Plastics have become an insidious presence in our lives – human blood, placentas and breast milk haven't been spared. These fragments, smaller than 5 millimetres, have infiltrated our daily existence– in the clothes we wear, the air we breathe, and yes, the food we eat.

These tiny particles, composed of chemicals, stabilisers, lubricants, fillers, and plasticizers, pose a significant health risk. Laboratory studies have shown that microplastics can damage human cells, causing cell death, allergic responses, and cell wall damage. Some particles are small enough to penetrate human tissues, potentially triggering immune reactions.

A groundbreaking study in early 2024 discovered microplastics in more than 50% of fatty deposits from clogged arteries, establishing a direct link between these particles and human health.

Adults ingest about 900 particles per day, and we defecate about 200 particles per day; the other 700 aren't currently accounted for. The true number can be higher, as only a small number of foods and drinks have been analysed for plastic contamination. 

Two theories explain how microplastics cause cell breakdown: either their sharp edges puncture the cell wall or the chemicals within the microplastics harm the cell.

But how do microplastics enter our food?

In 2022, more than 400 million metric tons of plastic was produced and a significant part of it went into the food and beverage industry for packaging. When exposed to heat, plastic breaks down into smaller fragments - microplastics - which contaminate our food.

Microplastics also enter the food chain through industrial discharge into irrigation water sources. They're absorbed into the human body from cosmetics and synthetic clothes, leached into water sources during laundering, and shed by vehicle tyres. Rain and wind transport these tiny particles into water bodies.  

Even fruits and vegetables absorb microplastics through their roots. These particles spread throughout the plant, reaching seeds, leaves, and fruits, with distribution varying based on particle size.

Health risks

Exposure to microplastics from plastic packaging poses significant health risks such as: 

1. Endocrine disruption: Plastic packaging contains chemicals that mimic hormones in the body, disrupting natural functions and increasing the risk of chronic conditions like infertility and polycystic ovary syndrome.
2. BPA impact: Exposure to BPA, a common plastic additive, can reduce the availability of reproductive hormones like oestrogen and testosterone.
3. Chronic disease risk: Long-term exposure to endocrine-disrupting microplastics raises the risk of type 2 diabetes and heart disease by causing inflammation, insulin resistance, and obesity.
4. Immune system impairment: Microplastic exposure induces inflammation and disrupts gut health, weakening immunity by causing dysbiosis and promoting the growth of harmful bacteria.
5. Bacterial contamination: Microplastic surfaces can harbour harmful bacteria, compounding the negative impact on immune health and increasing susceptibility to infections.

Some common microplastics that are found in the food we consume include: 

• Phthalates: Additives that enhance flexibility, transparency, and durability of plastics, commonly found in food packaging.
• Polyethylene and polypropylene: Lightweight and durable materials used in packaging.
• Bisphenol A (BPA): A plasticizer used in the production of polyvinyl chloride.
• Dioxin: A byproduct of herbicides and paper bleaching.
• Additional microplastics present in food in smaller quantities include BPA, BPF, mono-(3-carboxypropyl), mono-(carboxyisononyl), and mono-(carboxyisoctyl).

Way forward

Though brining the usage of plastics to a complete halt in an instant might not be a very practical option, there are things that one can do to reduce their harmful impacts: 

• Choose whole foods: Opt for whole and minimally processed foods over highly processed ones like hamburgers, ready-to-eat meals, and canned foods to reduce exposure to phthalate microplastics, which are linked to chronic conditions like heart disease, especially in children.
• Eco-friendly packaging: Select sustainable packaging options such as glass storage containers, stainless steel water bottles, and bamboo utensils to minimise exposure to and migration of microplastics in the food supply.
• Avoid plastic water bottles: Reduce exposure to microplastics by switching from plastic water bottles to glass or stainless steel alternatives.

Research conducted by Leiden University in the Netherlands reveals that crops have the capability to absorb nanoplastic particles, which are minute fragments measuring between 1-100 nanometers. These particles, significantly smaller than a human blood cell by about 1,000 to 100 times, are taken in from the surrounding water and soil through tiny fissures in the plant roots.

The majority of these plastics accumulate in the roots of the plants, with only a minute portion migrating upwards to the shoots. Consequently, leafy vegetables like lettuce and cabbage are likely to have relatively low concentrations of plastic, whereas root vegetables such as carrots, radishes, and turnips pose a greater risk of containing microplastics for consumption.

