My Science School

We depend on nature for everything from air, water, food and shelter to sources of energy to run our factories and businesses. So, conserving nature and preserving its biodiversity must be our priority. Here are ten simple tips to do your bit for the planet.

1. Plant trees

Trees are carbon sequesters and increasing the tree cover is perhaps one of the easiest ways to conserve nature. A tree can absorb approximately 25kg of CO2 per year. So, plant a tree to mark this day. Make it a tradition to plant a tree during prominent or celebratory occasions of your life. It can be your birthday or when you finish your academic year or any moment you feel is worth celebrating. If you do not have enough space in your home, see if you can adopt your friend's yard or make use of the space managed by your area's residents' association. Where you do it, make sure that the plant is taken care of Encourage friends and family to take up the practice as well.

2. Conserve energy

 We derive our energy from nature. Everything that is manmade runs on energy obtained from nature. Quite often, a lot of energy also goes to waste. By changing a few habits you can help save energy at home. These include small actions such as turning off the lights (when not in use or when you can depend on daylight), unplugging appliances when not in use, not charging your phone overnight, turning off your faucet when you aren't using water, taking less time in the shower, reusing waste water in the kitchen gardens and so on. This will help reduce carbon footprint and in turn help in conserving nature. PHOTO: UNSPLASH IMAGES

3.3Rs

The 3Rs of "Reduce", "Reuse", "Recycle" is perhaps one of the ultimate mantras for nature conservation. These three small words will help manage waste, save the ecosystem, prevent marine animal casualties and address climate change. The first step is to reduce the waste you generate. This will ensure that less waste ends up in landfills or oceans. Effective waste segregation is the key to this. This helps recover materials for recycling and composting. Reuse articles that you can. And lastly, recycle. This helps prevent soil and water pollution. PHOTO: UNSPLASH IMAGES

4. Use public transport

 One of the major polluters is the global transport sector. It is responsible for approximately one-quarter of greenhouse gas emissions, according to experts. And 95% of the world's transport energy is still obtained from fossil fuels. Personal transportation adds to the probelm, adding to the greenhouse emissions. The easiest way to avoid this is by switching to public transport. If this is not a practical solution every time, you can still choose public transport twice or thrice a week or during specific hours. This, when done on a regular basis, can significantly help reduce carbon emissions. Alternately, switching to green modes of travel such as a bicycle can help prevent your carbon footprint.

5. Stop using single-use plastics and disposables

 Single-use plastics and disposable cups and utensils have infiltrated our day-to-day life and upended it. Those disposable grocery bags and disposable utensils you use eventually ends up on the earth, polluting our soil. oceans, and marine life. These disposables can easily be replaced with environmentally responsible counterparts. Make a commitment to take out at least one disposable article from your lifestyle. Perhaps. carry a cloth bag to the supermarket instead of asking them for a plastic one. Maybe switch out your lunch box for one made of metal. This can be a good start. And slowly you can make a lifestyle switch by eschewing other disposables. PHOTO: UNSPLASH IMAGES

6. Eat less meat

It is estimated that 80% of forest loss is caused by the conversion of forest land to agricultural land. It leads to habitat destruction and loss of our green cover. Eating less meat can help prevent this and preserve biodiversity and the ecosystem. Since we all have our food preferences, it may not be easy to switch to vegetarianism or veganism. But you can be more aware and mindful of the food on your plate and choose to eat less meat. For instance. you can limit meat consumption to one or two days a week or reduce the number of meals with meat. PHOTO: UNSPLASH IMAGES

7. Use windows and not AC

 Our world is heating up and the surging heat has made us all dependent on air conditioning, the demand for which is increasing by the day. Did you know that air conditioners are also a contributor to the climate crisis? They consume more electricity than any other appliance in your home and consume about 10% of global electricity (along with electric fans). So next time, when possible, open the windows and let the cool breeze in.

8. Explore thrifting

 Fast fashion is one of the greatest threats to the environment. Did you know that it takes about 2,700 litres of water to make just one t-shirt. Or that a pair of jeans requires 7,600 litres of water? With a consumer base that updates its wardrobe according to trends in the fashion industry, the damage to the planet has been exponential. This trend depletes natural resources and harms the planet. This is where thrift shopping comes in. Anyone who has had an older sibling would be no stranger to using their toys, books, or school paraphernalia, thus giving the article a fresh lease of life. This is the concept of thrift shopping. It means using hand-me-downs or second-hand articles. It applies to all forms of merchandise such as clothes, games, toys, shoes, books, appliances, furniture, and so on. It's time to break the cycle of single-use apparel or appliances and shop at thrift stores. Also, remember to let your friends and family know you are using a thrifted article and the positive impact your move has on nature's conservation.

