THE CC.

THE CARBON CYCLE

We all know that carbon is a big part in our everyday lives, yes as we are all carbon based life forms.  Although the carbon cycle does bare some very strong similarities to the nitrogen cycle, they are still different.

http://i383.photobucket.com/albums/oo273/mat_061/carboncycle_sm.jpg 

As shown in the photo above or as you will see when you copy the url and paste it somewhere else as blogspot does not like me, we all have a very important role to play in the carbon cycle.

1.      Carbon is present in the atmosphere in the state of carbon dioxide. Through the process of photosynthesis, carbon dioxide is being used by plants to make food. 

2.      Animals then consume the plants which ensure that carbon is still being passed on. Animals that eat other animals also get carbon transferred through this method.

3.      As plants and animals die or defecate their bodies and feces and other dead plant parts decay and decompose which hence brings carbon into the ground. Over the span of millions of years, they eventually become fossil fuels. 

4.      To power their industries humans then dig into these sources, burn fossil fuels which release the carbon into the atmosphere which hence causes the carbon cycle to repeat again. 

5.      Also, carbon dioxide is partially soluble hence oceans, seas and other bodies of water soak up the carbon in the atmosphere.

Much like in our song, 

-Humans are one of the extreme causes of why many people deem the carbon cycle as a bad thing. Firstly, humans are using environmentally unfriendly methods of executing industrial activities. Every year, 5.5 billion tones of billion tons of carbon dioxide is released into the atmosphere. Okay here’s how the vicious cycle works:

1.       -Firstly, carbon dioxide is a greenhouse gas. Like other greenhouse gases (e.g. water vapour and methane), it helps to trap heat in the atmosphere so earth doesn’t become a frozen wasteland.

2.       However, with human activities nowadays, we have helped to increase the amount of carbon dioxide in the atmosphere my 30%.

3.      -Carbon also remains on our earth for long periods of time. For example, over millions of years of weathering, rocks on land can add carbon to surface water which eventually runs off to the ocean. Over long periods of time, carbon is removed from seawater when the shells and bones of marine animals and plankton collect on the sea floor. These shells and bones are made of limestone, which contains carbon. When they are deposited on the sea floor, carbon is stored from the rest of the carbon cycle for some amount of time. The carbon can be released back to the atmosphere if the limestone melts or is metamorphosed.

4.       Because these things happen, innocent creatures like cows are being blamed for their contribution of methane gases. Though it is 23 more times powerful than carbon dioxide in terms of heat storage capacity, it is nothing compared to what we as humans produce in terms of our carbon emissions.

So yes, in short, we should all learn to do things that will help save the environment and prevent cows from being blamed anymore.  We could

-         -Help plant more trees, as they help to reduce carbon dioxide in the atmosphere as they take it in during photosynthesis. Also we could help to increase our dying vegetation as many forests are being cut down for resource sake, which also helps to increase carbon dioxide emissions as there is a decrease in the number of trees and also if forests are being depleted by means of fires, that would boost the amount of carbon dioxide in the atmosphere.

-          -Recycle more. For goods like paper, it would help to preserve some of our natural vegetation. And for other goods such as plastic and glass, it would help decrease the amount of burning factories have to do to help get rid of our trash.

-          -Sing the song we made up along Orchard and help increase awareness :D

References

http://www.windows2universe.org/earth/Water/co2_cycle.html

P.S. My blog probably isn’t as informative as Paula’s, Ling’s or Gan Tian’s so you should read theirs and not mine. LOL.

Short wave and Long wave activities.

 

 

 

 

These two pictures above are the diagrams that show the balance of short and long wave energy exchange.

If you think your version is better, pls pass me your work and I will post them.

Carbon Cycle--Video Watching,-Global warming

Today, the video showed the effects of the global warming.
Global warming is a big issue that we face today. Alot of effects we experience today are made by the global warming.
Most of the people think that the main cause for global warming is that the CO2 released by human activites.i.e. Burning of fossil fuels, emission of gas from cars. However, there are others who still think that CO2 increases without human influences. The average temperature of Earth increases every year. In fact, the amount of CO2 we produce is also increasing. The amount of CO2 generated by humans is equivalent to seven of volcanoes the size of the volcano Mount Helen erupting every day. The galciers are melting faster and faster due to the increasing average temperature caused by the CO2.

