I’m the head of marine education and conservation at DIVEIndia, headquartered at Andaman Islands. I have a masters degree in wildlife biology and conservation. Apart from marine life, I’ve also studied Draco lizards and amphibians. I’ve assisted evolutionary biologist Dr. V.V Robin where I studied the evolution of song in shortwings, a Western Ghats mountain specialist bird. My current work revolves around connecting people with the ocean by educating them about the marine ecosystem. Ask me anything!


Chetana is here to answer all your questions. Here are some examples to get you started!

  • Ask her about her typical day as a researcher, educator, and conservationist.
  • Stuff related to the marine ecosystem.
  • Stuff about her research work in wildlife.

Don’t spam or bump. Have a great session!

Discussion

55 Comments
    • Chetana Purushotham
      Chetana Purushotham

      Well. Are there animals that could hurt humans in the ocean ? Yes quite a few. Are they ‘dangerous’? That’s subject to where humans put themselves with respect the animals and what they are trying to do.

      Marine animals are super chill πŸ™‚

      Look up stonefish, lionfish, scorpionfish, blue ringed octopus, sting ray. Beautiful, brilliantly evolved venomous animals.

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    I want to know why life originally was present in water then slowly evolved so that it can survive on land?

    • Chetana Purushotham
      Chetana Purushotham

      Hi Lohith. That’s a great first question to ask. Like most evolutionary events from the past, we can only propose theories based on available fossil clues, genetics, dating methods and knowledge of current animals and plants. When life first began, land wasn’t as inhabitable. To answer your question of β€˜why’. It is most likely that it happened out of chance. Marine animals often jump out of water for various reasons. At some point predecessors of land animals were able to see in air, and not just in water. By this time, land was also perhaps inhabitable. Slowly these animals evolved adaptations to live life on land. Hope this answers your question. πŸ™‚

    • Chetana Purushotham
      Chetana Purushotham

      You may have read in your books that ocean used to be an organic soup. That’s true. Remember life starts at the microbe level. Not just fish and mammals. The change started there.

  • Mango Education

    So here is one from our curated list, Chetana.

    The marine ecosystem is diverse, and honestly, the deepest part of the ocean is wild and mysterious just like the outer space. As a marine biologist, how do you look at it? What’s the deepest you have explored?

    • Chetana Purushotham
      Chetana Purushotham

      The truth is that despite all the marine exploration that has been taking place overall the past few decades. We have barely explored 5% of it. This includes deep, shallow and open ocean water exploration.

      Countries continue to fund space explorations significantly, which is great but the amount of money dedicated to ocean exploration is not a patch on that!

      The deepest I have to is 30 meters.

      There is life to be seen every where. Starting from ankle deep sea water at edge of the beach!

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    I’m Nithin. 13 years old. I have read about a jellyfish that can return to it’s polyp stage after reaching maturity. Is it true?

    • Chetana Purushotham
      Chetana Purushotham

      Hi Nithin! Jelly fish reproduction is really fascinating. It is possible that a jellyfish in their medusa stage go through or bud off into a polyp stage again. And continue the cycle from there again. This is definitely not a generic statement for all jellies but there are a couple of species.

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    Prateeksha

    It is told that coral reefs are destroyed… How can we stop it from destroying?? And why is it destroyed??

    • Chetana Purushotham
      Chetana Purushotham

      This is a fascinating discussion in its self and one that you can thoroughly research on from here. To know what is happening and what you can so about it. I will try to be as comprehensive as possible.

      Coral reefs are built by animals called coral. They are relatives of jellies. They need a optimum temperature range to survive.

      Due to climate change, the atmosphere has been heating up at a steady pace. The ocean is a major absorber of atmospheric heat, just like forests. In the past 20 years due to global warming, the oceans have at regular points become hot enough that corals across the world could feel it and went through β€˜coral bleaching’. By the end of which corals die.
      When corals die, the reef fish and other animals are immediately affected.

      Reefs can recover when left alone. But have we left them alone ?
      No! We are in India alone, severely overfishing, polluting, ocean mining, cutting forests, among many other Stressful factors.

      The main thing you can do where ever you are for the ocean is reduce yours, your families and friends carbon footprint every single day. 😊

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        I have taken a coral reef out of sea , when I went to Thailand. My parent said it is a living thing. But I couldn’t find the difference between living and dead one. How can I find?

            • Chetana Purushotham
              Chetana Purushotham

              It is most likely dead. If it is alive it will be brightly coloured from the zooxanthelle living in them. Nevertheless my recommendation is to never remove any thing from the oceans to take with you. Alive or dead. For instance corals and shells eventually crush and breakdown to give us the White sandy beaches we love to visit. Also picking up corals and many species of shells is illegal in India. You could go to jail!

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    Nitin Surya

    Hi mam, I am Nitin Surya 12 year old I want to know how electricity is produced by electric eel.

    • Chetana Purushotham
      Chetana Purushotham

      Hi! I would genuinely recommend going on YouTube and checking out the exact physical and chemical reaction behind how the electric eel produces electricity. There are some great videos that demonstrate the reactions. But in a gist, they have specific organs, around 3 located lower down in the body. That has specific tissues that use sodium channels to create differences in polarity for electricity to be generated. It also has a neural network that links the brain to this process whenever it sees prey and wants to catch it!

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    This is Shayana, 9 years old.. I heard box jellyfish contains venom?? Is it true?? If it stings the venom, how many person could it kill??

    • Chetana Purushotham
      Chetana Purushotham

      Hi! Yes the box jellies have some of the most potent venom in the natural world. Some species have enough venom to theoretically kill 50 odd full grown humans.
      But these statistics in my opinion are not very useful and paint a very unnecessary picture of these animals.

