies, grow, develop, and to reproduce, autotrophs produce organic matter from inorganic substances, including bothminerals and gases such as carbon dioxide. These chemical reactions require energy, which mainly comes from the sun and largely by photosynthesis, although a very small amount comes from hydrothermal vents andhot springs. A gradient exists between trophic levels running from complete autotrophs that obtain their sole source of carbon from the atmosphere, to mixotrophs (such as carnivorous plants) that are autotrophic organisms that partially obtain organic matter from sources other than the atmosphere, and completeheterotrophs that must feed to obtain organic matter. The linkages in a food web illustrate the feeding pathways, such as where heterotrophs obtain organic matter by feeding on autotrophs and other heterotrophs. The food web is a simplified illustration of the various methods of feeding that links an ecosystem into a unified system of exchange. There are different kinds of feeding relations that can be roughly divided into herbivory,carnivory, scavenging and parasitism. Some of the organic matter eaten by heterotrophs, such as sugars, provides energy. Autotrophs and heterotrophs come in all sizes, from microscopic to many tonnes - fromcyanobacteria to giant redwoods, and from viruses and bdellovibrio to blue whales.23

6: DISCUSS BRIEFLY THE TROPHIC LEVELS IN A FOOD WEB

Food webs have trophic levels and positions. Basal species, such as plants, form the first level and are the resource limited species that feed on no other living creature in the web. Basal species can be autotrophs or detritivores, including "decomposing organic material and its associated microorganisms which we defined as detritus, micro-inorganic material and associated microorganisms (MIP), and vascular plant material." Most autotrophs capture the sun's energy in chlorophyll, but some autotrophs (the chemolithotrophs) obtain energy by the chemical oxidation of inorganic compounds and can grow in dark environments, such as the sulfur bacterium Thiobacillus, which lives in hot sulfur springs. The top level has top (or apex) predators which no other species kills directly for its food resource needs. The intermediate levels are filled with omnivores that feed on more than one trophic level and cause energy to flow through a number of food pathways starting from a basal species.

In the simplest scheme, the first trophic level (level 1) is plants, then herbivores (level 2), and then carnivores (level 3). The trophic level is equal to one more than the chain length, which is the number of links connecting to the base. The base of the food chain (primary producers or detritivores) is set at zero. Ecologists identify feeding relations and organize species into trophic species through extensive gut content analysis of different species. The technique has been improved through the use of stable isotopes to better trace energy flow through the web.It was once thought that omnivorous was rare, but recent evidence suggests otherwise. This realization has made trophic classifications more complex. 7 :WHAT DO YOU MEAN BY FOOD CHAIN? A common metric used to quantify food web trophic structure is food chain. Food chain is another way of describing food webs as a measure of the number of species encountered as energy or nutrients move from the plants to top predators.There are different ways of calculating food chain length depending on what parameters of the food web dynamic are being considered: connectance, energy, or interaction.In its simplest form, the length of a chain is the number of links between a trophic consumer and the base of the web. The mean chain length of an entire web is the arithmetic average of the lengths of all chains in a food web In a simple predator-prey example, a deer is one step removed from the plants it eats (chain length = 1) and a wolf that eats the deer is two steps removed (chain length = 2). The relative amount or strength of influence that these parameters have on the food web address questions about:

• the identity or existence of a few dominant species (called strong interactorsor keystone species)

• the total number of species and food-chain length (including many weak interactors) and

• how community structure, function and stability is determined.

8.WRITE A SHORT NOTE ON ECOLOGICAL PYRAMIDS

In a pyramid of numbers, the number of consumers at each level decreases significantly, so that a single top consumer, (e.g., a polar bear or a human), will be supported by a much larger number of separate producers. There is usually a maximum of four or five links in a food chain, although food chains in aquatic ecosystems are more often longer than those on land. Eventually, all the energy in a food chain is dispersed as heat.

Ecological pyramids place the primary producers at the base. They can depict different numerical properties of ecosystems, including numbers of individuals per unit of area, biomass (g/m2), and energy (k cal m−2 yr−1). The emergent pyramidal arrangement of trophic levels with amounts of energy transfer decreasing as species become further removed from the source of production is one of several patterns that is repeated amongst the planets ecosystems. The size of each level in the pyramid generally represents biomass, which can be measured as the dry weight of an organism.[ Autotrophs may have the highest global proportion of biomass, but they are closely rivaled or surpassed by microbes. 25

9: WRITE SHORT NOTE ON DESERT ECOSYSTEM.

Deserts host plants and animals living in what strikes many humans as oppressive environments. Solar energy that green plants convert into food fuels life here. Although in most ecosystems plants compete for sunlight, here most plants are adapted to minimize the effects of too much solar energy.

Annuals compress their life cycles and go dormant as conditions grow unfavorable. Sudden carpets of wildflowers mark their waking from dormancy as seeds, like time travelers, quickly germinate, flower, and renew their species before seasonal moisture dries up once again. Patient perennials ply an alternate strategy: Joshua trees flourish in moist periods, then bide their time in long dry periods.

Many animals get their energy by eating plants, but desert plants give up the fruit of their production very reluctantly. Sharp spines and chemical-laden leaves discourage plant-eaters. The kangaroo rat avoids these obstacles by eating seeds that, while safe to eat, can be hard to find. Many are small and look like grains of sand. With sensitive front paws a kangaroo rat sifts sand to find seeds by touch, eats them and transforms them into animal tissue. The plant's solar energy flows through the ecosystem as kangaroo rats, and other herbivores like jackrabbits, fallprey to carnivores like great horned owls, coyotes, bobcats or snakes. The different components of a desert ecosystem are:26

(A)Abiotic Component The abiotic component includes the nutrients present in the soil and the aerial environment. The characteristic feature of the abiotic component is lack of organic matter soil and scarcity of water. (B)Biotic Component The various biotic components representing three functional groupsare: (a)Producer organisms The producers are mainly shrubs or bushes, some grasses and a few trees. The most famous desert plant is the cactus. There are many species of cacti. The saguaro cactus is the tall, pole shaped cactus. The saguaro can grow up to 40 feet tall. It can hold several tons of water inside its soft tissue. Like all cacti, the saguaro has a thick, waxy layer that protects it from the Sun. Other succulents include the desert rose and the living rock. This strange plant looks like a spiny rock. Its disguise protects it from predators. The wellischia are a weird looking plant. It has two long leaves and a big root. This plant is actually a type of tree and it can live for thousands of years. There are many other kinds of desert plants. Some of them have thorns; others have beautiful flowers and deadly poisons. Evening the worst conditions, these plants continue to thrive. (b)Consumers These include animals such as insects and reptiles. Besides them, some rodents, birds and some mammalian vertebrates are also found. Desert Insects and Arachnids: There are plenty of insects in the desert. One of the most common and destructive pests is the locust. A locust is a special type of grasshopper. They travel from place to place, eating all the vegetation they find. Locusts can destroy many crops in single day. Not all desert insects are bad, though. The yucca moth is very important to the yucca plant, because it carries pollen from the flower to the stigma. The darkling beetle has a hard, white, wing case that reflects the Sun’s energy.This allows the bug to look for food duringthe day.There are also several species of ants in the desert. Theharvester ants gather seeds and store them for use during the dry season. And the honeypot ants have a very weird habit. Some members of the colony eat large amounts of sugar, so much that their abdomens get too large for them to move. Therese of the colony feeds off this sugar. There are also arachnids in the desert. Spiders are the mostnotable arachnids, but scorpions also belong in this group. Some species of scorpions have poison in their sharp tails. They sting heir predators and their prey with the piercing tip in the soil and scarcity of water. Desert Reptiles