Further reading from the internet:

Derek Markham

Global Warming Effects and Causes: A Top 10 List

123 comments

June 7, 2009 in Global Warming

One of the biggest issues facing us right now is global warming. Its effects on animals and on agriculture are indeed frightening, and the effects on the human population are even scarier. The facts about global warming are often debated, but unfortunately, even if we disagree about the causes, global warming effects are real, global, and measurable. The causes are mainly from us, the human race, and the effects on us will be severe.

Global Warming Effects and Causes: A Top 10 List

1. Global Warming Cause: Carbon dioxide emissions from fossil fuel burning power plants

Our ever increasing addiction to electricity from coal burning power plants releases enormous amounts of carbon dioxide into the atmosphere. 40% of U.S. CO2 emissions come from electricity production, and burning coal accounts for 93% of emissions from the electric utility industry [EPA, pg. 10]. Every day, more electric gadgets flood the market, and without widespread alternative energy sources, we are highly dependent on burning coal for our personal and commercial electrical supply.

2. Global Warming Cause: Carbon dioxide emissions from burning gasoline for transportation

Our modern car culture and appetite for globally sourced goods is responsible for about 33% of emissions in the U.S. [EPA pg. 8] With our population growing at an alarming rate, the demand for more cars and consumer goods means that we are increasing the use of fossil fuels for transportation and manufacturing. Our consumption is outpacing our discoveries of ways to mitigate the effects, with no end in sight to our massive consumer culture.

3. Global Warming Cause: Methane emissions from animals, agriculture such as rice paddies, and from Arctic seabeds

Methane is another extremely potent greenhouse gas, ranking right behind CO2. When organic matter is broken down by bacteria under oxygen-starved conditions (anaerobic decomposition) as in rice paddies, methane is produced. The process also takes place in the intestines of herbivorous animals, and with the increase in the amount of concentrated livestock production, the levels of methane released into the atmosphere is increasing. Another source of methane is methane clathrate, a compound containing large amounts of methane trapped in the crystal structure of ice. As methane escapes from the Arctic seabed, the rate of global warming will increase significantly.

4. Global Warming Cause: Deforestation, especially tropical forests for wood, pulp, and farmland

The use of forests for fuel (both wood and for charcoal) is one cause of deforestation, but in the first world, our appetite for wood and paper products, our consumption of livestock grazed on former forest land, and the use of tropical forest lands for commodities like palm oil plantations contributes to the mass deforestation of our world. Forests remove and store carbon dioxide from the atmosphere, and this deforestation releases large amounts of carbon, as well as reducing the amount of carbon capture on the planet.

5. Global Warming Cause: Increase in usage of chemical fertilizers on croplands

In the last half of the 20th century, the use of chemical fertilizers (as opposed to the historical use of animal manure) has risen dramatically. The high rate of application of nitrogen-rich fertilizers has effects on the heat storage of cropland (nitrogen oxides have 300 times more heat-trapping capacity per unit of volume than carbon dioxide) and the run-off of excess fertilizers creates ‘dead-zones’ in our oceans. In addition to these effects, high nitrate levels in groundwater due to over-fertilization are cause for concern for human health.

6. Global Warming Effect: Rise in sea levels worldwide

Scientists predict an increase in sea levels worldwide due to the melting of two massive ice sheets in Antarctica and Greenland, especially on the East coast of the U.S. However, many nations around the world will experience the effects of rising sea levels, which could displace millions of people. One nation, the Maldives, is already looking for a new home, thanks to rising sea levels.

7. Global Warming Effect: More killer storms

The severity of storms such as hurricanes and cyclones is increasing, and research published in Nature found:

“Scientists have come up with the firmest evidence so far that global warming will significantly increase the intensity of the most extreme storms worldwide. The maximum wind speeds of the strongest tropical cyclones have increased significantly since 1981, according to research published in Nature this week. And the upward trend, thought to be driven by rising ocean temperatures, is unlikely to stop at any time soon.”

