Aquatic ecosystem-Ponds

The aquatic ecosystem deals with water bodies. The major types of organisms found in aquatic environments are determined by the water's salinity.
Based on the salinity of water water bodies are classified into:

1. Fresh water bodies (Ex: Ponds, streams, lakes and rivers)
2. Salt water bodies (Ex: Oceans, Seas, Estuaries)

Pond is a freshwater aquatic ecosystem where water is stagnant. It receives enough water during rainy season. It contains several types of algae, aquatic plants, insects, fish and birds.

1.  Pond is only seasonal
2. It is a stagnant freshwater body
3. Ponds get polluted easily due to limited amount of water

STRUCTURE AND FUNCTION OF POND ECOSYSTEM
Abiotic components
Ex:  Temperature, light, water, organic and inorganic components
Biotic components

  

Producers: They are green photosynthetic organisms and are of two types. phytoplanktons are             microscopic aquatic plants that freely float on the surface of water. Ex: Algae, small floating plants like volvox, pandorina, anabena and cosmarium. Microphytes are large floating plants and submerged

plants. Ex: Hydrilla, Jussiaea, wolfina and demna.

1. Consumers: Primary consumers are microscopic animals that freely float on the surface of water. They are called zooplanktons and they feed on phytoplanktons. Ex: Protozoa, very small fish, ciliates, flagellates and protozoans.Secondary consumers feed on zooplanktons. Ex: Insects like water beetles and small fish. Tertiary consumers feed on small fish. Ex: Large fish
2. Decomposers: They decompose the dead plant and animal matter thereby releasing the nutrients to be reused by green plants. Ex: Fungi, Bacteria and flagellates.

STRUCTURE OF A POND ECOSYSTEM
A pond is defined as any body of water that is greater than 1 m2 and is inundated for more than 8 months of the year. If a pond is shallow, (not greater than 90cm in depth) and well planted, it will support a vast array of plants and animals.
 

Ponds are freshwater bodies surrounded by land while lakes are large freshwater bodies surrounded by land. Ponds are seasonal and exist for a few months of the year while lakes exist for hundreds of years or more. Ponds and lakes have limited species diversity as they are isolated from each other and other water bodies like rivers and oceans. Based on depth of water body and its distance from the shoreline, zones of ponds and lakes are divided into:

• Littoral zone
• Limnetic zone &
• Profundal zone

LITTORAL ZONE

• It is the top most zone
• Light reaches to the bottom of the zone
• It is always warm
• It consists of rooted plants with leaves on water surface
• This zone consists of mesophytic plants and phytoplanktons
• This zone contains a diverse community like algae, rooted and floating aquatic plants, snails, clams, insects, crustaceans, fishes and amphibiansThe vegetation and animals in this region are food for turtles, snakes and ducks

LIMNETIC ZONE

• This is the intermediate zone and its depth is upto effective light penetration
• Plankton, nektons and neustons are the biotic community
• This zone consists of hydrophytes and submerged hydrophytes
• Primary producers are hydrophytes and phytoplanktons
• Consumers are zooplanktons, fish, etc

PROFUNDAL ZONE

• It is the deepest portion
• Sunlight does not penetrate in this zone
• No producers are present in this zone
• This zone is colder and denser than the other two zones
• The organisms living in this zone are called benthos
• When planktons die, they fall in this zone
• Fauna are heterotrophs that eat dead organisms and use oxygen for cellular respiration
• Profundal zone is absent in ponds
• In ponds, littoral zone is large and limnetic and profundal zones are small or absent. Whereas in lakes, littoral zone is small and limnetic and profundal zones are large