Module - 2 Environmental Science and Engineering.docx

**ENVIRONMENTAL SCIENCE AND ENGINEERING** **CE-ESE101** **MODULE \#2: ENVIRONMENTAL AND ECOLOGICAL CONCEPTS** I. **ECOSYSTEMS** **[TERMINOLOGIES]**   ***INDIVIDUAL -*** any specie that has the ability to interact w/ its environment & the ability to produce offspring of its kind. ***POPULATIO...

**ENVIRONMENTAL SCIENCE AND ENGINEERING** **CE-ESE101** **MODULE \#2: ENVIRONMENTAL AND ECOLOGICAL CONCEPTS** I. **ECOSYSTEMS** **[TERMINOLOGIES]**   ***INDIVIDUAL -*** any specie that has the ability to interact w/ its environment & the ability to produce offspring of its kind. ***POPULATION* -** group of individuals occupying a specific habitat ***COMMUNITIES* -** interacting groups of organisms in w/c each organism has a specific niche or role to play. ***HABITAT -*** the environment in w/c a particular organism lives ***NICHE** -* the functional role of an organism in a habitat All living organisms, whether plant or animal or human being is surrounded by the environment, on which, it derives its needs for its survival. Each living component interacts with non-living components for their basic requirements from different ecosystem.   **ECOLOGY-** study of interactions among organisms with their environment. The study of ecosystem.   **TWO VIEW POINTS OF ECOLOGY** 1. The environment and the demands it places in the organisms in it. 2. Organisms and how they adapt to their environmental conditions.   What do a tide pool on the California coast and the Amazon rainforest of South America have in common? Despite being many orders of magnitude different in size, both are examples of ecosystems---communities of organisms living together in combination with their physical environment. An **ecosystem** is a geographic area where plants, animals, and other organisms, as well as weather and landscape, work together to form a bubble of life. Ecosystems contain **biotic** or living, parts, as well as **abiotic** factors, or nonliving parts. Biotic factors include plants, animals, and other organisms. Abiotic factors include rocks, temperature, and humidity.   **Ecosystem** is the basic functional unit of ecology. The term ecosystem is coined from a Greek word meaning study of Home.   **Ecosystems can be very large or very small**. Tide pools, the ponds left by the ocean as the tide goes out, are complete, tiny ecosystems. Tide pools contain seaweed, a kind of algae, which uses photosynthesis to create food. Herbivores such as abalone eat the seaweed. Carnivores such as sea stars eat other animals in the tide pool, such as clams or mussels. Tide pools depend on the changing level of ocean water. Some organisms, such as seaweed, thrive in an aquatic environment, when the tide is in and the pool is full. Other organisms, such as hermit crabs, cannot live underwater and depend on the shallow pools left by low tides. In this way, the biotic parts of the ecosystem depend on abiotic factors.   **[STRUCTURE (or) COMPONENTS OF AN ECOSYSTEM]** The term structure refers to the various components. So the structure of an ecosystem explains the relationship between the abiotic (non --living) and the biotic (living) components.   **TWO MAJOR COMPONENTS OF THE ECOSYSTEM** - Biotic (living) components - Abiotic (non-living) components   - **BIOTIC COMPONENTS** - The living organisms or living members in an ecosystem collectively form its community called **biotic components or biotic community.** - Producers (Plants) - Consumers (Animals) - Decomposers (Micro-organisms) a. ***[PRODUCERS (Autotrophs)]*** - ***Synthesize their food through photosynthesis.***   a. ***[CONSUMERS (Heterotrophs)]*** - ***Organisms that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter.*** [CLASSIFICATION OF CONSUMERS:] 1. **Primary Consumers** (Herbivores) (Plant Eaters) - They directly depend on plants for their food. 2. **Secondary Consumers** (Primary Carnivores)(Meat Eaters) - They feed on primary consumers. They directly depend on herbivores for their food. 3. **Tertiary Consumers** (Secondary Carnivores)(Meat Eaters) - They feed on secondary consumers. Depends on primary carnivores for their food. a. ***[DECOMPOSERS]*** - ***Microorganisms like bacteria and fungi. Decomposers attack the dead bodies of producers and consumers and decompose them into simpler compounds. During decomposition, inorganic nutrients are released. The inorganic nutrients together with other organic substances are then utilized by the procedures for the synthesis of their own food.