The evidence is clear: governments must acknowledge and address this unwanted emission. Tackling the issue requires a proactive approach combining innovation, policy interventions, and individual actions.

By choosing sustainable alternatives to plastic packaging, investing in research for effective mitigation strategies, and promoting public awareness, we can safeguard human health and environmental integrity. 

In the 1970s, Japanese scientist Akira Miyawaki introduced a way to grow small forests quickly. His method is now used worldwide to turn empty lots and old parking areas into self-sustaining mini-forests.

Miyawaki planted over 40 million trees in more than 15 countries. Now, these tiny forests are growing all over the world, with hundreds in India and thousands in Japan. But as the method gains traction, a pressing question emerges: Is this truly the panacea for urban greening and urban forestry, or are we overlooking crucial ecological nuances?

How it works

Miyawaki grouped Japanese forest plants into four types: main tree species, subspecies, shrubs, and ground-covering herbs.

Here's how the method works:

1. The method begins by improving the soil by analysing the designated forest site to assess its composition and condition.
2. The soil quality is then improved using locally available sustainable materials.
3. Approximately 50 to 100 local plant species are selected and planted in clumps as seedlings to simulate a natural forest
4. Seedlings are densely planted, ranging from 30,000 to 50,000 per hectare, significantly higher than the typical 1,000 per hectare in commercial forestry.
5. The site is monitored, watered, and weeded for two to three years

The forests need maintenance only for the first two to three years. After that, the grove is allowed to develop naturally. The dense planting encourages rapid growth among the seedlings as they compete for sunlight.

A brief history

Born in Okayama Prefecture in 1928, Akira Miyawaki's early research into weeds piqued the interest of German botanist Reinhold Tüxen. This led to the former’s departure for Germany in 1958 to further his studies.

There, Tüxen introduced him to the idea of potential natural vegetation, which became the foundation of Miyawaki's future work. Inspired by this idea, he returned to Japan in 1960 to document the country's native plant life. Despite centuries of human intervention, Miyawaki found reference points in the undisturbed forests surrounding Shinto shrines.

With the backing of Japanese corporations, Miyawaki’s method gained international recognition. In the late 1980s, Mitsubishi Corporation proposed the first project to restore a tropical rainforest in Malaysia, marking the technique’s expansion into Southeast Asia. Miyawaki's in-depth knowledge of the region's vegetation proved invaluable in this endeavour.

Collaborating with multinational companies to apply his method overseas led Miyawaki in 1999 to propose that “quasi-natural forests can be built in 15-20 years in Japan and 40-50 years in Southeast Asia.”

Why the Miyawaki method?

The forests grown in the Miyawaki fashion have several advantages compared to the traditional forests – but only when done right.

Shubhendu Sharma, founder and director of Afforestt, a native forest-planting firm that popularised the Miyawaki method in India, believes that most opposition to Miyawaki is against poorly executed projects. “Properly following the methods would yield results,” he said.

“Finding the native species in a region is a complex process. Many who say they practise ‘Miyawaki’ don’t take it seriously and go to a nearby nursery to identify the local species. Identifying the right species and the combination of plants that can go together is the crux,” he added. 

Benefits include‍ 

1. Rapid forest regeneration: Miyawaki forests grow much faster than traditionally planted forests due to the dense planting of native species, encouraging healthy competition.

2. Low maintenance: Miyawaki forests require minimum maintenance after the initial three years, making them a cost-effective solution in the long run.

3. Environmental benefits

• Captures carbon: Absorb 30 times more carbon than monoculture plantations.
• Air and water purification: Improve air quality by absorbing pollutants and filtering water runoff.
• Biodiversity enhancement: Create habitats for various plant and animal species, promoting biodiversity.
• Soil health: Prevent soil erosion, improve soil health, and increase water retention.

4. Economic benefits

• Ecotourism potential: These forests can be developed into recreational areas and educational centres, generating revenue through ecotourism activities.
• Sustainable forestry: By incorporating native trees with economic value, Miyawaki forests can provide a sustainable source of timber.

