My Science School

In our fight against global warming and climate change, trees are considered part of the solution. But emerging research suggests that trees are also part of the problem.

Trees are carbon sinks locking up vast amounts of carbon dioxide from the atmosphere. This way, they help protect the planet from the harmful effects of the greenhouse gas. But there seems to be another face to trees, that scientists have uncovered only recently. They find that trees emit methane, which is a greenhouse gas 45 times more potent than carbon dioxide at warming our planet. Scientists unofficially call this treethane (tree methane). However, it's currently unknown just how much of methane is emitted by trees.

Emission of methane from cottonwood trees was first observed in 1907, but the finding was reported mainly as a novelty and was largely ignored. Subsequent research has picked up only recently, but in a big way. An expanding network of researchers has discovered methane release from trees from the vast flooded forests of the Amazon basin to Bomeo's soggy peatlands, from temperate upland woods in Maryland and Hungary to forested mountain slopes in China.

Source of methane

Some lowland forest trees such as cottonwood emit flammable methane directly from their stems, which is likely produced by microbes living within. Scientists think trees may also be emitting methane from a direct photochemical reaction thought to be driven by the ultraviolet wavelengths in sunlight Research in this area is still in its early stages and so there is a lot left to be understood.

But understanding why, how and which trees emit the most methane is crucial, as trillions of trees are being planted across the world in an effort to mitigate climate change. However, scientists point out that the amount of methane emitted by trees is generally dwarfed by the amount of carbon dioxide they take in over their lifetime. Forests are still key to maintaining a safe climate, they point out.

 

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The Indian cobra (Naja naja), also known as the spectacled cobra, Asian cobra, or binocellate cobra, is a species of the genus Naja found, in India, Pakistan, Bangladesh, Sri Lanka, Nepal, and Bhutan, and a member of the "big four" species that inflict the most snakebites on humans in India. It is distinct from the king cobra which belongs to the monotypic genus Ophiophagus. The Indian cobra is revered in Indian mythology and culture, and is often seen with snake charmers. It is now protected in India under the Indian Wildlife Protection Act (1972).

Naja naja is considered to be the prototypical cobra species within the subgenus Naja, and within the entire genus Naja. All Asiatic species of Naja were considered conspecific with Naja naja until the 1990s, often as subspecies thereof. Many of the subspecies were later found to be artificial or composites. This causes much potential confusion when interpreting older literature.

The Indian cobra varies tremendously in colour and pattern throughout its range. The ventral scales or the underside colouration of this species can be grey, yellow, tan, brown, reddish or black. Dorsal scales of the Indian cobra may have a hood mark or colour patterns. The most common visible pattern is a posteriorly convex light band at the level of the 20th to 25th ventrals. Salt-and-pepper speckles, especially in adult specimens, are seen on the dorsal scales.

Specimens, particularly those found in Sri Lanka, may exhibit poorly defined banding on the dorsum. Ontogenetic colour change is frequently observed in specimens in the northwestern parts of their geographic range (southern Pakistan and northwestern India). In southern Pakistan, juvenile specimens may be grey in colour and may or may not have a hood mark. Adults on the other hand are typically uniformly black in colour on top (melanistic), while the underside, outside the throat region, is usually light.

 

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Terrestrial Ecoregions of the World (TEOW) is a map with a bio-geographic regionalization of the Earth's terrestrial biodiversity. The bio-geographic units are eco-regions, which are defined as relatively large units of land or water containing a distinct assemblage of natural communities sharing a large majority of species, dynamics, and environmental conditions.  The map has been prepared through compilation and correlation of existing global and regional maps, gap-filling from landform and vegetation information, followed by reclassification and validation by regional experts.

TEOW differentiates 867 terrestrial eco-regions, classified into 14 Major Habitat Types such as forests, grasslands, or deserts. Each eco-region is portrayed in detail in terms of geographical location, area description, floral and faunal biodiversity features, current conservation status, and types and severity of threats.

 

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On average, newborn calves stand about 9 m (3 ft.) high and weigh 120 kg (264 lb.) at birth. Newborn male African elephants may weigh up to 165 kg (364 lb.). Newborn Asian elephant calves weigh about 91 kg (200 lb.).

The newborn is helped to its feet by its mother and other females. Calves are able to stand on their own within minutes of birth.

The mother and other females help guide the calf to nurse almost immediately. The trunk of the calf is still short, so it uses its mouth to nurse.