Reptiles are some of the most interesting creatures of the desert. Reptiles can withstand the extreme temperatures because they can control their body temperatures very easily. We can put most of the desert reptiles into one of two categories; snakes and lizards.Many species of rattlesnakes can be found in the desert.Rattlesnakes have a noisy rattle they use to warn enemies tostay away. If the predator ins’t careful, the rattlesnake will strike, injecting venom with its sharp fangs. Other desert snakes include the cobra, king snake and the hognose. Lizards make up the second category of desert reptiles. They are probably the most bizarre looking animals in the desert. While some change colors and have sharp scales for defense, others change their appearance to look more threatening. One such creature is the frilled lizard. When enemies are near, the lizard opens its mouth, unveiling a wide frill. This makes the lizard look bigger and scarier. The shingleback has a tail with the same shape as its head. When a predator bites at the tail, the shingleback turns around and 27

bites back. There are only two venomous lizards in the world, and one of them is the Gila monster. It has a very painful bite. Desert Mammals Like the other inhabitants of the desert, birds come up within eresting ways to survive in the harsh climate. The sandgrouse has special feathers that soak up water. It can then carry the water to its young trapped in the nest. Other birds, like the gila woodpecker, depend on the giantsaguaro s its home. This woodpecker hollows out a hole in the cactus for a nest. The cool, damp inside is safe for the babies. The roadrunner is probably the most well-known desert bird.Galahs is interesting birds, in that the number of eggs they lay depends on the climate. If the desert is in a drought, they don’t lay any. However, during more tolerable years, the galamaylay as many as five eggs. Many desert mammals are burrowers. They dig holes in the ground and stay there during the hot days. They return to the surface at night to feed. Hamsters, rats and their relative’sareal burrowers. Not only do the burrows keep the animals cool, they are also a great place to store food. Of course, not all animals live in holes in the ground. The kangaroo and spicy anteater both live in the Aureliandesert region. Spiny anteaters are unusual mammals because they lay eggs. The desert is also full of wild horses, foxes and jackals, which are part of the canine family. And we can’t forget the cats. Lions are found all over the deserts of southern Africa. They get their water from the blood of their prey. Camels – The Cars of the Desert Camels could be included in the mammal section. Camelsare the cars of the desert. Without them, people would have great difficulty crossing the hot terrain. There are two types of camels: Bactrian and dromedary. The main difference between the two is the number of humps. Dromedaries have one hump andBactrian have two. Both kinds are used by people, but only Bactrian’s are found in the wild. Camel is great transportation because they use very littlewater. Camels can withstand very high temperatures without sweating. They also store fat in their humps for food. If a Bactrian camel travels a long distance without eating, its hump will actually get smaller. (c) Decomposers Due to poor vegetation the amount of dead organic matter is very less. As a result the decomposers are very few. Common decomposers are some bacteria and fungi, most of which are thermophiles 10: WHAT ARE THE FUNCTIONS OF AQUATIC ECOSYSTEM?

Aquatic ecosystems perform many important environmental functions. For example, they recycle nutrients, purify water, attenuate floods, recharge ground water and provide habitats for wildlife. Aquatic ecosystems are also used for human recreation, and are very important to the tourism industry, especially in coastal regions.28

The health of an aquatic ecosystem is degraded when the ecosystem's ability to absorb a stress has been exceeded. A stress on an aquatic ecosystem can be a result of physical, chemical or biological alterations of the environment. Physical alterations include changes in water temperature, water flow and light availability. Chemical alterations include changes in the loading rates of bio-stimulatory nutrients, oxygen consuming materials, and toxins. Biological alterations include over-harvesting of commercial species and the introduction of exotic species. Human populations can impose excessive stresses on aquatic ecosystems.There are many examples of excessive stresses with negative consequences. Consider three. The environmental history of the Great Lakes of North America illustrates this problem, particularly how multiple stresses, such as water pollution, over-harvesting and invasive species can combine. The Norfolk Broadlands in England illustrate similar decline with pollution and invasive species. Lake Pontchartrain along the Gulf of Mexico illustrates the negative effects of different stresses including levee construction, logging of swamps, invasive species and salt water intrusion. 11: DESCRIBE BRIEFLY THE CONCEPT OF ECOLOGICAL SUCCESSION Ecological succession is the observed process of change in the species structure of an ecological community over time. The community begins with relatively few pioneering plants and animals and develops through increasing complexity until it becomes stable or self-perpetuating as a climax community.

It is a phenomenon or process by which an ecological community undergoes more or less orderly and predictable changes following disturbance or initial colonization of new habitat. Succession may be initiated either by formation of new, unoccupied habitat (e.g., a lava flow or a severe landslide) or by some form of disturbance (e.g. fire, severe wind-throw, logging) of an existing community. Succession that begins in new habitats, uninfluenced by pre-existing communities is called primary succession, whereas succession that follows disruption of a pre-existing community is called secondary succession. 12: DESCRIBE BRIEFLY THE GRASSLAND ECOSYSTEM

A biological community that contains few trees or shrubs, is characterized by mixed herbaceous (non-woody) vegetation cover, and is dominated by grasses or grasslike plants. Mixtures of trees and grasslands occur as savannas at transition zones with forests or where rainfall is marginal for trees. Grasslands occur in regions that are too dry for forests but that have sufficient soil water to support a closed herbaceous plant canopy that is lacking in deserts. Thus, temperate grasslands usually develop in areas with 10–40 in. (25–100 cm) of annual precipitation, although tropical grasslands may receive up to 60 in. (150 cm). Grasslands are found primarily on plains or rolling topography in the interiors of great land 29

masses, and from sea level to elevations of nearly 16,400 ft (5000 m) in the Andes. Because of their continental location they experience large differences in seasonal climate and wide ranges in diurnal conditions. In general, there is at least one dry season during the year, and drought conditions occur periodically. There are many more invertebrate species than any other taxonomic group in the grassland ecosystem. Invertebrates play several roles in the ecosystem. Most of the reptiles and amphibians in grassland ecosystems are predators. Relatively few bird species inhabit the grassland ecosystem, although many more species are found in the flooding pampas of Argentina than in the dry grasslands of the western United States. Their role in the grassland ecosystem involve within the grassland ecosystem are enormous numbers of very small organisms, including bacteria, fungi, algae, and viruses. From a systems perspective, the hundreds of species of bacteria and fungi are particularly important because they decompose organic material, releasing carbon dioxide and other gases into the atmosphere and making nutrients available for recycling. Bacteria and some algae also capture nitrogen from the atmosphere and fix it into forms available to plants. Much of the grassland ecosystem has been burned naturally, probably from fires sparked by lightning. Human inhabitants have also routinely started fires intentionally to remove predators and undesirable insects, to improve the condition of the rangeland, and to reduce cover for predators and enemies; or unintentionally. Thus, grasslands have evolved under the influences of grazing and periodic burning, and the species have adapted to withstand these conditions. If burning or grazing is coupled with drought, however, the grassland will sustain damage that may require long periods of time for recovery by successional processes. Structure and Function The different components of a grassland ecosystem are: Abiotic Component These are the nutrients present in the soil and other components present in the air. The basic elements are supplied by carbon dioxide, water, nitrogen, sulphates etc. All these are present in atmosphere and soil of that location. Biotic components In grasslands the producers are mainly grasses, herbs and shrubs. All these contribute to production of biomass. Common species of grass are sp. Condon etc. As regards the consumersthe basic three types are Primary, Secondary and Tertiary.Primary consumers feed directly on grass. All the grazinganimals as well as the termites and insects come under thiscategory. The secondary consumers feed on these primaryconsumers and include snakes, lizards etc. The tertiaryconsumers feed on secondary consumers. Examples are eagles and vultures. Fungi, bacteria etc. are the decomposers. 13: WRITE A SHORT NOTE ON FOREST ECOSYSTEM

A forest ecosystem is one major ecologic unit that exists as "home" for a community of either native orintroduced classified organisms. The forest ecosystem is just one of a number of unique ecosystems including prairies, deserts, polar regions and great oceans, smaller lakes and rivers. A forest ecosystem typically is associated with land masses covered in trees and those trees are often classified by foresters into forest cover types.

A forest ecosystem community is directly related to species diversity. Generally, you can assume that the more complex the structure, the greater is its species diversity. You should remember that a forest community is much more than just the sum of its trees. A forest is a system that supports interacting units including trees, soil, insects, animals, and man. Complex forest ecosystems are extremely diverse, ranging from dry desert shrub land to 30

large temperate rain forests. These natural resource professionals have categorized forest ecosystems in North America by placing them into forest biomes. Forest biomes are broad categories of natural tree/plant communities

Forest ecosystems tend to always be moving toward maturity or into what foresters call a climax forest. This maturing, also called forest succession, of the ecosystem increases diversity up to the point of old age where the system slowly collapses. One forestry example of this is growth of trees and the entire system toward an old growth forest. When the ecosystem is exploited and exploitation is maintained or when components of the forest begins to naturally die, then the maturity of the forest ecosystem declines.

Management of forests for sustainability is desirable when forest diversity is threatened by overuse, resource exploitation, old age and poor management. Forest ecosystems can be disrupted and harmed when not properly sustained. A sustained forest that is certified by a qualified certification program gives some assurance that the forest is managed to allow maximum diversity while satisfying the manager's environmental and economic demands.

