How Octopuses Are Able to Taste by Touching

Giesen et al.Molecular Basis of Chemotactile Sensation in Octopus. Cell, October 2020.

Octopuses have often captured human interest with the ability to use their eight suction-cup covered tentacles for touch and taste. Scientists have wondered for decades how their appendages work but very few have studied what happens on a molecular level. In a new report, researchers got a glimpse into how the nervous system in an octopus’ tentacles manage these functions. They identified a novel family of sensors in the first layer of cells inside the suction cups that have adapted to react and detect molecules that do not dissolve well in water. The chemotactile receptors on these sensory cells use those molecules to help the animal figure out what it is touching and whether or not that object is prey. This allows an octopus to distinguish between a rock versus a tasty crab. The underlying mechanism is that there are two types of sensory cells in the suckers that line their tentacles: mechanosensory cells for touch and chemosensory cells for taste.  Both taste- and touch-oriented cells are critical for helping octopuses to decide when to hunt and when to retreat. It is well known that particles on land easily travel through the air before they might be sniffed by a bear or a wolf’s nostrils. However, the process of smelling or tasting is much less clear in cephalopods that live in the ocean. Some chemicals can travel far from their underwater source and thus make it possible for some creatures to catch a smell of their prey from afar. But for chemicals that don’t move through the ocean easily, a touch-taste strategy can be useful for marine animals, including octopuses. While people tend to perceive five basic tastes – sweet, bitter, sour, salty and umami (meaty) – octopuses experience the world of taste differently. Instead, scientists found the most success by stimulating octopuses to respond to what are called terpenoid molecules, a secretion that is often released by marine invertebrates that functions as a defense or warning signal. They smell these molecules and can, in a way, smell fear in their prey.

Natural Forest Regrowth May Be the Best Method to Combat Climate Change

Cook-Patton et al. Mapping carbon accumulation potential from global natural forest regrowth. Nature, September 2020.

Reforestation has been considered the leading strategy in the fight to mitigate the effects of climate change with previous studies highlighting the role it can play in capturing and storing atmospheric carbon. There are many ways to incorporate trees into our landscapes, however one of the cheapest and easiest options is to allow forests to regrow on their own if conditions can permit them to. Now, a new study has mapped the potential carbon accumulation in naturally regrown forests over the next 30 years. Researchers from 18 countries brought together more than 13,000 georeferenced measurements of carbon accumulation to generate a wall-to-wall, one-kilometer-resolution map spanning 43 countries that highlights areas with the greatest carbon returns if trees were allowed to reforest naturally. The team demonstrated that natural forest regrowth can capture up to 23 percent of global carbon dioxide (CO²) emissions from the atmosphere every year. This is on top of the carbon sequestration already provided by existing forests, which absorb around 30 percent of annual CO² emissions. The biggest advantage of natural restoration of forests is that it often requires nothing more than human inaction. Nature is constantly at work doing its duty to restore forests often unseen on the edges of fields, on abandoned pastures, and wherever forests lie degraded or former forest land is abandoned. Moreover, natural forest regrowth may promote the re-establishment of local tree species that are best equipped to survive in a given location and support the many organisms that eat them or dwell amongst their branches and roots.

However, natural regrowth may not always be the answer. For example, at sites that are highly degraded, or seed sources are far away, actively planting trees can help to start or speed recovery while helping to establish the right species mix for current and future conditions. While planting trees can sometimes be necessary it should usually be the last option since it is one of the most expensive and often least successful methods of combating climate change. It is estimated that humanity should collectively plant about a trillion trees over the next three decades to effectively fight climate change, which averages out to about a thousand new trees planted in the ground every second and assumes that every tree survives and grows in a healthy manner. Once the cost of nurseries, soil preparation, seeding, and thinning are accounted for, it would easily cost hundreds of billions of dollars. If natural forest growth is cheaper and better then why not work to protect the existing trees and let forests to grow on their own?

Li et al. Innate connectivity patterns drive the development of the visual word form area. Scientific Reports, October 2020

A new study suggests that humans are born with a part of the brain that is prewired to be receptive to seeing words and letters. Researchers analyzed brain fMRI scans of 40 newborns and found that the “visual word form area” (VWFA) was already connected to the language network of the brain, which is akin to the scans of 40 adults. These findings are quite surprising considering some researchers had hypothesized that the pre-reading VWFA starts out like any other part of the visual cortex that are sensitive to seeing faces, scenes, or other objects and only becomes selective to words and letters as children learn to read or at least as they learn language. However, a new study shows that even at birth, the VWFA is more functionally connected to the language network of the brain than it is to other areas. It is likely that experience with spoken and written language will strengthen connections with specific aspects of the language circuit and further differentiate this region’s function from its neighbors as a person gains literacy. The main goal of this study is to learn how the brain becomes a “reading brain” and to help understand the differences in reading behavior, which could become useful in the study of dyslexia and other developmental disorders.

Hsueh MF et al. Analysis of “old” proteins unmasks dynamic gradient of cartilage turnover in human limbs. Science Advances, October 2019.

Humans may not be able to regrow amputated limbs, but a recent study showed that damaged cartilage may regrow through a process similar to that of animals such as salamanders and zebrafish. Scientists collected 18 specimens of joint tissue from the hips, knees, or ankles of patients who underwent surgery. They then placed the tissue in a mass spectrometer and measured the age of the cartilage proteins in the sample. These analyses showed that the age of cartilage largely depended on where it resided in the body. Cartilage in ankles is young, middle-aged in the knee, and old in the hips. This correlation between the age of human cartilage and its location in the body suggests that limb repair occurs in humans in a similar fashion to certain animals in which tissue regeneration takes place at the furthest tips such as the ends of legs or tails. This finding also helps to explain why injuries to people’s knees and, especially, hips take a long time to recover and often develop into arthritis, while ankle injuries heal quicker and less often become severely arthritic. The researchers further identified the molecules that are instrumental in the regulation of this region-specific regeneration process. They are called microRNAs and, not surprisingly, are present at very high levels in animals that are known for limb, fin, or tail repair including salamanders, zebrafish, and lizards. Scientists believe that these regulator microRNAs can be utilized in the regeneration of degenerated cartilage of an arthritic joint to reverse arthritis. Regeneration of part or all of an injured human limb may even be possible by finding components salamanders have and we don’t. Finally, it is also possible that this could be a fundamental mechanism of repair that could be applied to many tissues, not just cartilage, which might open up many new avenues in the regenerative medicine.

The universe might have many Earth-like exoplanets

Doyle AE et al. Oxygen fugacities of extrasolar rocks: Evidence for an Earth-like geochemistry of exoplanets. Science, October 2019.

