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Subject: Environment

  • Species in news: Band-tail Scorpionfish

    A rare band-tail scorpionfish was recently found in the Gulf of Mannar.

    A stand-alone species being mentioned in the news for the first time (and that too from Southern India) find their way into the prelims. Make special note here. Usually, note the species and its habitat location (IUCN status if available), in the purview of a generic prelims question.

    Band-tail scorpionfish

    • The band-tail scorpionfish (Scorpaenospsis neglecta) camouflages within the seagrass meadows.
    • It is well-known for its stinging venomous spines and ability to change colour.
    • The fish has the ability to change colour and blend with its surrounding environment to escape from predators and while preying.
    • The fish is called ‘scorpionfish’ because its spines contain neurotoxic venom.

  • Expansion of the Amery Ice Shelf

     

    There would be a 24% increase in the expansion of the Amery Ice Shelf (AIS) boundaries in Antarctica by 2021 and another 24 per cent by 2026 from its 2016 positions, the National Centre for Polar and Ocean Research (NCPOR) in Goa has predicted.

    Practice question for mains:

    Q. Discuss the interrelation between Cryosphere and Climate change in context to the melting ice shelves in the Antarctic region.

    Amery Ice Shelf (AIS)

    • The Amery Ice Shelf is a broad ice shelf in Antarctica at the head of Prydz Bay between the Lars Christensen Coast and Ingrid Christensen Coast.
    • It is part of Mac. Robertson Land.
    • The name “Cape Amery” was applied to a coastal angle mapped on February 11, 1931.
    • The AIS is one of the largest glacier drainage basins in the world, located on the east coast of Antarctica, at about 70ºS Latitude, 70ºE Longitude.
    • The AIS dynamics and mass balance help in understanding the changes in the global climate scenario.

    Significance of the study

    • NCPOR observations revealed a critical cooling of the sea surface temperature, resulting in an advancement of the ice shelf by 88 per cent in the past 15 years.
    • These changes would contribute in a major way to climate variability.
    • The study clearly demonstrated the future dynamism of ocean heat fluctuation and Antarctic Amery ice shelf mass shifting-extent.

    Back2Basics: Ice Shelves

    • The floating sheets of ice called ‘ice shelves’ play a multi-faceted role in maintaining the stability of a glacier. Ice shelves connect a glacier to the landmass.
    • The ice sheet mass balance, sea stratification, and bottom water formation are important parameters for the balancing of a glacier. Latent and sensible heat processes do play important roles here.
    • The insulation of ice shelves from atmospheric forcing is dependent on a temperature gradient that the ocean cavity beneath the ice shelves provides.
    • It is the pressure exerted by the ice shelves upon the ocean cavity that determines this temperature gradient.

  • Species in news: Amaltas or Indian Laburnum

    The Amaltas or Indian laburnum has begun blooming this summer.

    Try this PYQ from CSP 2018:

    Q. Why is a plant called Prosopis juliflora often mentioned in news?

    (a) Its extract is widely used in cosmetics.

    (b) It tends to reduce the biodiversity in the area in which it grows

    (c) Its extract is used in the pesticides.

    (d) None of the above

    Amaltas Tree

    • The Amaltas (Cassia fistula linn), native to South-East Asia is one of the most widespread trees in India and South-East Asia, with their presence both in cities as well as in moist and dry forests.
    • It has drooping clusters of bright fragrant yellow flowers with five petals and characteristic cylindrical fruits.
    • The Amaltas is known by so many names — Indian Laburnum, Golden Shower, Purging Fistula, Pudding-pipe tree, Girmala, Rajbrikh, Alash, Kiar, Kirwara, Ali — showing us how common and loved it is.
    • It is both the national tree and the national flower of Thailand and is also the state flower of Kerala.

    Features of Amaltas

    • This middle-sized deciduous tree is leafless only for a brief time, between March and May.
    • The new leaves are glossy, a trait that they lose on maturing, and are mostly bright green, though sometimes a rich copper too.
    • It flowers from April to June, partly alongside the emergence of new leaves, but it’s not uncommon to find the Amaltas in flower as late as September.
    • The bark is yellowish at first, slowly coarsens with age and turning dark grey.