14: Summarize the roles of producers, consumers, and decomposers in relation to a food chain and all of the food web interactions. Producers (photosynthetic organisms) capture solar energy and take in materials (elements such as carbon, hydrogen, oxygen, nitrogen, etc.) and make food which is then passed on to the consumers. Consumers generally carry on a process of cellular respiration which releases the energy for use for their own life functions. Both the producers and the consumers die and produce waste products which are then passed on to the decomposers (saprophytes). Decomposers are mainly bacteria and fungi that break down the materials in the waste and dead bodies and recycle them back to the producers. Note that materials are recycled but energy is not. For this reason, it is important that the Earth receive solar energy since it is the solar energy that drives the entire cycle of life, that is all the interactions and feeding relationships that we refer to as the food web. 15: WHAT IS THE ROLE OF DECOMPOSERS IN AN ECOSYSTEM? In the end every living thing in an ecosystem dies and is eaten by the decomposers. When they make material rot they release the nutrients from it, these sink back into the soil and get used again.Without decomposers soil would quickly run out of nutrients so no plants would grow and ecosystems would collapse. 16: WHAT DO YOU MEAN BY A BIOME? A biome is a large ecosystem. It is an area on the earth's surface that has similar climate, plants and animals.There are 8 main biomes: Tundra ,Taiga, Temperate forest, Tropical rainforest, Desert, Mediterranean , Savanna Temperate grassland31

17: HOW THE CLIMATE AFFECTS THE VEGETATION? Precipitation: Particularly the total amount and how it’s distributed through the year. Temperature: Especially the seasonal pattern and the length of the growing season. Number of Sunshine Hours: Which determines the amount of light for photosynthesis. Rates of evaporation, transpiration, and humidity. 18: HOW CAN WE CONSERVE FOREST ECOSYTEM? Forest Reserves. •Areas of forest that are completely protected from all activities. •They are often close to areas known as extractive reserves. Afforestation •This is planting of new trees once mature trees have been felled. •This ensures the canopy is maintained. Agro-forestry •Practice of growing trees in combination with agricultural crops. •Farmers take advantage of the protective canopy and nutrients from decomposing plant matter. Selective Logging •Individual trees felled only when they have matured. •Helps preserving canopy layer and helps slower growing hardwoods. Tree Measuring •Felling should occur only when tree has reached a specific height. •This ensures younger trees have a chance of survival. Education •A good strategy is to educate the users of the forest to become its protector. 19: HOW DOES ENERGY FLOW IN LIVING ORGANISMS? Autotrophs, such as plants, use the sun’s energy to turn water and carbon dioxide into sugar molecules. An organism that can make its own food is a producer. Producers are the source of all the food in an ecosystem. Heterotrophs cannot make their own food. They depend on auto trophs for food and energy. An organism that obtains energy by feeding on other organisms is a consumer. Consumers areclassified by what they eat. Consumers that eat only plants are called herbivores. Consumers that eat only animals are called carnivores. A consumer that eats both plants and animals is called an omnivore. An organism may play more than one role in an ecosystem. Heterotrophs that break down wastes and dead organisms and return the raw materials to the environment are called decomposers. As decomposers obtain energy for their own needs, they return simple molecules to the environment to be used again by other organisms. Ecologists use a diagram called a food chain to show to flow of energy from organism to organism in an ecosystem. In general, energy flows from producers to consumers to decomposers in an ecosystem. A diagram called a food web show many food chains are connected. 20: WHAT HAPPENS WHEN BIOMASS DECAYS? The total amount of living matter, and the remains of dead organisms, in an area is the area’s biomass. When living things die, decomposers break down the material in the biomass,and the biomass decays. The decay of biomass produces matter in the form of small molecules. This chemical breakdown also releases the energy stored in the chemical compounds in the biomass.32

21: WHAT DO YOU MEAN BY ECOLOGICAL SUCCESSION? Succession is a sequential change in the relative abundances of the dominant species in a community following a disturbance. There are 2 kinds of succession:

• Primary succession - the community develops from an essentially abiotic situation following a cataclysmic disturbance

• Secondary succession - the community develops in a habitat that has been disturbed, but not so severely as to destroy all life.

Sere - the entire sequence of stages in succession Climax - the final stage of community change. Secondary succession is faster than primary succession, because soil and some organisms remain and the abiotic conditions are not as inhospitable. There are 3 fundamental types of successional change:

• Facilitation: The organisms at a given successional stage make the environment more suitable for later successional stages. Examples: lichens breaking down rock into soil, nitrogen-fixing plants improve fertility of soil

• Tolerance: The organisms of a given successional stage have little impact on later successional stages. Example: Oldfield succession (possibly)- species of all stages get started at the same time, but are dominant at different times because of different life histories.

• Inhibition: The organisms at a given stage resist invasion by organisms of later stages. Succession proceeds when the individuals of a given stage die.

Since, the initial stage of succession depends upon the intensity and extent of the disturbance. The final stage of succession just determines by climax and topography.

22: WHAT DO YOU MEAN BY TROPHIC LEVEL? Trophic level - the order in which organisms receive solar energy / each of the steps in a food chain. 33

• First trophic level: autotrophs

Plants & some autotrophic bacteria

• Second trophic level: herbivores

Herbivores, consumers of green plants. For example: Cow

• Third trophic level: some carnivores

Carnivores, predators feed upon the herbivores. For example: Wolf

• Fourth trophic level: secondary carnivores

Secondary carnivores, which are predators that feed on predators. For example: Tiger

• Fifth...

( Many organisms fit in several levels. Examples: omnivores ) Omnivores are consumers of feeding on both plants and animals; belong to the second and third trophic level. Parasites can be in any trophic level except producers, depending upon what they parasitize. Decomposers / detritivores: all-important organisms that feed on dead or dying organic matter.; they can be in any consumer trophic level; the most common ones are fungi or bacteria, in soil or water (critical to nutrient cycling). 23: WHAT DO YOU MEAN BY FOODCHAIN AND A FOOD WEB? Food Chain: The passage of energy from a primary producer through a series of producers at higher trophic levels.

• Example:

1. Energy from sun to producers (corns) > Primary consumers (earthworths) > Secondary consumers (wasps) > tertiary consumers (spiders)

2. Energy from sun to producers (corns) > Herbivores (cows) > Carnivores (wolves) > Secondary carnivores (tigers)

• Basic unit:

1. producers

2. herbivores

3. carnivores

4. omnivores

5. decomposers: macro & micro

b. Food Web: interconnecting or interacting of a number of food chains in an ecosystem. It can be reflecting of reality.

Simple food chain Simple food web34

24: NAME 3 MAJOR BIOLOGICAL COMPONENTS IN TERMS OF ENERGY FLOW Major biological components in terms of energy flow:

• The sun is the ultimate source of energy for most ecosystems.

• Primary producers capture a fraction of energy in sunlight striking the earth and convert it into chemical energy (carbohydrate) that is stored in tissues of the primary.

• Energy in tissues of primary producers transferred to consumers as each consumes tissue of other organisms -- about 90% - 95% of energy present in one component is lost as heat at each transfer -- very inefficient process -- very little energy left when decomposers get to it.

25: DISCUSS BRIEFLY MAJOR BIOMES

• Tundra

i. Locate on northernmost

ii. Low-growing vegetation withstand to cold weather

iii. Short growing season

• Evergreen coniferous forest / Boreal forest

i. Locate on south of tundra

ii. Coniferous trees are dominant e.g. black and white spruce

iii. Occur in Russia ...

• Temperate coniferous forests / Taigas

i. Plants with tough narrow leaves, needles

ii. spruces, pines are dominated plants

iii. acidic and poor soil, because of slow decay of fallen leaves

Temperate communities

1. Deciduous forest

i. broad-leaved trees

ii. lose their leaves seasonally

iii. soil is well differentiated

Temperate grasslands

i. Moderate precipitation

ii. Deep, mineral-rich soil

iii. well suited to the growing of grain crops

Chaparral

i. small-leaved shrubs

ii. develop modest rainfall

iii. mild winter

Deserts

i. very little moisture

ii. less than 40 cm of precipitation

iii. either hot or cold.

iv. dry

v. Other deserts can form where mountains receive most of the rain. This is called the rain shadow. e.g. The great Gobi Desert of Mongolia has little rainfall because the Himalaya Mountains to the south prevent rainfall from moving to this region.

vi. High daytime temperatures and cold nighttime temperatures make desert environments very inhospitable

vii. vegetation in a desert is short grasses, sagebrush, creosote bush, and cactus

Tropical rain forest

i. hot, moist biome

ii. in equatorial regions

iii. dense canopies of vegetation

iv. Very little vegetation is found at ground level except for occasional shrubs and small trees.

v. the rainforest bacteria and other microorganisms are always very active

vi. Plants are also very active. They grow fast, and they take nutrients from the soils. So the rainforest soils are very infertile.

vii. Small animals, including monkeys, birds, snakes, rodents, and lizards are common in the tropical rainforest.

viii. poor soils.

