BIOLOGY FOLIO 

CHAPTER 9 ;

ENDANGERED ECOSYSTEM

CONTENTS1

1 Human activities that endangered an ecosystem 3

2 Air pollution 4

3 Water pollution 9

4 Thermal pollution 13

5 Noise pollution 16

6 Strategies to solve problems related to pollution 19

7 The greenhouse effect 20

8 The thinning of the ozone layer 22

9 The importance of Proper management of development activities and the ecosystem

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Human activities that endangered an ecosystem

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The world’s population has grown to over6 billion today, so conflicts arise betweenthe need to meet the immediate humandemands in the short term and the need toprotect and conserve ecosystems fromlong-term damage

Most of the problem related to theenvironment are the results of humanactivities and

human interference with theecosystem function

Human activities, if unplanned andmismanagement of ecosystems result invarious

environmental problems; air andwater pollution, the greenhouse effect, global warming

and the depletion of natural resources

These problems bring about negative effects that increasingly threaten theeconomic resources, health and survivalof ecosystem

Humans often take the role a healthy ecosystem plays in daily life for granted. The

ecosystem provides clean water, filters pollution from the air and much more. In fact, 80

percent of the world's medicines come from plants, according to the Action Bioscience

website. With this in mind, it is important to remember that many of the things humans

do on a daily basis have a serious impact on the ecosystem and its ability to continue to

provide these things and many more.

Air pollution

Air pollution is the introduction of chemicals, particulate matter, or biological materials

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that cause harm or discomfort to humans or other living organisms, or damages the natural

environment into the atmosphere.

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.

Air pollution from World War II production

Pollutants

An air pollutant is known as a substance in the air that can cause harm to humans and the

environment. 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 either primary or secondary. Usually, primary pollutants

aresubstances directly emitted from a process, such as ash from a volcanic eruption, the carbon

monoxide gas from a motor vehicle exhaust or sulfur dioxide released from factories.Secondary

pollutants are not emitted directly. Rather, they form in the air when primary pollutantsreact or

interact. An important example of a secondary pollutant is ground level ozone— one of the

many secondary pollutants that make up photochemical smog. Note that some pollutants may

be both primary and secondary: that is, they are both emitted directly and formed from other

primary pollutants.About 4 percent of deaths can be attributed to air pollution, according to the

Environmental Science Engineering Program at the Harvard School of Public Health.

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causes and effects of air pollution: (1) greenhouse effect, (2) particulate contamination, (3) increased UV

radiation, (4) acid rain, (5) increased ozone concentration, (6) increased levels of nitrogen oxides

Major primary pollutants produced by human activity include:

Sulphur oxides (SOx) - especially sulfur dioxide, a chemical compound with the formula

SO2. SO2 is produced by volcanoes and in various industrial processes. Since coal and

petroleum often contain sulfur compounds, their combustion generates sulfur dioxide.

Further oxidation of SO2, usually in the presence of a catalyst such as NO2, forms

H2SO4, and thus acid rain. This is one of the causes for concern over the environmental

impact of the use of these fuels as power sources.

Nitrogen oxides (NOx) - especially nitrogen dioxide are emitted from high temperature

combustion. Can be seen as the brown haze dome above orpl ume downwind of cities.

Nitrogen dioxide is the chemical compound with the formula NO2. It is one of the

several nitrogen oxides. This reddish-brown toxic gas has a characteristic sharp, biting

odor.NO2 is one of the most prominent air pollutants.

Carbon monoxide - is a colourless, odourless, non-irritating but very poisonous gas. It is

a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular

exhaust is a major source of carbon monoxide.

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Carbon dioxide (CO2) - a greenhouse gas emitted from combustion but is also a gas vital

to living organisms. It is a natural gas in the atmosphere.

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

enhanced 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 suspect carcinogens

and may lead to leukemia through prolonged exposure. 1,3-butadiene is another

dangerous compound which is often associated with industrial uses.

Particulate matter - Particulates, alternatively referred to as particulate matter (PM) 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 particulate matter can be man made

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 disease, altered lung function and lung

cancer

Minor air pollutants include:

A large number of minor hazardous air pollutants.

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A variety of persistent organic pollutants, which can attach to particulate matter.

Persistent organic pollutants (POPs) are organic compounds that are resistant to environmental

degradation through chemical, biological, and photolytic processes. Because of this, they have

been observed to persist in the environment, to be capable of long-range transport,

bioaccumulate in human and animal tissue, biomagnify in food chains, and to have potential

significant impacts on human health and the environment.

