Define Plankton, Nekton and Benthos.
Define Plankton, Nekton and Benthos. Plankton : Plankton are organisms that drift freely in the water. Plankton , marine and freshwater organisms that, because they are nonmotile or too small or weak to swim. N ekton : The second group includes the larger, active swimmers in a body of water called nekton. Fish, turtles, and whales are all nekton. Nekton are heterotrophic and have a large size range. Benthos : The third group, organisms that live on the bottom of a body of water, are called benthos . Benthos , from the Greek benthos meaning "depth of the sea", is the community of organisms that live on, in, or near the seabed, river, lake, or stream bottom.