8. Global Warming Effect: Massive crop failures

According to recent research, there is a 90% chance that 3 billion people worldwide will have to choose between moving their families to milder climes and going hungry due to climate change within 100 years.

“Climate change is expected to have the most severe impact on water supplies. “Shortages in future are likely to threaten food production, reduce sanitation, hinder economic development and damage ecosystems. It causes more violent swings between floods and droughts.”" – Guardian: Global warming causes 300,000 deaths a year

9. Global Warming Effect: Widespread extinction of species

According to research published in Nature, by 2050, rising temperatures could lead to the extinction of more than a million species. And because we can’t exist without a diverse population of species on Earth, this is scary news for humans.

“Climate change now represents at least as great a threat to the number of species surviving on Earth as habitat-destruction and modification.” Chris Thomas, conservation biologist at the University of Leeds

10. Global Warming Effect: Disappearance of coral reefs

A report on coral reefs from WWF says that in a worst case scenario, coral populations will collapse by 2100 due to increased temperatures and ocean acidification. The ‘bleaching’ of corals from small but prolonged rises in sea temperature is a severe danger for ocean ecosystems, and many other species in the oceans rely on coral reefs for their survival.

“Despite the oceans’s immensity — 71 per cent of the Earth’s surface with an average depth of almost 4km (2½m) — there are indications that it is approaching its tipping point. For reefs, warming waters and acidification are closing in like a pair of jaws that threaten to make them the first global ecosystem to disappear.” – Times Online: 21st-century Noah’s Ark needed to save coral reefs from extinction

Read more about global warming effects and causes:

• Global Warming Worldbook at NASA
• The Top 100 Effects of Global Warming
• Cause and effect for global warming
• Nine alien insects to cause pain, illness and even death in Britain as climate warms up
• Climate change may act as ‘threat multiplier’ in strife-torn Middle East, study shows

Images: FlyingSinger Mikael Miettinen Simone Ramella net_efekt Ben Sutherland nattu CoreBurn brankomaster Lars K. Jensen In Veritas Lux at Flickr under Creative Commons License

Reference:http://planetsave.com/2009/06/07/global-warming-effects-and-causes-a-top-10-list/

Carbon Cycle

Link to see a bigger picture of the CC :)

Carbon is the major chemical constituent of many organic compounds like fossil fuels.

Carbon is stored on our planet in the following major sinks:

(1) as organic molecules in organisms (both dead and alive) found in the biosphere;

(2) as the carbon dioxide gas in the atmosphere;

(3) as organic matter in soils;

(4) in the lithosphere as fossil fuels and sedimentary rock deposits such as limestone;

(5) in the oceans as dissolved carbon dioxide and as calcium carbonate shells of marine organisms.

Feel free to go to http://www.youtube.com/watchv=U3SZKJVKRxQ&feature=related for a 5 min summary of the Carbon Cycle. Hopefully, it will help you remember it better :D


Interesting Idea(s) brought up during lesson:

• The idea of carbon credit VS carbon offset

 Carbon Offset
“A carbon offset is a reduction in emissions of carbon or greenhouse gases made in order to compensate for or to offset an emission made elsewhere.”
Taken from http://en.wikipedia.org/wiki/Carbon_offset

Basically, carbon offset is a set of measures that helps to counter the impact of the carbon emissions by balancing the carbon output and input. For example, in an attempt to offset my carbon emissions from the combustion of fossil fuels, I plant the equivalent of 100 trees. This helps to balance the carbon input and output from the cycle.


 Carbon credit
“A carbon credit is a generic term for any tradable certificate or permit representing the right to emit one tonne of carbon or carbon dioxide equivalent (CO2-e). Carbon trading is an application of an emissions trading approach.”
Taken from http://en.wikipedia.org/wiki/Carbon_credit

Basically, carbon credit is the trade between countries/companies about the right to emit carbon. Parties, who need to emit more carbon, have to buy the right from parties who have excess credits, to emit their extra carbon. This helps to regulate the amount of carbon released into the atmosphere globally, by regulating the amount of carbon emitted to a price.

