Introductiona)EutrophicationEutrophication or moreprecisely hypertrophication, is a water body enriched withnutrients,with an excess amount of it.Certain nutrients are needed for survival of theliving thing.Primarily,nature is efficient enough to provide right amount ofnutrients,not less nor too much. This is absolutely true in aquatic ecosystemsbecause they are so dynamic.Water will be oligotrophic if there is too muchnutrient.

Consequently,serious problems will occur if there is no nutrients in theaquatic environment of the organisms.However,problems can also occur when there is too much nutrients too. When this occurwe get eutrophication. A eutrophic stream, river or lake occurs when too manynutrients,such as nitrogen and phosphorous, are present, usually as a result ofoverflow of the land.

Algae, plankton and other microorganisms attracted to thesetypes of nutrients, and when they are too much these aquatic organisms can takeover. When eutrophication occurs in a lake, river or other aquatic system,itgives a negative impact on the organisms itself including humans,birds andfishes.b)DeforestationClearing of trees or removalof trees from the forest to make it into non-forest is called deforestation andit is also used for urban development.Conversion of forestland to farms, ranches, or urban use are also examplesof deforestation.

Tropical rainforests are the most commondeforestation area.One of the largest and severe issue in global land is noneother than deforestation. Croplands and grazing lands are estimated arearegarding deforestation which includes cutting down trees for wood products andso on due to urban usage.Due to this,whole forest is no more and wiped out due tono more trees left in the forest. In some cases,forest structure would bealtered if illegal logging and so called accidental fire occurs.

The practiceof slash-and-burn agriculture isthe major contributor for deforestation.Small-scale farmers clear land producesfor only a few years and then must forests by burning them and then grow cropsin the soils fertilized by the ashes.InSoutheast Asia such as Indonesia, tropical Africa, and the Americas forpermanent oil palm plantations practiceopen fire burning to clear out the forests.  c) Global WarmingTheobserved century-scale rise in the average temperature of the Earth’s climate system andits related effects called Global warming commonly known as climate change,The increase of average world temperatures as a result ofwhat is known as the greenhouse effect is global warming too. Ingreenhouse,certain gases in the atmosphere acts like glass, sunlight is allowedto heat the earth’s surface but it radiates back to the space if we trap theheat. The Earth gets hotter when the greenhouse gases build up in theatmosphere.Consequently,this phenomena is called climate change.

Sincethe mid-20th century the Scientist have gathered detailed observations ofvarious weather phenomena(such as temperatures, precipitation,and storms) and of related influences on climate (suchas oceancurrents and the atmosphere’s chemical composition).Earth’s climate indicated that it has changedover almost every conceivable timescale since the beginning of time and thatthe influence of human activitiessince at least the beginning of the IndustrialRevolution has been deeply contributed to the climatechange.d) Ozone depletionOzone is very importantand crucial to us and gives us the pros and cons.Asa result of many chemical reaction regarding air pollution which caused byheavy traffic and UV light formed ozone near the ground which eventually causeda lot of respiratory problems particularly for children and the elderly.However,the stratosphere, ozonefilters out incoming radiation from the Sun in the cell-damaging ultraviolet (UV)part of the spectrum are known as high up in the atmosphere in a region.

Life onearth would not have evolved in the way it has without this ozone layer. Single-celled organisms such as algae that make upthe bottom rung of the food chain inhibits the reproductive cycle ofphytoplankton with the help of extra UV B radiation shone onto Earth.The onlything fears the Biologist is that reductions in other animals due to low numberof phytoplankton..Excess ultraviolet B.Chlorofluorocarbons (CFCs), chemicalsfound mainly in spray aerosols heavily used by industrializednations for much of the past 50 years, are the primary culprits in ozone layerbreakdown which ultimately causes the change in the reproductive rates of youngfish, shrimp, and crabs as well as frogs and salamanders.UV breaks down into substancesuch as chlorine due to CFC in the upper atmosphere exposed to UV.Chlorinereacts with the oxygen particle and tears down the ozone.

e)PollutionWhen pollutants contaminate the naturalsurroundings; which changes our normal lifestyles quickly is called pollution.Ourecosystem and the balance in the environment are disturbed due to pollution.Pollution occurs in Different forms of pollution can be found such as air,water, soil, radioactive, noise, heat/ thermal and light.There are two sourcesof pollution occurrence; the point and the non-point sources.The non-pointsources are hard to control whereas the point sources are easier toidentify,monitor and control.Firstly,Air pollution is a contamination of natural air with dangerousgases.It is one of the major contributor to environmentalpollution.