***   - **ABIOTIC COMPONENTS** - are non-living factors that impact an ecosystem. These factors are part of the ecosystem and influence the associated living things but they are not living. The term abiotic is a mix of two words, these are a- which means without, and bio which means life.   - *Organic Substances -* Protein, Lipids, Carbohydrates, etc. - *Inorganic Substances -* All micro (Al, Co, Zu, Cu) and macro elements (C, H, O, P, N, K) and few other elements. **ECOLOGICAL SUCCESSION** In an area one community may be replaced by another community or by a series of communities. Thus the progressive replacement of one community by another till the development of stable community in a particular area is called ecological succession.   Stages of ecological succession 1\. **Pioneer community** - The first group of organism, which establish their community in the area is called 'Pioneer' Community. 2\. **Seres (or) Seral stage** - The various developmental stages of a community is called '**seres**'.   **TYPES OF ECOLOGICAL SUCCESSION** Ecologists recognize two types of ecological succession, used on the conditions present at the beginning of the process. 1\. **Primary succession** - It involves the gradual establishment of biotic communities on a lifeless ground. a\. *Hydrarch (or) Hydrosere* b\. *Xerarch or Xerosere* 2\. **Secondary succession** - It involves the establishment of biotic communities in the area, where some type of biotic community is already present.   **PROCESS OF ECOLOGICAL SUCCESSION** The process of ecological succession can be explained in the following steps. 1\. **Nudation** - It is the development of a bare area without any life form 2\. **Invasion** - It is the establishment of one or more species on a bare area through migration followed by establishment. a. *Migration* -Migration of seeds is brought about by wind, water or birds. b. *Establishment* - The seeds then germinate and grow on the land and establishes their pioneer communities. 3\. **Competition** - As the number of individual species grows, there is a competition with the same species and between different species for space, water and nutrients. 4\. **Reaction** - The living organisms take water, nutrients and grow and modify the environment is known as reaction. This modification becomes unsuitable for the existing species and favor some new species, which replace the existing species this leads to seral communities. 5\. **Stabilizations** - It leads to stable community, which is in equilibrium with the environment   **[FUNCTION OF AN ECOSYSTEM]** - The function of an ecosystem is to allow flow of energy and cycling of nutrients.   - Energy and Material flow - Food chains - Food webs - Food Pyramids     **TROPHIC FEEDING LEVELS -** levels of nourishment The various steps through which food energy passes in an ecosystem is called as tropic levels. 1. The producers (plants) represent the first trophic level. 2. Herbivores (primary consumers) present the second trophic level. 3. Primary carnivores (secondary consumers) represent the third trophic level 4. Top carnivores (tertiary consumers) represent the last level.   The tropic levels are arranged in the following way as where, - The green plants or producers represent first tropic level T1, - The herbivores or primary consumers represent second tropic level T2. - The carnivores or secondary consumers represent third tropic level T3. - The tertiary consumers are fourth tropic level T4. - Finally decomposers represent last tropic level T5  **FOOD CHAIN** -- the passage of energy from one trophic level to the next as a result or organism consuming another; an idealized pattern of flow of energy in a natural ecosystem; in the classical food chain, plants are eaten only by primary consumers, primary consumers are eaten only be secondary consumers, and so on. **TYPES OF FOOD CHAIN** Food chains are classified into two main types: 1. *[Grazing food chain]* 1. *[Detritus food chain]*   **FOOD WEB** - The interlocking pattern of various food chains in an ecosystem is known as food web. In a food web many food chains are interconnected, where different types of organisms are connected at different tropic levels, so that there is a number of opportunities of eating and being eaten at each tropic level **Example** Grass may be eaten by insects, rats, deer\'s, etc., these may be eaten by carnivores (snake, tiger). Thus there is an interlocking of various food chains called food webs.  **DIFFERENCE BETWEEN FOOD CHAIN AND FOOD WEB** In a linear food chains if one species gets affected (or) becomes extinct, then the species in the subsequent tropic levels are also affected. But, in a food web, if one species gets affected, it does not affect other tropic levels so seriously. There are number of options available at each tropic level.   **SIGNIFICANCE OF FOOD CHAIN AND FOOD WEB** 1. Food chains and food webs play a very important role in the ecosystem. Energy flow and nutrient. 2. Cycling takes place through them. 3. They maintain and regulate the population size of different tropic levels, and thus help in maintaining ecological balance. 4. They have the property of bio-magnification. The non -- biodegradable materials keep on passing from one tropic level to another. At each successive tropic level, the concentration keep on increasing. This process is known as bio-magnification.   **TYPES OF ECOSYSTEM** 1. **Terrestrial Ecosystem -** related to land. Ex. Grassland ecosystem, forest ecosystem, desert ecosystem, etc. ***FOREST ECOSYSTEM*** **TYPES OF FOREST ECOSYSTEM** Depending upon the climate conditions, forests can be classified into the following types. **Characteristics of forest ecosystems** **Structure and Function of forest ecosystem** c. Tertiary consumer: They depend on the primary carnivores for their food. 1. **Aquatic Ecosystem -** related to water. It is further sub classified into two types based on salt content. - Fresh Water Ecosystem - Running Water Ecosystems (Rivers, Streams) - Standing Water Ecosystems (Pond, Lake) - Marine Ecosystems (Sea, Sea Shore)   **LAKE OR RIVER ECOSYSTEM**   **LIMNOLOGY** - The study of limnology includes aspects of the biological, chemical, physical, and geological characteristics of fresh and saline, natural and man-made bodies of water.** ** A **lake or a river** is an ecological unit with its drainage basin; an artificial unit since many of its characteristics are determined by the nature, size, and shape of the land surrounding it and by the drainage waters that enter it. **Zones of Lake** Depending upon their depth and distance from the shore, likes consists of four distinct zones. **LAKE STRATIFICATION -** is the tendency of lakes to form separate and distinct thermal layers during warm weather. - **Epilimnion** -- upper layer of water in a lake - **Hypolimnion** -- lower layer of water in a lake or pond, w/c will remain at a constant temperature during the summer months - **Metalimnion** -- the middle layer of water in a lake, where the thermocline occurs (temperature & oxygen content fall off rapidly w/ depth)  **Plankton** -- are any small free-floating organisms living in a body of water; phytoplankton refers to the plant species (algae), & zooplankton to the animal species (crustaceans, rotifers, protozoa) feeding on other forms of plankton. **Macrophytes** -- larger aquatic plants  **Algal blooms** -- enormous populations under favorable conditions producing water color & distinctive odors & tastes **Eutrophication** - is the natural process of nutrient enrichment that occurs, over time, in a body of water. **TYPES OF LAKES** - **Eutrophic** -- lakes in which the nutrient level is high - **Oligotrophic** -- lakes with low nutrients level - **Mesotrophic** -- lakes with intermediate nutrients level A diagram showing how a water body looks when it is healthy and free from excessive nutrients. A diagram showing what happens when a water body has excess nutrients  1. **Man-made or Artificial Ecosystems** - operated or maintained by man himself. Ex. Croplands, Gardens II. **ENERGY AND MATERIAL FLOWS IN ECOSYSTEMS** **ENERGY FLOW IN THE ECOSYSTEMS**   **WHAT IS ENERGY?** Energy is the capacity for doing work. It can exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other various forms.   In Environmental Engineering, Energy is the most essential requirement for all living organism. Solar energy is the only source to our planet earth. Most of the solar energy that falls on the earth is usually reflected back into space by the earth's atmosphere. This effective solar energy is termed as the Photo synthetically Active Radiation (PAR).   Overall, we receive about 40 to 50 percent of the energy having Photo synthetically Active Radiation and only around 2-10 percent of it is used by plants for the process of photosynthesis. This is the most essential step to provide energy for all living organisms in the ecosystem.   