Category Ecology

WHAT IS THE ROCK CYCLE?

Rocks are continually being recycled to make new rocks in a process called the rock cycle. For example, igneous rocks are gradually worn away by the weather. The weathered fragments are washed down to the sea and eventually form sedimentary rocks. Similarly, metamorphic rocks can be formed from both igneous and sedimentary rocks.

The rock components of the crust are slowly but constantly being changed from one form to another and the processes involved are summarized in the rock cycle. The rock cycle is driven by two forces: (1) Earth’s internal heat engine, which moves material around in the core and the mantle and leads to slow but significant changes within the crust, and (2) the hydrological cycle, which is the movement of water, ice, and air at the surface, and is powered by the sun.

The rock cycle is still active on Earth because our core is hot enough to keep the mantle moving, our atmosphere is relatively thick, and we have liquid water. On some other planets or their satellites, such as the Moon, the rock cycle is virtually dead because the core is no longer hot enough to drive mantle convection and there is no atmosphere or liquid water.

Magma is rock that is hot to the point of being entirely molten. This happens at between about 800° and 1300°C, depending on the composition and the pressure, onto the surface and cool quickly (within seconds to years) — forming extrusive igneous rock.

Magma can either cool slowly within the crust (over centuries to millions of years) — forming intrusive igneous rock, or erupt onto the surface and cool quickly (within seconds to years) — forming extrusive igneous rock. Intrusive igneous rock typically crystallizes at depths of hundreds of metres to tens of kilometres below the surface. To change its position in the rock cycle, intrusive igneous rock has to be uplifted and exposed by the erosion of the overlying rocks.

Through the various plate-tectonics-related processes of mountain building, all types of rocks are uplifted and exposed at the surface. Once exposed, they are weathered, both physically (by mechanical breaking of the rock) and chemically (by weathering of the minerals), and the weathering products — mostly small rock and mineral fragments — are eroded, transported, and then deposited as sediments. Transportation and deposition occur through the action of glaciers, streams, waves, wind, and other agents, and sediments are deposited in rivers, lakes, deserts, and the ocean.

Unless they are re-eroded and moved along, sediments will eventually be buried by more sediments. At depths of hundreds of metres or more, they become compressed and cemented into sedimentary rock. Again through various means, largely resulting from plate-tectonic forces, different kinds of rocks are either uplifted, to be re-eroded, or buried deeper within the crust where they are heated up, squeezed, and changed into metamorphic rock.

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HOW MANY TYPES OF ROCKS ARE THERE?

There are three kinds of rocks: igneous, sedimentary and metamorphic. Igneous rocks are formed when red-hot magma flows up from Earth’s hot core and cools down. Sedimentary rocks form when debris, including plant and organic matter, usually deposited on the seabed in layers, is built up, compressed and cemented into solid rock over millions of years. Metamorphic rocks are created when movements of Earth’s crust or the heat of its magma transforms one kind of rock into another.

Rocks are mineral aggregates with a combination of properties of all the mineral traces. Any unique combination of chemical composition, mineralogy, grain size, texture, or other distinguishing characteristics can describe rock types. Additionally, different classification systems exist for each major type of rock. There are different types of rocks existing in nature.

Rocks which are found in nature rarely show such simple characteristics and usually exhibit some variation in the set of properties as the measurement scale changes.

Types of Rocks

There are three types of rocks:

Igneous Rock

Igneous rock is one of the three main rock types. Igneous rock is formed through the cooling and solidification of magma or lava. Igneous rock may form with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks.

Sedimentary Rock

The sedimentary rocks are formed by the deposition and subsequent cementation of that material within bodies of water and at the surface of the earth. The process that causes various organic materials and minerals to settle in a place is termed as sedimentation.

Metamorphic Rocks

The metamorphic rocks make up a large part of the Earth’s crust and are classified by texture and by chemical and mineral assemblage. They may be formed simply by being deep beneath the Earth’s surface, subjected to high temperatures and the great pressure of the rock layers above it.

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Does deserts ‘breathe’ water vapor?

Deserts are arid ecosystems, receiving fewer than 25 cm of precipitation a year. They are hot dry and deserted. But the sand dunes aren’t just inert masses. They, in fact. “breathe” water vapor and are very much alive. Scientists have developed a super-sensitive probe that has recorded how water vapor from the surrounding air percolate between sand grains.

Researchers at Cornell University, New York, and University of Nantes, France, developed over a decade a new form of instrumentation called capacitance probes. to study the moisture content in sand dunes to better understand the process by which agricultural lands turn to desert. The probe uses multiple sensors to record everything from solid concentration to velocity to water content, all with unprecedented spatial resolution. It is so sensitive to moisture that it can pick up tiny films of water on a single grain of sand!

Conducting the research at Qatar, they combined data on wind speed and direction as well as ambient temperature and humidity. The study revealed just how porous sand is, with a tiny amount of air seeping through it.

When wind flows over the dune, it creates imbalances in the local pressure. This forces air to go into and out of the sand. “So, the sand is breathing, like an organism breathes,” the researchers note. This breathing could be the reason behind how microbes live deep in sand dunes, even when no liquid water is available. The researchers also found that at the surface of the dune, the probe measured less evaporation than scientists were predicting. This shows that the leaching of moisture from the sand dune to the atmosphere is a slow chemical process.

The team’s paper has been published in the Journal of Geophysical Research-Earth Surface. Probes that can sensitively measure moisture within sand could help experts find invisible signs of water, say, on Mars.

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Six environmental issues and how to solve them?

Earth has undergone many environmental changes in its history. But the current ones are being caused by one species: humans. Our activities contribute to global warming, climate change, extreme weather events, species extinction, resource depletion, and what not. Let’s take a closer look at six of them to mark Earth Day, observed on April 22.