New astrophysical and geochemical evidence suggests that Earth may not be that unique, and Earth-like planets may be common in the universe. All of the planets in our solar system orbit around the Sun. Planets that orbit around other stars are called exoplanets.  The first exoplanets were discovered in the early 1990s. Since then, thousands of exoplanets have been revealed with over 4,000 confirmed and a further 4,495 potential candidates. There have been major efforts to narrow down the exoplanets that may have properties similar to Earth with conditions suitable for life. This includes being a rocky planet that is not too hot or cold so that liquid water can exist. When searching for exoplanets that are similar to Earth, astronomers typically look for worlds in orbit around a type of star called a red dwarf or an M-dwarf. These types of stars are somewhat similar to our sun and make up about 70% of the stars in our galaxy. However, a new study shows that rocky exoplanets in orbit around a different type of star, a white dwarf, can have interiors that are surprisingly similar to our planet. White dwarf stars are dense remains of normal stars that have exhausted their nuclear fuel. These stars are typically composed of light elements such as hydrogen and helium, but in some cases they attract heavier elements such as magnesium, iron, and oxygen in their atmospheres due to their extreme gravity. These heavy elements are thought to be introduced when a rocky exoplanet crashes into a star, which gives astronomers evidence of what the exoplanets were like before they were destroyed. In this recent study, scientists looked at six white dwarfs located 200 to 665 light-years from Earth and rocks from the planets that once orbited it. Their analyses showed that five out of the six white dwarfs had sucked up fragments whose chemical composition is similar to rocks on Earth, Venus, and Mars. While the conditions suitable for life depend upon many additional factors, this study points towards the idea that many rocky planets are likely very familiar in terms of their general composition and, therefore, structure and behavior. This study also made a substantial leap forward in being able to make inferences for bodies outside of our own solar system and indicates that it is very likely that there are truly Earth analogs out there.

Artificial leaf points to a sustainable path to carbon-neutral fuels

Andrei V et al. Bias-free solar syngas production by integrating a molecular cobalt catalyst with perovskite–BiVO4 tandems. Nature Materials, October 2019.

An artificial leaf from which a “clean” fuel alternative to petrol could be produced has been developed. Synthetic gas can be obtained from the lead by using only sunlight, carbon dioxide, and water.

Synthetic gas, also called syngas, is typically a mixture of carbon monoxide and hydrogen. It is largely produced by exposing fossil fuels such as coal or natural gas to high temperature steam and pressure, and the process releases carbon dioxide. Syngas is broadly used in a wide range of commodities including fuels, plastics, and fertilizers. While the utilization of fossil fuels has enabled large-scale industrial development in human history, the burning of fossil fuels is the largest source of emissions of carbon dioxide, which is one of the greenhouse gases that contributes to global warming. For decades scientists have been trying to discover new ways to produce syngas in order to close the global carbon cycle and to establish a sustainable chemical and fuel industry. In a recent study, researchers got inspired by leaves. These perfect little machines use sunlight to convert carbon dioxide and water into fuel for plants through photosynthesis. An artificial leaf has been designed to have two light absorbers, similar to the molecules in plants that harvest sunlight, and a catalyst made from the naturally abundant element cobalt. When the leaf is immersed in water, one light absorber uses the catalyst to produce oxygen and the other one carries out the chemical reaction that reduces carbon dioxide and water into carbon monoxide and hydrogen, thus forming the syngas mixture. The scientists are now searching for ways to use their technology to produce a sustainable liquid syngas that could serve as an alternative to petrol. Although major efforts to generate renewable energy sources are being made, the development of synthetic petrol is critical as electricity can currently fulfill about 25% of our total global energy demand. There is a huge demand for liquid fuels to power heavy transport, shipping, and aviation sustainably.

After the discovery of using steel to reinforce concrete, reinforced concrete buildings became extremely popular and presented a significant solution to the housing needs of urban populations.

The composition of concrete

Concrete is a structural material formed via blending sand, gravel, cement, and water. The specifications and ratios of the materials present in the mix directly determine the quality of the concrete. Generally, this ratio is 31 sand, 46 gravel, 15 cement, and 8 water. These ratios may vary depending on the construction needs.

The mixture of sand and gravel is described as an aggregate. Usually, aggregates up to 7 mm are called sand, and aggregates between 7-70 mm are called gravel. The most important role of the aggregate as a fill material is to reduce the volumetric changes of the concrete. The dough composed of water and cement displays great changes in volume. The introduction of sand and gravel into the cement helps to lessen these changes and also saves resources, since it is cheaper than cement. In order to obtain a concrete of good quality and applicable texture, the sand and gravel grains should be as round as possible and have similar diameters to each other.

Cement is produced from grinding a mixture of clay stones and limestone (CaCO3) that are cured at high temperatures. Cement is very important; when combined with water, it helps concrete to quickly solidify. The time the mix takes to solidify is called the setting time, and it is usually between an hour and an hour and a half, depending on environmental conditions. This time is shorter on warmer days and longer on colder days. Concrete begins to gain endurance (hardening) as it solidifies. It takes 28 days for the concrete to reach an endurance of 60-90 , and a much longer time to reach 100, depending on conditions. The cement amount in a cubic meter of concrete is called the dosage. One common and incorrect perception is that concrete endurance changes with the dosage. However in a mixture of a well adjusted sand and gravel ratio, concrete endurance depends on the water-cement ratio.

The water that can be used in the concrete mixture should be drinkable water that does not contain acids and salts. It is important that the water has a pH value higher than 7 and is free of carbonic acid, manganese compounds, ammonium salts, free chlorine, mineral oils, and industrial waste. Therefore, it should not be forgotten that sea water must not be used in the concrete mixture because of the salt it contains.

The properties of steel

Iron alloys that can be processed mechanically – either through pressing or rolling – are called steel. Iron is the most abundant metal in the Earth’s crust, making up nearly 4.5 of it. The most important element that specifies the property of steel is carbon. The role of carbon in steel’s structure is to harden the iron alloy and prevent the shifting of iron atoms. By adjusting the amount of carbon in the alloy, steel’s hardness, ductility, and endurance can be changed. Both the endurance and hardness of steel increases as the amount of carbon is enriched. However, this application increases steel’s fragility, reducing some of its features, such as ductility. Therefore, a 5 carbon level in the raw iron obtained through the melting of iron ore is decreased to 0.1 0.2, enabling steel to be processed. Iron alloys (steel) composed of elements such as carbon, silicon, manganese, chromium, copper, nickel and molybdenum are utilized in building structures.

The conformity of concrete and steel as reinforced concrete

Reinforced concrete materials are used in the construction of buildings, bridges, dams, and tunnels. The use of reinforced concrete became common at the end of the nineteenth century. For the best final product, the concrete and steel should be well integrated, and both should be of high quality.