9. Embrace minimalism

 Minimalism is a lifestyle choice where you make mindful, deliberate choices of buying only what you truly need. As such you make do with less and avoid overconsumption, which is one of the major contributors to the exploitation and depletion of natural resources. By consuming only what's essential for your living, your ecological footprint gets reduced. Thereby, the individual environmental impact is limited. Replace consumerism with eco-minimalism. PHOTO: UNSPLASH IMAGES

10. Spend time volunteering

 One way to help conserve nature is to help organisations that are working in the field directly. You can do this by volunteering your time and services at non-profit environmental organisations. These organisations run on donations and they are always on the lookout for people who can help them. Here you may get to actively participate in the community and work on projects aimed at conserving nature and get on-field experience.

Picture Credit: Google

How do plants transport their seeds for propagation? Do you know that they employ different ways to spread their seeds widely? Let's look at some of them today

Plants have various ways to ensure that their seeds are spread widely and have a chance to grow. Some employ animals and birds, others wind and water, while still others use their own power to transport their seeds.

 

Dodo tree

The tambalacoque tree grows only in Mauritius and is valued for its timber. In the 17th century, all of a sudden, the tambalacoque lost the ability to grow from seeds. Existing trees continued to live, but not one of the seeds they produced would germinate. By the 1970s, there were only 13 sickly trees left.

An American ecologist. Stanley Temple, observed in 1977 that the tree had stopped growing from seed at about the same time that the DID YOU KNOW? The seeds of a type of tomato plant that grows in the Galapagos Island germinate only when they are eaten by a tortoise and pass through its digestive system! flightless bird of Mauritius, the dodo, became extinct. Temple concluded that the seeds, which had a thick hard covering, would germinate only if they were eaten by the dodo and passed through its digestive system! Without the grinding in the dodo's gizzard, the seed could not break through the tough exterior and sprout.

He force-fed the seeds to wild turkeys and some of them germinated- the first tambalacoque saplings seen in 300 years!

Launch pad

The squirting cucumber of the Mediterranean fills with a slimy juice as it ripens. Soon, the pressure within increases so much that the cucumber is launched off its stalk like a miniature rocket. The seeds stream out from a hole in its base and land as far away as six metres from the parent plant!

The Brazilian hura tree or monkey's dinner-bell has a more dramatic way of sending off its seeds. It has a detonating seed container. After it dries out fully, it explodes with a deafening bang, hurling its seeds over a distance of 12 metres! The pods of the broom plant become hot and dry and split open down the middle, catapulting is tiny black seeds in all directions.

Wind and water

Some plants fuave seents so tiny, that they are easily carried away by the wind. Kapok trees auf cotton bushes provide their seeds with a convenient tuft of threads that are long and durable. They catch the wind and float many miles before they land in fertile soil and germinate Dandelion seeds have a tiny parachute and are attached to the top of a stem like a fragile globe. The merest breath of wind can cause millions to take off and sail high into the sky.

The coconut palm on the other hand, sends its seed by sen packed in a fibrous waterproof shell containing water and a supply of rich food in the form of the kernel to nourish it on its long journey.

Winging their way

Many tall trees have winged seeds that travel some distance before falling on the ground to germinate, thus avoiding their shade.

The Anisoptera and Alsomitra are two of the tallest trees in Asia. Their seeds come equipped with a pair of wings. Anisoptera seeds are spear-shaped and spin like the rotors of a helicopter when released. Alsomitra seeds are fitted with paper-thin wings. They descend very slowly and travel over nine metres before falling to the ground.

Critters as couriers

Plants use animals as seed carriers. Some have thomy, stick-on seeds which attach to the fur of the animal as it brushes past. The South African grapple plant has seeds with hooks that embed in the soles of a rhino or elephant's feet and fall off after the animal has walked some distance.

The best advertisement for most plants are their delicious fruits! if the animal swallows the seed with the fruit, the coating ensures the seed passes out undamaged.

It wouldn't do if the seed is eaten before it matures, so the plant craftily makes the fruit hard and sour. Once the seed is ready, the fruit tums sweet and aromatic inviting animals to have a feast!

Picture Credit: Google

The rings of Satum have fascinated and captivated humankind for over 400 years. It was in 1610 that Italian astronomer Galileo Galilei first observed these features through a telescope, though he had no idea what they were.

While our understanding of Saturn's rings has matured over these four centuries, the age of these rings haven't been determined precisely yet. The assumption that the rings likely formed at the same time as Satum draws flak as the rings are sparkling clean when compared to the planet.

A new study at the University of Colorado Boulder has provided the strongest evidence so far that the rings of Saturn are remarkably young. The research, published in May in the journal Science Advances, places the age of Saturn's rings at around 400 million years old. When we compare this with Saturn itself, which is 4.5 billion years old, the rings are really young.

