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.

In the northern hemisphere, where annual average rainfall is around 100 kg per square meter in cold and dry regions, boreal forests, with needle-leaf trees, dominate. The southern hemisphere is dominated by savanna; bushes and meadows occupy millions of hectares.. In these regions, natural fires can be the most important factor of ecosystem changes. When looking at the results of these fires, it sometimes seems they were preprogrammed as to when, where, and how they spread.

Examples of fire dependent ecosystems

The cone of the Jack Pine species (Pinus banksiana), which is widely distributed throughout North American forests, requires absolute forest fire in order to release its seeds. The cone of this species can remain on the trees without releasing seeds for years because of climate and the resin layer covering it. Seeds preserved in the cones wait for the next fire; the cone’s scales open with the heat generated during such a fire. The seeds then start their journey towards a piece of soil that they can grow into. Here the role of fire is very important, not only for the dispersal of seeds but also in preparation of germination. The high humidity and low temperatures in the forests of these regions delays the decomposition of fallen leaves. This layer of dead material over the mineral soil is another hindrance for seeds to meet the soil. When scales of the cones open with the help of forest fire, this thick layer of dead leaves is also removed, having burned down to create fertile new soil.

Another example of fire benefiting plants is the chaparral vegetation of the North American forest. This type of plant cover is composed of short, perennial wooden plants and annual non-woody plants. During the hot, dry weather of summer, this vegetative cover becomes particularly vulnerable to fire. A dark black cover composed of unburned parts, frames, and ashes of the plants is left behind. This sight, which is saddening at first, actually hides various beauties in it, and these beauties only emerge after a series of events.

Golden eardrops (Dicentra chrysantha), which is a member of the perennial Chaparral family, is deeply affected by fire. The seed of this plant requires a fire event in the germination season and should be exposed to smoke for at least 10 minutes.

The positive effects of forest fires can also be seen in the healthy survival of an ecosystem. Due to its thick bark, the widely distributed Ponderosa pine (Pinus ponderosa), of North America, is minimally affected by the low, medium level cover fires that happen every five to twenty years. The weak and unhealthy individuals in this dense forest get burned as a result of natural forest fires, leaving healthy, thick barked trees. This way, possible epidemics of harmful forest organisms, via these unhealthy trees, is prevented. In the meantime, due to periodic fires, dead cover, or fallen and dead trees are removed, thus preventing bigger fires.

In the eastern Mediterranean, brutia pine, yellow pine, black pine, aleppo pine, and stone pine can are widely distributed. Among these, brutia pine is spread across a wide area, especially in most fire sensitive regions. It is created with a thicker bark around the trunk compared to other pines. This species can be minimally impacted from low and medium level cover fires. On the other hand, seeds in the cones of brutia pine are thrown far away by the heat of the fire, reaching fertile germinating grounds, thus helping to spread the forest.

References

• Fuller, M. 1991. Forest Fires: An Introduction to Wildland Fire Behavior, Management, Firefighting, and Prevention, SD421.F84, Wiley & Sons, Inc., NY, pp. 238.
• Keeley, J. E. 2007. “Chaparral and Fire,” Fremontia, Volume 35:4, pp. 16-21.
• Bond, W. J., Wilgen, B.W. 1996. Fire and Plants, SE18HN, UK, Chapman & Hall, UK, pp. 259.

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.

This ‘book’ or exhibition was once much more dazzling; like a magnificent vessel sailing in the ocean of love and ecstasy or a chandelier with one thousand and one lights, it was beautiful beyond imagination. With its emerald hills and slopes and exhilarating valleys and plains, with its forests inhabited by thousands of kinds of cheerful animals and paradise-like gardens, fields and orchards, and with its singing birds and merry-making insects, this ‘book’ was the realm neighboring the other world. Divine mercy poured onto it in the form of rain to make the earth more fertile and, in return, hands were held open towards it in profound gratitude.