From solar energy, it is then transformed into chemical energy through photosynthesis. The chemical energy is then used by the plants for their growth and the remaining is transferred to consumers by the process of eating.   Thus the energy enters the ecosystems through photosynthesis and passes through the different trophic feeding levels. This energy flow is based on two different laws of thermodynamics:   I. *FIRST LAW OF THERMODYNAMICS -* states that energy can neither be created nor destroyed. It can only change from one form to another. II. *SECOND LAW OF THERMODYNAMICS -* states that as energy is transferred, more and more of it is wasted.  **SOURCES OF PRIMARY ENERGY:**   **RENEWABLE ENERGY -** resources that are replaced in a reasonable length of time or that are usually readily or can be regenerated by natural processes.   Ex. Hydroelectric energy, tidal forces, geothermal, biomass, and solar.   **HYDROELECTRIC POWER --** uses the force of moving water to produce electricity **GEOTHERMAL ENERGY --** taps in the heat under the earth\'s crust to boil water. The hot water is the used to drive electric turbines to produce electricity **WIND POWER --** it is used to drive with turbines to generate electricity **BIOMASS --** energy from plants **SOLAR ENERGY --** energy from the sun that is then converted to electricity using solar cell **TIDAL ENERGY --** the energy from the sea wave is used to drive turbines to generate electricity **[Environmental Benefits and Impacts of Renewable Energy:]** +-----------------------+-----------------------+-----------------------+ | **Energy Source** | **Benefits** | **Impacts** | +=======================+=======================+=======================+ | Hydroelectric Energy | \- produces no air | \- degradation of | | | pollution and | forest, farmland, | | | greenhouse gases | wild habitats and | | | | scenic areas | | | | | | | | \- it can cause | | | | radical changes in | | | | river ecosystems | +-----------------------+-----------------------+-----------------------+ | Geothermal |   | \- it requires a | | | | large amount of water | | | | for cooling, it might | | | | cause thermal | | | | pollution of river | | | | system | | | | | | | | \- emission of H~2~S, | | | | SO~2~, CO~2~, NO~2~ | | | | and volatile organic | | | | compounds | | | | | | | | \- generation of | | | | sludge (solid waste) | | | | containing silica | | | | compounds, chlorides, | | | | arsenic, mercury, | | | | nickel and other | | | | toxic heavy metals | +-----------------------+-----------------------+-----------------------+ | Biomass | \- burning of biomass | \- reducing air | | | produces a minimal | pollution and water | | | air pollution | pollution | | | | | | | | \- planting energy | | | | crops (source of | | | | biomass) makes | | | | streams cleaner | | | | | | | | \- energy crops | | | | improve soil quality | | | | | | | | \- biomass crops can | | | | create better | | | | wildlife habitat | +-----------------------+-----------------------+-----------------------+ | Wind | \- it produces no air | \- degradation of | | | and water pollution | lands due to | | | | construction of wind | | | \- no cooling water | turbine | | | needed | | | | | \- this might cause | | | \- no toxic or | the death of birds | | | hazardous wastes | | | | | | | | \- posses no threat | | | | to public safety | | +-----------------------+-----------------------+-----------------------+ | Solar | \- no air and water | \- the manufacture of | | | pollution | voltaic cells and | | | | components (materials | | | \- no toxic or | used in some solar | | | hazardous wastes | system) requires | | | during the generation | hazardous materials | | | of electricity | such as arsenic, | | | | cadmium and inert | | | | silicon | | | | | | | | \- also requiring | | | | cooling water | +-----------------------+-----------------------+-----------------------+ | Tidal | \- it produces no air | \- degradation of | | | and water pollution | lands due to | | | | construction of | | | \- no cooling water | turbine | | | needed | | | | | | | | \- no toxic and | | | | hazardous wastes | | | | | | | | \- posses no threat | | | | to public safety | | +-----------------------+-----------------------+-----------------------+   **NON-RENEWABLE ENERGY** - resources that are not replaced by natural processes or whose rate of replacement is so slow as to be ineffective and the amount of these materials