They are built of elements grouped around chains or rings made of carbon atoms Carbon All living things, plants and animals alike, contain the chemical element Carbon. A number of the Carbon atoms existing in all living things are radioactive There are some natural greenhouse gases: However, over the past fifty years, production of carbon dioxide, nitrous oxide and methane has risen sharply, and a new type of chemical - the chlorofluorocarbon, or CFC - has been introduced as a refrigerant, solvent and aerosol propellant, but it is also a very powerful greenhouse gas, because it can trap a lot of radiation - one molecule of CFC is 12, to 16, times as effective at absorbing infra-red radiation as a molecule of carbon dixide Light Reaction of Photosynthesis The main difference between C3 photosynthesis, C4 and CAM photosynthetic pathways is in the process of carbon dioxide fixation.
The carbon dioxide captured by the Rubisco enzyme and added to RuBP inside the chloroplast produces 3? Deforestation has many effects: Discuss 10 marks Another effect of deforestation is a Disruption of the Water Cycle.
Trees contribute in a large way in maintaining the water cycle. In fact, the amount of reduction that would begin to have serious effects on plant life is a mere 2 parts out of 10 thousand. So, given that a small decrease in the amount of carbon dioxide in the global atmosphere would be detrimental to plant life, what about the biological and environmental effects of increasing the amount available to plants?
As it turns out there exists an enormous body of research into this question and to that important matter we will now turn. Studies going back decades have demonstrated conclusively that carbon dioxide is indispensable to a healthy biosphere, having remarkable effects on plants of all types.
I could not possibly go into detail on the hundreds of studies performed throughout the 20th century making the case that enhanced carbon dioxide concentrations have a positive effect on the biosphere, but I will discuss enough of them to make the point.
Awareness of the beneficial botanical effects of carbon dioxide enhancement goes back centuries. In the early s a citizen of Brussels, Jean-Baptiste van Helmont, planted a 5 pound willow tree in a container in which he placed pounds of soil.
For five years van Helmont carefully monitored the amount of water provided and at the end of 5 years the tree weighed over pounds but the soil was diminished in weight by only 2 ounces. Economic Botany , Vol. The United States Department of Agriculture has, since its inception, published annual summaries of research and work relevant to agriculture. In the Experiment Station Record for , the Department provided a summary and translation of the experimental work of M.
Demoussy, originally published in French in In the early 20 th century Demoussy performed an experiment in France demonstrating the effects of carbon dioxide on a variety of plants. These experiments were an early demonstration of the benefits of carbon dioxide enrichment. The author has repeated his experiments with 16 species of plants, representing a wide range of families. Duplicate series were grown, one in normal atmosphere containing about 3 parts of carbon dioxide in 10,, and the other series in an atmosphere enriched daily by about five times the normal quantity of carbon dioxide.
The experiments were continued for about 2 months, after which several portions of the plants were weighed. Among the species studied were coleus, lettuce, geraniums, centaury, mint, tobacco, balsam, fuchsias, etc. In all except the fuchsias there was a decided increase in the weight of the plants, the average amounting to over 60 percent increase. In addition the geraniums, begonias, mints, etc.
For the original article in French see Demoussy, M. The control group of plants was exposed to the ambient CO 2 concentration, at that time measuring about parts per million. The experimental group was exposed to 5 times that amount, or about parts per million.
At the end of two months the average increase in the weights of the various species of plants exposed to CO 2 enrichment as compared with control groups was over 60 percent.
In other words the plants responded exuberantly to the increase in their food supply and thrived strikingly. Wittwer and Robb, referenced above, discuss an early experiment that demonstrated the positive effects on plants of carbon dioxide enrichment, citing the work of M. Jones in , published in the Vermont Station Bulletin. Augmented supplies of carbon dioxide were supplied for 8 hours each day to plants growing in open boxes. Wittwer and Robb summarized the findings of Cummings and Jones: Yields of pods and seeds were enhanced in peas and beans.
Potatoes produced more leaves and tubers. Large and heavier leaves were formed by foliage crops. Lettuce was very responsive. Flower crops produced blossoms earlier and in great profusion.
