ecosystem Environment

What does a pond do?

A small container pond full of Azolla plants

What comes to your mind when you hear of a pond?

The word ‘pond’ refers to a body of water that is usually shallow (no more than 2m deep) and smaller than a lake. Unlike a stream or a river, a pond is enclosed. Therefore, pond water is always stagnant. Natural ponds are filled by rainwater or underground springs and there are also man-made ponds.

Despite its small size, a pond plays an important role in maintaining ecosystem functions and supporting the biodiversity of an area. A pond is home to aquatic animals like shrimps and fishes, and smaller wildlife like beetles, water striders, and snails. It also attracts water-loving creatures such as dragonflies, damselflies, frogs and toads. These animals lay their eggs in the pond, where their young hatch and mature.

Many pond animals feed on debris or fresh organic materials like leaves of plants. Some predatory pond wildlife prey on other smaller animals such as tadpoles and insect larvae. Terrestrial animals like birds will also visit a pond for drinking or bathing.

A dragonfly preys on other insects such as mosquitoes. Photo by Siti Syuhada

Aside from animals, there are various plants that grow in and around a pond. These plants are good for the pond. For example, the mosquito ferns (Azolla sp.) and the Mexican sword plant (Echinodorus palifolius). They absorb nutrients from pond water or sediment. In turn, these water plants supply oxygen to the pond, inhibit algae growth, purify pond water and provide food, shade and hiding places for wildlife.

There are also many other pond plants, categorised according to their growing zone. Plants that grow at the edge of pond are known as marginal plants. The floating plants, for example, duckweed, have tiny roots that absorb nutrients directly from water. Some deep water plants such as water lilies have leaves on the water surface and roots that are buried in the mud at the bottom of the pond. There are also submerged plants that are completely under water, like the Indian swamp weed (Hygrophila polysperma), but they do need some exposed surfaces of pond to receive sunlight and carry out photosynthesis.

Floating leaves and flower of water lily. Photo by Goh Shang Ming

There is so much going on in ponds. The next time you find a pond, take a closer look to see all the life it can hold.

By ShangMing

A plant lover. I like small, medium, gigantic, ordinary, exotic, local, foreign plants. Just because they thrive to stand out.