The abyssal zone is the lower depths of the ocean below approximately 2000 metres, where there is effectively no light penetration. Abyssal organisms are adapted for living under high pressures in cold dark conditions. Research Abyssal Zone
The abyssal zone is the region of an ocean between 2000 and 6000 metres deep, lying between the bathyal zone above and the hadal zone below. The abyssal zone is too far from the surface for light to penetrate, and hence too far for photosynthesis to take place. Research Abyssal Zone
 
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Matt and Leela Probert