Natural sources

Effects

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Air pollution is responsible for major health effects.Every year, the health of countless people is

ruined or endangered by air pollution.

Many different chemicals in the air affect the human body in negative ways.Just how sick

people will get depends on what chemicals they are exposed to, in what concentrations, and for

how long.

Studies have estimated that the number of people killed annually in the US alone could be

over 50,000.

Older people are highly vulnerable to diseases induced by air pollution.Those with heart or

lung disorders are under additional risk.Children and infants are also at serious risk. Because

people are exposed to so many potentially dangerous pollutants, it is often hard to know

exactly which pollutants are responsible for causing sickness.Also, because a mixture of

different pollutants can intensify sickness, it is often difficult to isolate those pollutants that are

at fault.

Many diseases could be caused by air pollution without their becoming apparent for a long

time.Diseases such as bronchitis, lung cancer, and heart disease may all eventually appear in

people exposed to air pollution.

Air pollutants such as ozone, nitrogen oxides, and sulfur dioxide also have harmful effects on

Natural eco systems.They can kill plants and trees by destroying their leaves, and can kill

animals, especially fish in highly polluted rivers.

Water Pollution

Water pollution is the contamination ofwate r bodies (e.g.lakes,ri ve rs,oceans andgro

undwater). Water pollution affects plants and organisms living in these bodies of water; and, in

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almost all cases the effect is damaging not only to individualspecie s and populations, but also

to the natural biological communities.

Water pollution occurs whenpollutants are discharged directly or indirectly into water bodies

without adequatet r e atm ent to remove harmful compounds.

Pollutants

Water pollution is usually caused by human activities. Different human sources add to the

pollution of water. There are two sorts of sources, point and nonpoint sources.Point sources

discharge pollutants at specific locations through pipelines or sewers into the surface water.

Nonpoint sources are sources that cannot be traced to a single site of discharge.

Pb poisoning is another serious source of environmental pollution which causes water

pollution. Pb poisoning is characterized by CNS damage, anaemia and deposition of Pb in bones

and teeth. The major sources of this pollutant are paint manufacturing industries/factories,

lead smelting works; petrol engines discharged inorganic Pb salts, metallic Pb and organic Pb

respectively. Pb (C2H4)4 – is used as an anti knock in petrol engines and is a pollutant. The

anaemia caused by Pb is due to inhibition of haem biosynthesis. Inorganic Pb inhibits

aminolaevulinic acid dehydratase and ferrochetalase (haem synthetase) which catalyses the

formation of the pyrrole porphobilinogen and incorporation of Fe 2+ into protoporphyrin IX

respectively.

There are a lot of types of water pollution. One of them is caused by toxic substances. This

is when someone dumps out a chemical pollutant into water. One of the greatest contributors

to toxic pollution is a factory compound.

Once water is contaminated, it is difficult, expensive, and sometimes impossible to remove

pollutants. Technologies to remove contaminants from groundwater are air stripping, granular

activated carbon, and advanced oxidation. Air stripping involves pumping out the contaminated

water, then heating it to evaporate the contaminant. The cleaned water is reinjected into the

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ground. Pumping out contaminated water and absorbing the pollutant on activated charcoal

can remove less volatile compounds.

Pollutants in water include a wide spectrum of chemicals, pathogens,

and physical chemistry or sensory changes.Many of the chemical substances

are toxic. Pathogens can produce waterborne diseases in either human or

animal hosts. Alteration of water's physical chemistry include acidity,

electrical conductivity, temperature, and eutrophication. Eutrophication is

the fertilisation of surface water by nutrients that were previously scarce. Even many of the

municipal water supplies in developed countries can present health risks.

[One] class of water pollutants are nutrients; they are water-soluble nitrates and

phosphates that cause excessive growth of algae and other water plants, which deplete the

water's oxygen supply. This kills fish and, when found in drinking water, can kill young children.

Heat is a water pollutant—increased water temperatures result in the deaths of many

aquatic organisms. These increases in temperature are most often caused by discharges of

cooling water by factories and power plants.

At industrial sites, chemical spills that contain toxic substances, smoke stacks that spew

emissions and uncovered or unprotected outdoor storage or waste areas can contribute

pollutants to storm water runoff.

Sources

The specific contaminants leading to pollution in water include a wide spectrum of

chemicals, pathogens, and physical or sensory changes such as elevated temperature and

discoloration. While many of the chemicals and substances that are regulated may be naturally

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occurring (calcium,so di um,iron,m angane se, etc.) theconcentration is often the key in

determining what is a natural component of water, and what is a contaminant.