5. Social benefits

• Community engagement: Planting and maintaining Miyawaki forests can foster a sense of community ownership and environmental awareness.
• Urban green space: These forests create green spaces in urban areas, improving residents' overall quality of life

Disadvantages

The forestry technique has a fair share of experts and practitioners raising concerns related to the method:

1. Applicability and unintended consequences

• Limited ecological suitability: Many experts question whether the method works across all climates, particularly tropical regions.
• Disrupting existing ecosystems: Planting trees in historically non-forested areas like Kutch, Jaipur, and Hyderabad can disrupt existing plant and animal life adapted to those dry conditions.
• Altered hydrology: Pumping water and nutrients for Miyawaki forests in dry areas can deplete resources needed by native plants and grasses, impacting the region's natural water cycle.
• Introducing non-native species: Often, ecological niches are overlooked, and non-native plants are selected for the Miyawaki technique. This shallow understanding of native species can disrupt established ecological processes and cause unforeseen problems.

2. Resource intensive

• The method requires significant labour, materials, land, and energy, which can be expensive and logistically challenging.

3. Limited ecological benefits and potential drawbacks

• False equivalence to natural forests: Miyawaki forests have limited space, may not reflect the region's true complex ecosystem, and may limit space for wildlife movement compared to natural forests.
• Uncertain impact on rainfall: The actual effect of Miyawaki forests on rainfall is still being determined.
• Focus on timber trees: Prioritising timber trees reduces the natural diversity of tree types within the ‘forest’.

4. Climate concerns and greenwashing

• Fossil fuel reliance: Implementation and maintenance reliant on fossil fuels could negate the carbon benefits of the ‘forest’.
• Some use Miyawaki forests to justify cutting down old-growth forests, which are irreplaceable and have unique ecological value.

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An answer to deforestation?

‍While some laud the technique as a promising solution for areas with land scarcity and heightened air pollution, many argue that dense and impenetrable Miyawaki forests are not ideal for cities.

Many perceive that these patches of ‘forest’ in cities should be welcoming spaces for people and pets, encouraging interaction with nature while preserving local biodiversity. They should be open, inviting, and visually appealing, allowing plants to flourish naturally.  

While creating green spaces in urban areas is the need of the hour, Miyawaki ‘forests’ cannot replace extensive native forests. Efforts must continue to protect and preserve existing forest ecosystems threatened by commercial activities and unsustainable practices.

Carbon is everywhere. It is found in all living things, and life on Earth would not be possible without this unique element. 

Carbon is one of the only elements with four electrons in its outermost shell, except for silicon. This allows it to form strong and stable bonds, which are the building blocks of life. These include hydrocarbons, amino acids and other proteins. As a result, carbon-based compounds move constantly through living organisms, the oceans, the atmosphere, and the Earth's crust. 

Due to its versatile nature, carbon can also drive changes in the atmosphere and tilt the scales of global temperatures, which now the world struggles with as global warming is no longer just a faraway threat.

Scientists say that life has existed on Earth for about 4.5 billion years; our ancestors have been pretty good at handling carbon, at least 99 per cent of the time. Whatever carbon comes out from different organisms and the atmosphere goes right back to the Earth's core. However, slowly carbon has been destabilizing due to excessive burning of fossil fuels and deforestation of large areas around the globe.

CO2 is also released naturally through the decomposition of plants and animals. Carbon dioxide is a very effective greenhouse gas—with the capability to absorb infrared radiation emitted from Earth’s surface. As CO2 concentration rises in the atmosphere, more infrared radiation is retained, and the average temperature of Earth’s lower atmosphere rises.

According to a 10-year research project undertaken by Deep Carbon Observatory (DCO) since 2009, Earth contains 1.85 billion billion tonnes of carbon. Scientists say that if it were all combined into a single sphere, it would be larger than many asteroids.

Most of the carbon is located deep into the Earth's mantle, and only about one per cent of the total is available in the atmosphere. The carbon in the air, land, and ocean amounts to just 43.5 trillion tonnes, which is gradually changing, tipping the geological scales of carbon dioxide (CO2) in the environment in the other direction causing destruction. The National Oceanic and Atmospheric Administration (NOAA), a regulatory agency in the US, reports that Earth's temperature has risen by an average of 0.11° Fahrenheit (0.06° Celsius) per decade since 1850, or about 2° F in total. The rate of warming since 1982 is more than three times as fast: 0.36° F (0.20° C) per decade.

