Human interferences in ecosystems
- 1. By, DAMARIS BENNY DANIEL II Msc. Zoology
- 2. Ecosystems have always been subjected to change. Under the impact of anthropogenic influences, change may be accelerating in many ecosystems. Some are deliberately created, others are a consequence of human activities. Weather modifications Artificial rain making Desalination Green House Effect Destruction of ozone umbrella Acid rain
- 3. It is the act of intentionally manipulating or altering the weather. The most common form of weather modification is cloud seeding to increase rain or snow. Weather modification can also have the goal of preventing damaging weather, such as hail or hurricanes, from occurring. It includes Cloud seeding and production of artificial rain Fog dissipation Frost prevention Lightning and hail suppression
- 4. Is the act of attempting to artificially induce or increase precipitation. Process of normal rain fall….. Rainfall occurs when cloud droplets grow large enough to fall to earth. Growth of cloud droplets occurs around a cloud seed. Cloud seeds or cloud condensation nuclei (CCNs) are small particles typically 0.2μm about which cloud droplets coalesce. No CCN – no rainfall Cloud seeding is a process which attempts to change the amount or type of precipitation that falls from clouds, by dispersing substances into the air that serve as CCN.
- 5. Any technique of cloud seeding depends on the release of millions of tiny particles of dry ice or silver iodide into a cloud. Methods Ignite solid silver iodide in burners on the ground. The smoke thus formed consists of many tiny particles of the compound which are then carried upward into a cloud. Dropping the seeding agent from an airplane onto the top of the cloud (spraying) The particles are fired into clouds from aircraft-mounted flare guns at a height of over 2,000m. Cloud seeding is the most common method of rain making.
- 7. Dry ice grains with high-pressurized air at almost sonic speed is blasted into the fog. The dry ice grains collide with the fog droplets, acts as a seeding agent The fog droplets grows in size and precipitates out of air. Thus fog may disappear. It can be applied anywhere where fog hinders functioning like airports, roads, harbours etc.
- 8. Hail - devastating effects on crops Hail can be prevented if the atmosphere is flooded with nuclei on which moisture can condense and freeze. The more nuclei present, the less likely large pieces of ice (hail) are to form. Relatively little work is now being done in the field.
- 9. Desalinisation is the process that remove salt and other minerals from saline water to create fresh water. Imp in places where availability of freshwater is limited. One potential byproduct of desalination is salt. 2 main methods Multistage flash distillation Reverse Osmosis (Membrane desalination process)
- 10. Water is heated in a container called brine heater. The heated water then flows to a second container called stage, where pressure is lower. Low pressure causes water to boil, some part forms steam The remaining water is moved into the next stage. The vapour produced is condensed in tubes of heat exchange. Same process repeated, so produces clean water & brine.
- 12. It is done by reverse osmosis (RO) Reverse osmosis is a process where the solvent molecules move across a semi permeable membrane from high solute concentration to low solute concentration. It requires input of energy. A RO membrane is a semi permeable membrane that allows the passage of water molecules but not majority of dissolved salts and other larger molecules. Saltwater is forced through membrane sheets at high pressures (600 to 1000 psi) Process produces clean water and brine
- 13. A greenhouse is a glasshouse in which plants are grown in colder countries. Principle The sun's energy enters through the greenhouse glass easily, plants absorb it and utilize it. A part of the radiation is re -emitted by the plants and soil It cannot get out as easily thus heat gets trapped inside. Earth’s atmosphere acts as a green house.
- 14. Incoming solar radiations passes through the atmosphere and reaches earth’s surface. The earth’s surface absorbs the solar energy and releases it back to the atmosphere as IR radiations some of which goes back into the space. Some of the IR radiations emitted by the earth is absorbed by green house gases in the atmosphere & they re-emit the energy as heat towards the earth’s surface. This increases earth’s surface temperature and this process is known as ‘Green House Effect’.
- 15. GREEN HOUSE GASES Water vapour: It is responsible for about two-thirds of the natural greenhouse effect. A part of water cycle. Carbon dioxide: Main contributor to the enhanced (manmade) GHE Globally, it accounts for over 60% of Enhanced GHE. The major source - from the burning of fossil fuels Methane: Mining and burning of fossil fuels, livestock husbandry , rice cultivation – major contribution. Methane can trap heat 23 times more effectively than CO2.
- 16. Nitrous oxide (N2O) Is released naturally from oceans and rainforests and by bacteria in soils. Human-influenced sources include nitrogen-based fertilisers, fossil fuel combustion and industrial chemical production. Fluorinated greenhouse gases: These are the only greenhouse gases that do not occur naturally, but have been developed by man for industrial purposes. Share - around 1.5%. But they are extremely powerful can trap heat up to 22,000 times more effectively than CO2 can stay in the atmosphere for thousands of years. The best known of these gases are chlorofluorocarbons (CFCs), which are not only fluorinated greenhouse gases, but also deplete the ozone layer. They are being phased out under the 1987 Montreal Protocol on Ozone Depleting Substances.
- 17. CAUSES Evaporation EnhancedGreenhouseeffect ANTHROPOGENIC NATURAL Volcanic eruptions Methane gas from cattle dung. Burning of fossil fuels Deforestation Use of fertilizers CFC’s from AC , fridges etc
- 18. Enhanced GHE would lead to global warming and other climate changes. Due to rise in global temp oceans will become warmer – affect living organisms. Melting of glaciers and polar ice caps will lead to rise in sea level and flooding of many low lying areas – islands at the risk of submergence. Several plant and animal species will become extinct due to their inability to adjust quickly to new conditions. Coral reefs would be severly threatened. Water scarcity & drought. Spread of several diseases. Extreme weather events – rising intensity of floods, droughts, storms etc.
- 19. We are running out of time act now before its too late. Reduce fossil fuel consumption. Use of cleaner energy sources. Energy efficient practices. Preservation and maintenance of existing forests Plant more trees. Better agriculture practices. SOLUTIONS
- 20. Humans have been interacting with ecosystems and modifying them for as long as human life has existed on Earth. The scale, speed and degree of change that is occurring threatens the survival and integrity of many ecosystems and also human life. The number of human-induced modifications to ecosystems has increased as population and technology has increased. Its high time we address the consequences and take appropriate steps to reduce the impacts.
- 21. Using supercomputers, MIT (Massachusetts Institute of Technology ) researchers have come up with a new approach for desalinating water–using sheets of graphene, a one-atom-thick form of the element carbon Graphene sheets with precisely controlled pores have potential to purify water more efficiently and less expensively than existing methods.
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