Studying dust                                                                        

The researchers arrived at this number by studying dust. By studying how rapidly the layer of dust built up on Saturn's rings, they set out to put a date on it. It was, however, not an easy process.

The Cassini spacecraft provided an opportunity by arriving at Saturn in 2004 and collecting data until it intentionally crashed into the planet's atmosphere in 2017. The Cosmic Dust Analyzer, which was shaped a little bit like a bucket and was aboard this spacecraft, scooped up small particles as the spacecraft whizzed by.

Just 163 grains

The researchers were able to collect just 163 grains of dust that had originated from beyond Saturn's close neighbourhood during these 13 years. This quantity. however, was enough to make their calculations, placing the age of Saturn's rings at a little less than 400 million years.

With this, we now know approximately how old Saturn's rings are and that they are a relatively new phenomena in cosmic terms. With a previous study suggesting that Saturn's rings could entirely disappear in another 100 million years, questions pertaining to how these rings were initially formed and why these short-lived, dynamic rings can be seen just now still remain.

Picture Credit : Google 

Mercury is the smallest planet in our solar system. Located closest to the Sun, it is also the fastest planet in our solar system, travelling at a speed of nearly 47 kilometres per second. In fact, the closer a planet is to the Sun, the faster it travels. Mercury completes one circle around the Sun in just about 88 Earth-days.

When observed from its surface, the Sun would appear more than three times as large as it does when viewed from Earth, and the sunlight is as much as seven times brighter. But despite this proximity to the Sun, Mercury is not the hottest planet in our solar system- it is Venus. The reason for this is Venus' dense atmosphere.

Another interesting aspect of Mercury is that the Sun appears to rise briefly, set, and rise again from some parts of the planet's surface due to its elliptical and egg-shaped orbit, and sluggish rotation. The same phenomenon happens in reverse during sunset.

Picture Credit : Google 

The largest planet in our solar system, Jupiter, is located fifth from the Sun. It is more than two times the size of all the planets in our solar system combined. Jupiter has also been instrumental in our understanding of the universe and our place in it. In 1610, Galileo discovered Jupiter's four large moons: lo, Europa, Ganymede and Callisto. This confirmed the Copernican view that the Earth was not the centre of the universe as these newly discovered celestial objects were revolving around another planet.

It is estimated that eleven Earths could fit across Jupiter's equator. To put it in other words, if our planet is the size of a grape, then Jupiter is the size of a basket-ball. It has an iconic Great Red Spot, which is a giant storm that has been active in Jupiter's atmosphere for hundreds of years. This storm is bigger than the Earth!

Jupiter's orbit is about 778 million kilometres or 5.2 Astronomical Units (AU) from the Sun (Earth is one AU from the Sun). Jupiter is a gas giant, which lacks an Earth-like atmosphere. Even if it has a solid inner core at all, it would only be about the size of the Earth. Jupiter's atmosphere contains mainly hydrogen (H) and helium (He) and has more than 75 moons. It rotates about its axis once every 10 hours (a Jovian day), and takes about 12 Earth years to complete one revolution about its orbit around the Sun (a Jovian year).

In the year 1979, NASA's Voyager mission discovered Jupiter's faint ring system. We have discovered that all the four giant planets of our solar system have ring systems. Till date, nine spacecraft have visited Jupiter. Of them, only the most recent one landed on Jupiter. Seven of them only flew by this gas giant and the other two just orbited it. Juno, the latest spacecraft, arrived on Jupiter in 2016.

Although it is the biggest planet in our solar system, Jupiter cannot support life as we know it. But we have come to know that some of its moons have oceans beneath their crusts, which could possibly support some form of life.

Picture Credit : Google

Researchers find out an often overlooked key role played by the orbit of Jupiter on Earth.

Most planets have eccentric orbits. While circular orbits around a star would ensure that the distance between the star and the planet never changes, these eccentric orbits mean that the planets traverse around a star in an oval-shape. As a result, the planet would receive more heat when it goes closer to the star, affecting the planet's climate.

Alternative solar system

Based on this knowledge and using detailed data from the solar system as we know it today, researchers from the University of California Riverside created an alternative solar system. In this hypothetical theoretical system, they were able to show that if Jupiter's orbit were to become more eccentric, then it would lead to big changes in Earth's orbit, thereby making the Earth more hospitable than it is currently.

This is because Jupiter in this theoretical system would push Earth's orbit to be even more eccentric. As a result, parts of Earth would sometimes get closer to the sun. This would mean that even parts of Earth's surface that are now sub-freezing will get warmer. In effect, the habitable range on the surface of the Earth would be increased.

Assumptions proven wrong

 The findings of this research, published in September in Astronomical Journal, go against two long-held scientific beliefs with respect to our solar system. One of these is that the current avatar of Earth is the best in terms of habitability. The second one is that changes to Jupiter's orbit could only be bad for Earth.