India, a fast-growing economy, has seen a considerable jump in its carbon dioxide numbers. India recently submitted its Third National Communication (TNC) and Initial Adaptation Communication to the United Nations Framework Convention on Climate Change (UNFCCC) in December 2023. A report by the Down to Earth website noted that India’s net national emissions in 2019 stood at 2.6 billion tonnes of carbon dioxide equivalent (CO2e), a 4.56 per cent increase from 2016 levels and a 115 per cent increase since 1994, the TNC report reflected.

What is carbon ‘sequestration’?

In this fight against climate change, the concept of carbon sequestration has emerged as a powerful ally. It could be our savior in mitigating the impacts of greenhouse gas emissions and leaving a greener planet for our coming generations. At its core, carbon sequestration is the process of capturing carbon dioxide (CO2) from the atmosphere and securely storing it away to prevent its release into the atmosphere. This can be achieved through various natural processes or advanced technological solutions.

Breaking down the terminology ‘sequestration’ also means the act of separating and storing a harmful substance such as carbon dioxide in a way that keeps it safe. Britannica, the encyclopedia, notes that CO2 is produced due to excessive anthropogenic (created by humans) activities such as the burning of fossil fuels from its long-term geologic storage –coal, petroleum, and natural gas- and has pushed it into the atmosphere.

Creating ‘carbon sinks’ can help mitigate these challenges. These sinks can be natural or artificial, and they play a vital role in balancing carbon emissions. These sinks will act as reservoirs that can absorb and store CO2, thereby reducing greenhouse gasses.

Natural carbon sinks include forests, oceans, wetlands, grasslands, and soil. These ecosystems capture CO2 through biological processes such as photosynthesis, in which plants and other organisms absorb CO2 from the atmosphere and convert it into organic matter. The carbon is then stored in biomass—such as trees, vegetables, fruits, flowers, and more. It can also be stored in the soil, where it can remain for varying periods, ranging from years to centuries.

How to push CO2 back where it belongs?

With evolving technology, researchers are continuously on the lookout for newer ways to sequester carbon. Currently, there are very two clear distinctions, natural or biological and the other one being artificial sequestering. According to the Intergovernmental Panel on Climate Change (IPCC), improved agricultural practices and forest-related mitigation activities can make a significant contribution to the removal of carbon dioxide from the atmosphere at a relatively low cost. In simple words, growing more tree species that can hold more carbon in the ground can be a starting point—unfortunately, infrastructural development comes in the way. Researchers say we just don’t need a couple of hundred trees but dense forests and grasslands for this to truly be the solution and reduce our carbon footprint.

In the method of Geological Carbon Sequestration or Carbon Capture and Storage (CCS) carbon is separated from other gasses contained in industrial emissions. It is then compressed and transported to a location that is isolated from the atmosphere for long-term storage. It is injected underground into geological formations such as depleted oil and gas reservoirs or saline aquifers, where they can be stored securely for long periods and later used.

A novel technology in the works is Coastal Carbon Capture which aims to remove carbon dioxide from the atmosphere through the deployment of carbon-removing sand, which increases the alkalinity of seawater, which in turn will enhance the capacity of seawater to absorb CO2. Through this, the carbonic acid to bicarbonate and the consequent and subsequent uptake of CO2 from the atmosphere would be increased in seawater.

Crucial to sequester carbon

• One of the top priorities is mitigating climate change. CO2 is a major greenhouse gas responsible for global warming and using different methods can reduce the amount of greenhouse gasses in the atmosphere.

• If we take the natural way such as allowing more forest covers, wetlands, and grasslands to grow, it's a win-win situation. Natural ecosystems will be restored, biodiversity will be conserved, soil erosion will be prevented, water will be purified, and temperatures will automatically drop.

• Instead of depleting our non-renewable resources, the world can adopt sustainable energy and develop technologies that promote the use of energy systems available in abundance.

• To get started, carbon sequestration can be used as a means to ‘offset carbon emissions’-- one compensates for various activities such as cutting forests, transportation, and industrial growth by investing in carbon sequestration projects and reducing carbon footprint.

While solutions are changing every day, climate action is not a one-time effort and needs strong commitment from policymakers that can be applied in a top-to-bottom fashion for a healthier planet.