Strawberries yield fruit far in excess of the controls. Wittwer and Robb also mention that extensive experimentation was being conducted in Europe as well. They note that some of these experiments showed that the yield of some food plants such as tomatoes and cucumbers was doubled, or even tripled, by the addition of CO 2. In the s botanists with the Department of Plant Physiology and Pathology, Imperial College of Science and Technology, London, designed and constructed apparatus to improve standardization of testing, which prior to this time lacked sufficient controls to perform a reliable statistical analysis.
Annals of Botany , Vol. The results of their initial testing were published in Fischer published the year before: Increased greenness has been observed throughout the above series of experiments. An increase is evident within two or three days from the beginning of the experiment. These results are quite extraordinary. This report described a series of experiments conducted from to at the Plant Science Greenhouses at Michigan State University with a variety of crops grown in containers.
In this study they remark that:. Alternatively, carbon dioxide levels in plant growing atmospheres maintained substantially above the normal should favor growth. Two points should be emphasized here. First — the authors advise that, because of the great demand by plants for carbon dioxide, it is likely that in a greenhouse environment the atmosphere might quickly become depleted in this essential gas to the extent that it begins to impede plant growth, supporting the idea that ambient atmospheric amounts of CO 2 are, in point of fact, precariously low relative to the requirements of the biosphere, a point I will come back to later in this essay.
Second — plant growth could be stimulated through enrichment of carbon dioxide in the greenhouse atmosphere with potential economic benefit. The authors go on to describe the results of experiments in the tank culture of algae in which it was found that:. In fact, carefully controlled experiments, the results of which for many plant species have now accumulated, show that neither the normal carbon dioxide concentration of the air, nor this gas in water.
The authors are here pointing out that normal carbon dioxide amounts in both air and water are not sufficient for maximizing photosynthesis. In other words, the plants could readily consume a great deal more carbon dioxide than they presently are under ambient conditions. There is an important implication here. The following photographs from Wittwer and Robbs report dramatically demonstrate the remarkable effects of CO 2 enrichment on a variety of plants.
These show only a few of the many similar experimental results but are typical. Tomatoes grown in a controlled environment with CO2 concentrations varying between and ppm. Present global atmospheric concentrations are right at ppm. Compare with the next image. Tomato plants grown in an environment with CO 2 concentrations varying between and ppm, that is, 2x and 5x the current atmospheric concentration.
From Wittwer and Robb In the image below Wittwer and Robb show results of carbon dioxide enrichment on several plant varieties after 30 days. The plants in the top row are leaf lettuce, second from the top is bibb lettuce, second from the bottom are tomato plants and the bottom is cucumber. The column on the left are plants grown in an environment with approximately parts per million carbon dioxide, similar to the present concentration, and the column on the right shows plants grown with ambient CO 2 concentrations of ppm.
The difference in growth is obvious and impressive. Table 1 below from Wittwer and Robb displays the effects on 8 varieties of lettuce. In every case the weight of the lettuce variety grown in an enriched environment was substantially greater. Experiments were also performed on a variety of tomatoes with the results shown below in Table 4 from Wittwer and Robb. Again, the remarkable effect on yield is impressive. In summarizing their experiments, conducted at the Plant Science Greenhouses at Michigan State University, Wittwer and Robb discussed the effects on growth and development they observed during their experiments:.
Tomato fruit yields were significantly increased. Fruit harvest was more consistent and less subject to fluctuating outdoor weather. Size and fruity quality were enhanced. Our data for cucumbers are supported by those of Daunicht where percent increases in fruit production were several fold greater than those for vegetative growth. More rapid growth rates, from carbon dioxide enrichment of a greenhouse atmosphere, have resulted in earlier maturity and higher yields of lettuce. Three crops of lettuce in place of two during fall, winter, and spring production are possible.
Other benefits from growing crops in high levels of carbon dioxide in a greenhouse atmosphere have been reported. The percent dry matter is increased. The essential oil content has been enhanced.
Rooting of cuttings was favored. Tomatoes had a higher vitamin C and sugar content, and plants were more resistant to some fungus and virus diseases and insects. In the conclusions to their report Wittwer and Robb confirm that their findings were similar to previous studies that found a substantial enhancement of plant growth. They made reference to Dutch botanist C.