Apart from upending these long-held assumptions, the researchers are looking to apply their findings in the search of exoplanets - habitable planets around other stars. While existing telescopes are adept at measuring a planet's orbit, the same cannot be said about measuring a planet's tilt towards or away from a star- another factor that could affect habitability.

The model developed in this research helps us better understand the impact of the biggest planet in our solar system, Jupiter, on Earth's climate through time. Additionally, it also paves the way to find out how the movement of a giant planet is crucial in making predictions about habitability of planets in other systems.

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Discovery about an Earth-like planet orbiting an M dwarf could imply that planets orbiting the most common star may be uninhabitable.

Is Earth the only planet that supports life? This is one of the many questions for which we don't have an answer yet. In a universe filled with countless stars and innumerable planets, our quest for life on a planet other than our own continues.

A new discovery could serve as a signpost and maybe even dramatically narrow our search for life on other planets. The discovery, explained in the Astrophysical Journal Letters in October by researchers from the University of California - Riverside, reveals that an Earth-like planet orbiting an M dwarf appears to have no atmosphere at all.

Most common type of star M dwarfs or red dwarfs are the most common type of star in the universe. This discovery could therefore imply that a large number of planets orbiting these stars may also lack atmospheres, and will therefore likely not support life.

The planet named GJ 1252b is slightly larger than our Earth, but is much closer to its star, an M dwarf, than the Earth is to the sun. On a single day on Earth, this planet orbits its star twice.

In order to find out if this planet lacks an atmosphere, astronomers measured infrared radiation from the planet as its light was during a secondary eclipse. In a secondary eclipse, the planet passes behind the star, and hence the planet's light along with the light reflected from its star are blocked.

Scorching temperatures

The radiation revealed the planet's daytime temperatures to be of the order of 2,242 degrees Fahrenheit. This, along with assumed low surface pressure, led the astronomers to believe that GJ 1252b lacks an atmosphere.

The researchers concluded that the planet will not be able to hold on to an atmosphere, even if it had tremendous amounts of carbon dioxide, which traps heat. Even if an atmosphere builds up initially, it would taper off and erode away eventually.

With M dwarf stars having more flares, the likelihood of planets surrounding them closely holding onto their atmospheres goes down further. The lack of atmosphere means that life as we know it is unlikely to flourish.

In Earth’s  solar neighbourhood, there are about 5,000 stars and most of them are M dwarfs. If planets surrounding them can be ruled -out entirely in the search for life based on this discovery, that would leave roughly around 1,000 stars similar to the sun that could be habitable.

For now, however, these can't be ruled out entirely. Nor can we rule out the possibility of a planet far enough away from an M dwarf star such that it retains its atmosphere. We need more research and results as we continue to embark on our search for life elsewhere.

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Ultraviolet (UV) radiation is a form of electromagnetic radiation that comes from the sun. Humans have found use for this radiation in industry and dentistry. However, too much exposure to UV rays harms not just humans but can alter our environment because it can inhibit growth in green plants. The ozone layer that protects us from harmful UV rays has faced depletion, primarily due to certain types of chemicals we humans manufacture.

Our natural source of UV radiation:

The sun

Some artificial sources of UV radiation include:

• Tanning beds
• Mercury vapor lighting (often found in stadiums and school gyms)
• Some halogen, fluorescent, and incandescent lights
• Some types of lasers

UV radiation is classified into three primary types: ultraviolet A (UVA), ultraviolet B (UVB), and ultraviolet C (UVC), based on their wavelengths. Almost all of the UV radiation that reaches earth is UVA though some UVB radiation reaches earth. UVA and UVB radiation can both affect health but UVA penetrates deeper into the skin and is more constant throughout the year.

Benefits

The production of vitamin D, a vitamin essential to human health.

Vitamin D helps the body absorb calcium and phosphorus from food and assists bone development. The World Health Organization (WHO) recommends 5 to 15 minutes of sun exposure 2 to 3 times a week.

Risks

Sunburn is a sign of short-term overexposure, while premature aging and skin cancer are side effects of prolonged UV exposure.
UV exposure increases the risk of potentially blinding eye diseases, if eye protection is not used.
Overexposure to UV radiation can lead to serious health issues, including cancer.

Skin cancer is the most common cancer in the United States. The two most common types of skin cancer are basal cell cancer and squamous cell cancer. Typically, they form on the head, face, neck, hands, and arms because these body parts are the most exposed to UV radiation. Most cases of melanoma, the deadliest kind of skin cancer, are caused by exposure to UV radiation.