Concrete and steel are two substances with very different characteristics. However, an inseparable coupling forms by balancing one’s disadvantages with the other’s advantages. Concrete is a material of high pressure endurance. And even though steel also has high pressure endurance, it still faces the risk of bending. The tensile strength of concrete is weak, but it is high in steel. Concrete is fire resistant; steel is vulnerable. Concrete is durable against external impacts, whereas steel is vulnerable, with a high risk of corrosion. Concrete has a brittle, breakable structure; steel, however, has a higher level of ductility. Even though concrete and steel generally behave the opposite of each other, they compensate for each other when they are together. For example, the tendency of steel to bend disappears after it is surrounded with concrete; concrete also increases steel’s resistance to fire and corrosion. Furthermore, with the steel’s presence inside it, the tensile strength of concrete is enhanced.

The first of the three characteristic features of reinforced concrete buildings is the compensation of all tensile forces via steel rods; the second one is the integration of concrete and steel into each other like the adherence of flesh and bone; and finally, concrete and steel have the same thermal expansion coefficients. The thermal expansion coefficient is the value that determines the amount a material will expand or retract when impacted by heat. The thermal expansion coefficients of substances on Earth vary greatly. For instance, aluminum has a coefficient of 2,2×10-5 L/0C, copper of 1,7×10-5 L/0C, gold of 1,4×10-5 L/0C and glass of 0,85×10-5 L/0C (L= Length). It is harder for materials of different thermal expansion coefficients to have conforming movements. The most important reason for the harmonious union of concrete and steel is that their thermal coefficient values are almost the same (1,2×10-5 L/0C). If this was not the case, because of the temperature differences of inside and outside environments, the concrete and steel that make up the reinforced concrete would expand at different speeds, resulting in cracks and fractures of the load bearing elements of the building (columns, beams, flooring).

Though concrete and steel have vastly different properties, their thermal expansion coefficient values are the same and this causes them to move together during temperature changes. A similar system is put to use during the creation of cartilage, bone, and connective tissues in our body. The fibers of the connective tissue resemble the iron and steel, the cells are similar to gravel, and the intercellular matrix resembles the cement. The difference is that this system is renewed dynamically, and is flexible and strong.

I am sure that there are a lot of people who’ve found themselves in a similar situation to the man above. Unfortunately, most of us are usually not aware of the things happening in this universe. One of the things we tend to overlook is the cleanliness of nature. This is a topic which needs to be considered carefully, but I will just touch on some important aspects of this issue.

First, let’s look at the oceans. The oceans cover three-fourths of the Earth’s surface. There is a bigger world under the ocean than above it. This huge mass hosts jelly fish and tuna, dolphins and octopus, crabs and plankton, sea stars and sea plants. Currently, there are 120,000 species living in the ocean. This is just the number of the species, and doesn’t account for how many variations there are within each species. When we consider the number of living organisms, there are millions of them. Every single day, lots of these organisms die. If there are millions of organisms and thousands of them die each day, then why cannot we see them on the surface of the ocean? Even if these dead organisms are very small, such as plankton, which has a size range from 0.2 m to 20mm, when millions of their dead bodies cluster on the surface, we should be able to see them. The answer lies in a perfect arrangement. For example, the job of cleaning the dead bodies of plankton (also the live bodies!) is performed by fish, sharks, and whales. A large percentage of the daily diet of these animals depends on plankton. Since these animals perform their job well, it is impossible to see any dirt that would have been caused by the dead plankton.

It might seem easy to get rid of the dead bodies of plankton, because they are small organisms. But what about big animals such as whales? What happens to dead whales? Let’s consider the cleaning of dead whales. When a whale dies, its dead body sinks to the bottom of the ocean. This is called a “whale fall” by scientists. There are a lot of species whose diet depends on dead whales. In 1988, a group of researchers at the University of Hawaii found that there are at least 12,490 single organisms which supply their daily diet from a whale fall in the deep North Pacific Ocean. After bigger organisms, such as fish, finish their job, which includes eating the flesh of the dead whale, the other cleaners come to the scene to perform their roles. At this part of the fall, bacteria play a key role in cleaning the bones left from the whale fall. This is not as easy as it might seem. Actually, it takes several years to really clean the dead body from the bottom of the ocean. This is not just a cleaning process at all. While the whale fall is being cleaned from the bottom of the ocean, the ecosystem is supported by the energy from the dead whale.

This cleaning process is not only seen in the oceans, but also on the land. Even though it is more apparent than undersea, we are not totally aware of the cleaning process on land. Decomposition is the chain of events by which a dead organism breaks down to its smaller parts. We must stop here and ask this question: “What would happen if these dead organisms stayed on the land forever?”

So let’s look at what happens to a dead animal on land.

When an organism dies, the process of decomposition starts shortly after its death. There are some stages in the decomposition of an animal. Shortly after the death of the organism, the enzymes in the cytoplasm of the cells start to break down the tissues. This process is called autolysis. It is one of the stages of decomposition in which bacteria plays a role. Bacteria start to break down the tissues. This is called putrefaction. Bacteria are not the only players who have roles in this process. Besides them, some fungi, insects, and even some carnivores are also involved. Live animals, water, air, and temperature (higher temperatures increase the decomposition rate) also help this process. During this time, fungi and bacteria, by using compounds from the dead organisms, convert carbon to carbon dioxide and organic nitrogen to ammonium (NH4+), and so they contribute to both the Carbon and Nitrogen Cycle. After this process is done, many organisms living in the ecosystem have benefitted. At the end of this cycle, soil is enriched with new nutrients which will help the new plants to grow up and the Carbon and Nitrogen cycles are enhanced.

By looking at the processes above, as well as other cycles (e.g. the Carbon cycle), it can be said that the Earth has its own recycling system. While modern societies have only recently understood the importance of recycling, Earth has been using this system thanks to the arrangements given to it.

The things shown here are just some examples of the extraordinary systems existing on the Earth. These systems have always been like this, since the very beginning of the universe. These perfects systems in nature perform their tasks without any human help. The only thing for us to do is to appreciate this harmony, understand its value, and keep it going for the next generations.

Carbon atom, which composes nearly 0.2% of the earth’s crust, has a very special place among elements. All living beings are formed from carbon-based compounds. In addition, 94% percent of compounds—that is, more than 4 million—contain carbon atoms. Certain carbon compounds form nearly 18% of the matter in living beings. The rest is mostly water. These compounds are used as building blocks in cell formation. Only carbon has the ability of compounding with other elements in sufficient variety and complexities in order to carry out the main functions that life is based on. As carbon atoms easily form chains by making chemical bonds, no other element is given such a quality. These chains formed in a line can separate into branches and can connect to form rings. These rings are actually polygons formed by three, four, five, six, or more carbon atoms. Due to this quality, carbon is the element that forms the basis of many things from the foods we eat, to the clothes we wear, from the fuels we use, to the furniture we have.