Briejer who published the results of his studies on plant responses to increased carbon dioxide concentrations in with the title Een verlaten goudmijn: The authors conclude by emphasizing the benefits to be realized by commercial greenhouse operators with the employment of carbon dioxide enrichment:. The production potential for greenhouse grown vegetable crops of the future is comparable to that which appeared a century ago when the agronomic benefits of chemical fertilizers were first realized.
The ultimate possible rewards are so great that growers of greenhouse vegetables can begin immediately to use and to benefit from the results of the research findings herein reported. I will return to that question.
After 21 more years of study, one of these authors, the late Sylvan Wittwer, who passed away in at the age of 95 reiterated the fact that there were benefits to the increase in atmospheric carbon dioxide.
But then he went on to say something else very interesting. Strain pondered the effect of the increasing supply of CO 2 on the planetary vegetation realm and speculated that:. Current data indicate that plants growing at higher than normal CO 2 levels are more tolerant of water, temperature, light, and atmospheric pollutant stresses.
There are effects on carbon metabolism, plant growth and development, microbial activity, and terrestrial and aquatic plant communities.
Strain Carbon dioxide levels in the biosphere: Effects on plant productivity: Critical Reviews in Plant Sciences , vol. We will come back to this question directly, and see that now, in , we do have enough data to draw some conclusions. Another fascinating fact about carbon versatility the different forms pure carbon come in. The properties of some chemical elements to exist in two or more different molecular forms are known as allotropes.
Allotropes are different structural modifications of an element. For example, carbon has three well known allotropes such as a diamond, where the carbon atoms are bonded together in a tetrahedral lattice arrangement.
Another allotrope that we use every day is graphite, where the carbon atoms are bonded together in sheets of a hexagonal lattice, and fullerenes, where the carbon atoms are bonded together in spherical, tubular, or ellipsoidal formations. Amorphous carbon is formed when a material containing carbon is burned without enough oxygen for it to burn completely. This black soot, also known as lampblack, gas black, channel black or carbon black, is used to make inks, paints and rubber products.
It can also be pressed into shapes and is used to form the cores of most dry cell batteries, among other things. A fourth allotrope of carbon, known as white carbon, was produced in It is a transparent material that can split a single beam of light into two beams, a property known as birefringence.
Very little is known about this form of carbon. New tests of carbon nanotubes, which are tiny cylinders expected to revolutionize medicine, electronics, and warfare. More tests reveal that, ounce for ounce, they are times stronger than steel and 30 times stronger than Kevlar used in bulletproof vests. The nanotubes, roughly 50, of which add up to the width of an average strand of human hair, are already known for their strength based on earlier tests on Kevlar-coated multiwalled carbon nanotubes.
Recent discoveries in carbon nanotube technology have shown the potential to alter drug delivery and bio-sensing methods for the better, thus, carbon nanotubes have recently garnered interest in the field of medicine. So why does carbon seem to have such a bad rap today in our culture? On the other hand, many of the more common carbon compounds exhibit strong toxicological effects, such as inhaling coal dust for extended periods of time.
Unless you are a coal miner it should not feel like such a threat. Yet our media cannot quit saying this word. There are two parts to a carbon footprint. The primary footprint is our direct use of fossil fuels, such as when you use your car or ride in an airplane. The secondary footprint is a measure of the indirect CO2 emissions from the whole life cycle of products we use.
Why has this suddenly become a reoccurring trend word in Google search and in our daily news? Wanting to save the earth is trendy.
- Introduction This paper examines the implications of using different approaches when it comes to accounting for carbon emissions. This essay provides a brief background on the Kyoto protocol. Then it goes into the issues surrounding accounting for carbon.
Oct 18, · Carbon Carbon is the fourth most common element in our universe, and the second most common element found in our bodies. Carbon comes in the .
The carbon cycle can be defined as the continuous biological process through which the carbon is exchanged between the environment and the organisms. It also refers to the thermonuclear reactions which are brought about by nucleus of a carbon atom when it absorbs protons. Essays from BookRags provide great ideas for Carbon essays and paper topics like Essay. View this student essay about Carbon.
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