Anyone can have harmful health effects from UV radiation, but the risks increase in people who:

Spend a lot of time in the sun or have been sunburned.
Have light-color skin, hair, and eyes.
Take some types of oral and topical medicines, such as antibiotics, birth control pills, and benzoyl peroxide products, as well as some cosmetics, may increase skin and eye sensitivity to UV in all skin types.
Have a family member with skin cancer.
Are over age 50.

To protect yourself from UV radiation:

Stay in the shade, especially during midday hours.
Wear clothes that cover your arms and legs.
Consider options to protect your children.
Wear a wide brim hat to shade your face, head, ears, and neck.
Wear wraparound sunglasses that block both UVA and UVB rays.
Use sunscreen with sun protection factor (SPF) 15 or higher, for both UVA and UVB protection.
Avoid indoor tanning. Indoor tanning is particularly dangerous for younger users; people who begin indoor tanning during adolescence or early adulthood have a higher risk of developing melanoma.

Credt : National centre for Environment health   

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As our planet warms, oceans across the globe absorb a large portion of the heat generated. In the process, the water expands, resulting in universal sea-level rise. In addition, the rise is also caused by the melting of glaciers and icebergs. Usually such melting during warmer months and freezing during colder months is a natural phenomenon. However, with global warming, there's more of the former than the latter, leading to alarming sea-level rise, threatening to submerge several cities within just a few decades.

Why does sea level change?

Causes sea level to rise because water expands as it warms up; melting of the world’s ice sheets. A large ice mass, which flows over hills and valleys and occupies a large portion of a continent. The world has only three major ice sheets today (Greenland, West Antarctica, and East Antarctica).

 In Greenland and Antarctica;  melting of smaller around the world; and decrease in the amount of water held on land, for example, in groundwater beneath the land and in reservoirs above the land. Ocean warming accounts for around half of the observed change in sea level (this is often called “thermal expansion”), with the melting of thousands of small glaciers accounting for the other half of the increase in sea level. Since the 1800s, the melting ice sheets in Antarctica and Greenland have contributed relatively little to sea level change. But, these ice sheets are starting to melt faster due to global warming and may push sea level up much more in the future.

How much could sea level rise?

Because of global warming, the thermal expansion of the ocean and glacier melting will continue to play a role in the rise of sea level in the future . If all of the planet’s remaining as small glaciers were to melt, sea level would rise about 50 cm. The amount that thermal expansion can raise sea level in the future will depend on the continued warming of sea water. The largest possible contribution to sea level rise in the future comes from the world’s large ice sheets in Greenland, West Antarctica, and East Antarctica. If these ice sheets melted completely, the level of the oceans would rise about 7 m from the Greenland ice sheet, 5 m from the West Antarctic ice sheet, and 53 m from the East Antarctic ice sheet. This is why many glaciologists (scientists who study ice) focus on how Greenland and Antarctica are changing because of global warming.

How will sea level rise affect the countries of the world?

The effect of ice sheet melting on sea level is different across the world.

So, when the sea level rises, people will be affected in different ways, depending on where they live. The UK is used to occasionally dealing with rising sea level for short periods of time, particularly when there are storms at the same time as when the tides higher than usual. If the IPCC predictions are correct, we must consider the possible increase in sea level on top of natural tidal surges. This will cause dangerously high tides to occur more often in the coming decades, and these future tides might be more destructive than we are used to.

In farming regions near the coast, seawater flooding on land can contaminate the soils with salt, making them less able to support the growth of crops. The salty water may also get into underground stores of fresh water (known as groundwater), which is the source of important drinking water and also for farmers to grow crops.

In coastal cities, sea level rise will cause more flooding to houses, businesses, and while it may seem sensible to consider moving cities away from harmful floods, especially as we know it will likely happen in the future, our cities cost so much to develop that we are more likely to simply try to protect them from rising sea levels. A vision of our cities near the sea involves them with walls facing the ocean several meters high, with the street level of the cities themselves being below the level of the ever rising sea.

Credit : Frontiers for young mind 

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Permafrost is permanently frozen ground comprising soil, rocks, and sand, and often spans the Arctic regions. Found both on land and below the ocean floor, it covers vast expanses, and is a habitat for several animals and plants. Melting permafrost is a concern because it releases vast amounts of trapped greenhouse gases into the atmosphere.

What is Permafrost Made Of?

Permafrost is made of a combination of soil, rocks and sand that are held together by ice. The soil and ice in permafrost stay frozen all year long.

Near the surface, permafrost soils also contain large quantities of organic carbon—a material leftover from dead plants that couldn’t decompose, or rot away, due to the cold. Lower permafrost layers contain soils made mostly of minerals.

A layer of soil on top of permafrost does not stay frozen all year. This layer, called the active layer, thaws during the warm summer months and freezes again in the fall. In colder regions, the ground rarely thaws—even in the summer. There, the active layer is very thin—only 4 to 6 inches (10 to 15 centimeters). In warmer permafrost regions, the active layer can be several meters thick.

