colloid. 1  a solid, liquid, or gaseous substance made up of very small, insoluble particles (as single large molecules or masses of smaller molecules) that remain in suspension in a surrounding solid, liquid, or gaseous medium of different matter.
Nekton. Nekton are the animals that can move by themselves in the ocean waters. Nekton live in all zones of the ocean. However, just like benthos and plankton, most live in the sunlight zone or shallow twilight zone since there is the most sunlight and it is easy to feed on smaller organisms such as krill and minnows.
The sunlit region near the surface in which photosynthesis can occur is known as the photic zone. The photic zone may be as deep as 200 meters in tropical seas, but just a few meters deep or less in rivers and swamps. âThe physical and chemical structure of the ocean provides habitats that marine organisms depend on.hotosynthetic algae, called phytoplankton, live in the photic zone. Zooplanktonâtiny free-floating animalsâeat phytoplankton. This is the first step in many aquatic food webs. Below the photic zone is the dark. aphotic. zone. , where photosynthesis cannot occur.