Oxygen-depleting substances may be natural materials, such as plant matter (e.g. leaves

and grass) as well as man-made chemicals. Other natural and anthropogenic substances may

cause turbidity (cloudiness) which blocks light and disrupts plant growth, and clogs the gills of

some fish species.

Many of the chemical substances areto xic. Pathogens can produce waterborne diseases in

either human or animal hosts. Alteration of water's physical chemistry includes acidity (change

in pH), electrical conductivity, temperature, and eutrophication. Eutrophication is an increase in

the concentration of chemical nutrients in an ecosystem to an extent that increases in the

primary productivity of the ecosystem. Depending on the degree of eutrophication, subsequent

negative environmental effects such asanoxia (oxygen depletion) and severe reductions in

water quality may occur, affecting fish and other animal populations.

Thermal Pollution

Thermal pollution is the degradation of water quality by any process that changes ambient

water temperature.

A common cause of thermal pollution is the use of water as aco o l ant by power plants and

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industrial manufacturers. When water used as a coolant is returned to the natural environment

at a higher temperature, the change in temperature (a) decreasesoxy gen supply, and (b)

affects ecosystemco m po sitio n. Urban runoff--stormwater discharged to surface waters

from roadsand parking lots--can also be a source of elevated water temperatures.

When a power plant first opens or shuts down for repair or other causes, fish and other

organisms adapted to particular temperature range can be killed by the abrupt rise in water

temperature known as 'thermal shock'.

Pollutants

Sources

The major sources of thermal pollution are electric power plants and industrial factories. In

most electric power plants, heat is produced when coal, oil, or natural gas is burned or nuclear

fuels undergo fission to release huge amounts of energy. This heat turns water to steam, which

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in turn spins turbines to produce electricity. After doing its work, the spent steam must be

cooled and condensed back into water. To condense the steam, cool water is brought into the

plant and circulated next to the hot steam. In this process, the water used for cooling warms 5

to 10 Celsius degrees (9 to 18 Fahrenheit degrees), after which it may be dumped back into the

lake, river, or ocean from which it came. Similarly, factories contribute to thermal pollution

when they dump water used to cool their machinery.

The second type of thermal pollution is much more widespread. Streams and small lakes are

naturally kept cool by trees and other tall plants that block sunlight. People often remove this

shading vegetation in order to harvest the wood in the trees, to make room for crops, or to

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construct buildings, roads, and other structures. Left unshaded, the water warms by as much as

10 Celsius degrees (18 Fahrenheit degrees). In a similar manner, grazing sheep and cattle can

strip streamsides of low vegetation, including young trees. Even the removal of vegetation far

away from a stream or lake can contribute to thermal pollution by speeding up the erosion of

soil into the water, making it muddy. Muddy water absorbs more energy from the sun than

clear water does, resulting in further heating. Finally, water running off of artificial surfaces,

such as streets, parking lots, and roofs, is warmer than water running off vegetated land and,

thus, contributes to thermal pollution.

Effects

Elevated temperature typically decreases the level of dissolved oxygen (DO) in water. The

decrease in levels of DO can harm aquatic animals such as fish,am phi bi a ns andco pepo ds.

Thermal pollution may also increase them etabo lic rate of aquatic animals, asenzym e activity,

resulting in these organisms consuming more food in a shorter time than if their environment

were not changed. An increased metabolic rate may result in fewer resources; the more

adapted organisms moving in may have an advantage over organisms that are not used to the

warmer temperature. As a result one has the problem of compromising food chains of the old

and new environments. Biodiversity can be decreased as a result.

It is known that temperature changes of even one to two degreesCelsius can cause

significant changes in organism metabolism and other adverse cellular biology effects. Principal

adverse changes can include rendering cell walls less permeable to necessaryo smo sis,

coagulation of cellprote ins, and alteration of enzyme metabolism. These cellular level effects

can adversely affectmortality andrepro duction.

Primary producers are affected by warm water because higher water temperature increases

plant growth rates, resulting in a shorter lifespan and species overpopulation. This can cause an

algae bloom which reduces oxygen levels.

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A large increase in temperature can lead to the denaturing of life-supporting enzymes by

breaking downhy dro gen- and disulphide bonds within the quaternary structure of the

enzymes. Decreased enzyme activity in aquatic organisms can cause problems such as the

inability to break downlipids, which leads tom alnutrition.

