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Unit-2 Natural Resources and Biodiversity Natural resources- occur naturally within environments that exist relatively undisturbed by mankind, in a natural form. Any component of the natural environment that can be utilized by human beings for their benefit are termed as natural resource. The natural resource can be a substance, an energy unit or a natural process or phenomena e.g. water, air, soil, minerals, coal, forests, crops, and wildlife are all examples of natural resources.
Natural resources are derived from the environment. Some of them are essential for our survival while most are used for satisfying our wants.
There are various methods of categorizing natural resources, these include source of origin, stage of development, and by their renewability, these classifications are described below-
- On the basis of origin
- Biotic – Biotic resources are obtained from the biosphere (living and organic material), such as forests and animals, 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.
- On the basis of development
- Potential Resources – Potential resources are those that exist in a region and may be used in the future. For example, petroleum may exist in many parts of India, having sedimentary rocks but until the time it is actually drilled out and put into use, it remains a potential resource.
- Developed Resources –are those that have been surveyed, their quantity and quality determined and are being used in present times.
- On the basis of renewability Renewability is a very popular topic and many natural resources can be categorized as either renewable or non-renewable:
- Renewable resources are ones that can be replenished naturally in a given span of time. Some of these resources, like sunlight, air, wind, etc., are continuously available and their quantity is not noticeably affected by human consumption. Though many renewable resources do not have such a rapid recovery rate, these resources are susceptible to depletion by over-use. 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 are resources that form extremely slowly. 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/recovery; a good example of this are fossil fuels, which are in this category because their rate of formation is extremely slow (potentially millions of years), meaning they are considered non-renewable. Some resources actually naturally deplete in amount without human interference, the most notable of these being radio-active elements
such as uranium, which naturally decay into heavy metals. Of these, the metallic minerals can be re-used by recycling them, but coal and petroleum cannot be recycled. The major natural resources are: •.1. Energy resources •.2. Forest resources •.3. Water resources •.4. Land resources •.5. Mineral resources •.6. Food resources
Energy Resources: Sources from which energy can be obtained to provide heat, light, and power. Sources of energy have evolved from human and animal power to fossil fuels, uranium, water power, wind, and the Sun. The principal fossil fuels are coal, lignite, peat, petroleum, and natural gas. Energy consumption is an index of advancement of a country.
It can be classified as renewable/ non-renewable, conventional/ non-conventional, traditional/ alternative.
i. Renewable/ Non-renewable
Renewable Energy - energy sources which are in-exhaustive and can be regenerated within a given span of time such as sunlight, wind, rain, tides, and geothermal heat. Renewable energy is an alternative to fossil fuels and therefore commonly called alternative energy.
Non-renewable Energy- Energy sources which are exhaustible and cannot be regenerated within a given span of time such as fossil fuel like coal, petroleum, minerals etc.
ii. Conventional/ Non-conventional
Conventional Sources of Energy
(i) The sources of energy which have been in use for a long time, e.g., coal, petroleum, natural gas and water power.
(ii) They are exhaust able except water.
(iii) They cause pollution when used, as they emit smoke and ash.
(iv) They are very expensive to be maintained, stored and transmitted as they are carried over long distance through transmission grid and lines.
Non-Conventional Sources of Energy
(i) The resources which are yet in the process of development over the past few years. It includes solar, wind, tidal, biogas, and biomass, geothermal.
(ii) They are inexhaustible.
(iii) They are generally pollution free.
(iv) Less expensive due to local use and easy to maintain.
iii. Traditional/ Alternative
Advantages of solar Energy:
•.i. It is free of cost.
•.ii. Its supplies are unlimited.
•.iii. It does not produce air or water pollution.
Disadvantages of Solar Energy:
i. It has indirect impacts on the environment.
ii. Large solar thermal farms can harm the desert ecosystems if not managed properly.
iii. The amount of sunlight that arrives at the earth’s surface is not constant. It depends on the location, time of day, time of year and weather conditions.
iv. Since sun doesn’t deliver much energy to a specific place at a specific time, a large surface area is required to collect the energy at a useful rate.