Calves are able to walk within one to two hours of birth.

Within two days, calves are strong enough to join the rest of the herd, which is waiting patiently nearby.

Calves nurse for the first six months of life. Elephant milk is high in fat and protein (100 times more than the protein contained in cow's milk).

On average, calves drink about 10 L (21 pt.) a day.

Calves begin to experiment with their developing trunks between four and six months of age by picking grasses and leaves to supplement their diet. Weaning from milk gradually follows this process. Calves are not completely weaned until they are over two years of age and may weigh between 850-900 kg (1,874-1,984 lb.).

 

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The Japanese eagerly await the cherry blossom season every spring. The seasonal spectacle of white and pink flowers bursting across cities also draws thousands of tourists to the country. Crowds flock to popular locations to take photos and have picnics underneath the branches.

The cherry blossom season is extremely important for Japan, both economically and culturally. The flowers experience a peak bloom that only lasts a few days and it signifies the Japanese concept of mono no aware, the wistful realisation that nothing lasts forever. The season has been revered, and the time of peak bloom has been predicted and tracked for more than a thousand years. Imperial court documents and ancient diary entries on the nation's cherry blossom festivals can be traced back to 812 AD.

Today, these flowers also carry the warning signs of climate change. In 2021, after an unusually warm spring, the city of Kyoto witnessed peak bloom on March 26, the earliest in more than 1,200 years. The earliest blooming date so far had been March 27 in the year 1409. Scientists warn that it's a symptom of the larger climate crisis threatening ecosystems everywhere.

CHERRY-PICKED FACTS FOR YOU

• The Japanese cherry generally refers to ornamental cherry trees. There are over 300 different varieties of cherry trees also known as cultivars. Taking advantage of the mutable traits of cherry trees, many cultivars have been created for cherry blossom viewing, especially in Japan.


• Eighty % of cherry trees in Japan are the popular Somei Yoshino variety.


• Most flowers are shades of white or pink, but some trees bear yellow and green flowers.


• Cherry blossom species naturally have five petals, but there are some cultivars that have more than 100 petals per flower. Many cherry flowers and leaves are used as food ingredients in Japan.


• Sakura is the Japanese word for cherry blossom and is the country's most popular girls name.


• Cherry blossom-viewing celebrations date back to the 9th Century when Japanese emperors held viewing parties with their courts. According to folklore, the mountain deity travelled to rice paddies on floating cherry blossom petals and nurtured the crops.

CHANGING WITH THE CLIMATE

• Studying data from the past years, scientists have mapped out a clear trend in the timing of cherry blossom peak, and it changes with changes in climate. Scientists find that as spring arrives earlier in the Northern Hemisphere due to global warming, cherry trees are also shifting their patterns of activity.


• Since the 1830s, data show, the Japanese mountain cherry tree has been flowering earlier and earlier.


• While cherry blossoms in Kyoto may start to flower in March, their full bloom date lay historically around April 17. But in the past century this date has advanced to April 5,


• It is not just Kyoto, other places in Japan are also experiencing changes in flowering pattern. This year, in Tokyo, the cherry blossom season arrived 12 days earlier than historical records. In Hiroshima, the season began on March 11, eight days earlier than in 2004. (Even) cherry trees in Washington DC, the US, have begun to flower earlier after unseasonably warm springs. In 2020, the blooms arrived roughly two weeks ahead of the long-term average of April 3).


• Scientists predict that if the temperature rises by 2.5 °C, cherry blossoms will have already dropped in the mountainous city of Takayama by March-April.


• While early blooms are caused by warm springs, delayed blooms could result from warming winters, say experts. Southern Japan is already seeing delayed blooms.

Why does this matter?

Plants and animals changing their patterns in response to climate change can put entire ecosystems out of sync. The vital interactions between species will be affected. Pollination, food source, and reproduction will go for a toss. Farmers who depend on the plants, their flowers, and fruits will also be affected.

CHERRY BLOSSOM IN WASHINGTON

In 1912, Japan gifted more than 3,000 cherry blossom trees to the United States as a gesture of friendship and political alliance between the two countries. They were planted along the Tidal Basin in Washington D.C., which now shares the yearly blossom-viewing tradition.