      Yes the box jellies have a lot of venom. But why? What is venom.it is nothing but a mix of proteins produced by the animals using a lot of its energy.It’s their way of catching prey and staying clear of predators. They are not out to get humans.

      It is quite cool to see how box jellies produce their venom and how they deliver it to their prey.

      In terms of human safety. We know very well which places have box jellies, there will be signage. So take notice and stay away. πŸ™‚

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    Hello mam ,I’m Iniyan 13 yr old…what kind of human threat do the marine animals encounter?

    • Chetana Purushotham
      Chetana Purushotham

      This question can end up having a long answer.

      Let me try to keep it concise.

      Humans have been dependent on the sea, interacting with it for centuries. We need the ocean to travel, we get our food, recreation, climate control, coastline protection, carbon and heat sink.. 50% OF THE AIR WE ALL ARE BREATHING RIGHT NOW.
      What has changed now is that we are doing everything at very damaging scales.

      Bottom trawling fishing to catch fish has emptied India’s oceans almost. That’s how we get most of our seafood. Did you know?

      Climate change included coral bleaching and ocean acidification.

      Deforestation resulting in pollution

      Fishing out animals for live animal aquarium trade, sea shells to keep in our homes in the cupboards among other things.

      More recently, India has begun mining for minerals in the ocean.

      We use cargo ships to dump our garbage out at sea where we think it won’t find us again!
      The worst being plastic.

      These and many more that are happening all at the same time.

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    Sharvesh

    I am Sharvesh and I am 12 yrs old.How do animals survive in the deepest part of the ocean where there is very less penetration of sunlight?

    • Chetana Purushotham
      Chetana Purushotham

      Awesome question. And please read further after this discussion. You are right that light is absent at depth and animals are literally living in pitch darkness. In fact it starts to get quite dim at about 50-60 meters, imagine 100-1000s of meters.

      The key is adaptation!

      Some animals produce their own light like the deep sea anglerfish. Some use smells, electro receptionand vibrations instead and forget about light altogether. Like many sharks.

      Others have eye adaptations, like barrel shaped upward facing eyes to get alteast a little bit of light. Check the barrel eye

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    Hai mam, I’m SHREYAS and I’m 13 yrs old. When you are at work, what kind of challenges do you face every day?

    • Chetana Purushotham
      Chetana Purushotham

      Great question! I would encourage you to read further about this. The colour of the water has a lot to with the bottom substrate of the sea floor and suspended particles in the water.

      For instance Andaman sea floor is largely made of calcium based sand.. From old crushed coral, shells etc. And there is relatively less suspended matter in the water. Less particles, less organic matter and so more light goes through and isn’t reflected back by the particles.

      In Chennai, the sand has more silica.. Means it’s from the land, and more nutrient rich suspended particle matter.

      This is a naturally occurring difference πŸ™‚ there is still a lot to see in Chennai beaches. Just look closely

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    Saramati

    I am Saramati aged 9 years from Chennai.. Are there marine reptiles? If yes, can you name few of them..

    • Chetana Purushotham
      Chetana Purushotham

      After I dived for the first time I fell in love with the ocean. And I wanted to show it to as many people as I could. It is truly one of the most extraordinary place so on this planet. ❀️

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    I am Sarita, 13 years old….can you tell me about zooanthellae… It is somewhat related to coral bleaching….I wanted to know how it affects corals…

    • Chetana Purushotham
      Chetana Purushotham

      Nice question!

      Zooxanthelle are single cell algae that live in symbiosis with corals. Corals give them shelter and zoox produce and give up to 90% of the food to corals. Each coral tissue will have millions of these single cell plants. It’s the main reasons corals are able to grow so far and wide.

      Coral bleaching is when the coral expels the zooxanthelle out of stress because of increased temperature.

      The corals without zooxanthelle look white. You see Only the corals calcium skeletons which are white.

    • Chetana Purushotham
      Chetana Purushotham

      It is actually exhaling! Through its blow hole. But because of the temperature difference, any water vapour around will condense to form a spray. Many air breathing marine mammals will have a blow hole like dolphins as well.

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    Hello, It is Lohith again.What is the reason for the concentration of marine life in coral reefs?

    • Chetana Purushotham
      Chetana Purushotham

      Great question πŸ™‚ because of corals and the complex ecosystem they initiate. Also coral reefs generally tend to be shallow and close to shore where there are more nutrients available. Shallow water has more light and so in general there is higher productivity.

      But this statement may not be valid much longer because we are starting to find that deep seas are also extremely Rich and diverse. It’s just that we haven’t gotten a chance to explore it much.

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    Can zooxanthellae survive without the help of corals or is it a disadvantage for them when they are expelled by corals?

    • Chetana Purushotham
      Chetana Purushotham

      That’s the general understanding so far. They could be surviving as free algae in the plankton floating in the water but they are more likely going to get eaten. Corals maybe providing better protection.

    • Chetana Purushotham
      Chetana Purushotham

      Do watch Chasing Coral on Netflix. It’s a must. And will answer a lot of your questions. πŸ™‚

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    I have another question, don’t the cnidoblasts produce by coelenterates affect complex life systems?

    The cnidoblasts are used by the coelentrates are for paralyzing it’s prey. So can it paralyze highly developed organisms like sharks or whale ?

    • Chetana Purushotham
      Chetana Purushotham

      Ahh like that. Over all Ceolentratesnot really. Venomous jellies like the box, perhaps with smaller creatures.

      Corals and hydroids can burn if you accidentally brush past them. So please also never touch coral or anything else underwater even if a professional is say it’s OK. It’s not being respectful!

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    Scientists labelled gerrothorax as a prehistoric amphibian. How did they know about it with only the bones…

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