According to International Energy Agency Report 2016, the top ten countries in Installed Solar Power Capacity are:
- China (2) Germany (3) Japan (4) U.S.A (5) Italy (6) U.K. (7) France (8) Spain
(9) Australia (10) India
Gujarat has been a leader in solar power generation and contributes 2/3rd of the 900 MW of photovoltaics in the country. The State has commissioned Asia’s biggest solar park at Charanka village, District Patan. The park is already generating 214 MW solar power out of its total planned capacity of 500 MW. Rajasthan and Maharastra are the other leading states generating solar energy.
•.2. Wind Energy: is the energy produced through wind. Wind is air in motion. It is caused by the uneven heating of the earth’s surface by the sun. Wind energy is mainly used to generate electricity. Wind is a renewable source of energy.
Wind energy is harnessed through wind mill. A windmill is a machine that collect the wind kinetic energy and converts the energy into rotational energy by means of vanes called sails. Originally, windmills were developed for milling grain for food production. An important use of it is to pump water, either for land drainage or to extract groundwater.
The operation speed of wind to produce power is 4-5 m/s, maximum power can be obtained when speed of wind is 15 m/s whereas at a speed of 25 m/s the wind farm has to shut down to reduce damage to wind mills.
A wind farm is a group of wind turbines in the same location used to produce electric power. Large wind farms consist of hundreds of individual wind turbines which are connected to the electric power transmission network. A large wind farm may consist of several hundred individual wind turbines, and cover an extended area of hundreds of square miles, but the land between the turbines may be used for agricultural or other purposes. A wind farm may also be located offshore. As of 2013, Denmark is generating
more than a quarter of its electricity from wind. Top 10 wind power countries in the world are (according to Global Wind Energy Council): Top states of India Producing wind energy are
- Tamil Nadu (40% of total wind power) 2. Gujarat 3. Maharastra 4. Rajasthan
Advantages of Wind Energy
- Wind Energy is an inexhaustible source of energy and is virtually a limitless resource.
- Energy is generated without polluting environment.
- This source of energy has tremendous potential to generate energy on large scale.
- Like solar energy and hydropower, wind power taps a natural physical resource.
- Windmill generators doesn’t emit any emissions that can lead to acid rain or greenhouse effect.
- Wind Energy can be used directly as mechanical energy.
- In remote areas, wind turbines can be used as great resource to generate energy.
- In combination with Solar Energy they can be used to provide reliable as well as steady supply of electricity.
- Land around wind turbines can be used for other uses, e.g. Farming.
- (^) Big dams increase the risk of earthquake because the huge amount of standing water puts enormous pressure on land. But hydroelectric power doesn't necessarily require a large dam. Some hydroelectric power plants just use a small canal to channel the river water through a turbine. Hydropower is the most important and widely-used renewable source of energy. Large dams produces 30 MW and more of hydro power energy, small hydel projects produces 100 KW- 30 MW, Micro hydel projects produces 5-100 KW of energy and Pico hydel projects produces below 5KW of energy. Hydropower represents 19% of total electricity production. China is the largest producer of hydroelectricity, followed by Canada, Brazil, and the United States. India is blessed with immense amount of hydro-electric potential and ranks 5th in terms of exploitable hydro-potential on global scenario. The present installed capacity as on 30-06-2011 is approximately 37,367.4 MW which is 21.53% of total Electricity Generation in India. The public sector has a predominant share of 97% in this sector. National Hydroelectric Power Corporation (NHPC), Northeast Electric Power Company (NEEPCO), Satluj jal vidyut nigam (SJVNL), Tehri Hydro Development Corporation, NTPC-Hydro are a few public sector companies engaged in development of Hydroelectric Power in India. Karnataka is producing maximum hydro power energy followed by Himachal Pradesh, Maharastra and Punjab.
