Hello,

The first major distinction is between the pelagic and benthic zones. The pelagic zone refers to the water column, where swimming and floating organisms live. The benthic zone refers to the bottom, and organisms living on and in the bottom are known as the benthos.

• Animals that live on the sea floor are called benthos. Most of these animals lack a backbone and are called invertebrates. Typical benthic invertebrates include sea anemones, sponges, corals, sea stars, sea urchins, worms, bivalves, crabs, and many more.
• Examples of organisms living in this zone are plankton, floating seaweed, jellyfish, tuna, many sharks and dolphins.

Hope this helps!!!!