What’s at the bottom of the ocean?

Question: What's at the bottom of the ocean?
- Keywords:
  ocean,
  sea
Asked by 782yttc52 to Anna, Hayley, Iain, Rebecca on 19 Jun 2015.
- Iain Bethune answered on 19 Jun 2015:
  
  The bottom of the ocean is one of the least well known areas of the planet. Mostly it is just dark, cold, and covered with sand, but I’m sure there are some new species we have never seen before, especially around energy sources like hydrothermal vents & subterranean lava flows.

Question: What's at the bottom of the ocean?