Those who sensed nature in that manner could not help but establish a deep heartfelt relation with the sound, melody, taste, smell and beauties which issued from it by the Hand of Power. For they were so intimate and familiar with it that whenever they gazed on it, they felt different things pertaining to the worlds beyond.

Like the elegance and grace in the architecture of a palace inspiring in us different things beyond the palace itself, nature, this exhibition of the miracles of Divine art, inspires in our hearts an intuition of the existence of One who, being the real source of all harmony and beauty, has brought it into existence and designed it, One who, although He makes us feel Himself through every work of His, is beyond the capacity of direct human perception.

The natural world and the heavens are as if in each other’s arms. It is as if in response to the strong desire of mountains to meet with heavens which they show by making their peaks lean on their skirts, heavens hang their skirts down over them. Like bees flying from one flower to the other, human imagination travels through the reflections of the Creator’s beauty and goes as fas as the horizon. When it reaches the horizon, thinking that the road goes on far into eternity beyond heavens, it sets out for a new journey and man begins to hear the melodies belonging to the worlds beyond. Those who, through their imaginations, can stay in those worlds for a long time, succeed in meeting the true beloved, with the love of whom they are consumed and for the union with whom they long.

For those who have resolved to make a journey through this realm of nature which provides knowledge of God for the traveller and where the heart, spirit and conscience overflow with innumerable kinds of pleasures, with its exhilarating spectacles, multi-coloured hills and slopes, impressive mountains that lead one into day-dreams, amorous gardens, awe-inspiring forests, streams and rivers murmuring in their way to union with seas-it is especially in spring and summer, a realm of joy, pleasure, peace and imagination. 

There is a magnificence, a charm, and a poetical harmony in every corner of this ‘book’ or exhibition. It is as if-with all its variety of beauty diversified in colours and forms, and the sheer charm of its general appearance, such that one would say, It is impossible for it to be more beautiful than this!-nature were in a sort of beauty competition. Those who have awakened to those beauties observe it differently and hear from it melodies of unimaginable beauty. Those ‘intoxicated’ spirits see trees dancing mentioning His Name and flowers announcing Him in the languages particular to themselves, and they hear everything in nature whispering peculiar messages from that symphony of beauty.

There are parts of nature which know of neither winter nor autumn. They are so dazzling and charming that you feel near the pont of touching the ultimate reach of beauty where this and other worlds are as if concentric with each other. The slopes of those places give you the impression that you are in gardens of Paradise, the rivers flowing through them bring to your mind the rivers of Paradise, and the swaying of their trees bring you a gust of breezes in gardens of Paradise. In short, in the beauties exhibited in those places you feel and observe the eternal beauties and, thinking that the worldly life is too short to experience all those beauties perfectly, you feel an earnest desire for eternity and turn to the Infinitely Powerful One so that that vital desire of yours may be realized.

What a pity it is that this magnificent book, this charming exhibition, which the Infinitely Merciful One has created and presented to man to observe and study and to be exhilarated by, is no longer given any more care than is given to a heap of junk or rubbish. Worse than that, it is more and more becoming a wasteland and like a dunghill.

Today, air, that magnificent conductor of Divine commands, is a suffocating smoke and a perilous ‘whirlpool’. Water, that source of life and other Divine bounties, is either a hazardous flood or forms desolate expanses of pitch. And earth, that treasure of Divine grace and munificence, is a wilderness no longer productive and a ruin without any ecological balance.

Like everything else entrusted to us, we have deplorably treated this ‘book’, this magnificent exhibition, which is an embodiment of Divine grace and mercy. How deplorably and awkwardly we have treated plains and residential places, which we have changed into deserts and heaps of ruin. How deplorably and gracelessly we have treated seas and rivers, which we have polluted. Again, how deplorably and awkwardly we have treated air and water, and fields, forests, and gardens, which we have made unfavorable to any life. Truly, by changing this Paradise-like world to a hell, how deplorably and awkwardly we have treated ourselves!

Unless we improve this world, whose order we have destroyed and which we have polluted, and restore it to its essential beauty and magnificence, it will inevitably collapse on us in heaps of wreckage.