My opinions on carbon credit and credit offset
Personally, I feel that the purpose of the carbon credit (which is to reduce the amount of carbon emissions by increasing the finianical costs of it) is very much limited by man's need to emit carbon. Thus, it is unable to fully meet its inital purpose. Well it deters a handful companies and countries from reducing their emissions, it doesnt stop those who really need and can afford to emit carbon.

On the other hand, I feel that credit offset is a better alternative to control the amount of carbon emission since it tackles the output and input of the carbon cycle (property of a system :D). However, it will not be the best alternative, especially for sustained periods of time. This is because, even if i plant trees in hope of reducing my country's carbon emissions, the same amount of carbon (or even more) will still be released when the trees die. Furthermore, there are that many trees you can plant.

However, on the whole, its still a better alternative compared to carbon credits :)

What do you think? Free feel to share your views in the comments :D

Carbon Cycle Songs (:

Lion King Song

In the jungle, the mighty jungle,

plants photosynthesiseeeee

In the jungle, the mighty jungle,

taking in carbon dioxideeeeeee.

They help reduce carbon emissions

from cows backsidessssss.

OH CO2, CO2, or CH4, CH4, CO2, CO2, CH4, CH4.

Telephone

hello hello companies you're burning everything

and you blame it all on the cows you say say

should have owned up to your own mistake-askes

and followed the kyoto protocol exactly-lyy

kyoto exactly-lyy

kyoto exactly-lyy

and followed the kyoto protocol exactly-lyy

yes cows do contribute with their farts of methane-ane

and it beats carbon dioxide by a factor of twenty-three-ee

Although they take a little of the blame-ame-ame

all you care about is powering your industries

STOP FARTING

STOP FARTING

I DON'T WANNA THIS HEAT ANYMORE

STOP TAKING FOSSIL FUELS FROM THE SEABED FLOOR

eh-eh-eh-eh-eh

stop taking it eass-yyyy

we all still need to keep breath-inginginginging

you can burn all you want

and have no fear

but there's still CO2 in the atmosphere 

Imagine 

Imagine there's no carbon, all of us would just die
Being a greenhouse gas, found in the atmosphere
It starts from the animals
as well as the plants 

YOO-HOO-OOO

Through the food chain they're eaten
Where the carbon is transferred.
That's when the animals die
And carbon absorbed by the ground

Some turn to fossil fuels in a million years
Turns to carbon as well, a cycle in our life
Each time you exhale
To the atmosphere it goes 

YOO-HOO-HOO

Lastly from atmosphere to oceans
As well as back to the plants
 So that's the carbon cycle 
It goes on, to work as one 

Done By:

Mathilda Chua

Jaspreet Kaur

Rachel Tan

Tay Li Lin

Renee Yeong   

Carbon Cycle Poem

Life as a Carbon

Life as a Carbon is not that easy

To travel through stages effortlessly

Dissolve we must into the sea

To reach the plants and organisms underneath

With us they can photosynthesize,

Like all the other plants up there outside.

Through this process we transform

Into sugars to be stored.

Some day plants and animals would finally cease

To live and provide, no longer they breathe.

But our life as Carbons will not yet end,

For we got unfinished business to attend.

Our old friends, fungi and bacteria,

will break us down faster than eva.

After that it's back home to the sky,

But we'll always be on standby.

The cycle may never end,

But for us, that's something that's hard to transcend.

Nichole Ho

Sim Yi Shien

Vu Tuan Duc

Yu Jia Cheng

Nguyen Trung Hieu

Nitrogen Cycle (II)

Nitrogen is used by living organisms to produce a number of complex organic molecules. (as mentioned by Cho Ling above) Major stores of nitrogen include the atmosphere, living organisms, and organic matter in soil and the oceans.

Figure 1: Yellow arrows indicate human sources of nitrogen. Red arrows indicate microbial conversions of nitrogen. Blue arrows indicate physical forces acting on nitrogen. While green arrows indicate natural processes affecting the form of nitrogen.

