• Question: Why is there sand at the bottem of the sea?

    Asked by georgieuplandsbabz to Clare, Dave, Glo, Ozge, Sean on 16 Jun 2011.
    • Photo: Dave Sproson

      Dave Sproson answered on 15 Jun 2011:

      The two most common chemical elements on the Earth are silicon and oxygen. When you mix these together, you get silicon dioxide (silica) which is exactly what sand is, so you get sand almost everywhere! Some sand though, is also made from ground up bit of calcified sea animals such as corals. I think the beautiful white sandy beaches that you imagine around a tropical island are mostly coral sands!

    • Photo: Sean Clement

      Sean Clement answered on 15 Jun 2011:

      What Dave has tactfully avoided saying is that these coral sands are often broken down into sand by a 3rd party first. They’re broken down by being chewed up and passed through the body of fish such as Parrotfish…

      So, in away, you could say that all those lovely white tropical beaches that you see are all made up of fish poo…

    • Photo: Ozge Ozkaya

      Ozge Ozkaya answered on 15 Jun 2011:

      There is also the rocks that are eroded that become sand eventually

    • Photo: Clare Woulds

      Clare Woulds answered on 15 Jun 2011:

      Weathering processes on land break rocks (and corals and everything else) down into sand and mud, and this is washed out to sea by rivers. The smaller the grains of sand, the further out to sea they can float. If you go to the very middle of the ocean no sand can float that far, and the only grains that sink to the bottom of the sea there are fine dust blown out on the wind. Also, there are lots of tiny animals living in the surface of the ocean, and they build themselves tiny shells. When the animals die, the shells sink and become part of the sediment on the seafloor.

    • Photo: Gloeta Massie

      Gloeta Massie answered on 16 Jun 2011:

      Take what everyone else said – but add another butt. Sean is right – much of that sand was pooped out by parrotfish; however, he left out another group of animals that hangs out in a lot more places than parrot fish: the sea cucumber. Sea cucumbers are the hoovers of the sea. They go around scooping up coral grounds, mud, sand, gunk, goo, dead stuff, etc., then poop it out all clean! So – next time you’re digging your feet into beautiful sand – thank the animals for poop!

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