The heat level that makes carbon compounds possible is between -20 and +120 0C. Carbon compounds begin freezing at -20 0C and they begin breaking at 120 0C. In space, where extreme heat and freezing cold exists, the only heat range that makes carbon compounds possible is found on earth and this is a very sensitive heat range. Temperatures in our neighboring planets give a better idea: as hot as 450 0C in Venus, and as cold as -53 0C in Mars. Under these temperatures, it is impossible for carbon element to form compounds and thus living beings. Therefore, the earth is the only planet created with the suitable conditions that make life possible.

Crystal structures of carbon atom

Particular repeating arrangement of atoms in three dimensional space to form a certain geometric shape is known as a crystal structure.

Different crystal structures of the same substance are named “allotrope.” Carbon has three different allotropes found in nature: amorphous carbon (coal), graphite, diamond. In addition to these, an artificially produced allotrope is fullerene.

Amorphous carbon (coal)

Amorphous structure is one without a definite crystal structure; that is, one where atoms take their places in free order. A mass of carbon atoms of amorphous structure is known as coal. After plants die, they undergo chemical transformation with the activities of microorganisms. If dead plants collect in a suitable wetland and are buried into the ground with a geological process, the carbon amount in their body increases and they begin transforming into coal. Types of coal are categorized according to the carbon percentage they contain. Geologically, this transformation process takes a period of 15 to 345 million years. Coal is one of the most commonly used forms of energy.

Graphite

In graphite, carbon atoms are found in a hexagonal crystal structure. These sheets, resembling the surface of a honeycomb, pile up and form graphite. As the sheets are not connected with firm bonds, they easily shift when some force is applied. This is why graphite is used for eliminating friction at machine industry. The black substance in pencils is graphite hardened by adding some clay. Graphite can resist very high temperatures. Therefore it is used within the steel industry and melting metals. In addition, it is a very good conductor of electricity. For this reason, the brushes of the electric engines in household machines such as a washing machine and a vacuum cleaner are made of graphite. In recent years, graphite has been used as heat shields of space shuttles.

Diamond

Diamond is the hardest natural substance we know. In spite of being a transparent substance and having no color of its own, it can be found in pastel colors such as yellow, brown, or even dim black, owing to being mixed with other minerals. Diamond is a perfect electric isolator and is the substance with highest heat conductivity. For this reason, it can be cut without being deformed. In diamond, carbon atoms are found in a pattern to form a cubical crystal structure. Extraordinary resistance of carbon-carbon bond and its hard and integrated structure prevents its reacting with other things around. It burns at a heat of 850 0C. In a piece of diamond, there can be other atoms that cause impurity and decrease the value. In good quality natural diamonds, there is only 1 alien atom versus 100,000 carbon atoms. In addition to jewelry, diamonds are widely used at industrial products such as drills, glass cutters and the like. 75-80 % of diamond production is used in this industry.

Formation of coal, graphite, or diamond from carbon

Carbon based organic compounds were buried underground as a result of movements by the earth’s crust millions of years ago. Physical and chemical changes occurred with those organic masses through heat and pressure. Gradually, water, carbon dioxide, oxygen, and—in the highest phases—hydrogen leaves these masses. This organic matter called “turba” (first transforms into lignite, then to sub bituminous coal, then to bituminous coal, and then to anthracite). If the conditions allow, it transforms into graphite. Coal is the first type of substance formed by carbon atoms on their journey to become diamond. As lower values of heat, pressure, and time suffice for coal formation, graphite requires much higher values. Diamond is formed in the mantle layer of the earth at about 150-200 depth. This valuable substance is later carried to the surface of the earth by volcanic rocks such as lamproite and kimberlite. In order for diamond to form, an atmospheric pressure of 50,000 atm, 2,400 0C of heat, and a period of 3 billion years are required. Without this immense pressure and long time, the substance to be formed by carbon will simply be graphite. It is possible to transform graphite into diamond artificially; however, according to calculations, a minimum pressure of 10,000 atm is required. In 1955, for the first time artificial diamond was obtained under 100,000 atm, 2,500 0C heat, and by using chrome as catalyzer. However, the pieces of diamond obtained were small and black, most of them did not classify as jewels. In another attempt made in 1962, graphite turned into diamond under 200,000 atm, 5,000 0C heat, without using any catalyzer.

The similarity between carbon and human beings

As carbon atoms’ properties change according to the crystal structure, people’s lifestyle and view of life depends on the community they live in and their position in that community. In order to become diamond, the highest level of its kind, a person needs to undergo hard conditions. If carbon atoms were to say, “this is more than we can bear, we prefer easier conditions,” then they can be nothing more than graphite. If the conditions for graphite are avoided as well, then one cannot go beyond the level of coal. Diamonds are kept in safes and worn in most important occasions and graphite has different kinds of practical use as an industrial material. As for coal, it ends up in fire. The situation of human beings in a way resembles carbon atoms. Every person is made of the same elements biologically. Their value will naturally be different, according to the processes they underwent and the behaviors they presented. Some show patience in the face of misfortune, put their sincere trust in God, and become the diamonds of humanity. Some others, whom we can compare to graphite, attain a desirable level even if they cannot become diamonds. Those who choose to assume the lowliest form are likely to face a similar fate with the coal.

References

• H. W. Kroto, J. R. Heath, S. C. O’Brien, R. F. Curl ve R. E. Smalley. 1985. “C60: Buckminsterfullerene.” Nature 318. DOI:10.1038/318162a0.
• L. Vlasov, D. Trifonov. 2005. 107 Stories about Chemistry, TUBÝTAK., Ankara.

White blood cells (leukocytes) are fewer in number and their duty is to fight against germs. How this process works is to be expounded by the immune system under a separate title. The red blood cells are my main building blocks and they are born by the dividing of the main cells in the bone marrow. After passing through a few phases, they lose their nucleus and are filled instead with hemoglobin, a magnificent substance containing iron. Hemoglobin’s most vital function is its binding oxygen and then carbon dioxide after releasing it. Hemoglobin reaches everywhere, traveling with the blood stream. When it comes to the lungs, hemoglobin dumps the carbon dioxide and replaces is with oxygen. Then it supplies this oxygen to the cells and removes the carbon dioxide, which is produced by burning organic compounds. So its short life passes with the same ceaseless cycle to continue your life. Hemoglobin molecules’ longevity is approximately 120 days. They contain no cell elements like ribosome, mitochondria, and nucleus and therefore cannot repair themselves. They simply die when they get old. Sad? Not at all! Red blood cells fulfill the duty they were created for and leave the stage for new ones. They are broken down in the liver and bone marrow and the iron they contain is absorbed. A certain part is transformed into bilirubin, giving bile its yellow color. As you see, nothing is truly wasted.

