[Environment] Krill-Food chain,Non Native Species, Nisargruna Biogas

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Unacademy Plus Mrunal Economy for Prelims and Mains UPSC!

In this article, we’ll examine certain key topics that are important for Environment-Biodiversity section in civil service exam.

  1. Krill and food chain
  2. Hydrocarbon-eating bugs
  3. Adipic acid: Nylon
  4. Rhino horn powder
  5. Non-native/Invasive species: Asian Ladybug
  6. New Sperm Freezing method
  7. Pollution related
    1. Nisargruna biogas technology
    2. Biodegradable electronic devices
  8. Agro related
    1. Senescence in fruits
    2. Why Water=Transparent?
    3. Sapota
    4. Rice blast
    5. Chawki
    6. PSTOL1
  9. Disasters
    1. Mt Tongariro
    2. L’Aquila quake
    3. Climate change and Rainfall

Krill and food chain

  • The whale is not a fish but a mammal
  • Krill= Shrimp-like planktonic creatures = they’re favorite food of whale.
  • Krill eat  phytoplankton, which are microscopic plants that live near the surface of oceans and lakes.
  • Phytoplankton are mainly one-celled organisms and are autotrophic.


  • autotrophic= they depend on the sun for the energy they need to produce their food.
  • Thus microscopic phytoplankton are very important to all living organisms in the sea.
  • The blue whale feeds throughout the summer on krill that are abundant in the cold,  polar water of both the northern and southern hemisphere.
  • In the late fall, the blue whale migrates on the warmer waters of the tropics where the water is warmer.
  • There are no krill in tropical areas of the ocean so the blue whale must live off its blubber for the entire time it spends there. (Blubber  = fat stored in Whale body)
  • When there is oil-spill, it reduces the planktonic creature and thus affects the whole food chain.

Hydrocarbon-eating bugs

  • In early 2012, there was an oil spill in Gulf of Mexico- from British Petroleum’s Deepwater Horizon rig.
  • Scientists found growing population of carbon-eating bacteria about six miles from the leak. (oceanospirillale)
  • Each time the scientists got back to the laboratory to test the sea-water samples, the bugs had already eaten all the oil in them.

Adipic acid: Nylon

  • Adipic acid is produced from fossil fuel, and the pollution released from the refinement process contributes significantly to global warming
  • Adipic acid is required for nylon production.
  • Now scientists have came up with process to produce eco-friendly adipic acid.
  • They’ll convert cheap sugars into adipic acid, instead of using fossile fuel.

Rhino horn powder

  • Rich and affluent people in Vietnam, are using Rhino horn power to spice up their alcoholic drink in parties. (miracle cure for cancer, AIDS..you get the idea, just like tiger bones)
  • Because of this demand, more and more rhinos are hunted in Africa.
  • Vietnamese government, is accused of not taking the crisis seriously, despite pressure from the Convention on International Trade in Endangered Species (Cites).
  • Vietnam is the only country in the world where rhino horn grinding bowls are mass produced. It shows that Vietnamese Government is not serious in cracking this illegal business.

Non-native/Invasive species: Asian Ladybug

  • Aphids= plant sucking insect.
  • Asian ladybug= these were introduced into Europe and USA  to combat aphids problem.
  • But these Asian ladybugs are displacing the native European ladybugs. (Because Asian Ladybugs eats aphids as well as European ladybygs.) and thus,  its population exploded, now infesting the buildings.
  • Thus  Asian ladybug = a threat to native species and biodiversity in Europe and America.
Asian Ladybug

Asian Ladybug

New Sperm Freezing method

  • Previously, elephant breeders could only use a limited number of elephant bulls living in zoos, as semen could not be frozen and had to be used within twelve hours. But scientists have now solved this problem using the new sperm freezing method.
  • This new freezing method could also be used with other endangered species like rhinoceros and gorilla

Nisargruna biogas technology

  • developed by the Mumbai-based Bhabha Atomic Research Centre (BARC).
  • This technology can produce more methan and organic manure from biowaste (compared to the conventional gobar gas plant)
  • This methane enriched biogas can be used directly for heating (instead of LPG) or for generating electricity.