 

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More than 930 million tonnes of food sold in 2019 landed in waste bins, according to the Food Waste Index Report 2021, released by the United Nations last month. The report reveals that 17% of all food is just dumped. Some food is also lost on farms and in supply chains, indicating that overall a third of food is never eaten. The study reveals that households discard 11% of food at the consumption stage of the supply chain, while food services and retail outlets waste 5% and 2%, respectively. The household food waste in India is about 68.7 million tonnes a year and average of 50 kg per person per year. The report looked at food waste that occurs in retail outlets, restaurants and homes-counting both food and inedible parts like bones and shells and presents the most comprehensive food waste data collection, analysis and modelling to date.

Hunger on the rise

On the one side, we waste so much of food, and on the other, scores of people are dying of hunger every day. In 2019, some 690 million people were impacted by hunger and three billion were unable to afford a healthy diet, says the report. According to the United Nations Food and Agriculture Organisation (FAO), globally, one in three persons is not getting the right food in right quantity.

By dumping uneaten food from our plate, by buying in excess and leaving dishes to rot in the fridge, we waste quite a lot of food as consumers. There are also other ways through which food is lost throughout the supply chain from production to consumption. These include loss due to problems in harvesting, storage and packing and the accidental dropping of perishable goods during transportation, etc.

Why is it a matter of concern?

Food waste has substantial environmental, social and economic impacts. When you dump a container of previous night's leftover, you are not just throwing away food, but all the resources that went into producing it, including effort, energy, water and fuel.

Food waste translates to an enormous amount of water wastage. According to the FAO's Food Wastage Footprint report 2018, 250 km3 of water is used each year to produce food that is ultimately lost or wasted.. Similarly, 1.4 billion hectares of land 28 per cent of the world's agricultural area is used annually to produce food that is lost or wasted.

Food waste that ends up in landfills produces a large amount of methane - a powerful greenhouse gas.

According to an estimate, if food waste were a country, it would be the third largest greenhouse gas emitter next to China and the United States.

How to reduce food waste

• Make a grocery list before you go shopping and stick to the list. Be careful when buying in bulk, especially with items that have a limited shelf life.


• Ensure you consume the product before the expiry date.


• Be careful with how much you take on your plate. If you need more, you can always go for a second helping.


• Sometimes vegetables and fruits that have dents or physical imperfection may not be rotten. Check before discarding.


• When eating out, request a takeaway, instead of leaving it on your plate. You may want to consume it later or share with it someone who may need it.


• Always look for options to reuse or recycle food.


• Donate excess food to a food bank.


• Each one of us - right from farmers, food processors, retailers, people involved in the storage and transportation of food, and consumers-should act responsibly to prevent food wastage.

 

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Human journey into space began in 1957, when the Soviet Union (today's Russia) launched Sputnik, the first ever artificial satellite. Since then, thousands of rockets have been launched, which have put into space numerous satellites, spacecraft, and space stations. Not all of them are functional today, nor has everything been brought back to Earth. Several of them, their parts, and random objects such as nuts and bolts are still up there as space junk. Worse, they are tumbling through space at a high speed putting functional satellites in Low Earth Orbit (LEO) at risk. There are fears that collisions between debris could set off a chain reaction, with the result that LEO would become unusable.

In 2007, China tested an anti-satellite missile by destroying one of its weather satellites. Two years later, an American and a Russian spacecraft accidentally collided. According to an estimate, these two events alone increased the amount of large debris in the LEO by about 70%. Space agencies have begun taking steps to mitigate the problem. A Japanese company launched one such initiative recently. Called Elsa-D, the mission intends to demonstrate a space debris removal system.

Mission Elsa-D

On March 22, 2021, a Soyuz rocket put 38 payloads into space. Among them was the ‘The End-of Life Services by Astroscale demonstration mission’ (Elsa- D), developed by a Japanese company called Astroscale. It is the world's first Commercial mission to demonstrate a space debris removal system. Elsa-D consists of two spacecraft: a 175-kg "servicer and a 17-kg client". Client is the fake debris that the servicer will have to release, grab, and repeat.

How does it work?

Astroscale's demo mission aims to test its magnet strategy. A magnetic plate has been built into both the servicer and the client. The mission was designed to separate both the components a few weeks after the launch. Once released the servicer will hunt the client down, latching on to it using the magnetic docking plate, then releasing the client for another capture practice.