•.4. Geothermal Energy - The word geothermal comes from the greek words geo (earth) and therme (heat). Geothermal energy is heat from within the earth. The steam and hot water produced inside the earth can be used to heat buildings or generate electricity. Geothermal energy is a renewable energy source because the water is replenished by rainfall and the heat is continuously produced inside the earth. Temperature hotter than the sun’s surface are continuously produced inside the earth by the slow decay of radioactive particles. Most geothermal reservoirs are deep underground with no visible clues showing above ground. Geothermal energy can be on the surface in the form of volcanoes, hot springs, geysers. Naturally occurring large areas of hydrothermal resources (resources where ground water trapped in porous rock is heated up by magma) are called geothermal reservoirs. Current worldwide installed capacity is 10,715 megawatts (MW), with the largest capacity in the United States (3,086 MW), Philippines, and Indonesia. Uses of Geothermal Energy iv.1. Direct use - hot springs are used for bathing, cooking and heating. iv.2. Geothermal Power Plants - use hydrothermal resources which have two common ingredients water and heat. They require high temperature (300-700 degree Fahrenheit) These resources can be used by drilling wells into the earth and piping the steam or hot water to the surface.
Advantages
- It can be extracted without burning a fossil fuel such as coal, gas, or oil.
- Geothermal fields produce only about one-sixth of the carbon dioxide that a relatively clean natural-gas-fueled power plant produces. Binary plants release essentially no emissions.
- Unlike solar and wind energy, geothermal energy is always available, 365 days a year. It's also relatively inexpensive; savings from direct use can be as much as 80 percent over fossil fuels. Disadvantages
- Disposal of some geothermal fluids, which may contain low levels of toxic materials.
- Although geothermal sites are capable of providing heat for many decades, eventually specific locations may cool down.
- Sometimes hydrogen sulfide gas is released, a gas that smells like rotten egg at low concentrations. Forest resources- forest are one of the most important natural resources on this earth. These forests not only produce innumerable material goods, but also provide several environmental services which are essential for life. Forest is derived from latin word ‘foris’ meaning ‘out of door’.
Forests are central to all human life because they provide a diverse range of resources: they store carbon, aid in regulating the planetary climate, purify water and mitigate natural hazards such as floods. Forests also contain roughly 90 percent of the world's terrestrial biodiversity.
India is one of the 12 mega biodiverse regions of the world. Total forest cover of India as by Forest Survey of India 2015 report is 21.34%.
Indian forests types include tropical evergreens, tropical deciduous, swamps, mangroves, sub-tropical, montane, scrub, sub-alpine and alpine forests. These forests support a variety of ecosystems with diverse flora and fauna.
There are three major types of forests according to latitude:
1. Tropical- They are characterised by the greatest diversity of species. They occur near the equator, within the area bounded by latitudes 23.5 oN to 23.5 o^ S. - Only two seasons are present i.e. rainy and dry. The length of daylight is 12 hours and varies little. - The average temperature is 20-25oC and varies little throughout the year.
which they take in carbon dioxide and produce oxygen. •.v. Protective functions- forests protect our waters and manage our climate. When it rains in the forests, the leaves allow the water to slowly drip to the ground. Without trees the rain pours hard on the unprotected soil. The dirt washes into streams, muddying the water. This is unhealthy for the fish and can cause flooding and soil erosion. Also without trees the moisture in the air evaporates quickly, changing the climate of nearby forests. Plant cover, root systems, and the quality of topsoil enable good infiltration and water retention. Forests also play a role as landscape and recreation areas. •.vi. Regulative Functions- forest regulates temperature, humidity, precipitation, shape soil environment and different hydrological cycles.
Deforestation- is the permanent destruction of indigenous forests and woodlands. It is the complete cleaning of tree formation and their replacement by using land for other purpose. According to Forest Survey of India Report (2011), forest cover of India is 21.05%.
