Zooplankton – plural zooplanktons – refers to a mass of tiny microscopic plants and animals drifting near the surface of large freshwater lakes and saltwater oceans.
Plankton consists of two chief components which are either phytoplankton (plants) or zooplankton (animals).
The animal organisms are mostly heterotrophic fish larvae and minute crustaceans which feed on phytoplankton.
Their vital role as 'secondary producers' transferring energy from photosynthesizing plants to larger marine animals should not be overlooked.
Hundreds of thousands of zooplankton species and organisms survive in many different and challenging marine environments playing a crucial role in the food chain link between plants and animals in saltwater and freshwater biospheres.