is finite. Referred primarily to fossil fuels or to radioactive minerals. **CRUDE OIL (PETROLEUM) --** naturally occurring oil that consists chiefly of hydrocarbons with some other elements such as sulfur, oxygen and nitrogen. **Crude Oil Reserves:** **Country** **Reserves (in billion barrels)** ----------------- ----------------------------------- Saudi Arabia 261.7 Iraq 115 Iran 99.1 Kuwait 98.9 UAE 62.8 **Philippines** **0.2** **NATURAL GAS --** a naturally occurring mixture of gaseous hydrocarbons that is found in porous sedimentary rocks in the earth's crust. It consists chiefly of methane, ethane, propane and butane. **Natural Gas Reserves:** **Country** **Reserves (in trillion ft^3^)** ----------------- ---------------------------------- Russia 1,700 Iran 939 Qatar 757.7 Saudi Arabia 228.2 UAE 204.1 **Philippines** **3.7** **COAL --** a brown or black carbon deposit derived from the accumulation and alteration of ancient vegetation. **Types of Coal** +-------------+-------------+-------------+-------------+-------------+ | **Coal** | **Color** | **Moisture* | **Fixed | **Heating | | | | * | Carbon** | Value** | | | | | | | | | | | | **(BTU)** | +=============+=============+=============+=============+=============+ | Lignite | Brown | 70% |   | 7000 | +-------------+-------------+-------------+-------------+-------------+ | Subbitumino | Black | 43% | 70% | 9000 | | us | | | | | +-------------+-------------+-------------+-------------+-------------+ | Bituminous | Black | 5% | 80% | 13500 | +-------------+-------------+-------------+-------------+-------------+ | Superbitumi | Black |   | 83% | 16000 | | nous | | | | | +-------------+-------------+-------------+-------------+-------------+ | Anthracite | Black | 2% | 90% | 13000 | +-------------+-------------+-------------+-------------+-------------+ **Coal Reserves:** **Country** **Anthracite and Bituminous** **Lignite and Subbituminous** **Total** **Share of Total** ------------- ------------------------------- ------------------------------- ----------- -------------------- USA 111,338 135,305 246,643 25.06% Russia 49,088 107,922 157,010 15.95% China 62,200 52,300 114,500 11.63% Australia 47,300 43,100 90,400 9.19% India 72,733 2,000 74,733 7.59% **NUCLEAR ENERGY --** energy released in the splitting or fusion of the nuclei of atoms. **[ENVIRONMENTAL IMPACTS OF NON-RENEWABLE SOURCES:]** **[Petroleum:]** 1. Emission of SO~2~, H~2~S, CO~2~, NO~x~ and hydrocarbons. 2. Ground water contamination by leaking tanks. 3. Used oil disposal 4. Interference with fisheries or land use. 5. Refinery effluents. **[Natural Gas:]** 1. Emission of SO~2~, H~2~S, CO~2~, NO~x~ and hydrocarbons. **[Coal:]** 1. Emission of CO~2~, SO~2~, small airborne particles, NO~x~, CO, hydrocarbons and volatile organic compounds (VOCs). 2. Generation of mercury, arsenic, lead, cadmium and uranium. 3. Generation of chlorine in wastewater. 4. It can cause thermal pollution. **[GLOBAL WARMING:]** - Since the beginning of the 20^th^ century, the mean surface temperature has increased by about 0.6^o^C. - Over the last 40 years, which is the period with most reliable data, the temperature has increased by 0.3^o^C. - Warming in the 20^th^ century is greater than in any time during the past 400-600 yrs. **EFFECTS OF GLOBAL WARMING:** - Mountain glaciers are receding - The Arctic ice pack has lost about 40% of its thickness over the past four decades - The global sea level is rising about three times faster over the past 100 years - More heat waves and droughts, resulting in more and more conflict for water resources - More extreme weather events, producing floods and property destruction - Greater potential for heat related illnesses and deaths as well as the wider spread of infectious diseases **[Nuclear Power:]** 1. Emission of radon from mine tailings 2. Contamination of the soil and water 3. Emission of radioactive materials both in mine and mineral processing **Effects of Short-Term Exposure to Radiation:** **Dose (rem)** **Effect** ---------------- ------------------------------------------------------- 0 to 25 No detectable clinical effects 25 to 50 Slight, temporary decrease in white blood cell counts 100 to 200 Nausea, marked decrease in white blood cells 300 and above It can cause death within 30 days after exposure **WORLD CONSUMPTION OF COMMERCIALLY PROVIDED ENERGY:** **Commodity** **Percentage** **Quantity (EJ)** --------------------- ---------------- ------------------- Crude Oil 