Factors causing deforestation
3.1. Natural- forest fire, soil erosion, drought
3.2. Economical- agriculture (growing food needs), establishment of heavy industries, development projects, urbanization (population growth), mining, quarrying, agribusiness (growing oil palm, rubber, fruit trees, ornamental plants) 3.3. Traditional- shifting cultivation, grazing, fuelwood gathering
Effects of Deforestation
3.1.Soil erosion 3.2.Expansions of deserts 3.3.Decrease in rainfall 3.4.Loss of fertile land 3.5.Effect of climate 3.6.Lowering of water table 3.7.Loss of flora and fauna 3.8.Environmental changes 3.9.Lack of fuelwood for tribal people Timber Extraction- unlimited exploitation of timber for commercial use leading to decimation of forests. The major effects of timber extraction on forests and tribal people include:
- (^) Degradation of forest
- Loss of biodiversity
- Sedimentation of irrigation systems
- Soil erosion
- Climatic Changes such as low precipitation
- Permit shifting cultivators and fuelwood gatherers to gain access to logged areas and fell the remaining trees
- Forest fragmentation
- Exploitation of tribal people by the contractors Mining- the major effects of mining operations on forests and tribal people include:
- Degradation of lands
- Loss of top soil due to deforestation
- Pollution of surface and ground water resources
- Lowering of ground water table
- Air pollution due to release of green house gases and other toxic gases
- Sediment production and discharge
- Subsidence above and near mine areas can change local hydraulic gradients and create numerous ponds
- Migration of tribal people from mining areas to other areas in search of land and food
- Tribal people may be forced into a new way of life for which they are unprepared Dams - the major impacts of dams on forests and tribal people are:
- Degradation of catchment area
- Reservoir induced seismicity
- Loss of flora and fauna including gene pool reserves due to submergence
- Increased incidence of water borne diseases
- Acute scarcity of fuelwood and other forest products for tribal people
- Rehabilitation and resettlement of affected people Forest conservation must be carried out because of the following benefits associated:
- The proper balance of atmospheric carbon dioxide is maintained by the trees which in turn help control the greenhouse effect.
- Forests are a source of various products that have economic values of there own. For example: timber, gum, raisins etc.
- (^) There are varieties of plants that are of medicinal values and as such conservation of the species becomes essential.
- Forests also provide shelter for wildlife and bird species. So in order to support them forest conservation is again essential.
recycled in the environment through hydrological cycle (water cycle). Due to human activities like industrialization, urbanization the surface water as well as ground water is depleting. Excessive use of fertilizers (Nitrogen, Phosphorous) is causing eutrophication.
Eutrophication
When aquatic plant growth is stimulated to produce excessive choking growth eutrophication occurs. The process involves a complex series of inter-related changes in the chemical and biological status of a water body mostly due to a depletion of the oxygen content caused by decay of organic matter resulting from a high level of primary productivity and typically caused by enhanced nutrient input. Sewage is an important source of organic materials in water bodies. Fertilizers and detergents containing Nitrogen and Phosphorous are also the major sources of nutrients. These nutrients greatly increase the productivity in aquatic environments and contribute to eutrophication. Algal blooms are an indication of eutrophication of a water body. A small part of the algal blooms are consumed by zooplanktons and other aquatic organisms like fishes and most of them stay and decay in the water depleting dissolved oxygen. Toxic gases like Hydrogen sulphide is generated. An unpleasant greenish slimy layer is formed on the surface of the water body. This results in the suffocation and eventually death of aquatic organisms. The water body emits bad odor. The anaerobic conditions (Lack of Oxygen) generate toxins in the algae, which can kill surface organisms like birds and animals. The water body cannot be used as a source of water supply nor used for any other activity like recreational use. Acquifer- is an underground layer of water bearing permeable rock from which ground water is extracted using a water well. It is of two types: Unconfined acquifer - water seeps through the permeable layer (permeable rocks or soil) present above it. Confined acquifer - impermeable layer (impermeable rocks) exist above it; water seeps from farther away where the impermeable layer doesn’t exist. Rainwater Harvesting - is the method of utilizing rainwater for domestic and agricultural use by capturing and storing the rainwater above the ground or recharge the underground for its later use. It is essential because-
- Surface water is inadequate to meet our demand and we have to depend on groundwater.
