There are many organisms that live in a marine environment. This website will focus particularly on two types of animals; those that live near hydrothermal vents, and those that are considered planktonic. Hydrothermal vent animals reside in and around cracks on the ocean floor, feeding off the nutrients from the expulsions and other organisms. Planktonic animals reside in pelagic zones of the oceans and float with the ocean currents.