Question: if the sun is the source of life then how do fish that live in the deepest part of the ocean where the sun is not present survive

Keywords: , , ,

  1. Terrific question! 😀

    Many creatures live in the deep ocean beyond where light reaches. A few communities live off energy sources other than the sun, such as sulphur vents in some of the mid ocean ridges. Most however rely on the suns energy.

    The reason they are able to live below where the sun penetrates is that they have adapted to surviving for a long time between meals! The sun energy is captured on the surface (top 100m) by phytoplankton. This plankton is a source of food for many species, some on the surface and some that migrate up for greater depths. Those the migrate up towards the surface take this food (as energy) back down into the depths incorporated within their bodies.

    In addition many species that live in the depths are scavengers and live off either the organic matter that “rains” down from the surface or dead carcasses (whole or part) of creatures that have died in the upper layers.

    There are intricate food chains and food webs in the deep ocean, they simply operate on different time frames to those we see at the surface. The vast majority however rely on the sun to provide the energy that sustains life, even though it doesn’t penetrate into the deep ocean. 😀


  2. Great Q – Not much more I can add here. BUt as I said in another answer the deep oceans are a rich opportunity for discovery


  3. I have nothing to add to James’s answer.


  4. James has answered this one very well.

    I’ll just add that the answer to this question is part of what drives the science of astrobiology. This is the study of the conditions required for life on other planets. They are basically looking at the extreme parts of the Earth that life exists, and searching for other places in the Solar System where the same conditions occur.