  Land pollution occurs due to excess of dumping of toxicwaste. This can be a chemical or other waste material.Sound pollutioncalled as noise pollution is a disturbance of silent environment withloud noises.Radiationpollutionis the pollution due to abnormal radiation in the environment. This occurs dueto use of radioactive elements from atomic energy stations.Thermal pollutionarises because of excess heat from thermal power plants,industries involved in metal molding.Water pollution is mainly aboutharmful toxic substances thrown by ignorant humans or released as residue byirresponsible companies.In other cases,ships release their unwanted oil intothe sea.

f) Acid depositionAny other form of precipitation that is unusually acidic, elevated levels of hydrogen ions(low pH) is known as Aciddeposition.Plants, aquatic animals and infrastructure had negative impacts dueto acid deposition.Emissions of sulphur dioxide and nitrogen oxide, which react withthe water molecules in the atmosphere to produceacids is called acid deposition.Wet and dry are the two types of deposition.Rain, snow, fog, hailor even dust that is acidic are included in the type of acid deposition.Dry deposition consist of acidicparticles and gases from atmosphere in the absence of moisture.

Duringatmospheric the acidic particles and gases may deposit to surfaces (waterbodies, vegetation, buildings) quickly or may react to form larger particlesthat can be harmful to human health. This acidic water flows over and throughthe ground, and can harm plants and wildlife, such as insects and fish when theaccumulated acids are washed off a surface by the next rain.The amount ofrainfall an area receives depends on the  amount of acidity in the atmosphere that depositsto earth through dry deposition.For instance,the ratio of dry to wet depositionis higher than an area that receives several inches of rain each year in thedesert areas.

Causes and why it happensA) EutrophicationFertilizers (nitratesand phosphates)Ignorant human actions predominantly causes Eutrophication.Nutrientaccumulation consists of agriculturalpractices and the use of fertilizers on lawns, golf courses,and other fields. Surface runoff into lakes, rivers, oceans and other surfacewaters washes away these nutrients with high concentrations of phosphorous andnitrogen when it rains, photosynthesis activity of the hungry plankton, algaeand other aquatic plant life increases and well fed.

Dense growth of algalblooms and plant life in the aquatic environments are the consequence of this.Concentratedanimal feeding operationsPhosphorus and nitrogen nutrients and Concentrated animal feedingoperations (CAFOs) are the main contributor for eutrophication. The nutrients arenormally discharged through animal feeding that finds way into rivers, streams,lakes, and oceans whereby accumulation occur in large quantity with recurringcyanobacterial and algal blooms plaguing the water bodies.Directsewage discharge and industrial waste into water bodies Sewagewater is directly discharged into water bodies such as rivers, lakes, andoceans in some parts of the world, especially thedeveloping nations. As a result, it stimulates the dense growth of algal bloomsand other aquatic plants which threatens survival of aquatic life in many waysdue to the newly introduced high amounts of chemical nutrients.

The sewage water may also be treated by some countries,but it is stilldischarged into the water after the treatment. Causing of the accumulation ofexcess nutrients, ultimately bringing about eutrophication,as much as the wateris treated. Similar outcomes are present when direct discharge of industrial waste water into water bodies.  Natural eventsFloods and thenatural flow of rivers and streams are natural events which can prevent excessivegrowth of algal blooms by washing away the excess nutrients off the land intothe water systems.

Accumulation of sediments as well as phosphorus and nitrogennutrients which contribute to the explosive growth of phytoplankton andcyanobacterial blooms will occur as lakes grow old.