The five main processes of the Nitrogen Cycle (taught in class)

1. Nitrogen fixation

2. Nitrogen Uptake

3. Nitrogen mineralisation (decay)

4. Nitification

5. Denitrification

Interesting Facts about the Nitrogen Cycle (:

• Scientists estimate that biological fixation globally adds ~140 million metric tons of nitrogen to ecosystems yearly.
• Denitrification is the only process that removes nitrogen from ecosystems, and it somewhat balances the amount of nitrogen fixed.
• The five processes in the nitrogen cycle-- are all driven by microorganisms.
• Human activities increase nitrate levels in drinking water by at least 10 times. From 1mg/L to 10mg/L.

 

WHAT GOES AROUND COMES AROUND

Like the Nitrogen Cycle, man and the atmosphere are both part of a system. Should one aspect of the system be affected (Eg. Nitrogen Cycle), later stages of the cycle would be affected too. (Eg. Man)

• Excess/unabsorbed fertilizer is washed off by irrigation/rain into groundwater or water bodies. Unfortunately, groundwater is often used as a direct drinking source.
  Excess nitrogen can lead to cancer in humans and respiratory problems in infants.
• On surface waters, excessive nitrogen can lead to eutrophication, the over-nourishment of phytoplankton. Eutrophication causes increased frequencies of coastal fish-kill events, harmful algal blooms, and even causes species shifts.
  (Hence, reduces the supply of fish and other seafood.)
• Atmospheric nitrogen (like NO₃^- and NH₄⁺) can also change the acidity of acid rain causing many long-term changes.For example forests' death and decline.
  (Hence, reducing the amount of carbon dioxide absorbed.)

Reflections and Key Learning Points

After last week's lesson and today's blog post, I have come to greater understanding about the word "systems", having applied it in today's blog post. I have come to understand that the man and the atmosphere are both part of a larger system, where if one aspect is missing/changes, it will ultimately affect the entire system. (Eg, the addition of man-made fertilizers) Ultimately, it will affect the entire Nitrogen Cycle and come back to affect Man.

"What goes around, comes around."

Personally, like the Carbon Cycle, i feel that each stage is as important as the next. There is a kind of interdepence within the cycle, without one the other cannot take place.  Another thing that I learnt while posting this blog entry was that microorganisms. Just when we thought they weren't so important, they're actually the driving force behind the whole cycle. I also marvel the work of Nature, how the whole large system can be at equilibrium so that there's just enough of everything to balance the entire Nitrogen Cycle :)

*Click the cycle for a bigger picture*

The Nitrogen Cycle

Biological Importance

Nitrogen is a constituent of amino acids, proteins, nucleic acid as well as a plant nutrient.

Different Forms of nitrogen

Used by plants

1.       Ammonium 

2.       Nitrate 

3.       Amino acids

Used by bacteria

1.       Ammonium

2.       Nitrate

3.       Amino acids

4.       Nitrite 

Used by animals (only organic forms)

1.       Amino acids

Since different organisms require different forms of nitrogen, there is the nitrogen cycle that provides them with the appropriate forms.

Sources of Nitrogen

·         Nitrogen gas – atmosphere which consist of 78% nitrogen

·         Bound nitrogen – soils, sediments of lakes, rivers and oceans

·         Dissolved nitrogen – surface water and ground water

Key processes

Nitrogen Fixation

Nitrogen rich waste from animals is converted into nitrates by nitrifying bacteria.

Nitrogen is also fixed by nitrifying bacteria in soil and by symbiotic (recall: a relationship between two types of animal or plant in which each provides for the other the conditions necessary for its continued existence) bacteria that live in nodules. The bacteria convert nitrogen gas in the atmosphere into ammonia. This passes out of the root nodules, dissolves in soil water and is then taken up by plant roots.

(Do you see why this relationship between the bacteria and the plant is symbiotic? Both parties benefit as the plant get a steady supply of nitrogen and the bacteria get a constant supply of sugars from the plant)

Some nitrogen is also fixed by lightning, known as atmospheric nitrogen fixation.Lightning discharges ozidize nitrogen gas to nitrate, which ends up in the soil.