38.5 144.4 Coal 26.8 100.5 Natural Gas 21.7 81.5 Hydroelectric Power 6.7 25.1 Nuclear Power 6.3 23.6 **FOSSIL FUEL RESERVES:** **Reserves** **Length of Time Consumption** **Expected Year of Depletion** -------------- -------------------------------- -------------------------------- Oil 22 2030 Natural Gas 47 2055 Coal 232 2240   **ENERGY** **UNITS OF MEASURE** - **BTU -** Amount of Energy required to heat one pound of water, one degree Fahrenheit - **CALORIE -** Amount of Energy required to heat 1 ml water 1 degree Celsius **ENERGY CONVERSION FACTORS** +-----------------------+-----------------------+-----------------------+ | **TO CONVERT** | **TO** | **MULTIPLY BY** | +=======================+=======================+=======================+ | BTU | Calories | 252 | | | | | | | Joules | 1054 | | | | | | | kWh | 0.000293 | +-----------------------+-----------------------+-----------------------+ | Calories | BTU | 0.00397 | | | | | | | Joules | 4.18 | | | | | | | kWh | 0.00116 | +-----------------------+-----------------------+-----------------------+ | Joules | BTU | 0.000949 | | | | | | | Calories | 0.239 | | | | | | | kWh | 2.78x10^-7^ | +-----------------------+-----------------------+-----------------------+ | Kilotwatt-hours | BTU | 3413 | | | | | | | Calories | 862 | | | | | | | Joules | 3.6x10^6^ | +-----------------------+-----------------------+-----------------------+ **HEAT ENERGY --** the flow of energy from a body at high temperature to at lower temperature when they are placed in thermal contact. **Law of Conservation of Energy:** "Energy in the universe is constant" \[rate of energy accumulated\] = \[rate of energy in\] -- \[rate of energy out\] + \[rate of energy produced\] - \[rate of energy consumed\] **\[rate of energy in\] = \[rate of energy out\]** ** \[rate of energy in\] = \[rate of useful energy out\] + \[rate of wasted energy out\]** ** Efficiency (%) = useful energy out / energy in x 100** ** ** **Sample Problems:** 1. A coal-fired power plant uses 1000 Mg of coal (note: 1 Mg is 1000kg). The energy value of the coal is 28,000 kj/kg. The plant produces 2.8 x 10^6^ kWh of electricity each day. What is the efficiency of the power plant? 2. A diesel electric generator that consumes 10,000 gallons of diesel per week has an efficiency of 38%. What is the amount of electricity produced of the generator? (The energy value of diesel is 138,000 BTU/gallon).   Conversion factors: 1 BTU = 252 cal = 1054J = 2.93x10^-4^ kWh ** ** ** ** **CALORIMETER: -** apparatus used to measure the amount of heat (energy) produced during chemical reaction  **q = mCΔT or Q = mCΔT** Where: q - energy out, J m - Mass of water, g C - Specific heat of water (4.18J/g^o^C) ΔT - change in temperature ** ** **Sample Problems:** 1. A calorimeter holds 4 liter of water. Ignition of a 10-gram sample of a waste-derived fuel of unknown energy value yields a temperature rise of 12.5^o^C. What is the energy value of this fuel? Ignore the mass of the bomb. 2. 15 grams of hydrocarbon compound with a heating value of 18,513 J/gram is burned in the calorimeter. The calorimeter that holds 15L of water is initially at 25^o^C. Calculate the final temperature of water. **[ENERGY BALANCE AT STEADY-STATE WITH TWO INFLOWS]**   Heat energy = mCΔt = mass of the material x absolute temperature of the material   Solving for T~3~: **T~3~ = T~1~Q~1~ + T~2~Q~2~ / Q~3~** Q~3~ = Q~1~ + Q~2~ ** ** Where: T -- Absolute temperature Q -- Flow, mass per unit time (or volume if constant density) 1 and 2 -- input streams 3 -- Output stream   **Sample Problem:** A coal fired-power plant discharges 3 m^3^/s of cooling water at 80^o^C into a river that has flow at 15 m^3^/s and a temperature of 20^o^C. What will be the temperature in the river immediately below the discharge? **III. BIOLOGICAL CYCLES IN THE ENRIVONMENT** **NUTRIENT FLOW OR NUTRIENT CYCLING OR BIOGEOCHEMICAL IN THE ECOSYSTEM** **NUTRIENTS -** The elements, which are essential for the survival of both plants and animals are called nutrients. **MACRONUTRIENTS** - The elements needed in large amounts. **MICRONUTRIENTS** - The elements needed in small amounts. **NUTRIENT CYCLES** The cyclic flow of nutrients between the biotic and abiotic components is known as nutrient cycle (or) biogeochemical cycles. The nutrients enter into procedures and move through the food chain and ultimately reach the consumer. The bound nutrients of the consumers, after death, are decomposed and converted into inorganic substances, which are readily used up by the plants (procedures) and again the cycle starts. The major nutrients like C, H, O and N are cycled again and again between biotic and biotic component of the ecosystem.   **Hydrological Cycle** Movement of water in a cyclic manner is known as hydrological cycle. The water cycle describes how water is exchanged (cycled) through Earth\'s land, ocean, and atmosphere. Water always exists in all three phases, and in many forms---as lakes and rivers, glaciers and ice sheets, oceans and seas, underground aquifers, and vapor in the air and clouds.   **Evaporation, Condensation, and Precipitation** The water cycle consists of three major processes: evaporation, condensation, and precipitation.   - **Evaporation** Evaporation is the process of a liquid\'s surface changing to a gas. In the water cycle, liquid water (in the ocean, lakes, or rivers) evaporates and becomes water vapor. - **Condensation** Condensation is the process of a gas changing to a liquid. In the water cycle, water vapor in the atmosphere condenses and becomes liquid. - **Precipitation** As is the case with evaporation and condensation, precipitation is a process. Precipitation describes any liquid or solid water that falls to Earth as a result of condensation in the atmosphere. Precipitation includes rain, snow, and hail.   **Other Processes**   - **Runoff**, for instance, describes a variety of ways liquid water moves across land. Snowmelt, for example, is an important type of runoff produced as snow or glaciers melt and form streams or pools. - **Transpiration** is another important part of the water cycle. Transpiration is the process of water vapor being released from plants and soil. Plants release water vapor through microscopic pores called stomata. The opening of stomata is strongly influenced by light, and so is often associated with the sun and the process of evaporation. Evapotranspiration is the combined components of evaporation and transpiration, and is sometimes used to evaluate the movement of water in the atmosphere.   **Influences of Water Cycle** Humidity and Temperature Humidity is simply the amount of water vapor in the air. As water vapor is not evenly distributed by the water cycle, some regions experience higher humidity than others. This contributes to radically different climates. Islands or coastal regions, where water vapor makes up more of the atmosphere, are usually much more humid than inland regions, where water vapor is scarcer. A region\'s temperature also relies on the water cycle. Through the water cycle, heat is exchanged and temperatures fluctuate. As water evaporates, for example, it absorbs energy and cools the local environment. As water condenses, it releases energy and warms the local environment.   Glacial melt and erosion caused by water are two of the ways the water cycle helps create Earth\'s physical features. **Carbon cycle** Carbon is the basic component in all the organic components. The carbon is present in all biotic components in different forms as food. Examples: Carbohydrates, proteins, fats and amino acids. Carbon is present in the atmosphere as CO2. The CO2 taken up by the green plants as a raw material for photosynthesis of different food. This food moves through food chain, finally the carbon present in the dead matter is returned to the atmosphere as CO2 by microorganisms. - *During respiration, plants and animals liberates CO2 in the atmosphere* - *Combustion of fuels also release CO2* - *Volcanic Eruptions also release CO2.*  **Nitrogen cycle** Nitrogen is present in the atmosphere as nN2 in large amounts (78%). The nitrogen is present in all biotic components in different forms as food. Examples: *Proteins, vitamins, amino acids, etc.*   The N2 from the atmosphere is taken up by the green plants as a raw material for biosynthesis of different foods (amino acids, proteins, vitamins) and used in metabolism. These food move through the food chain. After death of the plants and animals, the organic nitrogen in dead tissues in decomposed by several microorganisms ammonifying and nitrifying bacteria) into ammonia, nitrites and nitrates, which are again used by the plants. Some bacteria convert nitrates into molecular nitrogen (N2) which is again released back into atmosphere and the cycle goes on. **Nitrification** The conversion of ammonia into nitrates is termed as nitrification. This is brought about by nitrifying bacteria. Examples: Nitrobacteria, Nitrosamines.   **De-nitrification** The conversion of nitrates into nitrogen (N2) is termed de-nitrification. This process is brought about by denitrifying bacteria. Examples: Pseudomonas, flurescence. **Phosphorus cycle** Phosphorus is mainly present in the rocks and fossils. The phosphorus is present in all biotic components in different forms. Examples Bones, teeth, guano deposits. Phosphate rocks is excavated by man for using it as a fertilizers. Farmers use excess of fertilizers for the crops. The excess phosphate fertilizers move with the surface run-off reaches the oceans and are lost into the deep sediments. Sea birds eat sea -- fishes, which are phosphorus rich, and the excreta of the birds return the phosphorus to the land. Thus the sea birds, are playing an important role in phosphorus cycling animals and plants use these dissolved phosphates during the biosynthesis.  **IV. POPULATION DYNAMICS** **Population dynamics** is a study of the variation in the population of a particular species at a location over a given period of time. The population of each species has a unique physical distribution which changes over time and space based on how successful the species has been in thriving in that particular environment. The population of a species may contain individuals of different age and sex that number of which changes over time, either growing or shrinking. Population dynamics helps to answer how, when and why the changes occur. The change in the density of the population of a particular species in one location is dependent on the births, deaths, immigration, and migration of the species.  The values of these four factors birth (natality), deaths (mortality), immigration (influx) and emigration (outflux) help in determining whether the population in a given area will increase or decrease. A population whose density remains stable is said to be in equilibrium. **POPULATION PARAMETERS** **Importance of the study of Population dynamics** There is a growing need for awareness of the importance of the study of Population Dynamics. The study of this dynamism gives us an understanding of the link between the environmental changes and the subsequent changes in the population of a species. Assessing the impact of a biological effect on a species helps us to find ways to curb the negative factor that is influencing the decline of a population. With the growing global environmental changes, a number of species are on the brink of extinction. Population dynamics study helps the biologists identify these species and work towards the conservation of these endangered varieties of plant and animal life. The high mortality rate and the low reproductive rates have led to an increasingly aging population which has become a threat to many animal species. Although migration is always an option for an animal species in order to reach an environment that is more habitable, a global downslide in the environmental conditions has left little chance for the migrating species to thrive in a different location. **V. ENVIRONMENTAL LAWS TO PROTECT ECOSYSTEMS** **In order to protect our country\'s natural resources, laws and policies are then created and implemented by our government\'s environmental agencies. These laws are now being complied by local developers, other groups and organizations.**   **Legislation -** the preparing of and enacting of laws by local, state or national legislatures. In other contexts, it is sometimes used to apply to municipal ordinances and to the rules and regulations of administrative agencies passed in the exercise of delegated legislative functions.   Below is the list of summarized Philippine Environmental Laws by GreenDev: 1. **Philippine Environmental Policy** 1. **Philippine Environmental Impact Statement System** 1. **Strategic Environmental Plan for Palawan Act of 1992** 1. **Climate Change Act of 2009** 1. **Writ of Kalikasan** 1. **Philippine Disaster Risk Reduction and Management Act of 2010**   **LAWS AND POLICIES ON WASTE AND POLLUTIONS**   1. **Philippine Sanitation Code** 1. **Marine Pollution Decree of 1976** 1. **Water Code of the Philippines** 1. **Toxic Substances and Hazardous and Nuclear Wastes Control Act of 1990** 1. **Philippine Clean Air Act of 1999** 1. **Ecological Solid Waste Management Act of 2000** 1. **Philippine Clean Water Act of 2004** **ASSIGNMENT \#2:** Research: Any Type of Ecosystem Output: Paper (essay type), much better if creative (cards, posters, etc.)