From space, the Earth looks like a beautiful blue marble - and with good reason as over 70% of it is covered in water.
But it's not all that pristine azure blue.
Most of our seas and oceans are pretty dark - pitch black in fact - and it is in this area of the ocean that some of the most dynamic and enigmatic creatures live.
But how do they survive the crushing pressure and the scarcity of food in freezing temperatures with zero sunlight?
Professor Tracey T. Sutton from Halmos College of Natural Sciences and Oceanography of Nova Southeastern University and Director of the DEEPEND Consortium joins Jonathan to discuss.