What is a pond ecosystem? Read this article to know more about pond ecosystem.
The ecosystem is a basic unit in ecology, formed by the
interaction of plants, animals and microorganisms (biotic
factors) with their physical environment (abiotic factors).
A pond ecosystem refers to the freshwater ecosystem
where there are communities of organisms that are
dependent upon each other and with the prevailing water
environment, for their nutrients and survival. Usually,
ponds are shallow (hardly 12-15 feet) water bodies in
which sunlight can reach to its bottom permitting the
growth of the plants that grow there.
The organisms inhabiting a pond ecosystem include
algae, fungi, microorganisms, plants and fishes. These
organisms can be further classified as producers,
consumers and decomposers, based on their feeding habit.
The energy in a pond ecosystem flows from the producers
to the consumers. Decomposers, on the other hand
consume dead organisms by decomposing them. Let’s
look into the habitats and food chain in a pond ecosystem.
Habitats in a Pond Ecosystem - There are mainly four habitats in a pond ecosystem, namely
shore, surface film, open water and bottom water habitats.
Shore Habitat: The organisms inhabiting this habitat vary depending upon whether the shore is
rocky, sandy or muddy. In case of rocky shores, plants might not be able to grow, whereas in
muddy or sandy or mixed type, plants like grasses, algae and rushes can be present along with
organisms such as earthworms, protozoa, snails, insects, small fishes and microorganisms.
Surface Film Habitat: Surface film habitat, as the name suggests implies to the surface of the
pond. In general, insects like water striders and marsh traders, organisms that are free-floating
and those that can walk on the surface of water inhabit the surface habitat. They nourish on the
floating plants, dead insects, and sometimes, feed upon each other.
Open Water Habitat: Open water habitat is inhabited by fishes and the plankton (tiny
organisms). Both phytoplankton such as algae and zooplankton such as insect larvae, rotifers,
tiny crustaceans and invertebrates are present in this habitat. Fishes feed on plankton.
Bottom Water Habitat: Depending upon whether the pond is shallow or deep water, the bottom
habitat varies. For example, if a pond is shallow and has sandy bottom, organisms like
earthworms, snails and insects inhabit the bottom, whereas if the pond is deep and has muddy
bottom, microorganisms, flatworm, rat-tailed maggot and nymphs of dragonflies mostly inhabit
the bottom habitat.
Food Chain in a Pond Ecosystem - Food chain in a pond ecosystem is divided into three basic
trophic levels, namely the first, second and third trophic levels. The first trophic level is
represented by the producers or the autotrophs; for example, phytoplankton and plants. They
prepare their own food with the help of energy from sunlight through the process of
photosynthesis. The second trophic level is characterized by the herbivores such as insects,
crustaceans and invertebrates inhabiting the pond and which consume the plants. The third and
the topmost trophic level comprises of the carnivores, especially the fishes, which can feed on
both plants and the herbivores of the first and second trophic level respectively.
In addition to the three trophic levels, there are saprotrophic organisms, commonly known as
decomposers, which are located at the bottom of the food chain. Decomposers, mostly the
bacteria and fungi are very important in the nutrient cycle as all the organic matter from the dead
and decayed organisms is converted into carbon dioxide and nutrients such as nitrogen,
phosphorus and magnesium. These nutrients are generated in such a way that they can be readily
used by algae and plants for production of food to be consumed by the herbivores. Furthermore,
the carnivores consume the producers and herbivores. Thus, the flow of energy is maintained in a