The red blood cells in circulation number around 25 trillion, and this number does not vary greatly, as the dying ones are constantly replaced. Their measuring gives doctors an idea about possible diseases. The amount depends on various factors’ reciprocal balance. A hormone (erythropoietin) secreted by the kidneys increases the rate of production of red blood cells, in response to falling levels of oxygen in the tissues. If you lose blood due to an accident or medical operation, the stem cells in the bone marrow receive an emergency alert to produce more red blood cells. On the other hand, if you get a blood transfer, stem cells are ordered to stop producing, due to the excess of red blood cells. You see, even such basic knowledge about bodily systems fills the learner with wonder.

Deficiency of red blood cells, scientifically known as anemia, should not be ignored. It results in pallor and weariness; you feel like sleeping more. In order to avoid this condition, your body needs different things such as group B vitamins (B6, B11, B12), vitamin C, amino acids, and iron. Since it is hard to pinpoint the deficient substance, doctors generally prescribe iron-rich multivitamin supplements.

Red blood cells divide into four types, which determine the blood groups A, B, 0, and AB. In addition to the blood group, another feature known as Rh (rhesus) factor is important to know particularly before a blood transfer. Transferring the wrong type of blood may result in death.

Platelets, which are scale-shaped cells and circulate with me are not independent; they are pieces which came off bigger cells. In a cubic millimeter of blood, 250 to 350 thousand of these little scales are found and their duty is of vital importance. If it weren’t for these pieces, the slightest cut could cause death because your bleeding would not stop. Clotting is a great blessing. It usually blocks the surface of a wound within five minutes, stopping the flow of blood and saving your life. Clotting is realized through particular molecules in these minute scales as a result of a complex chain of reactions using enzymes, vitamins, and salts. Every step of this chain of reactions is another stitch to fix the wound. Other blood cells pile up and stick together behind this net and they dry up. If such clotting occurred inside the blood vessels, it would make a disastrous effect by blocking the bloodstream. I also have enzymes to break down little amounts of such clotting. As you see, everything is splendidly organized.

Peter! A blood test reveals very critical medical data. As I visit every organ, I exchange certain substances with them. Therefore, detection of an unusual substance in me can be an early warning for a disease. Nowadays, it even helps an early diagnosis of cancer.

It is not so easy for me to explain the wisdom behind all of my duties and capabilities. But to give you an idea, there are specialized departments for studying just me at medical faculties and research institutions throughout the world.

Blood is a highly specialized tissue circulating throughout the body to carry out essential functions for an organism. Some of the basic functions of blood can be listed as: warming or cooling the body, protecting it against infectious disease, supplying essential ingredients to the cells, getting rid of harmful and unwanted waste from cells, and carrying messengers to initiate physiochemical events at the cellular level.¹ An average adult has approximately five liters of blood which completes its cycle in several minutes.² Blood can be regarded as a flawless servant to human beings with a perfect design to fulfill delicate needs and tasks to maintain their lives. If blood stopped performing just one of these tasks in some way, the survival of humans would not be possible.

Plasma is one of the main components of human blood in which the red and white blood cells are suspended.³ These two “living cells” are responsible for the crucial job of maintaining the balance of the body. Blood cells have a definite life cycle, just as all living organisms do. The most generous and all-compassionate owner, God, even knows the needs of the tiniest creatures and for Him to recreate these two cells is as easy as resurrecting hundreds of thousands of fruits, vegetables and animals every spring. Interestingly, bone marrow acts as a factory to reproduce new blood cells in place of continuously dying cells.³

In order to generate energy required for all cellular processes, oxygen has to be carried into the cell and the resulting carbon dioxide should be carried away immediately. Red blood cells, known also as erythrocytes, contain an iron-rich protein called hemoglobin which performs this duty in an excellent way. Each red blood cell contains approximately 250 million hemoglobin molecules.⁴

Hemoglobin transports oxygen from the lungs to the rest of the body and carries carbon dioxide away from the body to the lungs by consecutive chemical events in harmony. Hemoglobin can bind oxygen and/or carbon dioxide reversibly and the preference for binding to either oxygen or carbon dioxide depends solely on the environment. Upon inhaling the air, the amount of oxygen will increase in the lungs and oxygen will bind to hemoglobin’s iron unit preferentially. Later, the heart pumps oxygen-rich blood all over the body to deliver it to where it is required. As blood travels through the body in artery veins, oxygen will be exchanged with the carbon dioxide, since the amount of carbon dioxide inside cells is higher than oxygen. Then, the bound carbon dioxide will be sent back to the lungs and this process will be cycled over and over again during the course of life.⁵ During these processes a lot of complex chemical and biological changes occur in a systematic way to optimize the speed, effectiveness and quantity of oxygen transportation.

Surprisingly, one hemoglobin unit can carry four oxygen molecules at the same time. However binding of four oxygen molecules does not happen at the same time, they rather prefer binding one after another. One of the most striking discoveries about these processes is that when the oxygen attaches itself to the iron in the hemoglobin, the shape of the hemoglobin changes and this phenomenon facilitates binding other oxygen molecules.⁶

At higher altitudes air contains less oxygen as compared to lower altitudes. In people accustomed to living at higher altitudes the amount of a chemical known as 2,3-BPG in blood was found to be higher than in people living at lower altitudes.6 Researchers showed that this chemical actually binds to hemoglobin to result in easier oxygen delivery in lower oxygen atmospheres. Without this chemical, at high altitudes people would start suffering from oxygen deficiency and some of the vital organs would start dying slowly. It is obvious that this is a decisive and self-evident proof that there is an ultimate power in the universe and He is the one Who is the most Merciful.

Also the hemoglobin in the fetus has a greater affinity for oxygen than its counterpart in adults. Fetal hemoglobin uses maternal oxygen from the mother’s bloodstream and this ability gives the fetus more access to oxygen for better survival.⁷ Otherwise, no baby would be able to grow fully in its mother’s womb. Divine mercy is aware of the need of even an incapable baby in the mother’s womb and His wisdom and generosity provide appropriate tools, decorations and ornaments to whoever is in need of them.

The human body can be seen as a perfect machine equipped with state-of-art components that functions magnificently to sustain human life without any conflict. It is designed to such an extent that even its slightest needs are satisfied with an amazing design planned by great wisdom and engineering. This beauty, extreme skill, and utmost perfection testify to the existence of the All-Wise Maker and All-Knowing Inscriber. Claiming that this masterpiece is not the work of a purposeful artist is as foolish as claiming that a beautiful painting is not the art of a good painter. Even in one of the sub-structures of red blood cells (hemoglobin) the highest degree of mastery and the exquisiteness of administration for each process show an irrefutable wise Creator who has utmost knowledge and proficiency. His unique power for marvelous creation is even more visible on the surface of the earth.

