• Question: Would the ocean be deeper if there were no sponges in it?

    Asked by Ayrton to Ed, Kerrianne, Nina, Oli, yoyehudi on 7 Nov 2017.
    • Photo: Kerrianne Harrington

      Kerrianne Harrington answered on 7 Nov 2017:

      Amazing question 😉

      I don’t think they would make a big difference, but then I’m not sure how much sponge is in the ocean.

    • Photo: anon

      anon answered on 7 Nov 2017:

      This is a great question. Rather than me telling you the answer, I think you should go and do an experiment for yourself. Get a measuring jug of water (to represent the sea) and a sponge (to represent sea sponges), and try adding and removing the sponge. Look at the scale on the jug to see what happens to the volume.

    • Photo: Oli Wilson

      Oli Wilson answered on 8 Nov 2017:

      It would probably be [spoiler deleted – do try and have a go at Theo’s experiment!]. In actual fact, most sponges in the ocean aren’t very absorbent – some are quite hard and glassy, and some can be enormous! The barrel sponge can grow about as wide as I am tall (1.8m), for instance.
      The other thing is that the world’s oceans are so enormous that taking stuff out of them doesn’t make a huge amount of difference to the sea level. Apparently, of you took all the ships on our planet out of the sea (and tidied them away somewhere else..?) the waters would only fall by 0.0006cm, about the thickness of a strand of spider silk. Have a read of the full answer to that question here: https://what-if.xkcd.com/33/

Comments