Life around deep sea vents

In 1977 scientists were shocked to find an abundance of life deep in the ocean, in a seemingly toxic environment. How could living things survive around underwater deep-sea smoking vents, gushing super-heated chemical fluids?

Most life on earth uses sun as its power source. Trees and plants use the energy in sunlight to combine water and carbon dioxide to make sugar. This process is called photosynthesis.

In the deep ocean, many hundreds of metres away from the sun's rays, another process is taking place. It is called chemosynthesis. Tiny microbes use chemical energy instead of light to combine water and carbon dioxide to make sugars.