Tropical grasslands

i. usually surrounds the region of the tropical rainforest

ii. hot but has a pronounced summer wet season and a dry winter season

iii. tall grasses

iv. occasional trees wherever tree roots can reach underground water

v. dry season makes life difficult for the large animals

vi. soils are of better quality than rainforest soils

vii. less rainfall

viii. Amazon of South America

Aquatic life zone The limiting factors of the aquatic life zone are the availability of light and oxygen There are 2 fundamental groups of aquatic systems: freshwater and marine system. Freshwater

1. Lentic system ( non-flowing )

i. For example: inland lake

ii. limiting factors: Light: trophogenic (upper layer with enough light) and tropholytic zone (lower layer with insufficient light); Temperature: epilimnion (above layer), metalimnion, thermocline, hypolimnion (lower layer); Zonation: near shore is called littoral zone where can allow the light penetrating and increase the plants grow.

iii. Lake can classify into: Oligotrophic lakes (low nutrients); Eutrophic lakes (high nutrients)

2. Lotic system (flowing)

i. For example: Stream

ii. higher oxygen content

3. Wetlands (the interface between terrestrial and aquatic system)

i. perpetually or periodically flooding

ii. for organism breeding place

iii. transition habitats between terrestrial and lentic or lotic system

iv. For example: marsh, bog

• Marine

1. Salt marshes

i. an offshore barrier

ii. plants should be tolerated water-logging soil, inundation with soil water, wave damage,

2. Estuaries

i. degree of salinity (water entering from the river tends to float on top of the denser saline waters from the sea).

ii. factorsaffect on salinity: evaporation, tidal influx of salt water, rotation of earth.

3. Mangroves

i. serve as nurseries for many marine species.

ii. commercial use to develop the shrimp

iii. plant in red mangrove can adapt to the warm, shallow, saline waters, produce salt-tolerant seeds.

4. Abyss

i. Since, it is too deep, the deep water is cold, dark and tremendous pressure

ii. Little light penetrating

iii. Bioluminesce occurs in that deep sea area.

26: WRITE NOTES ON VARIOUS AQUATIC LIFEZONES Lakes: A lake is a body of water completely surrounded by land. Lakes can either be salty or fresh water. Most lakes are in places where glaciers used to exist. When a glacier moves forward, it carves away a deep valley and when the ice melts it forms a lake in the valley. Other lakes are formed in craters or when a river changes its course. Lakes are short-lived surface features because the water can sink into the ground or evaporate into the sky. In order for alike to remain, it must be constantly fed by a river or rainfall. RiversandStreams: Rivers are very important to Earth because they are major forces that shaps the landscape. Also, hey providetransportation and water for drinking washing and farming.Rivers can flow on land or underground in deserts and seas.Rivers may come from mountain springs, melting glaciers or lakes. A river’s contribution to the cycle is that it collects water from the ground and returns it to the ocean. The water we drink is about 3 billion years old because it has been recycled over Andover since the first rainfall. A delta is where a river meets the sea. Usually the river flows more slowly at the delta than at its start because it deposits sediment. Sediment can be anything from mud, sand and every rock fragments. A special environment is created when the fresh water from the river mixes with the salty ocean water. This environment is called estuary. The longest river is the Nile River in Africa, and the Amazon River in South America carries the most water. The muddiest river is the Yellow River in China. Estuaries: An estuary is a unique environment where fresh water and saltwater come together. Estuaries are found on the coast where arriver or bay or other sources of fresh water has access to the open sea. A good example of an estuary is a salt marsh that can be found close to the coast. Another example is when a river feeds directly into the ocean. The largest estuary in the United States is the Chesapeake bay estuary on the east coast of theU.S.Estuaries are affected by the tides. So, there can be changeof salinity, temperature and other physical properties in anestuarial system which means the organisms there must be very tolerant to change. Even with that consideration, estuaries are among the most fertile places in the world. All kinds of plants and animals live there. When looking at estuaries, scientists quickly realized that these areas were extremely nutrient-rich because of sediment deposit of rivers, creeks or streams feeding into the salt water environment. Unfortunately, estuaries haven’t always been seen as valuable. In the past, they were seen as worthless and were used as dumps, or places for new land development (by filling in the marshy area). However, now the systems are being set up to establish, manage and maintain estuary reserves, and to provide for their long-term stewardship.37

Pond Ecosystem The definition of a pond is any body of water over 1m square that is inundated, “wet” for more than8 months of the year.That definition tells us quite a lot about a ponds ecosystem. The first is obvious, it doesn’t have to be large to be useful, infect even a bird bath will be visited by the water boatman if he is in need of a place to rest and eat. If a pond does dry out it isn’t a disaster, both plants and animals have adapted to this eventuality. The pond is the most valuable as far as wildlife is concerned, if the pond is reasonably shallow (no more than 90 cm) and very well planted it will support a vast array of animals and plants. Some potential inhabitants and visitors are frogs, Newts, Toads,Foxes, Hedgehogs, Badgers birds, Bats, Grass snakes, Slowworms, Water Voles, Birds of all sizes, Great diving beetles, Water boatman, Dragon fly Larvae and adults, Damsel flys,Daphnia, Cyclops, Spiders, Water scorpion (not dangerous),zoo plankton, Whirligig beetle, Pond skaters, Lace wings. The potential list of insects and other small things is huge

Pond ecosystem38

Module 3 Environmental pollution 1: WHAT DO YOU MEAN BY POLLUTION?

Pollution is the introduction of contaminants into the natural environment that causes adverse change.Pollution can take the form of chemical substances or energy, such as noise, heat or light. Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Pollution is often classed as point source or nonpoint source pollution. 2: WHAT DO YOU MEAN BY AIR POLLUTION?

Air pollution is the introduction into the atmosphere of chemicals, particulates, or biological materials that cause discomfort, disease, or death to humans, damage other living organisms such as food crops, or damage the natural environment or built environment.

The atmosphere is a complex dynamic natural gaseous system that is essential to support life on planet Earth.Stratospheric ozone depletion due to air pollution has long been recognized as a threat to human health as well as to the Earth's ecosystems.

A substance in the air that can be harmful to humans and the environment is known as an air pollutant. Pollutants can be in the form of solid particles, liquid droplets, or gases. In addition, they may be natural or man-made. Pollutants can be classified as primary or secondary. Usually, primary pollutants are directly emitted from a process, such as ash from a volcanic eruption, the carbon monoxide gas from a motor vehicle exhaust or sulphur dioxide released from factories. Secondary pollutants are not emitted directly. Rather, they form in the air when primary pollutants react or interact. An important example of a secondary pollutant is ground level ozone— one of the many secondary pollutants that make up photochemical smog. 3: WHICH ARE THE MAJOR PRIMARY POLLUTANTS? Major primary pollutants produced by human activity include:

Sulfur oxides (SOx) - especially Sulphur dioxide, a chemical compound with the formula SO2. SO2 is produced by volcanoes and in various industrial processes

Carbon monoxide (CO)- is a colorless, odorless, non-irritating but very poisonous gas. It is a product byincomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide.Nitrogen oxides (NOx) - especially nitrogen dioxide are emitted from high temperature combustion, and are also produced naturally during thunderstorms by electric discharge.Volatile organic compounds - VOCs are an important outdoor air pollutant. In this field they are often divided into the separate categories of methane (CH4) and non-methane (NMVOCs). Methane is an extremely efficient greenhouse gas which contributes to enhance global warming. Other hydrocarbon VOCs are also significant greenhouse gases via their role in creating ozone and in prolonging the life of methane in the atmosphere, although the effect varies depending on local air quality. Within the NMVOCs, the aromatic compounds benzene, toluene and xylene are suspected carcinogens and may lead to leukemia through prolonged exposure. 1,3-butadiene is another dangerous compound which is often associated with industrial uses.39

Particulates, alternatively referred to as particulate matter (PM), atmospheric particulate matter, or fine particles, are tiny particles of solid or liquid suspended in a gas. In contrast, aerosol refers to particles and the gas together. Sources of particulates can be manmade or natural. Some particulates occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power plants and various industrial processes also generate significant amounts of aerosols. Averaged over the globe, anthropogenic aerosols—those made by human activities—currently account for about 10 percent of the total amount of aerosols in our atmosphere. Increased levels of fine particles in the air are linked to health hazards such as heart diseases,altered lung function and lung cancer. 4: WHICH ARE ‘SECONDARY’ POLLUTANTS? Secondary pollutants include:

• Particulates formed from gaseous primary pollutants and compounds in photochemical smog. Smog is a kind of air pollution; the word "smog" is a portmanteau of smoke and fog. Classic smog results from large amounts of coal burning in an area caused by a mixture of smoke and sulfur dioxide. Modern smog does not usually come from coal but from vehicular and industrial emissions that are acted on in the atmosphere by ultraviolet light from the sun to form secondary pollutants that also combine with the primary emissions to form photochemical smog.

• Ground level ozone (O3) formed from NOx and VOCs. Ozone (O3) is a key constituent of the troposphere. It is also an important constituent of certain regions of the stratosphere commonly known as the Ozone layer. Photochemical and chemical reactions involving it drive many of the chemical processes that occur in the atmosphere by day and by night. At abnormally high concentrations brought about by human activities (largely the combustion of fossil fuel), it is a pollutant, and a constituent of smog.