Biodegradable electronic devices

  • electronic devices such as integrated circuits, chips and tools etc. when discarded, they are called e-waste.
  • It is estimated that e-waste alone accounts for over 70 per cent of toxic wastes currently found in landfills
  • we use electronic devices such as pacemakers and other sensors that are implanted in our bodies. The trouble with them is that once they are past their use, we need to surgically remove them (and perhaps implant a fresh one). How nice it would be if only they dissolve away and get removed from the body; much the way we discard our body liquids and solids every day!
  • Scientists are now working on such biodegradable electronic devices.

Agro related

Senescence in fruits

  • The non-greening of leaves is called senescence.
  • ripening in fruits also involves chlorophyll loss and an increase in production of yellow, orange, red or purple pigments.

Why Water=Transparent?

  • Light is a form of an electromagnetic energy with a wide range of wavelengths.
  • If a material absorbs all the visible range of light, then it ‘looks’ black to us because there is hardly any visible light left from the object to reach our eyes.
  • If a material does not absorb any part of the visible range of light, then the object either appears colourlessly transparent
  • Water has molecules that do not have the kind of electrons which absorb any portion of the visible range (but have electrons that absorb only in the invisible ultraviolet range) of light
  • That is why water appears transparent. Several other liquids, such as benzene, alcohol, chloroform, coconut oil, etc also look transparent for this reason.


  • Tropical fruit plant. (chikoo)
  • Grown widely in India for its fruit and milky latex which is the source of chicle used to make chewing gum.

Rice blast

is a fungal infestation known to occur in all the rice growing areas of the county. The disease attacks all the parts of the crop growing above the soil.


  • refers to young silk worms reared from hatching to second moult stage. The quality of these worms forms the crux of successful silkworm rearing.
  • If the chawki worms are not reared properly, the later stages will result in crop losses.
Chawki Rearing Nisargruna Biogas

Chawki Rearing


  • It is a gene that helps the rice plants to grow in phosphorus-deficient soil.
  • The absence of PSTOL1 from modern rice varieties underlines the importance of conserving and exploring traditional rice varieties.


Mt Tongariro

Volcano erupted here, in New Zealand

L’Aquila quake

  • Occurred in Italy, in 2009.
  • The scientists of Italy’s top disaster body had failed to predict it accurately.
  • Now Italian court sentenced them to jail.
  • This has outraged the international science community

Climate change and Rainfall

  • With every 1 degree Celsius rise in temperature, tropical regions will see 10 per cent heavier rainfall extremes, with possible impacts for flooding in populous regions


The Hindu S&T section, Sept-Oct 2012

Indian History Freedom Struggle Pratik Nayak

31 Comments on “[Environment] Krill-Food chain,Non Native Species, Nisargruna Biogas”


  2. Addicted to this blog… Refreshing the page whole day for new articles..

    Thanks a lot Mrunal…

  3. hi mrunal…….

    this ques relates to exam strategy section…


    isnt it important frm exam point of view………kindly help as many seniors have suggested about it as extremely important as well……

    thanks n all the best for ur preprations……..

  4. thanks

  5. Thanks a lot for maintaining such an incredibly informative website, Mrunal. You’re helping a lot of people.

    I like your new format but I am not sure how to download this page as PDF. Whenever I click on the ‘Print/PDF’ button at the top, it only gives a print option. Could you explain how to do it please?


    1. Okay, nevermind. Got it in the old format back again. Thanks anyway. :)

    2. I think there was some glitch.
      I’ve reset the settings.
      please try again (using Chrome browser).

  6. Hello Sir(Our benefactor),

    @Culture/Ancient/Medieval Part of History :

    Facing Problem in remembering the facts??
    ( most of the time its create confusions ) :(

    any way(guidance) to tackle this?

    i assume that many aspirants too facing the same problem..

    Thanks in Advance!!

  7. nisar runa bogas tech:This plant can process biodegradable waste such as kitchen waste, paper, grass, gobar and dry leaves. It offers �Zero garbage and Zero effluent� and provides high quality manure and methane gas. Weedfree manure obtained from such waste has high nitrogen contents and acts as an excellent soil conditioner. This plant could be set up for ecofriendly disposal of wet-waste generated in kitchens/canteens of big Hospitals/Hotels/Factories/residential complexes and can avoid health hazards due to dump sites. This technology of biphasic biomethanation has high potential of solving the solid waste management problems of the urban areas and provides organic manure and bio-gas as a fuel.