How Does Climate Change Affect Permafrost?

As Earth’s climate warms, the permafrost is thawing. That means the ice inside the permafrost melts, leaving behind water and soil.

Thawing permafrost can have dramatic impacts on our planet and the things living on it. For example:

1. Many northern villages are built on permafrost. When permafrost is frozen, it’s harder than concrete. However, thawing permafrost can destroy houses, roads and other infrastructure.
2. When permafrost is frozen, plant material in the soil—called organic carbon—can’t decompose, or rot away. As permafrost thaws, microbes begin decomposing this material. This process releases greenhouse gases like carbon dioxide and methane to the atmosphere.
3. When permafrost thaws, so do ancient bacteria and viruses in the ice and soil. These newly-unfrozen microbes could make humans and animals very sick. Scientists have discovered microbes more than 400,000 years old in thawed permafrost.
4. Because of these dangers, scientists are closely monitoring Earth’s permafrost. Scientists use satellite observations from space to look at large regions of permafrost that would be difficult to study from the ground.

Credit : Climate kids

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About 15 to 35 km above the Earth's surface is gas called Ozone that surrounds the planet. This layer shields the Earth from the UV radiation from the sun However, pollution has caused this layer to thin exposing life on the planet to harmful radiation. The Montreal Protocol on Substances That Deplete the Ozone Layer (which was adopted on September 15, 1987) is an international treaty designed to protect the ozone layer from depletion by phasing out the production of a number of substances believed to be responsible for ozone depletion.

How is Ozone created?

When the sun's rays split oxygen molecules into single atoms, Ozone is created in the atmosphere. These single atoms combine with nearby oxygen to form a three-oxygen molecule — Ozone.

 Who discovered the Ozone Layer?

 The Ozone Layer was discovered by the French physicists Charles Fabry and Henri Buisson in 1913.

 Why is Ozone Layer important?

 Ozone protects the Earth from harmful ultraviolet (UV) rays from the Sun. Without the Ozone layer in the atmosphere, life on Earth would be very difficult. Plants cannot live and grow in heavy ultraviolet radiation, nor can the planktons that serve as food for most of the ocean life. With a weakening of the Ozone Layer shield, humans would be more susceptible to skin cancer, cataracts and impaired immune systems.

 Is Ozone harmful?

 Ozone can both protect and harm the Earth — it all depends on where it resides. For instance, if Ozone is present in the stratosphere of the atmosphere, it will act as a shield. However, if it is in the troposphere (about 10 km from the Earth's surface), Ozone is harmful. It is a pollutant that can cause damage to lung tissues and plants. Hence, an upset in the ozone balance can have serious consequences.

Disruption of Ozone Balance in the atmosphere

 Since the 1970s scientists have observed human activities to be disrupting the ozone balance. Production of chlorine-containing chemicals, such as chlorofluorocarbons (CFCs), have added to depletion of the Ozone Layer.

 What is 'Ozone Layer depletion'?

Chemicals containing chlorine and bromine atoms are released in the atmosphere through human activities. These chemicals combine with certain weather conditions to cause reactions in the Ozone Layer, leading to ozone molecules getting destroyed. Depletion of the Ozone Layer occurs globally, but the severe depletion of the Ozone Layer over the Antarctic is often referred to as the 'Ozone Hole'. Increased depletion has recently started occurring over the Arctic as well.

Credit : Business standard

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Our atmosphere is made up of 78% nitrogen. This element is essential for all living beings but we cannot directly take the nitrogen from the environment. We must absorb it through our food. The nitrogen cycle follows the circulation of nitrogen from the atmosphere to the soil, to animals and back. Nitrogen in the atmosphere falls to the earth through snow and rain. Once in the soil, the nitrogen combines with the hydrogen on the roots of the plants to form ammonia. This process is called Nitrogen fixation. Additional bacteria further combine this ammonia with oxygen in a process called Nitrification. At this point, the nitrogen is in a form called nitrite, which is further converted into nitrate by the bacteria. Plants can absorb nitrogen in this state through a process called assimilation and the rest is utilised by the bacteria. The remainder is released back into the atmosphere through the process of denitrification.

Nitrogen Cycle Explained – Stages of Nitrogen Cycle

Process of the Nitrogen Cycle consists of the following steps – Nitrogen fixation, Nitrification, Assimilation, Ammonification and Denitrification. These processes take place in several stages and are explained below:

Nitrogen Fixation Process

It is the initial step of the nitrogen cycle. Here, Atmospheric nitrogen (N2) which is primarily available in an inert form, is converted into the usable form -ammonia (NH3).

During the process of Nitrogen fixation, the inert form of nitrogen gas is deposited into soils from the atmosphere and surface waters, mainly through precipitation.