• Peroxyacetyl nitrate (PAN) - similarly formed from NOx and VOCs.

5: WHAT ALL ARE THE ANTHROPOGENIC CAUSES OF POLLUTION?

• "Stationary Sources" include smoke stacks of power plants, manufacturing facilities (factories) and waste incinerators, as well as furnaces and other types of fuel-burning heating devices. In developing and poor countries, traditional biomass burning is the major source of air pollutants; traditional biomass includes wood, crop waste and dung.

• "Mobile Sources" include motor vehicles, marine vessels, aircraft and the effect of sound etc.

• Chemicals, dust and controlled burn practices in agriculture and forestry management. Controlled or prescribed burning is a technique sometimes used in forest management, farming, prairie restoration or greenhouse gas abatement. Fire is a natural part of both forest and grassland ecology and controlled fire can be a tool for foresters. Controlled burning stimulates the germination of some desirable forest trees, thus renewing the forest.

• Fumes from paint, hair spray, varnish, aerosol sprays and other solvents

• Waste deposition in landfills, which generate methane. Methane is not toxic; however, it is highly flammable and may form explosive mixtures with air. Methane is also an Asphyxiant and may displace oxygen in an enclosed space. Asphyxia or suffocation may result if the oxygen concentration is reduced to below 19.5% by displacement

• Military, such as nuclear weapons, toxic gases, germ warfare and rocketry

6: WHICH ARE THE NATURAL SOURCES OF POLLUTION? Natural sources

• Dust from natural sources, usually large areas of land with little or no vegetation

• Methane, emitted by the digestion of food by animals, for example cattle

• Radon gas from radioactive decay within the Earth's crust. Radon is a colorless, odorless, naturally occurring, radioactive noble gas that is formed from the decay of radium. It is considered to be a health hazard. Radon gas from natural sources can accumulate in buildings, especially in confined areas such as the basement and it is the second most frequent cause of lung cancer, after cigarettesmoking

• Smoke and carbon monoxide from wildfires

• Vegetation, in some regions, emits environmentally significant amounts of VOCs on warmer days. These VOCs react with primary anthropogenic pollutants—specifically, NOx, SO2, and anthropogenic organic carbon compounds—to produce a seasonal haze of secondary pollutants.[7]

• Volcanic activity, which produce sulfur, chlorine, and ash particulates

7: DESCRIBE BRIEFLY THE GREEN HOUSE EFFECT?

The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases

Solar radiation at the frequencies of visible light largely passes through the atmosphere to warm the planetary surface, which then emits this energy at the lower frequencies of infrared thermal radiation. Infrared radiation is absorbed by greenhouse gases, which in turn re-radiate much of the energy to the surface and lower atmosphere. The mechanism is named after the effect of solar radiation passing through glass and warming a greenhouse, but the way it retains heat is fundamentally different as a greenhouse works by reducing airflow, isolating the warm air inside the structure so that heat is not lost by convection

If an ideal thermally conductive blackbody was the same distance from the Sun as the Earth is, it would have a temperature of about 5.3 °C. However, since the Earth reflects about 30% of the incoming sunlight, this idealized planet's effective temperature (the temperature of a blackbody that would emit the same amount of radiation) would be about −18 °C. The surface temperature of this hypothetical planet is 33 °C below Earth's actual surface temperature of approximately 14 °C. The mechanism that produces this difference between the actual surface temperature and the effective temperature is due to the atmosphere and is known as the greenhouse effect. Earth’s natural greenhouse effect makes life as we know it possible. However, human activities, primarily the burning of fossil fuels and clearing of forests, have intensified the natural greenhouse effect, causing global warming. 41

8: NAME FOUR GREENHOUSE GASES By their percentage contribution to the greenhouse effect on Earth the four major gases are:

• water vapor, 36–70%

• carbon dioxide, 9–26%

• methane, 4–9%

• ozone, 3–7%

The major non-gas contributor to the Earth's greenhouse effect, clouds, also absorb and emit infrared radiation and thus have an effect on radiative properties of the atmosphere 9 SUBSTANTIATE THE ROLE OF GREEN HOUSE GASES IN CLIMATIC CHANGE

Strengthening of the greenhouse effect through human activities is known as the enhanced (or anthropogenic) greenhouse effect. This increase in radiative forcing from human activity is attributable mainly to increased atmospheric carbon dioxide levels. According to the latest Assessment Report from the Intergovernmental Panel on Climate Change, "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations"

CO2 is produced by fossil fuel burning and other activities such as cement production and tropical deforestation. Measurements of CO2from the Mauna Loa observatory show that concentrations have increased from about 313 ppm in 1960 to about 389 ppm in 2010. The current observed amount of CO2 exceeds the geological record maxima (~300 ppm) from ice core data. The effect of combustion-produced carbon dioxide on the global climate, a special case of the greenhouse effect first described in 1896 by Svante Arrhenius, has also been called the Callendar effect.Over the past 800,000 years,ice-core data shows that carbon dioxide has varied from values as low as 180 parts per million (ppm) to the pre-industrial level of 270ppm.[ Paleo-climatologists consider variations in carbon dioxide concentration to be a fundamental factor influencing climate variations over this time scale. 10: WHAT DO YOU MEAN BY WATER POLLUTION?

Water pollution is the contamination of water bodies Water pollution occurs e.g. lakes, rivers, oceans, aquifers and groundwater). When pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds.

Water pollution affects plants and organisms living in these bodies of water. In almost all cases the effect is damaging not only to individual species and populations, but also to the natural biological communities.42

11: WHICH ARE THE ORGANIC AND INORGANIC CONTAMINANTS OF WATER?

Contaminants may include organic and inorganic substances. Organic water pollutants include:

• Detergents

• Disinfection by-products found in chemically disinfected drinking water, such as chloroform

• Food processing waste, which can include oxygen-demanding substances, fats and grease

• Insecticides and herbicides, a huge range of organohalides and other chemical compounds

• Petroleum hydrocarbons, including fuels (gasoline, diesel fuel, jet fuels, and fuel oil) and lubricants (motor oil), and fuel combustionbyproducts, from storm-water runoff

• Tree and bush debris from logging operations

• Volatile organic compounds (VOCs), such as industrial solvents, from improper storage.

• Chlorinated solvents, which are dense non-aqueous phase liquids (DNAPLs), may fall to the bottom of reservoirs, since they don't mix well with water and are denser. • Polychlorinated biphenyl (PCBs)

• Trichloroethylene

• Perchlorate

• Various chemical compounds found in personal hygiene and cosmetic products.

Inorganic water pollutants include:

• Acidity caused by industrial discharges (especially sulfur dioxide from power plants)

• Ammonia from food processing waste

• Chemical waste as industrial by-products

• Fertilizers containing nutrients--nitrates and phosphates—which are found in stormwater runoff from agriculture, as well as commercial and residential use

• Heavy metals from motor vehicles (via urban stormwater runoff) and acid mine drainage

• Silt (sediment) in runoff from construction sites, logging, slash and burn practices or land clearing sites.

12: LIST IMPORTANT MARINE DEBRIS MARINE DEBRIS—large visible items polluting the water—may be termed "floatables"

• Trash or garbage (e.g. paper, plastic, or food waste) discarded by people on the ground, along with accidental or intentional dumping of rubbish, that are washed by rainfall into storm drains and eventually discharged into surface waters

• Nurdles, small ubiquitous waterborne plastic pellets

• Shipwrecks, large derelict ships.

13: DISCUSS BRIEFLY ABOUT DOMESTIC SEWAGE TREATMENT

Domestic sewage is 99.9 percent pure water, while the other 0.1 percent are pollutants. Although found in low concentrations, these pollutants pose risk on a large scale.[20] In urban areas, domestic sewage is typically treated by centralized sewage treatment plants. In the U.S., most of these plants are operated by local government agencies, frequently referred to 43

as publicly owned treatment works (POTW). Municipal treatment plants are designed to control conventional pollutants: BOD and suspended solids. Well-designed and operated systems (i.e., secondary treatment or better) can remove 90 percent or more of these pollutants. Some plants have additional sub-systems to treat nutrients and pathogens. Most municipal plants are not designed to treat toxic pollutants found in industrial wastewater.

Cities with sanitary sewer overflows or combined sewer overflows employ one or more engineering approaches to reduce discharges of untreated sewage, including:

• utilizing a green infrastructure approach to improve storm water management capacity throughout the system, and reduce the hydraulicoverloading of the treatment plant

• repair and replacement of leaking and malfunctioning equipment

• increasing overall hydraulic capacity of the sewage collection system (often a very expensive option).

