Interaction of biotic and abiotic components results in physical structure that is calculated by the characteristic of each type of ecosystem. .
The two important structural features of an ecosystem are:
(i) Species composition It is calculated by the identification and enumeration of plant and animal species of an ecosystem.
(ii) Stratification It is the vertical distribution of different species occupying different levels in an ecosystem,
* e.g. trees occupy top vertical strata or layer of a forest, shrubs the second and herbs and grasses occupy the bottom, (third) layers. .
The important functional aspects of an ecosystem are:
(a) Productivity (b) Decomposition
(c) Energy flow (d) Nutrient cycling
To understand the concept of an aquatic ecosystem, let us take a small pond ecosystem as an example.
Pond is fairly a self-sustainable unit, that explains even the complex interactions that exist in an aquatic ecosystem. A pond is a shallow water body in which all the above mentioned basic structural and functional components are present.