The entire process of Nitrogen fixation is completed by symbiotic bacteria, which are known as Diazotrophs. Azotobacter and Rhizobium also have a major role in this process. These bacteria consist of a nitrogenase enzyme, which has the capability to combine gaseous nitrogen with hydrogen to form ammonia.

Nitrogen fixation can occur either by atmospheric fixation- which involves lightening, or industrial fixation by manufacturing ammonia under high temperature and pressure conditions. This can also be fixed through man-made processes, primarily industrial processes that create ammonia and nitrogen-rich fertilisers.

Assimilation

Primary producers – plants take in the nitrogen compounds from the soil with the help of their roots, which are available in the form of ammonia, nitrite ions, nitrate ions or ammonium ions and are used in the formation of the plant and animal proteins. This way, it enters the food web when the primary consumers eat the plants.

Ammonification

When plants or animals die, the nitrogen present in the organic matter is released back into the soil. The decomposers, namely bacteria or fungi present in the soil, convert the organic matter back into ammonium. This process of decomposition produces ammonia, which is further used for other biological processes.

Denitrification

Denitrification is the process in which the nitrogen compounds make their way back into the atmosphere by converting nitrate (NO3-)  into gaseous nitrogen (N). This process of the nitrogen cycle is the final stage and occurs in the absence of oxygen. Denitrification is carried out by the denitrifying bacterial species- Clostridium and Pseudomonas, which will process nitrate to gain oxygen and gives out free nitrogen gas as a byproduct.

Conclusion

Nitrogen is abundant in the atmosphere, but it is unusable to plants or animals unless it is converted into nitrogen compounds.

Nitrogen-fixing bacteria play a crucial role in fixing atmospheric nitrogen into nitrogen compounds that can be used by plants.

The plants absorb the usable nitrogen compounds from the soil through their roots. Then, these nitrogen compounds are used for the production of proteins and other compounds in the plant cell.

Animals assimilate nitrogen by consuming these plants or other animals that contain nitrogen. Humans consume proteins from these plants and animals. The nitrogen then assimilates into our body system.

During the final stages of the nitrogen cycle, bacteria and fungi help decompose organic matter, where the nitrogenous compounds get dissolved into the soil which is again used by the plants.

Some bacteria then convert these nitrogenous compounds in the soil and turn it into nitrogen gas. Eventually, it goes back to the atmosphere.

These sets of processes repeat continuously and thus maintain the percentage of nitrogen in the atmosphere.

Credit : BYJU’S 

Picture Credit : Google 

Mangroves are bushes or trees that grow in thick clusters along sea coasts and riverbanks.

Their roots stick out of the mud in thick tangles and prevent the waves from washing away the sand (or dirt) from the coastline Sundarbans in Bangladesh and India is the world's largest single tract of mangroves.

Where Are Mangroves Found?

Mangroves grow in sheltered tropical and subtropical coastal areas across the globe. In general, this is an area between latitudes of 25 degrees north and 25 degrees south, however, geographical limits are highly variable depending upon the area of the world and local climates. In Eastern Australia, the mangrove Avicennia marina can grow as far south as 38 degrees and Avicennia germinans can grow as far north as 32 degrees in the Atlantic. A major restriction for where mangroves can live is temperature. The cooler temperatures of northern temperate regions prove too much for the mangroves. A fluctuation of ten degrees in a short period of time is enough stress to damage the plant and freezing temperatures for even a few hours can kill some mangrove species. However, rising temperatures and sea level due to climate change are allowing mangroves to expand their ranges farther away from the equator and encroach on temperate wetlands, like salt marshes. Also, on some isolated tropical islands, such as Hawaii and Tahiti, mangroves are not native and are sometimes considered invasive species.

Growth and Reproduction

Life by the ocean has its perks—for mangroves, proximity to the waves and tides helps with reproduction. 

For most plants, the seeds remain dormant until after they are dispersed to a favorable environment. Not mangroves. Mangrove offspring begin to grow while still attached to their parent. This type of plant reproduction is called vivipary. After mangrove flowers are pollinated the plants produce seeds that immediately begin to germinate into seedlings. The little seedlings, called propagules, then fall off the tree, and can be swept away by the ocean current. Depending upon the species, propagules will float for a number of days before becoming waterlogged and sinking to the muddy bottom, where they lodge in the soil. Propagules of Rhizophora are able to grow over a year after they are released from their parent tree, while the white mangrove, Laguncularia racemosa, floats for up to 24 days, though it starts losing its ability to take root after eight. The flotation time allows for the propagules to vacate the area where their parent grows and avoid competition with an already established mangrove.

