Aquatic Ecosystem

An ecosystem is defined as a functional unit wherein all living organisms interact with their surroundings and one another to sustain in the environment. In a broad sense, an ecosystem can be categorised as a land/terrestrial ecosystem or a water/aquatic ecosystem.

This particular article will offer you a fair idea of the types of aquatic ecosystem and their importance in brief!


What is the Aquatic Ecosystem?

The aquatic ecosystem definition states it is a water-based environment, wherein, living organisms interact with both physical and chemical features of the environment. 

These living creatures whose food, shelter, reproduction and other essential activities depend in a water-based environment are known as aquatic organisms.

 Some of the most common aquatic organisms are – nekton, plankton and benthos. Additionally, lakes, oceans, ponds, rivers, swamps, coral reefs, wetlands, etc. are a few popular aquatic ecosystem examples.


Features of Aquatic Ecosystem 

Salient features of aquatic ecosystem are highlighted in this figure below –

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Test Your Knowledge: Which aquatic biome is characterised by fresh flowing water?

  1. Coral reefs b) Streams/rivers c) Swamps d) Lakes/ponds.


Types of Aquatic Ecosystem

In general, there are two types of aquatic ecosystem, namely marine ecosystems and freshwater ecosystems. Both marine and freshwater ecosystems are further divided under different aquatic ecosystems.

Let’s Take a Look at the Aquatic Ecosystem and its Types Below.

  1. Marine Water Ecosystem

This particular ecosystem is the largest aquatic ecosystem and covers over 70% of the earth’s total surface. This ecosystem is relatively more concentrated in terms of salinity. 

Nonetheless, the body of aquatic organisms is well-adjusted to saline water, and they may find it challenging to survive in freshwater. These following categories comprise the marine ecosystem. 

  • Ocean Ecosystem 

Pacific Ocean, Atlantic Ocean, Indian Ocean, Arctic Ocean and the Southern Ocean are the five major oceans on earth. Notably, the Pacific Ocean is the largest and deepest of these five, while Atlantic is the second largest in terms of size. Also, the Southern Ocean harbours the largest population of Krill among them.

Other than that, the oceans serve as home to aquatic organisms like – turtles, crustaceans, plankton, corals, shellfish, blue whale, shark, tube worms, reptiles, etc.. 

  • Estuaries 

Typically, it is the meeting point of a sea and rivers, which makes the water slightly more saline when compared to freshwater and more diluted when compared to the marine ecosystem. 

Biologically, estuaries are considered to be productive as it stimulate primary production and trap plant nutrients. Some examples of estuaries include – tidal marshes, river mouth, and coastal bay.

  • Coral Reefs

These are fondly referred to as the Rain Forest of Oceans as they harbour a wide diversity of aquatic flora and fauna. 

  • Coastal Ecosystem 

It is one of the major aquatic ecosystems and is quite distinct in terms of structure and diversity. Coastal ecosystem is formed in the union of land and water. 

Coastal ecosystems harbour a variety of plants and algae and serve as a home to snails, shrimps, crabs, lobsters and fishes. 


  1. Freshwater Ecosystem

This aquatic ecosystem covers less than 1% of the earth’s surface and is broadly divided into – wetlands, lentic and lotic ecosystems. 

  • Swamps and Wetlands

These are marshy areas which are often covered in water and harbour a variety of flora and fauna. Wetlands are known to be a home of water lilies, marshes, swamps, Northern Pikes, dragonflies, Green Heron, etc.

  • Lentic Ecosystems

It includes standing water bodies like ponds and lakes and is a home to both floating and rooted plants, algae and invertebrates. Salamander, frogs, water snakes and alligators are commonly found in lentic ecosystems. 

  • Lotic Ecosystems

These aquatic ecosystems are characterised by rapid flowing water moving in one direction. They are a hub of a wide variety of insects like beetles, mayflies and stoneflies, among others. Also, it harbours species like river dolphins, beavers, otters, eel, minnow and trout. 


Test Your Knowledge 1: Odd one out – a) River b) Estuary c) Stream d) Lake

Test Your Knowledge 2: Which of these has the lowest saline concentration?

  1. Wetland b) Coral reef c) Ocean d) Lake. 


Functions of Aquatic Ecosystem 

These pointers highlight the importance of aquatic ecosystem -

  • Facilitates recycling of nutrients

  • Helps to purify water

  • Recharges groundwater

  • Is a habitat for aquatic flora and flora

  • Mitigates flood

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FAQ (Frequently Asked Questions)

1. What is the Definition of an Aquatic Ecosystem?

Ans. It is a water-based environment, wherein living organisms inhabit with each other and their surroundings to survive. Planktons, nektons and benthos are the three broad categories of organisms living in aquatic ecosystems.

2. What are the Characteristics of Aquatic Ecosystems.

Ans. Characteristics of aquatic ecosystems can be divided into abiotic and biotic factors. The abiotic factors include depth, nutrient, temperature, salinity, flow, temperature, etc., while the biotic factors comprise the living organisms.

3. State two Functions of the Aquatic Ecosystem.

Ans. Two of the functions of the aquatic ecosystem, and its types include – i. It helps to recycle nutrients and purify water. ii. It helps to recharge the groundwater level.