- Due to rapid urbanization, infiltration of rainwater into the subsoil has decreased drastically and recharging of groundwater has diminished.
Rainwater harvesting has the following objectives
- To reduce run-off loss
- To avoid flooding of roads
- To meet the increasing demand of water
- To raise the water table by recharging groundwater
- To reduce groundwater contamination
- To supplement groundwater supplies during lean season
- Prevents soil erosion and flooding especially in urban areas
The following methods are adopted for modern and traditional harvesting:
- Storage of rainwater on surface for future use by constructing pits, dug-well, lagoons, trench or check-dams.
- Recharge to groundwater uses pits, trenches, dug wells, recharge wells, recharge shafts, lateral shafts with borewells.
Components of Rainwater harvesting systems have the following 5 basic components:
- Catchment : the surface from which rainwater is collected for storage. This could be a rooftop, a paved flooring surface or a landscaped area. Catchment area is the area of that surface, usually calculated in square metres.
- Gutters and Downtake pipes : lead the water from the catchment surface to the storage tank
- Filters and first flush devices : remove grit, leaves and dirt that the rainwater may transport from the catchment, before the water enters the storage tank. When it rains after a long gap, the rooftops are usually very dirty and the rainwater also carries with it a lot of dissolved air pollutants. A first flush device diverts the water from the first rain so that it does not enter the storage tank.
- Storage tanks : These can be above the ground or below the ground.
- Delivery systems : Piping systems that convey the stored rainwater till the point of end-use. It is not recommended to use harvested rainwater for drinking, cooking and dishwashing unless water quality issues are verified and necessary treatment or purification systems installed.
Land Resources Land is finite and valuable resource on which we depend for our housing, food, fibre and fuel wood. Soil, especially the top soil is considered as renewable resources because it is continuously regenerated but the rate of regeneration is a slow process. It take almost 200-1000 year for the formation of 2.5 cm soil, depending upon
When they strike the surface again they either rebound back into the air or knock other particles into the air.
- Creep - The large particles which are too heavy to be lifted into the air are moved through a process called surface creep. In this process, the particles are rolled across the surface after coming into contact with the soil particles in saltation. b) Biotic agents: excessive grazing, mining, and deforestation are the major biotic agents responsible for soil erosion. Methods to reduce soil erosion are: 1) Terracing: Steep slopes are converted into broad terrace which run across the contour. Terracing retains water for crops at all levels and cut down soil erosion by controlling run-off.
- Strip cropping: strip of crops are alternated with strips of soil saving cover crops like grasses or grass legume mixture. So whatsoever run off comes from the cropped soil is retained by strip of cover crop and this reduce soil erosion.
- Alley cropping: It is also known as Agro forestry. In this type crops are planted between rows of trees or shrubs. So, when crops are harvested soil is not fallow so reduce the soil erosion. 4) Wind breaks or shelterbelts: These help in reducing soil erosion by strong winds. The trees are planted in long rows along the cultivated land boundary so that wind is blocked. The wind is substantially reduced which help in preventing wind erosion of soil.
