Also known as the midwater or mesopelagic, the Twilight zone is cold and its light is dim, but with flashes of bioluminescence light produced by living organisms. The region teems with life. Recent studies suggest that the biomass of fish in the twilight zone may be ten times greater than previously thought, more than in all the rest of the ocean combined. The ocean Twilight zone provides important ecosystem services, including supporting ocean food webs and commercial fisheries, and transferring carbon dioxide to the deep ocean.