  8. hi mrunal…..
    whr’s the monyhly archieve tab has gone……
    wht should i do to sezrch an article of say june….or some other month…..

    kindly guide me…….

    if anyone other than mrunal knws……he/she too can help…

    thnx in advance…

    1. thanks for reminding. I’ve fixed it, look at the left side bottom corner.

  9. hello sir,
    I am doing job 9 to 7 am how can I prepare for the exam.

  10. Thanks sir for such a great works

  11. nice collection….thank u sir!!!!!!

  12. Thanks …rightly said by Jayanth, i m also getting addicted to this blog..

  13. Keep this noble work going on, Mrunal Ji.

  14. hi mrunal….
    i have little doubt with the answe or water being transparent…..ans mentioned is right but does not differentiate b/w white and colorless….if any body does not absorb any visible wavelength than it may be white as it reflect all the color….body looks transparent when it allows photon to pass through it insted of reflecting it back as white body does….

  15. hi mrunal….
    I am a NIFT (Gandhinagar grad)….

    i have little doubt with the answer of water being transparent…..ans mentioned is right but does not differentiate b/w white and colorless….if any body does not absorb any visible wavelength than it may be white as it reflect all the color….body looks transparent only when it allows photon to pass through it insted of reflecting it back as white body does….

  16. hi Murnal ,is any drawback of hydrocarbon -eating bugs?

  17. Just to add few more point for Adipic Acid from MCQ viewpoint:-
    1. mild skin irritant
    2. white crystalline powder
    3. Adipic acid otherwise rarely occurs in nature
    4. Small but significant amounts of adipic acid are used as a food ingredient as a flavorant and gelling aid
    5. Adipic acid has medicinal properties for both weakly basic and weakly acidic drugs.

  18. hello mrunal…i have a question
    biogas contains methane, and when it burns it produces carbon dioxide, then how is biogas eco-friendly in anyway? please clarify….

    1. Methane is 21 times more potent as a Greenhouse gas than is Carbon dioxide. Therefore Carbon dioxide released on burning Methane is less a threat to the environment than Methane itself.
      Now a question could arise- why is then a need of producing biogas, as it contains more harmful Methane gas?
      The answer lies in the fact that organic matter if left to decompose naturally (without biogas plant) produces Nitrogen dioxide and Methane. Nitrogen dioxide warms the atmosphere 310 times more than Carbon dioxide and Methane 21 more than Carbon dioxide. So its wise enough to process organic waste in biogas plants as it not only eliminates the threat from more harmful Nitrogen dioxide but would also give less harmful Methane (less harmful than Nitrogen dioxide) that could be used to generate electricity. Also the gases released through open/ natural decomposition of organic matter is difficult to trap.

      1. thanks for the answer…any further reference to read more on this??

        1. Google it out!

  19. hey shashank
    basically biogas comprises of methane ,co2 but it uses them as fuel so lowering d greenhouse gases
    also hygiene condntns improved
    convert natural gas into fertilizer = more efficient n eco friendly den pesticides
    replace wood kerosene typo fuels
    less diseases as pollution content came down
    correct me if m wrong

  20. CH4[g] + 2 O2[g] -> CO2[g] + 2 H2O[l] + 891 kJ

    so while burning methane we get water as a bi-product. does’nt this water hinders the flame??

    1. Due to this 891 KJ of energy produced (as a result of combustion of methane)the water molecules are evaporated.
      But the more important point is water is not efficient to put off fire except in case of combustion of few ordinary substances. Reason is- water tries to put the flame off by absorbing heat from the combustible substance thereby lowering its temperature. But when the combustible substance involved is a gas (methane) or a liquid (petrol) the heat produce is so large that water couldn’t lower the temperature. This is the reason for using fire-extinguishers that make use of carbon dioxide or nitrogen to put off the fire. These substances (carbon dioxide and nitrogen) cut off the supply of oxygen to the combustible substance (i.e. gas or liquid).

  21. Thanks mrunal … & special thanks to kapil… for sharing.

  22. Much Appreciate this form of Forum Mr. Kunal. Would be interested in gaining more knowledge regularly. would love to have mails from your side which can notify of new updates. Thanks.

    Would like to know more about Nisargruna Bio gas.

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