My Science School

It's inevitable that often its climate change that makes global headlines. For years, experts have been cautioning us about the impending doom of our planet if we do not mend our ways. Among the suggestions to save Earth is the expansion of green cover. But studies point to the fact that simply expanding green cover alone may not really rescue us from the dire situation we find ourselves in. Here's why. It is an established fact that forests take in large quantities of carbon dioxide from the atmosphere. So it would make sense to increase such areas to tackle the growing carbon dioxide content in the atmosphere. But it is important to note that due to global warming, there are increasing instances of wildfires and drought globally, killing off several trees. Such trees, dying in large numbers, are adding to the carbon in the atmosphere.

Further, it is assumed that more carbon dioxide for a tree translates to greater growth due to photosynthesis. However, a study has shown that rather than photosynthesis it's the cell division that drives the growth of trees. And this process is severely affected by climate change impact such as drought.

Such studies appear to point to the fact that rather than only trying to increase forest areas for carbon offset, it is perhaps more urgent, pertinent, and wiser to protect what exists already. This calls for cutting down on emissions. thus bringing down instances of forests being lost to wildfires, drought, and tree-attacking insects that thrive in a warmer world.

Picture Credit : Google 

A dip in the waters in the Hirsholm islets off the northern shores of Denmark is like diving into a giant aquarium. Amidst the dazzling colours of its vibrant marine life, tiny bubbles from the seabed soar to the surface like clear blobs. The unique phenomenon is caused by the presence of methane gas. The gas was probably formed due to the microbial decomposition of plants deposited thousands of years ago under the sea. As the gas seeped up through funnels in the floor, chemical reaction with underwater microbes hardened the sand particles into sandstone structures. Water currents washed away the surrounding loose sand, leaving behind solid stone columns, arches and slabs, which became thriving hubs of plant and animal life. The methane constantly bubbles out through vents in these columns, resembling air bubbles in a fish tank. The site is an important centre of marine biology.

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A type of algae, kelp is crucial for thriving ecosystems the world over. However, kelp forests are shrinking. But, why? Let's find out

Most types of seaweed or marine algae grow along the coasts in shallow waters, where they can attach themselves to rocks, shells, or the sea floor. A root-like part called holdfast anchors them firmly and prevents them being washed away by strong waves or currents. A soft, flexible stem-like frond with outgrowths similar to leaves emerges from the holdfast. Though they carry out photosynthesis, algae are not plants as they don't have true roots, stems, leaves, or flowers. Marine algae can be green, brown, or red in colour. Red algae are delicate and feathery and prefer warm tropical seas. Small green algae are found everywhere in shallow waters. Brown algae called giant kelp grow in cool waters at depths ranging from 15 to 40 mt.

Extraordinary ecosystem

A kelp forest is one of the most valuable and productive: ecosystems on Earth. Kelp forests are found all over the world-the west coasts of North and South America, the southern tip of Africa and Australia, and off islands near Antarctica. In North America, kelp forests are found on the Pacific Coast from Alaska to California. A forest of kelp is home to a variety of creatures. They live and forage for food among its broad blades. The kelp provides shelter not only from predators. but also from storms. Mammals and birds that thrive in kelp forests include seals, sea lions, whales, sea otters, gulls, terms, egrets, and herons. Sea otters have an especially beneficial bond with kelp. Mother otters wrap their babies in kelp to keep them from drifting away while they go hunting. Adult otters also find the dense kelp canopies a secure place to snooze. The otters return the favour by eating sea urchins that dine on kelp. Kelp forests can shoot up in no time, growing up to 30 cm a day. Some species attain heights of over 45 mt!

Kelp farming is a big part of the billion-dollar global seaweed-farming industry. Kelp renders sea water less acidic. This enables kelp farmers to raise shellfish, which require low acidity. Kelp and mussels are grown on floating ropes, which also support baskets of scallops and oysters. One kelp farm can produce 40 metric tonnes of kelp and a million shellfish per hectare per year! As with other species of seaweed, kelp is used in many products,) including shampoos and toothpastes, as well as a wide range of foods such as salad dressings, puddings, cakes, dairy products, and ice cream. It is also employed in pharmaceuticals and in the manufacture of fireproof and waterproof textiles.

