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.
Three groups ofaquatic organisms include plankton, nekton, and benthos. Plankton are the organisms that float near the surface of the water. Two typesof plankton are microscopic plants called phytoplankton, and micro-scopic animals called zooplankton. Phytoplankton produce most ofthe food for an aquatic ecosystem. Nekton are free-swimming organ-isms, such as fish, turtles, and whales.