A household or business not served by a municipal treatment plant may have an individual septic tank, which treats the wastewater on site and discharges into the soil. Alternatively, domestic wastewater may be sent to a nearby privately owned treatment system (e.g. in a rural community). 14: DISCUSS BRIEFLY INDUSTRIAL WASTE WATER TREATMENT Some industrial facilities generate ordinary domestic sewage that can be treated by municipal facilities. Industries that generate wastewater with high concentrations of conventional pollutants (e.g. oil and grease), toxic pollutants (e.g. heavy metals, volatile organic compounds) or other nonconventional pollutants such as ammonia, need specialized treatment systems. Some of these facilities can install a pre-treatment system to remove the toxic components, and then send the partially treated wastewater to the municipal system. Industries generating large volumes of wastewater typically operate their own complete on-site treatment systems.

Some industries have been successful at redesigning their manufacturing processes to reduce or eliminate pollutants, through a process called pollution prevention. Heated water generated by power plants or manufacturing plants may be controlled with:

• cooling ponds, man-made bodies of water designed for cooling by evaporation, convection, and radiation

• cooling towers, which transfer waste heat to the atmosphere through evaporation and/or heat transfer

• co-generation, a process where waste heat is recycled for domestic and/or industrial heating purposes.

15: WHAT ALL ARE THE CONTROLLING MEASURES OF AGRICULTURAL WASTE WATER?

Nonpoint source controls

Sediment (loose soil) washed off fields is the largest source of agricultural pollution in the United States. Farmers may utilize erosion controls to reduce runoff flows and retain soil on their fields. Common techniques include contour plowing, crop mulching, crop rotation, planting perennialcrops and installing riparian buffers.

Nutrients (nitrogen and phosphorus) are typically applied to farmland as commercial fertilizer; animal manure; or spraying of municipal or industrial wastewater (effluent) or sludge. Nutrients may also enter runoff from crop residues, irrigation water,44

wildlife, and atmospheric deposition.Farmers can develop and implement nutrient management plans to reduce excess application of nutrients.

To minimize pesticide impacts, farmers may use Integrated Pest Management (IPM) techniques (which can include biological pest control) to maintain control over pests, reduce reliance on chemical pesticides, and protect water quality. Point source wastewater treatment

Farms with large livestock and poultry operations, such as factory farms, are called concentrated animal feeding operations or feedlots in the US and are being subject to increasing government regulation. Animal slurries are usually treated by containment in anaerobic lagoons before disposal by spray or trickle application to grassland. Constructed wetlands are sometimes used to facilitate treatment of animal wastes. Some animal slurries are treated by mixing with straw and composted at high temperature to produce a bacteriologically sterile and friable manure for soil improvement. 16: DISCUSS BRIEFLY ABOUT SOIL POLLUTION

Soil pollution is caused by the presence of xenobiotic (human-made) chemicals or other alteration in the natural soil environment. It is typically caused by industrial activity, agricultural chemicals, or improper disposal of waste. The most common chemicals involved are petroleum hydrocarbons, poly-nuclear aromatic hydrocarbons (such as naphthalene and benzo(a)pyrene), solvents, pesticides, lead, and other heavy metals. Contamination is correlated with the degree of industrializationand intensity of chemical usage.

The concern over soil contamination stems primarily from health risks, from direct contact with the contaminated soil, vapors from the contaminants, and from secondary contamination of water supplies within and underlying the soil-mapping of contaminated soil sites and the resulting cleanup are time consuming and expensive tasks, requiring extensive amounts of geology, hydrology,chemistry, computer modeling skills, and GIS in Environmental Contamination, as well as an appreciation of the history of industrial chemistry.

In North America and Western Europe that the extent of contaminated land is best known, with many of countries in these areas having a legal framework to identify and deal with this environmental problem. Developing countries tend to be less tightly regulated despite some of them having undergone significant industrialization. 17: HOW SOIL POLLUTION AFFECTS AN ECO SYSTEM?

Not unexpectedly, soil contaminants can have significant deleterious consequences for ecosystems. There are radical soil chemistry changes which can arise from the presence of many hazardous chemicals even at low concentration of the contaminant species. These changes can manifest in the alteration of metabolism of endemic micro organisms andarthropods resident in a given soil environment. The result can be virtual eradication of some of the primary food chain, which in turn could have major consequences for predator or consumer species. Even if the chemical effect on lower life forms is small, the lower pyramid levels of the food chain may ingest alien chemicals, which normally become more concentrated for each consuming rung of the food chain. Many of these effects are now well known, such as the concentration of persistent DDT materials for avian consumers, leading to weakening of egg shells, increased chick mortality and potential extinction of species

Effects occur to agricultural lands which have certain types of soil contamination. Contaminants typically alter plant metabolism, often causing a reduction in crop yields. This has a secondary effect upon soil conservation, since the languishing crops cannot shield the 45

Earth's soil from erosion. Some of these chemical contaminants have long half-lives and in other cases derivative chemicals are formed from decay of primary soil contaminants. 18: WRITE A SHORT NOTE ON SOIL POLLUTION

Noise pollution is excessive, displeasing human, animal, or machine-created environmental noise that disrupts the activity or balance of human or animal life. The word noise may be from the Latin word nauseas, which means disgust or discomfort. The source of most outdoor noise worldwide is mainly construction and transportation systems, including motor vehicle noise, aircraft noise, and rail noise. Poor urban planning may give rise to noise pollution, since side-by-side industrial and residential buildings can result in noise pollution in the residential areas. High noise levels can contribute to cardiovascular effects in humans, a rise in blood pressure, and an increase in stress and vasoconstriction, and an increased incidence of coronary artery disease. In animals, noise can increase the risk of death by altering predator or prey detection and avoidance, interfere with reproduction and navigation, and contribute to permanent hearing loss. 19: DISCUSS BRIEFLY ABOUT RADIO ACTIVE CONTAMINATION

(Fukushima Daiichi nuclear disaster, the Chernobyl disaster,)

Radioactive contamination, also called radiological contamination, is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids or gases (including the human body), where their presence is unintended or undesirable (from IAEA definition)

Such contamination presents a hazard because of the radioactive decay of the contaminants, which emit harmful ionizing radiation such as alpha or beta particles, gamma rays orneutrons. The degree of hazard is determined by the concentration of the contaminants, the energy of the radiation being emitted, the type of radiation, and the proximity of the contamination to organs of the body. It is important to be clear that the contamination gives rise to the radiation hazard, and the terms "radiation" and "contamination" are not interchangeable.

Contamination may affect a person, a place, an animal, or an object such as clothing. Following an atmospheric nuclear weapon discharge or a nuclear reactor containment breach, the air, soil, people, plants, and animals in the vicinity will become contaminated by nuclear fuel and fission products. A spilled vial of radioactive material like Uranyl nitrate may contaminate the floor and any rags used to wipe up the spill. Cases of widespread radioactive contamination include the Bikini Atoll, the Rocky Flats Plant in Colorado, the Fukushima Daiichi nuclear disaster, the Chernobyl disaster, and the area around the Mayak facility in Russia.

Cleaning up contamination results in radioactive waste unless the radioactive material can be returned to commercial use by reprocessing. In some cases of large areas of contamination, the contamination may be mitigated by burying and covering the contaminated substances with concrete, soil, or rock to prevent further spread of the contamination to the environment. If a person's body is contaminated by ingestion or by injury and standard cleaning cannot reduce the contamination further, then the person may be permanently contaminated.

20: WHAT ALL ARE THE EFFECTS OF CONTAMINATION OF RADIO ACTIVE POLLUTANTS?

Biological effects

The biological effects of internally deposited radionuclides depend greatly on the activity, the bio-distribution, and the removal rates of the radionuclide, which in turn depends 46

on its chemical form, the particle size, and route of entry. Effects may also depend on the chemicaltoxicity of the deposited material, independent of its radioactivity. Some radionuclides may be generally distributed throughout the body and rapidly removed, as is the case with tritiated water.

Some organs concentrate certain elements and hence radionuclide variants of those elements. This action may lead to much lower removal rates. For instance, the thyroid gland takes up a large percentage of any iodine that enters the body. Large quantities of inhaled or ingestedradioactive iodine may impair or destroy the thyroid, while other tissues are affected to a lesser extent. Radioactive iodine-131 is a commonfission product; it was a major component of the radiation released from the Chernobyl disaster, leading to nine fatal cases of pediatricthyroid cancer and hypothyroidism. On the other hand, radioactive iodine is used in the diagnosis and treatment of many diseases of the thyroid precisely because of the thyroid's selective uptake of iodine.

Mental health effects

The consequences of low-level radiation are often more psychological than radiological. Because damage from very-low-level radiation cannot be detected, people exposed to it are left in anguished uncertainty about what will happen to them. Many believe they have been fundamentally contaminated for life and may refuse to have children for fear of birth defects. They may be shunned by others in their community who fear a sort of mysterious contagion.