In limited cases, warm water has little deleterious effect and may even lead to improved

function of the receiving aquatic ecosystem. This phenomenon is seen especially in seasonal

waters and is known as thermal enrichment. An extreme case is derived from the aggregational

habits of them anatee, which often uses power plant discharge sites during winter. Projections

suggest that manatee populations would decline upon the removal of these discharges.

Noise Pollution

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Noise pollution(orenvironmental noise) is displeasing human, animal or machine-created sound

that disrupts the activity or balance of human or animal life. The wordnoise comes from the

Latin wordnause as, meaning seasickness.

The source of most outdoor noise worldwide is mainlyconstruction andtransportatio n

systems, including motor vehicleno ise, aircraft noiseand 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 area.

Indoor and outdoor noise pollution sources include car alarms, emergency servicesirens,

mechanical equipment,fi rew or ks, compressed air horns, groundskeeping equipment, barking

dogs, appliances,lighting hum, audio entertainment systems, electricm egapho nes, and loud

people.

Sources

Noise becomes irritating if you're in the comfort of your home and an endless drone of low

flying airplanes will pass overhead. It causes your blood pressure to rise since the occurrence

can shake your walls and rattle you window panes. On top of that, you have read so many

incidents about how accidents can happen; that by some stroke of misfortune any one of these

planes may accidentally use your roof as landing pads.

Noise becomes a form of pollution if you're living in the city and the traffic could bring a lot

of cars honking simultaneously as their way of trying to protest the long

hours they have been waiting in queue. Add the multitudes of pedestrians who'd rather walk

than wait it out in the city traffic, most of them talking simultaneously,

enough to create a din. Noise in the city can disrupt your sleep, invade your privacy when you

find it hard to carry on with a simple conversation or create an unpleasant atmosphere for work

done at home.

Efects

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Human health

Noise health effects are both healthand behavioral in nature. The unwanted sound is called

noise. This unwanted sound can damage physiological and psychological health. Noise pollution

can cause annoyance and aggression,hy pertension, high stress levels,tinnitus, hearing loss,

sleep disturbances, and other harmful effects.Furthermore, stress and hypertension are the

leading causes to health problems, whereas tinnitus can lead to forgetfulness, severe

depression and at times panic attacks.

Chronic exposure to noise may cause noise-induced hearing loss. Older males exposed to

significant occupational noise demonstratesignificantly reduced hearing sensitivity than their

non- exposed peers, though differences in hearing sensitivity decrease with time and the two

groups are indistinguishable by age 79.

High noise levels can contribute tocardio v ascular effects and exposure to moderately high

levels during a single eight hour period causes a statistical rise in blood pressure of five to ten

points and an increase instress[3] andv aso constrictio n leading to the increased blood

pressure noted above as well as to increased incidence of coronary artery disease.

Noise pollution is also a cause of annoyance.

Environment

Noise can have a detrimental effect on animals by causing stress, increasing risk of death by

changing the delicate balance in predator/prey detection and avoidance, and by interfering

with their use of sounds in communication especially in relation to reproduction and in

navigation. Acoustic overexposure can lead to temporary or permanent loss of hearing.

An impact of noise on animal life is the reduction of usable habitat that noisy areas may

cause, which in the case of endangered species may be part of the path toe xt inction. Noise

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pollution has caused the death of certain species of whales thatbe ache d themselves after

being exposed to the loud sound of military sonar.

Noise also makes species communicate louder, which is called Lombard vocal response.

Scientists and researchers have conducted experiments that show whales' song length is longer

when submarine-detectors are on.If creatures do not "speak" loud enough, their voice will be

maskedby anthropogenic sounds. These unheard voices might be warnings, finding of prey, or

preparations of net-bubbling. When one species begins speaking louder, it willmask other

species' voice, causing the whole ecosystem to eventually speak louder.

People living in urban environments are more likely to sing at night in places with high

levels of noise pollution during the day, suggesting that they sing at night because it is quieter,

and their message can propagate through the environment more clearly.The same study

showed that daytime noise was a stronger predictor of nocturnal singing than night-time Light

pollution, to which the phenomenon is often attributed.

Zebra finches become less faithful to their partners when exposed to traffic noise. This could

alter a population's evolutionary trajectory by selecting traits, sapping resources normally

devoted to other activities and thus lead to profound genetic and evolutionary consequences.

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Strategies to Solve Problems Related to Pollution

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We have seen the effects of pollution on living things and the environment. Wecannot continue

to pollute the environment, thinking that we will not suffer any of the consequences. All efforts

must be made to control and stop pollution. One wayto curb pollution is by formulating short-

term and long-term strategies to reduce or stop pollution before it happens.