If that basic manoeuver goes well, the task will become increasingly complex Astroscale will remotely instruct the components to tumble, spinning like a dead satellite normally would. That will force the servicer to assess its target and line up with the prototypes docking magnet

Eventually, the servicer will pull the "debris" towards the Earth's atmosphere where both the components will burn up. If such a technology were to be put to use, then future satellites should come built with this types of magnetic docking plate to enable removal once they become defunct and then?

Hundred million bits

 

Space debris refers to all the human-made objects such whole and abandoned satellites pieces of broken satellites deployed rocket bodies and other room objects such as tiny flecks of paint from spacecraft and event tools left behind by astronauts during space walk. Most of them orbit Earth and some even beyond it Some of the have made it to Venus and Man. Twenty tonnes of them have been found on the Moon, says NASA According to the European Space Agency, more than 2.400 dead satellites A computer generates artists impression of space junk. PHOTO: ESAVAFP and 100 million bits of debris are already circling Earth. And the debris keeps piling up as satellites have gotten smaller, cheaper, and easier to launch.

How are they monitored?

Scientists use radar to keep track of space debris. The US Space Surveillance Network keeps track of known orbital objects wing ground-based radar systems such as the TIRA Haystack and EISCAT radars and the Cobra Dane Telescopes and observatories such as the ESA Space Debris Telescope and the Goldstone provide additional data. As of 2020, the United States Space Surveillance Network was tracking more than 14,000 pieces of space debris larger than 10 on across. It is estimated that there are about 2.00,000 pieces between 1 and 10 and macros.

What are the risks?

In-orbit risks

• The damage can be as small as a dent on a shuttle window to the destruction of an entire satellite. In 1996, a French satellite was hit and damaged by debris from a French rocket that had exploded a decade earlier. Objects in LEO travel at speeds up to 10km/second, fast enough to cause significant damage to satellite, spacecraft or spacewalking astronauts. The rising number of space debris increases the potential danger to all space vehicles, especially to ones with humans aboard, the International Space Station (ISS), for instance.


• In 2020 alone, the ISS was manoeuvred away from space debris on three occasions, since a collision could endanger the astronauts on board. A number of space shuttle windows have been replaced because of damage caused by paint flecks.


• The density of the junk may become so great that it could hinder our ability to use weather satellites, and hence to monitor weather changes.

Debris that re-enters Earth

Space trash is often attracted by Earth's gravitational pull. It is pulled lower and lower until it finally reaches Earth's atmosphere. Most objects burn up when they enter Earth's atmosphere due to the compression of atmospheric gases, but larger objects can reach the Earth intact. But most of them fall into the ocean, simply because Earth is mostly covered by water. According to NASA website, an average of one catalogued piece of debris has fallen back to Earth each day over the last 50 years. But there have not been any significant damage. No one has ever been killed by re-entering space debris. People on Earth should avoid contact with the fallen debris, such as rocket parts, because of the possible presence of hazardous chemicals in them.

What is the solution?

• The solution involves steps to clean up the mess, mitigate damage, and avoid future debris. There are systems in place to track the debris and avert disasters. Various space organisations have been working on reducing the amount of trash by adopting better designs of rockets and other objects. For example, making rockets reusable could vastly cut down waste.


• The UK's TechDemosat-1 (TDS-1), launched in 2014, was designed in such a way that once its mission is over, a system, like a parachute, would drag the satellite to re-enter the atmosphere and bum up. Some satellites at the end of their lifecycle are made to fall out of orbit and bun up in the atmosphere, provided they still have fuel left in them for the descent Some satellites are sent even farther away from Earth.


• Technologies to remove space junk are also being developed. Cleaning the debris that already exists comes at a high cost, because it will take multiple trips to remove objects from space. Other proposals include the use of a laser to remove debris by changing their course and making them fall towards the atmosphere of Earth and later burn up.


• In December 2019, the European Space Agency awarded the first contract to clean up space debris. ClearSpace-1 is slated to launch in 2025. It aims to remove a 100-kg Vega Secondary Payload Adapter left by the rocket Vega flight W02 in an 800-km orbit in 2013. A "chaser" will grab the junk with four robotic arms and drag it down to Earth's atmosphere where both will burn up.

 

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Vulture and the antiseptic wash

The vulture is a bird of prey that feeds on carrions (the decaying flesh of dead animals and humans). It has special adaptations to protect itself from the harmful pathogens present in the decaying carcass. One of them is its strong stomach acid, believed to be 10 to 100 times stronger than that of humans. So, the disease-causing germs are killed soon after they enter the body.