“He Who has created seven heavens in harmony. You do not see any fault or incongruity in the creation of the All-Merciful. Look yet again: can you see any rifts?” (Mulk 67:3)

Mutations somehow alter the sequences of genes responsible for producing hemoglobin and as a result of inheriting these genes, some kinds of hereditary diseases may occur in future generations, such as thalassemia and sickle-cell.⁸ Since hemoglobin in these cases does not have the ability to carry oxygen properly, in some extreme cases blood transfusion is necessary to supply healthy hemoglobin for survival of patients. Instead of producing super quality hemoglobin, mutations lead to malfunctioning of the system. No observable mutation can generate meaningful and healthy changes in an organism. Trying to explain the formation of these beautiful, complex, harmonious, and utterly perfect cells by chance or coincidence and attributing the creation of these systems to unconscious nature as their creator is far beyond any reasonable scientific explanation.

“Was he not once a mere drop of semen poured forth? Then he became a clot clinging (to the womb wall), and He created and fashioned (him) in due proportions.” (Qiyama 75:37-38)

Ibrahim Yildiz is a graduate student of chemistry at the Miller School of Medicine, University of Miami.

Notes

1. Previte, J. J. Human Physiology McGraw-Hill, 1982.

2. Cecie, S., Taggart, R. Biology: The Unity and Diversity of Life. California: Wadsworth, 1989.

3. Jones, B. D. Delmar’s Comprehensive Medical Terminology. Thomson Delmar Learning, 2000.

4. Roberts, M. B. V. Biology: A Functional Approach Cheltenham: Thomas Nelson and Sons, 1986.

5. Mehler, R. E. How the Circulatory System Works Blackwell , 2000.

6. Ganong, W. F. Review of Medical Physiology McGraw-Hill, 2005.

7. Champe, P. C., Richard, A. H. Biochemistry Lippincott Williams & Wilkins, 2005.

8. Steinberg, M. H. Disorders of Hemoglobin: Genetics, Pathophysiology, and Clinical Management. Cambridge University Press, 2001.

There are many identified species of phytoplanktons. Phytoplanktons live for a day or two under normal conditions, and when they die they sink to the bottom. As a single-celled organism, phytoplankton is not only one of the main components of marine food chain, it is also assigned with an important role in carbon cycle which keeps atmospheric temperature in balance and the level of oxygen under control. Because of their significance, scientists have always showed considerable attention to phytoplanktons.

Photosynthesis in phytoplanktons

All living things need energy and organic building blocks in order to grow and maintain their lives. Plants transform sunlight into chemical energy and inorganic materials to organic materials. This process is called photosynthesis. Other living organisms consume plants to meet their food and energy needs. Like terrestrial plants, phytoplanktons also have chlorophyll pigments to process photosynthesis. This is how fish and other animals in the oceans obtain their food.

Global effects

The larger the world’s phytoplankton population, the more carbon dioxide gets pulled from the atmosphere through photosynthesis. Carbon dioxide is responsible for as much as 50% of the total greenhouse effect. There is a divine wisdom behind existence of phytoplanktons in big populations which help with the adjustment of carbon dioxide level in the atmosphere and thereby the greenhouse effect.

Phytoplanktons have an interactive relationship with their environment. This interactive relationship either increases or decreases the population of phytoplanktons in accordance with environmental changes. Scientists have found that a given population of phytoplankton can double once per day. Large populations of this organism, sustained over long periods of time, could significantly lower atmospheric carbon dioxide levels and, in turn, lower average temperatures. Populations of this marine plant will grow or diminish rapidly in response to changes in its environment. Changes in the trends for a given phytoplankton population-such as its density, spatial distribution, and rate of population growth or diminishment-will alert scientists that environmental conditions are changing there.

Phytoplanktons and sulfur cycle

Dimethylsulfide (DMS) is a sulfuric compound which is synthesized by phytoplanktons. This compound has an important role in softening climate and cloud formation. It has a peculiar odor and although it is frequently perceived as a harmfully polluting chemical, it fulfills a very important task within the bio-geo-chemical cycle on Earth. In order to better recognize climate changes on a global scale and to develop smarter environmental politics, we need to know more about this gas compound.

The production of DMS is dependent upon co-existence of various organisms. Some species of phytoplanktons synthesize the dimethylsulfoniopropionate (DMSP) molecule, from which DMS is broken down. Bacteria and phytoplanktons participate in this break down which assimilates DMSP into DMS or other compounds. Some of the produced DMS vaporizes into the atmosphere from the salty sea water and become tropospheric sulfate gas after oxidization. Consequently, this gas plays a direct role in the global radiation balance by the upward scatter of solar radiation, and an indirect role as cloud condensation nuclei (CCN). Clouds affect the Earth’s radiation balance and thereby greatly influence its temperature and climate. DMS represents 95% of the natural marine flux of sulfur gases to the atmosphere, and scientists estimate that the flux of marine DMS supplies about 50% of the global biogenic source of sulfur to the atmosphere.

In order for the sulfuric cycle in nature to continue, it is necessary that sulfuric compounds are transferred from the ocean to land through the atmosphere. DMS, the source for 95% of natural sulfuric gas coming from the oceans, served as cloud condensation nuclei and helps carry sulfuric compounds move to the land with rain.

DMS emissions that originate from phytoplanktons play a significant role in climate formations. One third of the radiation coming from the sun reflects back into the space from the clouds, ice, and snow. The remaining two thirds is absorbed to some extent by the atmosphere, and to a greater extent by oceans and rocks. This energy is converted to heat some of which is later reflected by land and ocean as ultraviolet rays towards the space warming the atmosphere. If the Earth intakes more energy than it loses, the end result is global warming; the opposite is global cooling.

The size of clouds and water driblets indicate global climate changes. The more cloud condensation nuclei (CCN), the smaller the water droplets and the denser a cloud. This, in turn, influences the cloud’s radioactivity.

DMS containing chemical reactions from poles to tropical waters are important for us to estimate man-based and natural effects on the chemistry of atmosphere and the climate more accurately. It sounds somewhat weird for us that we first destroy the environmental balance God has established before we try to discover what we have done using the natural laws He has enjoined.

References

• Norris, K.B., 2003. “Dimethylsulfide emission: Climate control by marine algae?” ASFA: Aquatic Sciences and Fisheries Abstracts, http://www.csa. com/discoveryguides/dimethyl/overview.php
• http://www.oceansonline.com/phytoplankton.htm
• http://www.sciencephotolibrary.com
• http://www.cedareden.com/phyto.html

Greenhouse Gases and the Greenhouse Effect

A greenhouse is a place that is usually covered with glass or plastic walls where early season vegetables and house-plants are cultivated. Rays from the Sun can easily penetrate a greenhouse, but once they hit the ground they are transformed into thermo-energy, with the wavelength of the beams shortening and their energy diminishing. As a result, these beams with a shorter wavelength cannot leave the greenhouse due to the glass or plastic walls. Therefore the warming of the greenhouse increases as more and more rays enter. We call this process the greenhouse effect.