    Significance

    • The tree is mostly known to be ornamental and few know of its benefits as a medicinal plant, and one that’s loved by some mammals, bees, and butterflies.
    • The bark is used to make dye and the pulp in the fruit pod also serves as a strong purgative agent, which also helps animals that feed on it.
    • A medicinal preparation with the roots of the tree is used to cure leprosy and skin diseases and the leaves are used to get rid ulcers, in traditional medicine.

  • Species in news: Asian Koel

    Asian Koel, the state bird of Puducherry, is now breeding across Delhi-NCR.

    For such species, related question, always focus on their habitat, endemic area, IUCN/Wildlife Protection Acr status.

    Another caution: Imp birds in the news that are almost “Least Concerned” eg. Amur Falcon (Nagaland), Asian Koel

    Asian Koel

    IUCN status: Least Concerned

    • The Asian Koel (Eudynamys scolopaceus) is a member of the cuckoo order of birds, the Cuculiformes.
    • It is found in the Indian Subcontinent, China, and Southeast Asia.
    • It forms a superspecies with the closely related black-billed koels, Indian cuckoos, and Pacific koels which are sometimes treated as subspecies.
    • The Asian Koel like many of its related cuckoo kin is a brood parasite that lays its eggs in the nests of crows and other hosts, who raise its young.

    Key Features

    • Sexual dimorphism is evident, where males are a glossy black with a greenish sheen to their bodies and females are brown with white dots on their wings and heavy streaking on their head and throat.
    • Both sexes have strong long greenish bills and captivating ruby-red eyes.
    • In the bird world, the males are generally more pleasant looking than the females, considering they woo females.

  • Heatwaves and its unusualness this year

    For the past five days, Rajasthan, Delhi, Uttar Pradesh, Madhya Pradesh, and Maharashtra have been experiencing severe to very severe heatwave conditions. Here is why this summer is slightly unusual.

    Heatwaves being more frequent phenomena, the UPSC may end up asking a prelim as well as mains question about it.  It may ask Q. What are heat waves and how are they classified? What are the external factors on which it is depended?

    A MCQ may be a statement based question mentioning the criteria for declaring a heatwave.

    What is a heatwave and when is it declared?

    Heatwaves occur over India between March and June.

    • IMD declares a heatwave event when the maximum (day) temperature for a location in the plains crosses 40 degrees Celsius.
    • Over the hills, the threshold temperature is 30 degrees Celsius.

    Following criteria are used to declare heatwave:

    To declare heatwave, the below criteria should be met at least in 2 stations in a Meteorological subdivision for at least two consecutive days and it will be declared on the second day.

    a) Based on Departure from Normal

    • Heat Wave: Departure from normal is 4.5°C to 6.4°C
    • Severe Heat Wave: Departure from normal is >6.4°C

    b) Based on Actual Maximum Temperature (for plains only)

    • Heat Wave: When actual maximum temperature ≥ 45°C
    • Severe Heat Wave: When actual maximum temperature ≥47°C

    How long can a heatwave spell last?

    • A heatwave spell generally lasts for a minimum of four days. On some occasions, it can extend up to seven or ten days.
    • The longest recorded heatwave spell, in recent years, was between 18 – 31 May 2015.
    • This spell had severely affected parts of West Bengal along with Odisha, Andhra Pradesh, and Telangana.
    • Heatwave conditions occurring in May have been observed to last longer, as the season reaches its peak this month.
    • Whereas those reported in June often die down sooner, often due to the onset of Southwest monsoon over the location or in its neighbourhood.

    Does all of India experience heatwave conditions?

    • Heatwaves are common over the Core Heatwave Zone (CHZ) — Rajasthan, Punjab, Haryana, Chandigarh, Delhi, West Madhya Pradesh, Uttar Pradesh, Chhattisgarh, Orissa, Vidarbha in Maharashtra.
    • The CHZ also includes parts of Gangetic West Bengal, Coastal Andhra Pradesh and Telangana, as categorised by IMD.
    • Several recent studies indicate that CHZ experience more than six heatwave days per year during these four months.
    • Many places in the northwest and cities along southeastern coast report eight heatwave days per season.
    • However, the regions in the extreme north, northeast and southwestern India are lesser prone to heatwaves.