Mangroves as Ecosystems

Mangroves are among the most productive and biologically complex ecosystems on Earth. They cover between roughly 53,000 and 77,000 square miles (138,000 and 200,000 square km) globally, acting as a bridge connecting the land and sea. Though most will be less than a couple miles thick along the coastline, in some areas of the world they are massive aquatic forests. The Sundarbans Forest, a UNESCO World Heritage site at the mouth of the Ganges, Brahmaputra, and Megha Rivers in the Bay of Bengal fronting India and Bangladesh, is a network of muddy islands and waterways that extends roughly 3,860 square miles (10,000 square km), two times the size of the state of Delaware. 

Credit : Ocean find your blues

Picture Credit : Google

Keystone species play a unique and crucial role in the functioning of an ecosystem. The animals and organisms that come under this category help to maintain biodiversity within their community either by controlling populations of other species that would otherwise dominate the community or by providing critical resources for the survival of a wide range of organisms.

These species act as the glue that holds the system together. The term was coined by Dr Robert Paine in 1969, to describe the power a single species exerts on an ecosystem. Examples of keystone species include starfish, sea otters, beavers, wolves, elephants, prairiedogs and bees.

Keystone Species Examples

Sea Otter

The sea otter (shown below) is considered a keystone species as their consumption of sea urchins, preventing the destruction of kelp forests caused by the sea urchin population. Kelp forests are a critical habitat for many species in nearshore ecosystems. In the absence of sea otters, sea urchins feed on the nearshore kelp forests, thereby disrupting these nearshore ecosystems. However, when sea otters are present, their consumption of sea urchins restricts the sea urchin population to smaller organisms confined to protective crevices. Thus, the sea otter protects the kelp forests by reducing the local sea urchin population.

Large Mammalian Predators

While small predators are important keystone species in many ecosystems, as mentioned above, large mammalian predators are also considered keystone species in larger ecosystems. For example, the lion, jaguar (shown below), and gray wolf are considered keystone species as they help balance large ecosystems (e.g., Central and South American rainforests) by consuming a wide variety of prey species.

Sea Star

Sea stars (shown below) are another commonly recognized keystone species as they consume mussels in areas without natural predators. In many cases, when the sea star is removed from an ecosystem, the population of mussels proliferates uncontrollably, and negatively effects the resources available to other species within the ecosystem.

Credit :  Biology dictionary  

Picture Credit : Google 

Jet streams are bands of strong wind that generally blow from the west to the east across the world. They impact weather, air travel and many other things that take place in our atmosphere. They form when warm air masses meet cold air masses in the atmosphere. The fast-moving air currents in a jet stream can impact the weather system in a region affecting temperature and precipitation. But if a weather system is far away from a jet stream, it might hover over one place, causing heat waves or floods.

What Causes Jet Streams?

Jet streams form when warm air masses meet cold air masses in the atmosphere.

The Sun doesn’t heat the whole Earth evenly. That’s why areas near the equator are hot and areas near the poles are cold.

So when Earth’s warmer air masses meet cooler air masses, the warmer air rises up higher in the atmosphere while cooler air sinks down to replace the warm air. This movement creates an air current, or wind. A jet stream is a type of air current that forms high in the atmosphere.

On average, jet streams move at about 110 miles per hour. But dramatic temperature differences between the warm and cool air masses can cause jet streams to move at much higher speeds — 250 miles per hour or faster. Speeds this high usually happen in polar jet streams in the winter time.

How Do Jet Streams Affect Air Travel?

Jet streams are located about five to nine miles above Earth’s surface in the mid to upper troposphere — the layer of Earth’s atmosphere where we live and breathe.

Airplanes also fly in the mid to upper troposphere. So, if an airplane flies in a powerful jet stream and they are traveling in the same direction, the airplane can get a boost. That’s why an airplane flying a route from west to east can generally make the trip faster than an airplane traveling the same route east to west.

How Do Jet Streams Affect Weather?

The fast-moving air currents in a jet stream can transport weather systems across the United States, affecting temperature and precipitation. However, if a weather system is far away from a jet stream, it might stay in one place, causing heat waves or floods.

Earth’s four primary jet streams only travel from west to east. Jet streams typically move storms and other weather systems from west to east. However, jet streams can move in different ways, creating bulges of winds to the north and south.

How Does the Jet Stream Help Us Predict the Weather?

Weather satellites, such as the Geostationary Operational Environmental Satellites-R Series (GOES-R), use infrared radiation to detect water vapor in the atmosphere. With this technology, meteorologists can detect the location of the jet streams.

Monitoring jet streams can help meteorologists determine where weather systems will move next. But jet streams are also a bit unpredictable. Their paths can change, taking storms in unexpected directions. So satellites like GOES-16 can give up-to-the-minute reports on where those jet streams are in the atmosphere — and where weather systems might be moving next.

Credit : Science jinks 

Picture Credit : Google