Urchin attack

The waters off the coast of northern California are home to lush forests of bull kelp. Since 2013, the population of purple sea urchins that feast on the kelp, has exploded, destroying almost 90 % of the kelp forest. Sea stars prey on purple urchins and keep their numbers in check. However, a mysterious disease killed off huge numbers of sea stars, leaving sea urchins to thrive. Sea snails (called red abalone) and red sea urchins, both of which are raised for meat and feed on bull kelp, died from starvation. Commercial red sea urchin and red abalone fisheries located on America's northwestern coast have closed down as a result.

Fact file

• Kelp forests are the ocean's lungs just as trees are the Earth's lungs. They absorb carbon dioxide and give out oxygen.

• Warming seas along the Australian coast have wiped out huge swathes of kelp forest.

•Extremely hot weather is harmful to kelp forests. Strong storms can wipe out large areas by uprooting the plants from the sea floor.

• There are 18 species of edible kelp, including kombu widely used in Japanese cuisine.

•Kelp is rich in calcium and Vitamin K.

Picture Credit : Google 

An unplanned, uncontrolled fire that burns in a natural area such as a forest, grassland, or prairie, wildfires can happen anywhere at any time. Likely caused by human activity or natural phenomenon like lightning, it is not known as to how over half of the recorded wildfires began. Even though wildfires keep the ecosystem healthy and are even essential for the continued survival of certain plant species, they also simultaneously impact weather and climate by releasing large amounts of carbon dioxide, carbon monoxide, and fine particulate matter into the atmosphere.

Wildfires can burn in vegetation located both in and above the soil. Ground fires typically ignite in soil thick with organic matter that can feed the flames, like plant roots. Ground fires can smolder for a long time—even an entire season—until conditions are right for them to grow to a surface or crown fire. Surface fires, on the other hand, burn in dead or dry vegetation that is lying or growing just above the ground. Parched grass or fallen leaves often fuel surface fires. Crown fires burn in the leaves and canopies of trees and shrubs.

Some regions, like the mixed conifer forests of California’s Sierra Nevada mountain range, can be affected by different types of wildfires. Sierra Nevada forest fires often include both crown and surface spots.

Wildfires can start with a natural occurrence—such as a lightning strike—or a human-made spark. However, it is often the weather conditions that determine how much a wildfire grows. Wind, high temperatures, and little rainfall can all leave trees, shrubs, fallen leaves, and limbs dried out and primed to fuel a fire. Topography plays a big part too: flames burn uphill faster than they burn downhill.

Wildfires that burn near communities can become dangerous and even deadly if they grow out of control. For example, the 2018 Camp Fire in Butte County, California destroyed almost the entire town of Paradise; in total, 86 people died.

Still, wildfires are essential to the continued survival of some plant species. For example, some tree cones need to be heated before they open and release their seeds; chaparral plants, which include manzanita, chamise (Adenostoma fasciculatum), and scrub oak (Quercus berberidifolia), require fire before seeds will germinate. The leaves of these plants include a flammable resin that feeds fire, helping the plants to propagate. Plants such as these depend on wildfires in order to pass through a regular life cycle. Some plants require fire every few years, while others require fire just a few times a century for the species to continue.

Wildfires also help keep ecosystems healthy. They can kill insects and diseases that harm trees. By clearing scrub and underbrush, fires can make way for new grasses, herbs, and shrubs that provide food and habitat for animals and birds. At a low intensity, flames can clean up debris and underbrush on the forest floor, add nutrients to the soil, and open up space to let sunlight through to the ground. That sunlight can nourish smaller plants and give larger trees room to grow and flourish.

While many plants and animals need and benefit from wildfires, climate change has left some ecosystems more susceptible to flames, especially in the southwest United States. Warmer temperatures have intensified drought and dried out forests. The historic practice of putting out all fires also has caused an unnatural buildup of shrubs and debris, which can fuel larger and more intense blazes.

Credit : National geographic 

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An area of land that is either covered by water or saturated with water, wetlands are those areas where water covers the soil. While most scientists consider swamps, bogs, and marshes to be the three main kinds of wetlands, there are other types like peatlands, sloughs, and mires as well. Even though wetlands were seen as wastelands for most of history as they don't support development, it has since been realised that these are among the most valuable ecosystems on Earth. Governments began recognising the value of wetlands from the 1970s and laws have been put in place in parts of the world to protect wetlands.