    Whats’ so unusual this year?

    • Summer season reaches its peak by May 15 in India when the day temperatures across north, west, and central India cross 40 degrees and hover close to 45 degrees then on.
    • This year, north India did not experience such temperatures till May 21.
    • It was mainly because of the continuous inflow of Western Disturbances that influenced the weather in the north till as late as April.
    • Since last winter, there was frequent passing of Western Disturbances over the north, appearing after every five to seven days.

    What are these Western Disturbances?

    • Originating in the Mediterranean Sea, Western Disturbances are eastward-moving winds that blow in lower atmospheric levels.
    • They affect the local weather of a region during its onward journey.
    • Between January and March this year, there were about 20 Western Disturbances, a record of sorts.
    • When Western Disturbances interact with weather systems heading from the two southern seas, that is, warm winds blowing in from the Bay of Bengal or the Arabian Sea, they cause snowfall or rainfall over the north.
    • A significant influence of Western Disturbances is experienced from December to February. However, this year, its influence persisted until early May.
    • The recent Western Disturbances got support from easterly winds blowing over from the Bay of Bengal.

    Has cyclone Amphan influenced the current heatwave?

    • Since the event of severe heat has emerged immediately after the passing of Cyclone Amphan, experts confirm its role in leading to the present heatwave spell.
    • Cyclone Amphan, which was a massive Super Storm covering 700 km, managed to drag maximum moisture from over the Bay of Bengal to entire Peninsula.
    • All the moisture that was otherwise built during the thunderstorm and rainfall got gradually depleted from over vast areas as the storm advanced towards West Bengal and Bangladesh between May 16 and 20.
    • It has now triggered dry north-westerly winds to blow over Rajasthan, Madhya Pradesh, Uttar Pradesh and Maharashtra causing severe heatwave.

  • Specie in news: Charru mussel (Mytella strigata)

    An invasive mussel native to the South and Central American coasts is spreading quickly in the backwaters of Kerala.

    Try this PYQ from CSP 2018:

    Q. Why is a plant called Prosopis juliflora often mentioned in news?

    (a) Its extract is widely used in cosmetics.

    (b) It tends to reduce the biodiversity in the area in which it grows

    (c) Its extract is used in the pesticides.

    (d) None of the above

    Charru mussel

    • The rapid spread of the Charru mussel (Mytella strigata) may have been triggered by Cyclone Ockhi which struck the region in 2017.
    • With a population as high as 11,384 per sq metre here, it has replaced the Asian green mussel (Perna Viridis) and the edible oyster Magallana bilineata (known locally as muringa).
    • Externally, the Charru mussel resembles the green and brown mussels (kallummekka in Malayalam) but is much smaller in size. Its colour varies from black to brown, purple or dark green.
    • Surveys show the presence of the Charru mussel in the Kadinamkulam, Paravur, Edava-Nadayara, Ashtamudi, Kayamkulam, Vembanad, Chettuva and Ponnani estuaries/backwaters.
    • Ashtamudi Lake, a Ramsar site in Kollam district, remains the worst-hit.

    Threats posed

    • Though this smaller mussel is edible, the overall economic loss and impact on biodiversity are much bigger, it is pointed out.
    • It is throwing out other mussel and clam species and threatening the livelihoods of fishermen engaged in shrimp fisheries.

  • Species in news: Dugong

    The dugong, commonly known as the sea cow, is fighting for its survival in Indian waters experts have said on the eve of ‘World Dugong Day’ on May 28, 2020.

    Try this question from CSP 2015:

    Q) With reference to ‘dugong’, a mammal found in India, which of the following statements is/are correct?

    1) It is a herbivorous marine animal.

    2) It is found along the entire coast of India

    3) It is given legal protection under Schedule 1 of the Wildlife (Protection) Act, 1972.