Forced evacuation from a radiation or nuclear accident may lead to social isolation, anxiety, depression, psychosomatic medical problems, reckless behavior, even suicide. Such was the outcome of the 1986 Chernobyl nuclear disaster in the Ukraine. A comprehensive 2005 study concluded that "the mental health impact of Chernobyl is the largest public health problem unleashed by the accident to date".Frank N. von Hippel, a U.S. scientist, commented on the 2011 Fukushima nuclear disaster, saying that "fear of ionizing radiation could have long-term psychological effects on a large portion of the population in the contaminated areas". Such great psychological danger does not accompany other materials that put people at risk of cancer and other deadly illness. Visceral fear is not widely aroused by, for example, the daily emissions from coal burning, although, as a National Academy of Sciences study found, this causes 10,000 premature deaths a year in the US. It is "only nuclear radiation that bears a huge psychological burden — for it carries a unique historical legacy" 21: WRITE SHORT NOTE ON WASTE MANAGEMENT

Waste management is the collection, transport, processing or disposal, managing and monitoring of waste materials. The term usually relates to materials produced by human activity, and the process is generally undertaken to reduce their effect on health, the environment oraesthetics. Waste management is a distinct practice from resource recovery which focuses on delaying the rate of consumption of natural resources. All wastes materials, whether they are solid, liquid, gaseous or radioactive fall within the remit of waste management

Waste management practices can differ for developed and developing nations, for urban and rural areas, and for residential and industrialproducers. Management for non-hazardous waste residential and institutional waste in metropolitan areas is usually the responsibility oflocal government authorities, while management for non-hazardous commercial and industrial waste is usually the responsibility of the generator subject to local, national or international controls.47

22: DISCUSS BRIEFLY ABOUT METHODS OF WASTE MANAGEMENT

Land fill: Disposal of waste in a landfill involves burying the waste, and this remains a common practice in most countries. Landfills were often established in abandoned or unused quarries, mining voids or borrow pits. A properly designed and well-managed landfill can be a hygienic and relatively inexpensive method of disposing of waste materials. Older, poorly designed or poorly managed landfills can create a number of adverse environmental impacts such as wind-blown litter, attraction of vermin, and generation of liquid leachate. Another common product of landfills is gas (mostly composed of methane and carbon dioxide), which is produced as organic waste breaks down anaerobically. This gas can create odor problems, kill surface vegetation, and is a greenhouse gas.

Design characteristics of a modern landfill include methods to contain leachate such as clay or plastic lining material. Deposited waste is normally compacted to increase its density and stability, and covered to prevent attracting vermin (such as mice or rats). Many landfills also have landfill gas extraction systems installed to extract the landfill gas. Gas is pumped out of the landfill using perforated pipes and flared off or burnt in a gas engine to generate electricity.

Incineration

Incineration is a disposal method in which solid organic wastes are subjected to combustion so as to convert them into residue and gaseous products. This method is useful for disposal of residue of both solid waste management and solid residue from waste water management.This process reduces the volumes of solid waste to 20 to 30 percent of the original volume. Incineration and other high temperature waste treatment systems are sometimes described as "thermal treatment". Incinerators convert waste materials into heat, gas,steam and ash.

Incineration is carried out both on a small scale by individuals and on a large scale by industry. It is used to dispose of solid, liquid and gaseous waste. It is recognized as a practical method of disposing of certain hazardous waste materials (such as biological medical waste). Incineration is a controversial method of waste disposal, due to issues such as emission of gaseous pollutants.

Incineration is common in countries such as Japan where land is more scarce, as these facilities generally do not require as much area as landfills. Waste-to-energy (WtE) or energy-from-waste (EfW) are broad terms for facilities that burn waste in a furnace or boiler to generate heat, steam or electricity. Combustion in an incinerator is not always perfect and there have been concerns about pollutants in gaseous emissions from incinerator stacks. Particular concern has focused on some very persistent organics such as dioxins, furans, PAHs which may be created which may have serious environmental consequences.

Recycling

Recycling is a resource recovery practice that refers to the collection and reuse of waste materials such as empty beverage containers. The materials from which the items are made can be reprocessed into new products. Material for recycling may be collected separately from general waste using dedicated bins and collection vehicles are sorted directly from mixed waste streams and are known as kerb-side recycling, it requires the owner of the waste to separate it into various different bins (typically wheelie bins) prior to its collection.48

The most common consumer products recycled include aluminium such as beverage cans, copper such as wire, steel food and aerosol cans, old steel furnishings or equipment, polyethylene and PET bottles, glass bottles and jars, paper board cartons, news papers, magazines and light paper, and corrugated fiberboard boxes.

PVC, LDPE, PP, and PS (see resin identification code) are also recyclable. These items are usually composed of a single type of material, making them relatively easy to recycle into new products. The recycling of complex products (such as computers and electronic equipment) is more difficult, due to the additional dismantling and separation required. The type of material accepted for recycling varies by city and country. Each city and country have different recycling programs in place that can handle the various types of recyclable materials. However, variation in acceptance is reflected in the resale value of the material once it is reprocessed.

Sustainability

The management of waste is a key component in a business' ability to maintaining ISO14001 accreditation. Companies are encouraged to improve their environmental efficiencies each year by eliminating waste through resource recovery practices, which are sustainability-related activities. One way to do this is by shifting away from waste management to resource recovery practices like recycling materials such as glass, food scraps, paper and cardboard, plastic bottles and metal.

Biological reprocessing

Recoverable materials that are organic in nature, such as plant material, food scraps, and paper products, can be recovered throughcomposting and digestion processes to decompose the organic matter. The resulting organic material is then recycled as mulch or compostfor agricultural or landscaping purposes. In addition, waste gas from the process (such as methane) can be captured and used for generating electricity and heat (CHP/cogeneration) maximizing efficiencies. The intention of biological processing in waste management is to control and accelerate the natural process of decomposition of organic matter.

Energy recovery

The energy content of waste products can be harnessed directly by using them as a direct combustion fuel, or indirectly by processing them into another type of fuel. Thermal treatment ranges from using waste as a fuel source for cooking or heating and the use of the gas fuel (see above), to fuel for boilers to generate steam and electricity in a turbine.

Pyrolysis and gasification are two related forms of thermal treatment where waste materials are heated to high temperatures with limited oxygen availability. The process usually occurs in a sealed vessel under high pressure. Pyrolysis of solid waste converts the material into solid, liquid and gas products. The liquid and gas can be burnt to produce energy or refined into other chemical products (chemical refinery). The solid residue (char) can be further refined into products such as activated carbon. Gasification and advanced Plasma arc gasification are used to convert organic materials directly into a synthetic gas (syngas) composed of carbon monoxideand hydrogen. The gas is then burnt to produce electricity and steam. An alternative to pyrolysis is high temperature and pressure supercritical water decomposition (hydrothermal monophasic oxidation).49

Resource recovery

Resource recovery (as opposed to waste management) uses LCA (life cycle analysis) attempts to offer alternatives to waste management. For mixed MSW (Municipal Solid Waste) a number of broad studies have indicated that administration, source separation and collection followed by reuse and recycling of the non-organic fraction and energy and compost/fertilizer production of the organic material via anaerobic digestion to be the favoured path.

Avoidance and reduction methods

An important method of waste management is the prevention of waste material being created, also known as waste reduction. Methods of avoidance include reuse of second-hand products, repairing broken items instead of buying new, designing products to be refillable or reusable (such as cotton instead of plastic shopping bags), encouraging consumers to avoid using disposable products (such as disposable cutlery), removing any food/liquid remains from cans, packaging, ...and designing products that use less material to achieve the same purpose (for example, light-weighting of beverage cans). 23 WHAT IS THE ROLE OF AN INDIVIDUAL IN CONTROLLING POLLUTION? The role of an individual in maintaining a pollution free, pure and congenial environment and in preserving its resources is actually the need of the hour. Individuals can, however, play an important role in abatement of air, water, soil or noise pollution in the following simple manners: 1) Use low-phosphate, phosphate-free or biodegradable dishwashing liquid, laundry detergent, and shampoo. 2) Don't use water fresheners in toilets. 3) Use manure or compost instead of commercial inorganic fertilizers to fertilize gardens and yard plant. 4) Use biological methods or integrated pest management to control garden, yard, and household pests. 5) Don't pour pesticides, paints, solvents, oils, or other products containing harmful chemicals down drain or on the ground. Contact the authorities responsible for their disposal. 6) Recycle old motor oil and antifreeze at an auto service center that has an oil recycling program. 7) If you get water from a private well or suspect that municipal water is contaminated, have tested by an EPA certified laboratory for lead, nitrates, tri halo methanes, radon, volatile, organic compounds and pesticides. 8)Run water from taps for several minutes every morning before using the water for drinking or cooking. Save it and use it to water plants.If you have a septic tank, monitor it yearly and have it cleaned out every three to five years by a reputable contractor so that it won’t contribute to groundwater pollution. Do not use a septic tank cleaner, which contain toxic chemicals that can kill bacteria important to sewage decomposition and that can contaminate groundwater if systems malfunction.50

9) Support ecological land-use planning in your community and form watchdog groups to help monitor, protect, and restore them.

