Taking a small pond as an example of an ecosystem list the four components of this ecosystem

Four Components of small pond ecosystem : 

abiotic components - air, water, soil, light, temperature, other climatic conditions. 

Biotic components - producers-phytoplanktons, some algae, floating and submerged plants. 

Consumers of various order - Zooplanktons 

Decomposers - fungi, bacteria and other flagellates. 

Components work as a unit for the following functions : 

Productivity : conversion of inorganic into organic material through photosynthesis with the help of solar energy and consumption of autotrophs by heterotrophs i.e. secondary productivity. 

Decomposition : decomposition and mineralisation of the dead matter and Nutrient Cycling-to release the nutrients/elements back for use by autotrophs. 

Energy Flow : Unidirectional flow of energy and its subsequent dissipation as one moves towards higher trophic levels.