Here’s a story: you’ve been eating too much junk and soon your clothes start feeling a bit tighter, each step you take down the road makes you puff and pant a little bit more, and finally your doctor reminds you of all the negative impacts these foods might have on your health. You decide to act, stick to a plan to cut down on junk, start cooking on your own, very careful of the calories you’re taking in. Two months down the lane, you see that you are starting to fit back in your clothes.

A story with a happy climax, ain’t it? Well, not so much. 

While switching to veggies, cooking on your own, and keeping a check on the calories you consume are all good, most people tend to overlook some crucial questions: how are these so-called ‘healthy’ vegetables farmed? What are the inputs that are used to cultivate these veggies? And what are the impacts on consuming these ‘healthy’ foods? 

In pursuit of answers to these pressing questions, numerous studies were undertaken. Their discoveries shed light on the presence of heavy metals in food production.

In a study conducted by the Environment Management and Policy Research Institute (EMPRI) by visiting 20 spots including high-end supermarkets, local markets, organic stores, and Hopcoms, it was found that the levels of cadmium, iron, and lead in our veggies are far above the permissible limit. 

In a different study, a group of agriculture scientists from Odisha University of Agriculture and Technology (OUAT), SOA University, and Birsa Agricultural University discovered that rice, pulses, and veggies around Narasinghpur block in Cuttack were packing higher levels of cadmium, lead, mercury, and arsenic than recommended. 

Similar results were also observed in a study by National Environmental Engineering Research Institute (NEERI), which showed that the vegetables sold in Delhi and grown along the Yamuna floodplains had high doses of lead. 

This calls for a deeper understanding of what goes into our foods and how they are farmed.

A study in Bengaluru

For the EMPRI study, the researchers took a close look at 10 veggies including brinjal, tomato, capsicum, etc. to see if they were carrying any heavy metals.

Turns out, some of these veggies were breaking the iron limit, pegged at 425.5 mg/kg. For example, beans from the organic shops had 810.20 mg/kg of iron! Coriander and spinach weren't far behind. Even the onions from Hopcoms had more iron than expected, with 592.18 mg/kg.

And it wasn't just iron causing trouble. Cadmium levels were supposed to be low, like 0.2 mg/kg. But brinjal from a supermarket in BTM Layout in Bengaluru had a whopping 52.30 mg/kg of cadmium! Coriander, spinach, and carrot weren't far off either.

The study also revealed a higher concentration of heavy metals in leafy vegetables. This appears to be linked to the increased transpiration rate of leafy greens. Transpiration is the process by which plants release water vapor through their leaves.

Given that the majority of Bengaluru's vegetables originate from neighboring districts such as Kolar, Chikkaballapur, and Bengaluru Rural, there has been a heightened focus on the project that pumps secondary-treated sewage water to these areas.

When farmers use wastewater, they're inadvertently loading up their crops with heavy metals. It's like the veggies are soaking up all the toxins from that water, leading to higher concentrations of heavy metals. 

The NGT had also registered a suo motu case after news reports came out regarding heavy metal contaminated food in Bengaluru.

Harmful effects

Before we discuss the harmful effects of these heavy metals, let us understand what they are. 

Heavy metals are dense metals with high atomic weights or numbers. They include common elements like iron, copper, gold, and aluminum. While some heavy metals are essential for life, others can be harmful when they enter the environment through industrial activities. 

Cadmium, notorious for its adverse effects on the liver and lungs, can also compromise the immune system. While the body typically eliminates cadmium ingested through food, elevated levels can accumulate in the kidneys, leading to impaired function.

Excessive consumption of lead can result in severe health issues, including neurological damage.

Although iron is essential in moderate amounts, excessive intake can lead to complications such as anemia. Furthermore, high doses of iron may interfere with the absorption of other vital nutrients like zinc and increase the risk of liver cancer and heart disease. 

Prevention strategies

Cleaning vegetables thoroughly with portable water removes external metal contamination. Soaking them in a 2% salt solution and washing again aids in eliminating contaminants. 

Cooking vegetables with ample water helps leach out internal metal traces. Consuming antioxidant-rich fruits and vegetables like gooseberries, oranges, lemons, strawberries, tomatoes, and blueberries counteracts metal contamination effects by reducing free radicals. 

Blanching fruits before juicing and vegetables before adding to salads reduces heavy metal presence. 

And beyond all, knowing more about your food, what goes into cultivating them, where it was cultivated, and switching to trustable organic brands could hold the key to a healthier future.