24: WHAT DO YOU MEAN BY PHOTOCHEMICAL SMOG

Smog is caused by the burning of large amounts of coal within a city; this smog contains soot particulates from smoke, sulfur dioxide and other components. Modern smog, is a type of air pollution derived from vehicular emission from internal combustion engines and industrial fumes that react in the atmosphere with sunlight to form secondary pollutants that also combine with the primary emissions to form photochemical smog. It is the chemical reaction of sunlight, nitrogen oxides and volatile organic compounds in the atmosphere, which leavesairborne particles and ground-level ozone. This noxious mixture of air pollutants can include the following:

• Aldehydes

• Nitrogen oxides, such as nitrogen dioxide

• Peroxyacyl nitrates

• Tropospheric ozone

• Volatile organic compounds

All of these chemicals are usually highly reactive and oxidizing. Photochemical smog is therefore considered to be a problem of modern industrialization. It is present in all modern cities, but it is more common in cities with sunny, warm, dry climates and a large number of motor vehicles.Because it travels with the wind, it can affect sparsely populated areas as well.The formation of photochemical smog is given above…. 25: WRITE A SHORT NOTE ON SEWAGE TREATEMENT

Sewage can be treated close to where it is created, a decentralized system (in septic tanks, bio-filters or aerobic treatment systems), or be collected and transported by a network of pipes and pump stations to a municipal treatment plant, a centralized system (see sewerage and pipes and infrastructure). Sewage collection and treatment is typically subject to local, state and federal regulations and standards. Industrial sources of sewage often require specialized treatment processes (seeIndustrial wastewater treatment). Sewage treatment generally involves three stages, called primary, secondary and tertiary treatment.

• Primary treatment consists of temporarily holding the sewage in a quiescent basin where heavy solids can settle to the bottom while oil, grease and lighter solids float to the surface. The settled and floating materials are removed and the remaining liquid may be discharged or subjected to secondary treatment.

• Secondary treatment removes dissolved and suspended biological matter. Secondary treatment is typically performed by indigenous, water-borne micro-organisms in a managed habitat. Secondary treatment may require a separation process to remove the micro-organisms from the treated water prior to discharge or tertiary treatment.

• Tertiary treatment is sometimes defined as anything more than primary and secondary treatment in order to allow rejection into a highly sensitive or fragile ecosystem (estuaries, low-flow rivers, coral reefs,...). Treated water is sometimes disinfected chemically or physically (for example, by lagoons and microfiltration) prior to discharge into a stream, river, bay, lagoon or wetland, or it can be used for the irrigation of a golf course, green way or park. If it is sufficiently clean, it can also be used for groundwater recharge or agricultural purposes.

Process flow diagram for a typical large-scale treatment plant

Process flow diagram for a typical treatment plant via subsurface flow constructed wetlands (SFCW)


Shortcut Key	Description
ALT+F11	Displays the Visual Basic Editor
ALT+F8	Displays the Macros dialog box
CTRL+0	Toggles Clean Screen
CTRL+1	Toggles Properties palette
CTRL+2	Toggles DesignCenter
CTRL+3	Toggles the Tool Palettes window
CTRL+4	Toggles Sheet Set Manager
CTRL+6	Toggles dbConnect Manager
CTRL+7	Toggles Markup Set Manager
CTRL+8	Toggles the QuickCalc palette
CTRL+9	Toggles the Command Line window
CTRL+A	Selects all the objects in drawing that are not locked or frozen
CTRL+SHITF+A	Toggles Groups
CTRL+B	Toggles Snap
CTRL+C	Copies objects to the Windows Clipboard
CTRL+SHIFT+C	Copies objects to the Windows Clipboard with Base Point
CTRL+D	Toggles Dynamic UCS
CTRL+E	Cycles through isometric planes
CTRL+F	Toggles running object snaps
CTRL+G	Toggles Grid
CTRL+H	Toggles PICKSTYLE
CTRL+SHIFT+H	Toggles the display of palettes with HIDEPALETTES and SHOWPALETTES
CTRL+I	Toggles the Coordinates display
CTRL+J	Repeats last command
CTRL+K	Inserts a hyperlink
CTRL+L	Toggles Ortho mode
CTRL+M	Repeats last command
CTRL+N	Creates a new drawing
CTRL+O	Opens an existing drawing
CTRL+P	Plots the current drawing
CTRL+SHIFT+P	Toggles the Quick Properties interface
CTRL+Q	Quits AutoCAD
CTRL+R	Cycles through the viewports on the current layout
CTRL+S	Saves current drawing
CTRL+SHIFT+S	Displays up the Save As dialog box
CTRL+T	Toggles Tablet mode
CTRL+V	Pastes data from the Windows Clipboard
CTRL+SHIFT+V	Pastes data from the Windows Clipboard as a Block
CTRL+X	Cuts objects from the current drawing to the Windows Clipboard
CTRL+Y	Cancels the preceding Undo action
CTRL+Z	Reverses the last action
CTRL+[	Cancels current command
CTRL+\	Cancels current command
CTRL+PAGE UP	Moves to the next layout tab to the left of the current tab
CTRL+PAGE DOWN	Moves to the next layout tab to the right of the current tab
F1	Displays Help
F2	Toggles Text Window
F3	Toggles OSNAP
F4	Toggles TABMODE
F5	Toggles ISOPLANE
F6	Toggles UCSDETECT
F7	Toggles GRIDMODE
F8	Toggles ORTHOMODE
F9	Toggles SNAPMODE
F10	Toggles Polar Tracking
F11	Toggles Object Snap Tracking
F12	Toggles Dynamic Input


Shortcut Key	Description
ALT+F11	Displays the Visual Basic Editor
ALT+F8	Displays the Macros dialog box
CTRL+0	Toggles Clean Screen
CTRL+1	Toggles Properties palette
CTRL+2	Toggles DesignCenter
CTRL+3	Toggles the Tool Palettes window
CTRL+4	Toggles Sheet Set Manager
CTRL+6	Toggles dbConnect Manager
CTRL+7	Toggles Markup Set Manager
CTRL+8	Toggles the QuickCalc palette
CTRL+9	Toggles the Command Line window
CTRL+A	Selects all the objects in drawing that are not locked or frozen
CTRL+SHITF+A	Toggles Groups
CTRL+B	Toggles Snap
CTRL+C	Copies objects to the Windows Clipboard
CTRL+SHIFT+C	Copies objects to the Windows Clipboard with Base Point
CTRL+D	Toggles Dynamic UCS
CTRL+E	Cycles through isometric planes
CTRL+F	Toggles running object snaps
CTRL+G	Toggles Grid
CTRL+H	Toggles PICKSTYLE
CTRL+SHIFT+H	Toggles the display of palettes with HIDEPALETTES and SHOWPALETTES
CTRL+I	Toggles the Coordinates display
CTRL+J	Repeats last command
CTRL+K	Inserts a hyperlink
CTRL+L	Toggles Ortho mode
CTRL+M	Repeats last command
CTRL+N	Creates a new drawing
CTRL+O	Opens an existing drawing
CTRL+P	Plots the current drawing
CTRL+SHIFT+P	Toggles the Quick Properties interface
CTRL+Q	Quits AutoCAD
CTRL+R	Cycles through the viewports on the current layout
CTRL+S	Saves current drawing
CTRL+SHIFT+S	Displays up the Save As dialog box
CTRL+T	Toggles Tablet mode
CTRL+V	Pastes data from the Windows Clipboard
CTRL+SHIFT+V	Pastes data from the Windows Clipboard as a Block
CTRL+X	Cuts objects from the current drawing to the Windows Clipboard
CTRL+Y	Cancels the preceding Undo action
CTRL+Z	Reverses the last action
CTRL+[	Cancels current command
CTRL+\	Cancels current command
CTRL+PAGE UP	Moves to the next layout tab to the left of the current tab
CTRL+PAGE DOWN	Moves to the next layout tab to the right of the current tab
F1	Displays Help
F2	Toggles Text Window
F3	Toggles OSNAP
F4	Toggles TABMODE
F5	Toggles ISOPLANE
F6	Toggles UCSDETECT
F7	Toggles GRIDMODE
F8	Toggles ORTHOMODE
F9	Toggles SNAPMODE
F10	Toggles Polar Tracking
F11	Toggles Object Snap Tracking
F12	Toggles Dynamic Input

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