Ammonification

Ammoification decomposes organic nitrogen to ammonium. Bacteria and fungi carry out most of the ammonification in the nitrogen cycle.

Nitrification
Ammonium is oxidized to nitrate by nitrifying bacteria such as Nitrosomonas while other bacteria such as Nitrobacter oxidize nitrite to nitrate .

Denitrification

Denitrifying bacteria such as Pseudomonas denitrificans reverse the process and return fixed nitrogen to the atmosphere

Feelings

Learning the nitrogen cycle has allowed me to realize the importance of nitrogen in our daily life. Before this lesson, I did not know that different organisms is only suited to certain forms of nitrogen. For example, animals can only used organic forms of nitrogen. It is also interesting that organisms on earth share such intimate relationships, where they depend on one another for survival. If the nitrogen cycle lacks any one of the organism, it would result in many implications. I believe many other biological process in life also work the same whay, where one cannot do without another.

Oxygen

Important points previously discussed during lesson

·         Oxygen, being soluble in water enables life in water bodies possible. Imagine if oxygen is not soluble, there would be no fish and aquatic plants!

·         Oxygen is a constituent of DNA. Previously, I only know oxygen supports life but did not know that it is actually part of our DNA.

·         Highly concentrated sources of oxygen promote rapid combustion. Too much oxygen can actually cause death indirectly if we are not careful in handling it!

·         Exposure to large amount of oxygen for a long period can cause lung damage. Isn’t it quite shocking that oxygen can also have harmful effects!

Interesting facts about oxygen

·         Excited oxygen is responsible for the bright red and yellow-green colours of the aurora.

·         Breathing too much oxygen will cause hallucinations and unconsciousness.

·         Pure oxygen atmosphere results in rapid metabolism and extremely fast cell death and aging in organisms.

·         The brain alone uses more than 25% of the oxygen used by the human body.

·         The brain stops function if no oxygen is supplied to it for 5 to 10 minutes, resulting in brain damage.

·         More oxygen gets into your lungs and into your brain when you yawn, making you feel more alert and energetic.

Feelings

Now I not only know oxygen as a gas that supports life, but also how variations in oxygen concentration in the body produce different reactions. Apart from the presence of oxygen in the human body, I have learnt that oxygen is also responsible for the natural and beautiful aurora. This made me realise that many things that we learn in the module can actually be used to explain phenomenons that we never thought has a scientific theory behind it.

Layers of the atmosphere

Note:

Sd-Questions asked in class

Vgd-Things taught in class

___-Important points

Layers of the atmosphere

The layers of the atmosphere are separated by "pauses," where there is no change in temperature with altitude change: the tropopause (between the troposphere and the stratosphere), the stratopause (between the stratosphere and the mesosphere), and the mesopause (between the mesosphere and the thermosphere).

Troposphere

The word troposphere derives from the Greek: tropos for "turning" or "mixing”. This is reflected in the fact that convective currents provide mixing of air masses with different temperatures in the troposphere.

In class, we have learnt that temperatures in the troposphere decreases with altitude. But by how much? Temperatures decrease by 6.3 °C with every 1000m increase in altitude. And why does this happen? This is because the Earth’s surface is warmed by solar radiation, which in turns heats the air around it by conduction, convection, and radiation.

At the utmost layer of the troposphere, the air temperature is about 76 degrees below
zero. This is very significant as it allows water vapour to be changed into ice, resulting in the formation of the cold trap .The cold trap prevents water molecules from rising beyond the troposphere. If no cold trap is formed, the water molecules would rise and be broken down into oxygen and hydrogen. Due to its small and light nature, the hydrogen molecules can then escape into space, causing Earth to lose its water. 

However, the temperatures in the troposphere do not always decrease with altitude, but increase. Such cases are known as temperature inversions where warm air is on top of cooler air. This situation prevent the vertical mixing of air, leading to air pollution when air pollutants released at ground level are trapped under the temperature inversion.