    Select the correct answer using the code given below.
    (a) 1 and 2
    (b) 2 only
    (c) 1 and 3
    (d) 3 only

    Dugong

    • Dugongs are mammals, which means they give birth to live young and then produce milk and nurse them.
    • It is the flagship animal of Gulf of Mannar Marine National Park.
    • Once the female is pregnant, she will carry the unborn baby, called a foetus for 12-14 months before giving birth.
    • Female dugongs give birth underwater to a single calf at three to seven-year intervals.
    • Dugongs graze on seagrass, especially young shoots and roots in shallow coastal waters. They can consume up to 40 kilograms of seagrass in a day.
    • Dugongs are an IUCN Endangered marine species like sea turtles, seahorses, sea cucumbers and others.
    • They are protected in India under Schedule I of the Wild (Life) Protection Act, 1972.

    Threats to dugongs

    • Human activities such as the destruction and modification of habitat, pollution, rampant illegal fishing activities, vessel strikes, unsustainable hunting or poaching and unplanned tourism are the main threats to dugongs.
    • The loss of seagrass beds due to ocean floor trawling was the most important factor behind dwindling dugong populations in many parts of the world.

    Why needs urgent attention?

    • There were just 250 dugongs in the Gulf of Mannar in Tamil Nadu, the Andaman and Nicobar Islands and the Gulf of Kutch in Gujarat according to the 2013 survey report of the Zoological Survey of India (ZSI).
    • Hundreds of dugongs inhabited waters off the Odisha, West Bengal and Andhra Pradesh coasts two centuries back. But they are extinct in these areas now, he added.
    • Seagrass in Odisha’s Chilika Lake is a proper habitat for dugongs. However, there is not an extant population in Chilika.

    Other facts:

    • The 13th CoP of the Convention on the Conservation of Migratory Species of Wild Animals (CMS), an environmental treaty under the aegis of the UNEP, was hosted by India this year at Gandhinagar in Gujarat.
    • India is a signatory to the CMS since 1983.
    • India has signed non-legally binding Memorandums of Understanding with CMS on the conservation and management of Siberian Cranes (1998), Marine Turtles (2007), Dugongs (2008) and Raptors (2016).
    • Proper conservation is the only way to save dugongs from extinction. Conservation in other places like Australia has seen their population crossing 85,000.

  • What is South Atlantic Anomaly?

    New data obtained by the European Space Agency (ESA) Swarm satellites has revealed the existence of a mysterious anomaly weakening the Earth’s magnetic field. Termed as ‘South Atlantic Anomaly’, it extends all the way from South America to southwest Africa.

    The term ‘South Atlantic Anomaly’ at its first sight looks similar to any climate/oceanic current related phenomena. But it’s not! This is where you can end up losing 2.66 marks in the prelims!

    What is South Atlantic Anomaly (SAA)?

    • The SAA is referred to the behaviour of Earth’s Geo-Magnetic field in an area between Africa and South America.
    • The SAA is an area where the Earth’s inner Van Allen radiation belt comes closest to the Earth’s surface, dipping down to an altitude of 200 kilometres.
    • This leads to an increased flux of energetic particles in this region and exposes orbiting satellites to higher-than-usual levels of radiation.
    • The effect is caused by the non-concentricity of the Earth and its magnetic dipole.
    • The SAA is the near-Earth region where the Earth’s magnetic field is weakest relative to an idealized Earth-centered dipole field.

    Weakening of the magnetic field

    • Over the last 200 years, the magnetic field has lost around 9% of its strength on a global average.
    • A large and rapid shrink has been observed in the SAA region over the past 50 years just as the area itself has grown and moved westward.
    • The weakening of the magnetic field is also causing technical difficulties for the satellites and spacecraft orbiting the planet.
    • The study conducted between 1970 and 2020, said that the magnetic field weakened considerably in a large region stretching from Africa to South America, known as the ‘SAA’.
    • This area has grown and moved westward at a rate of around 20 km per year.