Water logging and induced salinity: Mainly occurs due to faulty irrigation practice, where farmers applied more irrigation water than actually needed for the crop growth. However due to inadequate drainage water get accumulated and form a continuous column with water table. These type of soil are call waterlogged soil which affect crop production due to inhibition of exchange of gases. Water logging is most often associated with the salinity because irrigation water contain salts which get accumulated on soil during evaporation process. Desertification: Desertification is a process whereby the productive potential of arid and semi-arid lands falls by 10% or more. It can be categories as moderate(10-25%), severe ( 25-50%) and very severe( > 50%) drop in productivity. It leads to the conversion of rangelands or irrigated crop land to desert like condition in which agricultural production fall. It is characterized by devegetation, depletion of ground water, salinization and severe soil erosion.
Causes of Desertification: It can be natural due to change in the climate of any area or due to excess exploitation of land to human pressure. The major anthropogenic activities responsible for desertification are as follows:
- Deforestation: The process of denuding and degradation of forested land initiates a desert producing cycles. If there is no vegetation to hold back surface run-off, water drains out quickly before it can soak into the soil to nourish the plant and replenish the ground water.
- Overgrazing: Overgrazing areas are more under risk of desertification because it results into denude of the land area. The dry barren land becomes loose and more prone to soil erosion. The top fertile layer is also lost and thus plant growth is badly hampers in such soils.
- Mining and quarrying: These activities results into loss of vegetation cover and denudation of extensive land area leading to desertification. Land Resources in India
Conservation of natural resources: Role of an Individual Natural resources like forest, water, soil, food, mineral, energy and land plays a key role in the development of a nation. However these resources are facing risk of depletion due to increased exploitation for human need and required to conserve for future utilization. Conservation efforts are underway at national and international level however individual efforts are also necessary for the resource conservation. Some of the examples of individual conservation efforts are: Water resource:
- Don’t waste water by keeping water taps running during brushing, shaving, washing and bathing.
- Check water pipelines and taps for water leakage as a small pin shape hole can waste 640 liters of water in a month.
- Install water shaving toilets that not use much water for flushing purposes (not more than 6 liters).
- Install small system of rain water harvesting, which can be used for watering the plants and washing the vehicles. Energy resources: 1) Turn off light, fan, and other electric appliances when not in use. 2) Use solar water heater during winter seasons for domestic use. 3) Use of CFL bulbs conserve energy. 4) Use public transport system as much you can. Land resources:
Environmental problem associated with food resources: Environmental problem associated with food resources are associated with the production of food resources either from agriculture, cattle and poultry breeding and harvesting of fish and other aquatic products. a. Agricultural: Initially agricultural practice were less energy intensive with lower chemical inputs in form of fertilizers and pesticides. However with growing needs of food production agriculture become more energy intensive with more chemical inputs leading to degradation of water and land environment. Main problem associated with the modern agricultural are:
- Monoculture: most of the high yielding variety (HYV) encourage monoculture i.e. use of same genotype over vast area, so if there is an attack of pathogen, large tract of agricultural crop is going to affected.
- Fertilizer related problem: Application of fertilizer into agricultural land has variety of unwanted environmental affects such as:
- Micronutrient imbalance: Most of the applied fertilizer have micronutrient (N,P,K), which promote the growth of crop however during crop growth it also required micronutrient such as zinc which is not replenish resulting into the imbalance of soil nutrient.
- Nitrate pollution: nitrogen applied in the agricultural field find its ways to ground water and surface water in the form of nitrate which is a water pollutant. High concentration of nitrate results into methaemoglobinemia (Blue baby syndrome).
- Eutrophication of the inland and coastal ecosystem: Excessive supply of phosphate and nitrate from the agricultural land to water bodies result into the favorable growth of non-siliceous alga which are unpalatable resulting into their bloom which eventually consume all the oxygen present in the water bodies resulting into death of other aquatic species and destruction of whole ecosystem.
- Pesticides related problems: different types of pesticides are applied to control crop from pest such as DDT(Dichlorodiphenyl trichloroethane), however their application also had some adverse effects:
- Pest resistance and origin of new pest variety: After the time course resistance variety of pest started to arrived which make the application of pesticides unfruitful.