The latin word “makros” (meaning large) and “nutriens” (to nourish) make up the word macronutrients, and it’s not because the nutrients themselves are large! 

The reason they are called macronutrients, is because they are the nutrients required by our body in high quantities in order to be able to function properly. They perform many functions such as maintaining the body and cell structure, and providing energy.

Today, we’ll talk about macronutrients and why we need them. 

What are they?

Macronutrients are a class of organic compounds that include fats, carbohydrates, and proteins. Even fiber and water are considered to be macronutrients. While they are required in large amounts by our body, they are also required in specific quantities. 

Each macronutrient plays a different role in our body.  Fats are needed for creating cell walls, are an important source of energy, and insulates your body from the outside world. 

Carbohydrates provide fuel for your body, and an estimated 45% to 65% of your energy needs for day-to-day activities come from carbohydrates. However, they can also cause spikes in blood sugar level. 

Proteins are important for tissue structure, making hormones, regulating metabolism and plays a role in the transport system.

So we can see that all of these are important, to the functioning of life itself, and are fundamental to many processes. In fact, all animals and plants have some macronutrient requirements to be able to function properly, though their needs may differ from ours. 

Where can we find them?

We find macronutrients in all food - although it’s important to remember that it can also be present in unhealthy quantities in some foods. Colloquially, we call these “junk” or “unhealthy” foods. Foods such as ice creams and cakes may be high in carbohydrates (in the form of sugars) and fats, while very low in protein, whereas snacks such as chips might contain high amounts of fats and sodium, which affect the heart. 

Fats

Ideally, we should try to get about 20-35% of our daily calories from fats. There are different types of fats, however, such as monounsaturated fats, polyunsaturated fats, saturated fats and trans fats. It is important to do your own research and read more about these topics to stay informed, but in general monounsaturated fats and polyunsaturated fats are considered to be “healthy” fats. Too much saturated and trans fats can cause health issues including but not limited to high cholesterol, which in turn can lead to strokes, heart attacks and vascular dementia.

Some sources of healthy fats are: 

Monounsaturated fats: Olive oil, peanut butter, almonds, cashews, hazelnuts, peanuts and pistachios. 

Polyunsaturated fats: Salmon, mackerel, walnuts, sesame seeds and sunflower seeds.

Carbohydrates

Carbohydrates are sugars, and they are not bad for our health in moderation. They are classified into 4 main groups - monosaccharides, disaccharides, oligosaccharides, and polysaccharides. The classification depends mostly on the structure, as shown in fig.2. 

A lot of staples serve as primary sources of carbohydrates- for example, wheat, rice, corn and all grains. Dairy products are also a good source of carbohydrates. 

Carbohydrates make up the bulk of our calorie intake, and ideally we would hope that around 55% of our energy needs are met by carbohydrates, although this proportion might vary slightly from 40% to 65%. 

Foods rich in carbohydrates in our daily life include breads, pasta, noodles, legumes like dried beans, sugary items such as candy, desserts, cakes, and cookies, as well as starchy vegetables like potatoes, corn, and peas.

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Proteins

Proteins, or amino acids, are one of the fundamental building blocks of life. They make up much of the structural and functional components of the cell, which is why they are found everywhere. While proteins can be found in all living things, they are present in different forms and proportions as to what we need. The general amount of protein in your diet depends, and varies from about 10% to 35%, but in general, is slightly lower than the amount of carbohydrates consumed. There are two general classes of proteins when talking about nutrition, essential amino acids and nonessential amino acids. The main difference is that essential amino acids must be supplied to the body through its diet, since they cannot be made by the body directly. Nonessential amino acids on the other hand, can be made by our body, thus the need for dietary supply is lesser. 

Some examples of foods rich in protein include meats such as poultry (chicken, turkey, duck etc.), fish, dairy, eggs and legumes (lentils, peanuts, peanut butter, green peas, and so on). 

Now that we know what the different macronutrients are, we can think about what we eat on a daily basis by qualifying them into these categories. It is important to note that no food is a superfood - no single source of food will give us all of the different categories of macronutrients, but it is important to maintain a balanced diet and keep in mind that a doctor might be able to help and recommend a specific diet if there are issues. 

While not mentioned explicitly, water and fiber are also important macronutrients, so remember to drink water!