    Its impact

    • The magnetic shield has an important role to play in keeping unwanted radiation away as well as helping determine the location of magnetic poles.
    • Even though unlike global warming or any weather change, this anomaly doesn’t directly impact human lives, it could actually bring on a change in the way we access technology.
    • The reversal and apparent shift, which could keep extending could actually impact satellite and telecommunication system, which means that some of the internet and mobile phone functioning which depend on satellite signals can possibly get disrupted.
    • It could also affect the mapping and navigation systems in smartphones.
    • The weakening of earth’s magnetic field could also impact migratory movement.
    • Birds, animals- all those who migrate with the change in season depend on the earth’s mapping to move about can find it a little difficult.
    • This is only a possibility, but we don’t know the extent of the damage till now.

    About the Van Allen Radiation Belt

    • A Van Allen radiation belt is a zone of energetic charged particles, most of which originate from the solar wind, that are captured by and held around a planet by that planet’s magnetic field.
    • The belts are located in the inner region of Earth’s magnetosphere. The belts trap energetic electrons and protons.
    • Earth has two such belts and sometimes others may be temporarily created.
    • Most of the particles that form the belts are thought to come from solar wind and other particles by cosmic rays.
    • By trapping the solar wind, the magnetic field deflects those energetic particles and protects the atmosphere from destruction.

    Also read:

    https://www.civilsdaily.com/news/shifting-north-magnetic-pole-forces-urgent-navigation-fix/

    Back2Basics: Swarm  Constellation

    • Swarm is a European Space Agency (ESA) mission to study the Earth’s magnetic field.
    • It is ESA’s first constellation of satellites for Earth observation.
    • The Swarm constellation consists of three satellites (Alpha, Bravo and Charlie) placed in two different polar orbits, two flying side by side at an altitude of 450 km and a third at an altitude of 530 km.

  • Species in news: Cicadas

    A brood of periodical cicadas, noisy insects that breed underground for as long as 13-17 years are expected to emerge into some states of the US this year.

    A stand-alone species being mentioned in the news for the first time may find their way into the prelims. Make special note here.

    What are Cicadas?

    • Cicadas are insects that spend most of their lives underground and emerge from the soil mainly to mate.
    • Once out of the ground, their life span is fairly short, somewhere between two-four weeks.
    • At present, there are about 15 active broods of these cicadas as some have gone extinct.
    • The insects are found in America’s as well as New Zealand and Australia.
    • The name 13 and 17 year refers to the number of years that cicada nymphs take to reach adulthood.
    • It is not clear why their development period is so long, researchers suspect that it may be linked to avoiding predators above the soil.

    How are the fed?

    • During this time underground the nymphs feed on sap from plant roots.
    • After this developmental period, the cicada nymphs construct a “cicada hut” and burrow their way out from the soil and climb onto any nearby tree or vegetation.

  • Species in news: Puntius Sanctus fish

    Velankanni in Tamil Nadu has thrown up a new species of small freshwater fish.

    Last year one species from our newscard: Species in news: Hump-backed Mahseer made it into the CSP 2019.  The ‘Puntius Sanctus’ fish in the newscard creates such a vibe yet again.

    A stand-alone species being mentioned in the news for the first time (and that too from Southern India) find their way into the prelims. Make special note here.

    Q. Consider the following pairs

    Wildlife Naturally found in
    1. Blue-finned Mahseer Cauvery River
    2. Irrawaddy Dolphin Chambal River
    3. Rusty-spotted Cat Eastern Ghats

    Which of the pairs given correctly matched? (CSP 2019)

    (a) 1 and 2 only

    (b) 2 and 3 only

    (c) 1 and 3 only

    (d) 1, 2 and 3

    Puntius Sanctus

    • The silver-hued fish has been named Puntius Sanctus — ‘Sanctus’ is Latin for holy — after the popular pilgrim town.
    • Encountered in a small waterbody in Venlankanni, Puntius Sanctus is small, it grows to a length of 7 cm.
    • It found to use both as food and as an aquarium draw.
    • “The Puntius species are known locally as ‘Paral’ in Kerala and ‘Kende’ in Tamil Nadu.