Similarly, some gases in the strata of the atmosphere are called greenhouse gases since these gases cause the same greenhouse effect for the Earth. These gases include carbon dioxide, methane, nitrogen oxide, ozone, chlorofluorocarbon, and water vapor. These gases have been created with a property that does not prevent (or prevents to a very small extent) the light energy that comes from the Sun from reaching the Earth and that prevents the infrared heat energy waves that are formed after this energy reaches the Earth from radiating to the higher layers of the atmosphere. Both the Earth and the layers of the atmosphere close to the Earth are heated by these gases. If there were not any of these gases surrounding the Earth it is estimated that the Earth would be 33° C colder. Although there is a delicate balance and measure among the gases in the atmosphere that allows the maintenance of the Earth’s temperature at a sensible level, human beings are carrying out practices that can ruin this balance. We, as human beings, are responsible for the global warming that is perceived as a danger today.

Carbon Dioxide

Carbon dioxide is half the reason for the total greenhouse effect. This gas is formed as a result of the use of fossil fuels, the respiration of humans, animals, and plants, and the disintegration of organic substances. Industrial development has caused a rapid increase in carbon dioxide in the atmosphere. It is known that 85% of the carbon dioxide emitted into the atmosphere comes from fossil fuels, with 15-20% stemming from the respiration of living beings and the other ecological continuous cycles.

In the last 150 years, a total of 389 Gt of carbon dioxide has been emitted into the atmosphere. 265 Gt of this carbon dioxide comes from the consumption of fossil fuels and the production of cement. 124 Gt comes from changes in land use. 214 Gt of this total has been reabsorbed by land and sea ecosystems and the oceans. This means that there is a surplus of 175 Gt of carbon dioxide in the atmosphere.

The Importance of the Forests

Forests play an essential role in lowering the diffusions of greenhouse gases that are emitted into the atmosphere and in forming “carbon absorption” by occluding greenhouse gases in the atmosphere. Thus, except for sedimentary rocks, 67% of the carbon kept on the land is stored in the forest ecosystem. 75% of the carbon kept by vegetation is stored in the forests. In addition, as long as some long-lived wooden products (wooden houses, furniture, etc.) decay or are burnt they remain as carbon storages.

As we all know, during photosynthesis the carbon dioxide that is taken from the atmosphere is separated into carbon and oxygen molecules. Then the carbon is stored in the roots, trunks, branches, and leaves of plants, being used in order to form carbon hydrates. Therefore carbon dioxide, the most essential greenhouse gas, becomes balanced. We can compare this to a huge factory that works very quietly and causes no waste. It is such an efficient factory that it transforms harmful substances into useful ones. We cannot say that we human beings appreciate this factory or protect its resources. Although today forests cover 3.7 billion hectares, comprising 30% of all land, between the years 1990–2000 on average 9.4 million hectares of forest were annually removed. That means that during this period the forest regions of the world diminished by 2%. As a result of such negative occurrences, because the carbon balance of vegetation, soil and organic substances had been destroyed, the forests, one of the means of God’s mercy upon us, have become sources of carbon dioxide and a tragedy due to our exploitation.

Ligneous living masses increase each year, while falling leaves add to the carbon storage. As a result, forest ecosystems contain carbon. After the growth of trees, most of the carbon dioxide they occlude each year goes toward developing the biomass of the tree. This means that in the first 30-40 years a high rate of carbon storage occurs. As the forest ecosystem develops, the organic substance of the soil and the total respiration in the ecosystem (occlusion of carbon dioxide) increase. When the ecosystem has fully developed, it no longer has the characteristics of “carbon absorption” anymore. In this case, the amount of carbon taken from the atmosphere is equal to the carbon emitted back by the biomasses of the trees and is kept in the soil. The time it takes for a tree to fully develop depends on the type of tree and the climate zones. However most of the carbon storage occurs in the first 60-100 years. It has been determined by research that a well-developed 100 year-old beech tree absorbs 40,000,000 m_ of air with its leaves for photosynthesis and binds 1,200 m_ of carbon dioxide in the air as 6 tons of carbon.

As well as being a community of trees, forests are environmental systems and living communities, with soil that was created over a thousand years, with millions of plants, animals, and microorganisms, and their reciprocal relationships. It is very difficult for this system to be restored once destroyed by human beings. Forests provide an essential service in a consistent and balanced carbon flow between the biosphere and the atmosphere with respiration that is dependent on photosynthesis and the activities of life in the soil and the plants. Forests are the lungs of the Earth.

In the light of these facts, the duty of human beings is to protect the vegetation and to reforest the treeless lands, to decrease human pressure on existing forests and to improve forests that have been damaged. Oxygen, nitrogen, water vapor, and carbon dioxide were created as continuous cycles for the continuation of the life. When these treasures have been damaged as a result of the greed of human beings, the costs are too high for us to reverse the trend. Billions of people are victimized; yet they are nor directly responsible for such acts. These delicate balances can be revived if we lead a simple and modest life, where we consume less and we produce less. Those who ought to understand this first must promise to be more respectful to God and to change themselves. Even if we fulfill our responsibilities, we can do nothing today but hope that those whose destructive powers are great may desire such a spiritual revolution.

References

• Cepel, N., Ekolojik Sorunlar ve Cozumleri, Tubitak Populer Bilim Kitaplar›, Ankara: 2003.
• Roulet, N.T., Freedman, B., What Trees Can Do to Reduce Atmosferic CO2, Tree Canada Foundation, Ontario: 2003.
• Report by the Commission of Climate Change Experts, DPT (Turkey’s Official Planning Organization), Ankara: 2001.
• Food and Agriculture Organization of the United Nations, 2001, Global Forest Resources Assesment 2000, ISSN 0258-6150, FAO Forestry Paper:140.