Have you ever wondered about the invisible cycle that sustains life on Earth? It's a delicate dance between the atmosphere, living beings, and the soil beneath our feet. Every breath we take, every tree that sways in the wind, every creature that burrows underground – they're all part of a complex choreography, with carbon as the leading player.

Carbon is sequestered in the soil through biological processes. The sequestration of carbon is a continuous process: plants photosynthesize and capture carbon from the atmosphere, but they also respire – a process almost every living being undergoes, in which carbon dioxide is a byproduct. But what does all this mean? Is carbon sequestering in the soil a good thing or a bad thing?

Carbon is present everywhere on our planet. According to the Deep Carbon Observatory (DCO), the Earth contains about 1.85 billion billion tonnes of carbon, with only 0.02% present in its crust. It's not an infinite resource, and carbon needs to be recycled and stored, much like the water cycle – there is also a carbon cycle. For decades, research has emphasized the importance of soil in agriculture and organic farming, stressing the need to naturally replenish minerals like carbon, nitrogen, and other essential micronutrients. However, this article focuses on the carbon cycle's significance in the soil ecosystem.

Carbon sinks

We all know carbon is essential to life – a major building block in our bodies, forming compounds like proteins, fats, carbohydrates, and energy stores. But how does it move through the environment? We cannot directly extract carbon from the air, so we need sources to trap it – carbon sinks.

A carbon sink absorbs more carbon from the atmosphere than it releases. By this definition, plants, soil, and the ocean are all carbon sinks. The opposite, a carbon source (like cars, planes, and boats burning carbon), releases more carbon into the atmosphere than it absorbs. This isn't necessarily harmful – carbon sources are essential for completing the cycle. However, human activities' scale could lead to drastic changes like global warming and disruption of pre-existing cycles.

When plants and animals die, organisms like fungi break them down and decompose them into their constituent minerals. These varied organisms use processes to break down cells and digest them externally, leaving carbon ready in organic forms to dissolve into the soil (Fig.1).

Carbon cycle

The carbon cycle keeps carbon cycling through the atmosphere. Any living organisms have only "borrowed" from this cycle and will eventually become part of other organisms. Life leads to more life. In the soil context, fossil fuels are essentially carbon (hydrocarbon) reserves that can be utilized as energy stores. They represent carbon stored from organisms that died hundreds of millions of years ago, preserved by being buried in soil or underwater.

More readily available carbon sources for living organisms include wood, grasses and most plants. Since plants are sinks, they store carbon, which gets released into the soil as SOCs (Soil Organic Carbon). Humus – dead and decaying matter – is crucial because it stores carbon and other essential minerals. When these minerals are passed on to cows, humans, and other plants, they break them down and respire, a process that produces carbon dioxide as a byproduct. This atmospheric carbon dioxide is then exhaled into the atmosphere, and the cycle repeats.

But what does it have to do with soil?

According to the Global Forest Resources Assessment 2020, about 45% of carbon in forests is stored mostly in the SOM (Soil Organic Matter) and in living biomass (Fig.2). Only a small fraction is stored in dead wood and litter, meaning it's constantly being used by plants and soil organisms. Plants take in this carbon as SOCs. In agricultural areas, SOCs have been found to be lower than in natural ecosystems, as agriculture leads to the release of 50 to 100 Gigatons of carbon into the atmosphere. This is largely due to decreased plant roots and increased soil erosion. However, studies show that plants growing in higher CO2 concentrations will fix more carbon through photosynthesis, thus producing greater biomass.

Increased atmospheric CO2 also leads to global warming, reducing soil water availability and limiting photosynthesis. The increased temperature also accelerates SOM decomposition, releasing more carbon from the soil into the atmosphere, creating a feedback loop where higher temperatures lead to more SOM decomposition.

Without soil's carbon sequestration, we would have much higher atmospheric CO2 levels, making it vital to protect soil and forests – not just the number of plants and animals, but also their diversity, which plays a role in how much carbon is stored in the soil. When we plant crops, we create a debt.

Soil is vital to our survival. Research shows we can even try using agricultural land as a carbon sink by planting perennial crops with deeper roots that help the soil store more carbon.

Soil can't hold on to carbon indefinitely, but it can keep it for some time in rotation – forests can grow more, develop more niches for plants, and develop whole ecosystems by increasing the amount of trapped biomass.

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