1. POLLUTION

Since the industrial revolution, environmental pollution has been on the rise. Pollution is the introduction of harmful contaminants into the environment that negatively alters our surroundings. While pollution can take several forms, such as light and noise, the three major types are air, land, and water pollution. Humans contribute to each of these every day. Pollution affects biodiversity, ecosystems, and human health worldwide. Air pollution is attributed to 11.65% of deaths globally, for instance. Vehicular and industrial emission, and basically, our dependence on fossil fuel for energy, is the chief cause of air pollution. While water pollution comes from sewage, chemicals, agricultural runoffs, etc. land pollution is caused by indiscriminate dumping of garbage, toxic materials, and industrial waste. Not to mention the harm caused by plastic pollution to marine and terrestrial life. As economies and population grow, pollution too increases at an alarming rate globally.

 2.GLACIER MELT AND SEA-LEVEL RISE

Nineteen of the warmest years in the recorded history of the planet has occurred since 2000. Models predict that as the world consumes more fossil fuel, greenhouse gas concentrations will continue to rise, and Earth’s average surface temperature will rise with them. Average surface temperatures could rise between 2°C and 6°C by the end of the 21st Century. A warmer atmosphere causes glaciers and polar ice sheets to melt rapidly. Glacial melt has a direct impact on freshwater flow because glaciers store water in the form of ice during the colder seasons and release it during warmer seasons by way of melting. This serves as a water source for humans, animals, and vegetation. Glacier melt also contributes to unusual rise in sea level. The impact of sea-level rise includes flooding of coastal areas, increased soil erosion, disappearance of some low-lying islands, saltwater intrusion, and habitat destruction in coastal areas, which, in turn, can affect coastal ecosystems.

What can you do?

A few tips on how we can reduce our impact on global warming: 1. Urge your parents to switch to renewable sources such as solar to power your home.

2. Use energy-efficient appliances at home and school

3. Support local businesses that use and promote sustainable, climate-smart practices

3. DEFORESTATION

Deforestation is the destruction of forests in order to make the land available for other uses. Earth loses 18.7 million acres of forests per year, which is equal to 27 football fields every minute, according to the World Wildlife Fund. Farmers clear forests to use the land for agriculture. Trees are cut for mining. for use as fuel. housing, and urbanisation, contruction of dams and infrastructual projects, and for making furniture. Deforestation is considered to be one of the contributing factors to global warming and climate change. Trees absorb not only the carbon dioxide that we exhale, but also the other heat-trapping greenhouse gases that human activities emit. With increase in deforestation, larger amounts of these gases will enter the atmosphere and global warming will increase further. As much as 70 % of the world’s plants and animals live in forests. They are losing their habitats due to deforestation. Loss of habitat can lead to species extinction.

What can you do?

1. Plant saplings

2. Go paperless

3. Go for used-furniture instead of buying new ones every time.

4.WATER CRISIS

If global temperatures continue to rise, rainfall will increasingly become a thing of extremes: long dry spells here. dangerous floods there and in some places, intense water shortages. This will also affect agriculture. Worldwide, farmers are struggling to keep up with shifting weather patterns and increasingly unpredictable water supplies. Extreme weather patterns also destroy life, property. and livelihood. The rapid increase in population and the massive growth in the industrial sector have increased the demand for water multifold. Overexploitation and wastage of water are major issues, especially in urban areas. A UN report says that at least two billion people live in countries with high water stress. That is more than a quarter of the world population. Ecosystems and biodiversity are threatened by the scarcity of water resources. Water crisis can also lead conflict between States that share water sources such as river.

What can you do?

1. Do not waste water

2. Fix leaking tap and try to reuse water wherever possible

3. Urge your parents to install rainwater harvesting facility

4. Don’t pollute water: Do not dump household solid waste or oil and chemicals into the drainage system. Do not litter. They are likely to end up in a waterbody.

5.WILDFIRE

As warmer temperatures increase evaporation, the land becomes drier and drier, enhancing the chances of wildfires. The intense, destructive fires that have dominated headlines in recent years are expected to become more frequent, even in places such as the Arctic. Extreme fires are projected to rise up to 14% by 2030 and 30% by mid-century, according to a new report by the UN Environment Programme.

Wildfires not only destroy forests and cause loss of life, they emit large amounts of greenhouse gases such as CO2, methane, and carbon monoxide. The smoke from burning vegetation can pose serious risks to respiratory health. Animals are directly impacted by wildfire. They lose their life or their home and food source.

What can you do?

1. Build your campfire in an open location and far from flammables

2. Do not contribute to global warming

3. Avoid burning wastes around dry grass.

6. WILDLIFE TRADE

Wildlife trade is a big business, run by international networks. Animals and birds are trafficked across the globe for meat, skin, bone, fur, and other body parts. In addition, many species are sold as pets. Experts at TRAFFIC, the wildlife trade monitoring network, estimate that the illegal wildlife commerce runs into billions of dollars. Wildlife trafficking threatens the survival of some of the Earth’s most iconic species: tiger, elephant, rhinoceros, pangolin, etc. It affects food chain and threatens the local ecosystem. Wildlife trade also increases the chances of human-animal contact, putting humans at the risk of contracting diseases. COVID-19 was linked to wildlife trade and eating of wildlife. People who handled, killed, and sold wild animals made up nearly 40 % of the first cases of SARS. Poorly regulated wet markets and illegal wildlife trade offer a unique opportunity for viruses to spill over from wildlife hosts into the human population.

What can you do?

1. Create awareness among the public about wildlife trade.

2. Say no to exotic pets. They may have been trafficked and kept in unsafe conditions before being sold.

3. Avoid buying things made from ivory, horns, and leather. This discourages illegal trading.

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