But the vulture's legs too could pick up harmful bacteria when it hops around animal carcasses. But the bird has no worries - it has an ingenious way to sanitise itself. The vulture gives an antiseptic wash to its legs and feet by passing urine and excreting faeces onto them. Its waste is also acidic and acts as a disinfectant.

Did you know birds do not have separate rectal and urinary openings? Birds eliminate all waste through a single opening called the doaca.

Wombat and the building blocks

You can identify most animals from the shape of the faeces it leaves behind. They can be quite unique. Take the wombat, for instance. It is the only known animal to produce cube-shaped scat. But why and how does it do it? This has remained a mystery for years. Scientists have tried to come with various theories. One popular postulate is that the wombat excretes cubes so that it can use them like building blocks. The marsupial, native to Australia and Tasmania, stacks its scat to mark its territory. Many animals, including the tiger, mark their territory using their scat but the wombat sets its boundaries pretty clear. The method by which the wombat produces the cubic scat is not well understood, but it is believed that its intestine stretches differently at various points. Areas of varying muscle thickness help shape the cubes sharp comers as the intestine undergoes rhythmical contractions, say the scientists who came up with this explanation in 2018. The wombat's intestine is also excellent at extracting water, making its poop very dry. This probably helps the wombat maintain that dice-like shape.

Sloth and its risky business

For the sloth, an animal known for its slow movement, a trip to the loo can be a risky business. Rainforests of South and Central America are its homes, where it spends 90% of its time munching away leaves or hanging upside down on the tree top. The tree canopy gives it the perfect camouflage, protecting it from its predators. But once a week, the sloth leaves the safety of its homes to... defecate. It digs a hole on the ground to do its 'business'.

While the animal's slow movements help it remain undetected by its predators while on the tree, it becomes a limitation while on the ground as it cannot quickly flee from its attackers. But why does a sloth risk its life and insist on pooping on the ground? One of the hypotheses is that it could have an ecological significance and scientists are still trying to understand what exactly it is.

Parrotfish and the white beach

Strolling on the white beaches of Hawaii is on the bucketlist for many of us. While you are dreaming about it make a mental note of this interesting fact a significant portion of that pristine, white, beautiful sand is actually parrotfish's excreta. The parrotfish (called uhu in Hawaiin) is a colourful, tropical creature that spends about much of its day eating algae off coral reefs. It uses its parrot like beak to bite and scrape algae off dead corals. It grinds the inedible calcium carbonate part of its meal (mostly corals exoskeletan) and excretes it as sand. The parrotfish does not have stomach and so this waste particles pass straight through the long intestine, exploding in a cloud of sand out its body. How much sand does a fish help create? Well, larger parrotfish are like sand factories, producing as much as 840 pounds of sand per year!

MORE FACTS

 

• The study of faeces of animals is called scatology.


• The waste of whale acts like fertilizer for the oceans.


• The demodex mites that live on your face do not excrete. What a relief!


• The Tambaqui fish are marine pollinators of sorts. They eat the seeds of sea plants along the floor, and poop out undigested seeds quite some distance away, which helps to further the ecosystem along the bottom of the ocean.


• Some caterpillars are masters of disguise. They ward off hungry birds by looking like something really distasteful: bird droppings.

Adelie penguins and the pink potty

If you ever wished to see penguins upclose, this warning is for you - stay a few feet away from them. Penguins are known for their projectile defecation behaviour. They shoot their guano (penguin poop) as far as four feet away from their body. Scientists believe that penguins developed this behavior in order to keep their body relatively dean of faecal bacteria.

While this is fascinating, scientists are particularly interested in the guano of the Adelie penguin, because it is pink and plentiful The Adelie penguin lives across the coast of Antarctica and nearby islands, and thrive on a diet that is dominated by tiny pinkish crustaceans called krill, which gives its guano a striking pink colour. (When the penguins are munching on fish. their guano tends to come out white.) That poop stains the ground and their bodies. When a single penguin relieves itself, its waste hits the ground and decomposes. But when an entire colony of penguins discharges its load, it shows up pretty well in satellite images, especially because it contrasts with the surrounding white ice.

This is helpful for scientists who want to locate and count Adelie penguins all the way down in one of the most remote places on Earth.

 

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