Categories of Wetlands

Wetlands vary widely because of regional and local differences in soils, topography, climate, hydrology, water chemistry, vegetation and other factors, including human disturbance. Indeed, wetlands are found from the tundra to the tropics and on every continent except Antarctica. Two general categories of wetlands are recognized: coastal or tidal wetlands and inland or non-tidal wetlands.

Coastal/Tidal Wetlands

Coastal/tidal wetlands in the United States, as their name suggests, are found along the Atlantic, Pacific, Alaskan and Gulf coasts. They are closely linked to our nation's estuaries where sea water mixes with fresh water to form an environment of varying salinities. The salt water and the fluctuating water levels (due to tidal action) combine to create a rather difficult environment for most plants. Consequently, many shallow coastal areas are unvegetated mud flats or sand flats. Some plants, however, have successfully adapted to this environment. Certain grasses and grasslike plants that adapt to the saline conditions form the tidal salt marshes that are found along the Atlantic, Gulf, and Pacific coasts. Mangrove swamps, with salt-loving shrubs or trees, are common in tropical climates, such as in southern Florida and Puerto Rico. Some tidal freshwater wetlands form beyond the upper edges of tidal salt marshes where the influence of salt water ends.

Inland/Non-tidal Wetlands

Inland/non-tidal wetlands are most common on floodplains along rivers and streams (riparian wetlands), in isolated depressions surrounded by dry land (for example, playas, basins and "potholes"), along the margins of lakes and ponds, and in other low-lying areas where the groundwater intercepts the soil surface or where precipitation sufficiently saturates the soil (vernal pools and bogs). Inland wetlands include marshes and wet meadows dominated by herbaceous plants, swamps dominated by shrubs, and wooded swamps dominated by trees. Certain types of inland wetlands are common to particular regions of the country. 

Many of these wetlands are seasonal (they are dry one or more seasons every year), and, particularly in the arid and semiarid West, may be wet only periodically. The quantity of water present and the timing of its presence in part determine the functions of a wetland and its role in the environment. Even wetlands that appear dry at times for significant parts of the year -- such as vernal pools-- often provide critical habitat for wildlife adapted to breeding exclusively in these areas.

Credit : EPA 

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Waste management corresponds to the process of managing unwanted waste items. This includes collection, transport, processing or waste treatment, recycling, and disposal. Mainly done for waste produced by human activities, it started off in an effort to reduce their effect on human health or local aesthetics, but now addresses their effect on the natural world and environment at large as well. Wastes can be generated domestically, industrially, agriculturally, and commercially, among others, and its management can involve solid, liquid, or gaseous substances with different methods for each.

The aim of waste management is to reduce the dangerous effects of such waste on the environment and human health. A big part of waste management deals with municipal solid waste, which is created by industrial, commercial, and household activity.

Waste management practices are not uniform among countries (developed and developing nations); regions (urban and rural areas), and residential and industrial sectors can all take different approaches.

Proper management of waste is important for building sustainable and liveable cities, but it remains a challenge for many developing countries and cities. A report found that effective waste management is relatively expensive, usually comprising 20%–50% of municipal budgets. Operating this essential municipal service requires integrated systems that are efficient, sustainable, and socially supported. A large portion of waste management practices deal with municipal solid waste (MSW) which is the bulk of the waste that is created by household, industrial, and commercial activity. According to the Intergovernmental Panel on Climate Change (IPCC), municipal solid waste is expected to reach approximately 3.4 Gt by 2050; however, policies and lawmaking can reduce the amount of waste produced in different areas and cities of the world.[8] Measures of waste management include measures for integrated techno-economic mechanisms of a circular economy, effective disposal facilities, export and import control and optimal sustainable design of products that are produced.

In the first systematic review of the scientific evidence around global waste, its management and its impact on human health and life, authors concluded that about a fourth of all the municipal solid terrestrial waste is not collected and an additional fourth is mismanaged after collection, often being burned in open and uncontrolled fires – or close to one billion tons per year when combined. They also found that broad priority areas each lack a "high-quality research base", partly due to the absence of "substantial research funding", which motivated scientists often require. Electronic waste (ewaste) includes discarded computer monitors, motherboards, mobile phones and chargers, compact discs (CDs), headphones, television sets, air conditioners and refrigerators. According to the Global E-waste Monitor 2017, India generates ~ 2 million tonnes (Mte) of e-waste annually and ranks fifth among the e-waste producing countries, after the US, P.R. China, Japan and Germany.

Credit :  Wikipedia 

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