The Greenhouse EffectAnd The Thinning Of The Ozone Layer

The greenhouse effect

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When sunlight enters the Earth¶s atmosphere, some of its solar radiation is reflected

back into space.

As the Earth is warmed, heat in the form of infrared radiation is radiated back into

space.

However, much of this heat does not escape from the atmosphere, but remains trapped

bythe greenhouse gases.

At the same time, greenhouse gases also radiate heat in the form of infrared

radiationback to the Earth.

In this respect, greenhouse gases behave a lot like the glass panels of a greenhouse

whichtrap heat and warm the greenhouse, hence the term greenhouse effect.

The greenhouse effect is an important natural process.

Without it, the Earth would be too cold for the survival of living organisms.

Carbon dioxide, from coal-fired power stations and vehicle exhausts, is the

maingreenhouse gas.

Other contributary pollutants include chlorofluorocarbons (CFC)s, methane, nitrous

oxideand ozone.

Today, data collected around the world show a steady increase in the concentration

of greenhouse gases.

Since the beginning of the Industrial Revolution, the atmospheric concentration of

carbondioxide has increase by nearly 30% while the concentration of methane has more

thandoubled.

Scientists believe that the burning of fossil fuels and other human activities such

asdeforestation and industrial production are the primary reasons for

the increasedconcentration of atmospheric carbon dioxide.

As the concentration of greenhouse gases rises, the greenhouse effect

becomes morepronounced.

As more heat is trapped in the atmosphere, the Earth¶s average temperature rises.

This is known as global warming.

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In Malaysia, the temperature is rising at 0.18 C every decade.

In the absence of emission control policies, carbon dioxide concentrations are

projectedto be 30-150% higher than today¶s levels and the Earth¶s average

temperature may risebetween 1.5 C to 4.5 C by 2100.

We have examined how the change in the Earth¶s atmospheric composition increases

theability of the atmosphere to trap heat.

The thinning of ozone layer

The ozone layer is a region in the atmosphere, situated between 17 and 25

kilometresabove the Earth¶s surface.

The thinning of the ozone layer has been recorded by scientists since the 1970s.

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In 1985, it was reported that the stratospheric ozone concentrations over the

Antarcticahad declined by 40% since 1977.

The atmosphere in this area has very low ozone concentrations, resulting in the

formationof an ozone hole.

An ozone hole has now appeared above the Artic as well.

Consequently, ultraviolet radiation has since risen by 7% in a decade in

the northernhemisphere and in the southern hemisphere, the increase is 10%.

The destruction of the ozone layer is mainly due to the increasing levels

of chlorofluorocarbons (CFC) in the atmosphere.

CFCs are a group of chemical compounds that contain chlorine, carbon and fluorine.

These gases are used as coolants in air conditioners and refrigerators, as propellants

inaerosol cans and as foaming agents in the making of styrofoam packaging.

Since these chemicals are stable, they can persist in the environment for as long as 75 to

100 years.

Impact of the global warming and the thinning of the ozone layer on the ecosystem

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Global warming and the thinning of the ozone layer both have an enormous impact on

theecosystem.

The average increase in the Earth¶s temperature could change weather patterns

andagricultural output.

There is also convincing evidence from research carried out by scientists that links

themelting of the polar ice caps to global warming.

This is turn leads to a corresponding rise in sea levels.

By absorbing most of the ultraviolet radiation, the ozone layer shields living

organismson Earth from damaging effects of ultraviolet radiation.

The consequences of the thinning of the ozone layer can be quite severe.

The incidence of skin cancer and cataracts among the population will be on the

increase.

The Importance Of Proper Management Of Development Activities

And The Ecosystem

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We have examined closely how human activities can cause so much destruction to

theenvironment.

However, this does not mean humans always have to influence the environment in

anegative way.

We can also bring about positive effects on the environment by taking measures

to carryout proper management of development activities such as conserving and

preservingliving organisms and the environment.

As the country¶s population continues to increase, so do the people¶s needs.

The Earth¶s natural resources are relentlessly exploited to fulfil these needs.

Recall from unit 9.1 how the rainforests disappear to make way for development.

For example, to provide electrical power to the whole country, dams are

constructedacross rivers with little consideration of their impact on the environment.

In the process, human interfere with the balance of nature through their activities

andcontaminate the environment with pollutants.

Conflicts therefore arise, between the need to meet the requirements of an

increasingpopulation and the need to deal with growing environmental problems.

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