Refer to http://www.wrh.noaa.gov/slc/climate/TemperatureInversions.php for information on the occurrence of temperature inversions and their impact on the air quality.

Stratosphere

The stratosphere is characterized by a steady increase in temperature with altitude, caused by the concentration of ozone. Ozone absorbs ultra-violet radiation from the sun, heating the air around them.

The stratosphere allows for long-distant flight as it is above stormy weather and has strong, steady, horizontal winds. It also acts as a protective shield against meteorites which usually burn as they enter the earth’s gravitational field.

How does the ozone protect life from UV rays?

UV-C rays do not reach the Earth’s surface due to the ozone layer. When UV-C rays meet the ozone molecules, the energy inherent in them is sufficient to break apart the bond of the molecule and absorb the energy. Hence, no UV-C rays reach Earth. 

Some of UV-B rays reaches the Earth’s surface while some are absorbed by the stratospheric ozone by undergoing homolytic(decomposing into two uncharged atoms or radicals) fission to form an oxygen and an oxygen molecule.

UV-A rays reaches the earth’s surface almost unfiltered. This is because they do not have enough energy to split an ozone molecule and cannot be absorbed fully. Hence, it is important that we protect ourselves from these harmful rays.

Ozone can be both beneficial and harmful!

Naturally occurring ozone in the stratosphere helps to protect life on Earth by absorbing ultraviolet radiation from the sun.

However, ozone in the troposphere can be harmful to life on earth. Ozone causes damage to humans, vegetation and materials such as rubber and textiles.

The endangered ozone layer

With the lack of vertical convection in the stratosphere, materials that get into the stratosphere can stay there for long periods. An example is the  ozone-destroying chemicals called CFCs (chlorofluorocarbons). This can cause the depletion of the ozone layer when the CFC molecules are broken down by ultraviolet radiation, releasing their constituent chlorine atoms. These chorine atoms then react with the ozone molecules, resulting in their removal.

Do you know how is ozone formed?

In the stratosphere, ultraviolet light has enough energy to bring about photochemical reactions that convert dioxygen,  into ozone.

In the troposphere, ozone is formed from oxygen by photochemical reactions when oxides of nitrogen and hydrocarbons are emitted by motor vehicles, power stations and many other sources.

Mesosphere

Temperature in the mesosphere decreases with altitude as there is no water vapour, cloud, dust or ozone to absorb incoming radiation. It experiences the atmosphere’s lowest temperature of -90°C and strongest wind of about 3000km/hr.

The mesosphere protects life on earth by destroying meteors that fall on earth. (Did you know that about 40 tons of meteors fall on earth every day?) Without the mesosphere, we would not be able to survive. Meteors collide with gas particles in the mesosphere and burn, resulting in what we call the ‘shooting stars’.

In the troposphere, carbon dioxide and methane heat up the troposphere and cause the greenhouse effect. However, in the mesosphere, as heat is released from the mesosphere into the space, the carbon dioxide cools down. The methane gas is decomposed due to the solar light. (Learning point: Due to different properties of the layers, the same material can result in a different effect)

The night sky is completely dark. It surprises me how this is related to the properties of the mesosphere. The nightglow is formed by the sodium layer located just below the mesopause. The explanation to this mechanism can be found on http://en.wikipedia.org/wiki/Airglow under ‘Description’.

Thermosphere

Temperature rise rapidly with height in the thermosphere. This is due to an increasing proportion of atomic oxygen in the atmosphere which, like ozone, absorbs ultraviolet radiation. Although temperature can reach up to 2000°C, the gas molecules making up the air are so far apart the temperature is not felt. This explains why you would freeze to death in the thermosphere although the temperature at the thermosphere can reach beyond 1200°C.

Feelings

I was not aware of the importance of the layers of the atmosphere until we were taught about it. Life on earth is actually very dependent on the layers of the atmosphere which provide us with protection from the harmful rays and meteorites. These layers work together to ensure the survival of living things on earth and the absence of any of the layers would definitely result in the breakdown of the entire system. I now know how to appreciate the structure of the atmosphere.