The theory is simple: Cosmic particles coming from outer space continuously collide with stable carbon-12 atoms in CO2 molecules, which are widespread in the atmosphere. Each carbon-12 atom takes up two neutrons and is converted into a radioactive carbon-14 atom. Radioactive carbon-14 atoms rapidly mix and become uniform throughout the atmosphere. Deep oceans, the biosphere, and carbonate rocks are giant reservoirs of carbon and with the addition of the atmosphere they constitute the carbon cycle of the Earth. Within this cycle, radioactive carbon-14 is continuously created and disintegrated. Both processes are in equilibrium. Since the total amount of carbon on the Earth is constant, a constant ratio is established between the amount of stable and radioactive carbon. This same ratio is valid in all the reservoirs of carbon in this giant cycle. In the biosphere, both carbon-14 and carbon-12 atoms are added to the food chain via assimilation; first by plants through photosynthesis and then by animals through consumption of the plants. For an animal or a plant, a carbon-14 atom is no different from a carbon-12 atom in assimilation. Living beings continuously take up both atoms, so the ratio of both atoms in their bodies remains constant throughout their life. When an organism dies, the uptake of exogenous carbon is terminated. After this point, although the amount of carbon-12 remains constant, carbon-14 continues to disintegrate and the ratio starts to decrease after the body dies. Because the ratio after death is related to the time that has passed since death, it is possible to determine the date of death by measuring the amount of radiocarbon present.

The half-life of radiocarbon is 5,730 years. This means that after 5,730 years half of the total amount of radiocarbon in a dead body disintegrates. The remaining half decays in the following 5,730 years and only a quarter of the first amount remains. This goes on until a very minuscule, undetectable amount remains. In bodies less than 50,000 years in age the amount of radiocarbon can be detected. For an older body, the amount of radiocarbon is so small that the instruments would be unable to measure the amount of radiocarbon present. In addition, such a test obviously works only on the remains of things that were once alive, such as bones or wooden parts of an old structure.

But how accurate is an age determined by this method? How dependable is this technique for enlightening us about the past? Although the theory seems quite consistent from a general outlook, one can see it is not the case when analyzed more rigorously.

Archeologists have tried different ways to test the accuracy of the method. The results have revealed long-term and short-term variations from the actual ages. Long-term variations show systematic deviations of the radiocarbon age from the real age; that is as the date of the sample gets older the deviation increases. On the other hand, short-term variations show irregular fluctuations in the radiocarbon age from the real age. These deviations apparently reveal that the assumptions made concerning the radiocarbon technique were not accurate. The results of these important abnormal conclusions in radiocarbon dating were summarized in the Introduction to Prehistoric Archaeology as follows: “for years, it was thought that possible errors could have minor effects, however, recent research shows that the natural concentration of carbon-14 deviates at some certain periods, significantly affecting the calculated ages.”

The method is based on two assumptions that should be examined carefully: Firstly, the method assumes that the ratio of carbon-14 to carbon-12 has remained constant in the atmosphere from the time the body died to the present. However, recent scientific research has proven that this ratio has not remained constant during geological time.

Secondly, the method also assumes that the carbon supply to the organism was made only by the global carbon cycle and no other source of carbon has affected the system.

Initial concerns about the possible sources of error were focused on the constant ratio assumption. So, why did the constant ratio assumption turn out to be incorrect? Actually, many reasons were found to refute the validity of this assumption. The most important ones are explained below:

Changes in the Earth’s magnetic field are believed to be responsible for long-term deviations in radiocarbon dating. By investigating the orientation of magnetic minerals in ancient rocks, geologists have proven that the magnetic field surrounding the Earth has not been constant throughout the time. Today, it is widely accepted that both the strength and direction of the Earth’s magnetic field has changed. Interestingly, these changes are appreciable even within a century. Changes in the geomagnetism affect the radiocarbon production in the upper atmosphere; cosmic rays are deflected according to the strength of the Earth’s magnetic field. If the magnetic field is high, more cosmic rays are deflected away from the Earth and the production of radiocarbon falls. If it is low, production rises. When the production rate changes, a new equilibrium concentration in the carbon cycle as a whole can only be established after a considerable amount of time has passed. The likely time scale for achieving the complete new equilibrium level is about 10,000 years. This is about the same as the age of the sample that is to be dated! The bottom line is that anything that affects the density of cosmic rays reaching the atmosphere will affect the rate of radiocarbon production, thus affecting the ratio.

Short-term changes might be the results of different factors. One of these is the variation in sunspot activity. Sunspots appear as dark places on the surface of the Sun for a short period of time and generate strong geomagnetic storms. Sunspot activity increases the Earth’s magnetic field and leads to a decrease in the radiocarbon production rate. Therefore, again, anything that causes a change in the Earth’s magnetic field will affect this ratio.

Other effects for short-term variations are the changes in the Earth’s climate. It is widely accepted that the amount of carbon in the atmosphere during geological time is strongly related to temperature changes on the Earth. This fact is also key in understanding the global greenhouse effect, which occurs with the release of high amounts of carbon dioxide to the atmosphere by hydrocarbon combustion. The global sea level has also been affected by these climatic changes. During low temperature seasons (ice ages or glacial periods), large ice sheets covered most of the continents and as a result of this, the sea level dropped appreciably. During these periods, a high amount of carbon (as carbon-dioxide) was kept inside glaciers and they became C-14 depleted (dead carbon). By the end of the Ice Age, large amounts of dead carbon had been released into the system and they had decreased the global ratio of radiocarbon.

Actually, three more resources of dead carbon make a negative contribution to the ratio. One of them is the dead carbon that comes up from deep Earth through volcanic eruptions. Radiocarbon dating of an organism that lived in the vicinity of a volcano gives inaccurate results. Because of the expulsion of dead carbon, samples found close to volcanoes have less radiocarbon in their body than others. Consequently, the age determination of these samples gives significantly incorrect results.

As is obvious from the previous examples, the main problem arises in the lack of knowledge about the history of the sample being dated by this method. Another example is when the sample being tested is wood from the inner part of a tree; the radiocarbon method gives an incorrect result in this case. The reason for this is that the innermost part of a tree finishes the carbon cycle before the tree dies. If a sample was made from this part of the tree (it is impossible to know which part of a tree is being used) then the date produced would be greater than its real age.

Even human activity is an important resource for dead carbon. Although only effective since the last century, a high amount of dead carbon in the carbon dioxide has been released into the atmosphere by the burning of fuel. So the ratio of radiocarbon has decreased. Actually, compared to the factors above, this effect has a more profound influence on the application of radiocarbon dating: No recent organic material can be used as a modern standard. Because of this, the zero point of the timescale chosen is to be 1950 AD, as determined by the US National Bureau of Standards for quoting radiocarbon results.

Consequently, the ages determined by the radiocarbon method are not taken seriously by archeologists because of the problems in the basic assumptions upon which the method was established. Occasionally, the radiocarbon method is used to roughly determine whether an object is modern or of considerable antiquity; in essence, it is used as an authenticity test. Even then the answer may not be clear-cut; for example, an old piece of timber could have been carved to produce an authentic looking sculpture!

Radiocarbon dating is an example of how scientific tools should be used carefully to unfold the reality around us. Scientific theories are only poor models of what is happening in reality. The history of science is full of such examples, which sometimes may be misleading if not handled carefully.

Reference

Radiocarbon Dating, Sheridan Bowman, University of California Press, 1990