Aquatic Ecosystem

Habitat is a part of an ecosystem. The climate, plants, and animals are the identities of a habitat. Mainly ecosystem has two domains: Terrestrial or Land ecosystem and Aquatic or Water ecosystem.

Water supports many lives. Organisms which survive in water are called aquatic organisms. They depend on water for their food, shelter, reproduction and all other life activities.  

An aquatic ecosystem includes a group of interacting organisms which are dependent on one another and their water environment for nutrients and shelter. Examples of aquatic ecosystem includes oceans, lakes and rivers.

An aquatic ecosystem includes freshwater habitats like lakes, ponds, rivers, oceans and streams, wetlands, swamp, etc. and marine habitats includes oceans, intertidal zone, reefs, seabed and so on. The aquatic ecosystem is the habitat for water-dependent living species including animals, plants, and microbes.

Types of Aquatic Ecosystem

Aquatic Ecosystem : Marine

Different types of aquatic ecosystems are as follows:

Freshwater Aquatic Ecosystem

They cover only a small portion of earth nearly 0.8 percent. Freshwater involves lakes, ponds, rivers and streams, wetlands, swamp, bog and temporary pools. Freshwater habitats are classified into lotic and lentic habitats. Water bodies such as lakes, ponds, pools, bogs, and other reservoirs are standing water and known as lentic habitats. Whereas lotic habitats represent flowing water bodies such as rivers, streams.

Lotic Ecosystems: They mainly refers to the rapid flowing waters that move in a unidirectional way including the rivers and streams. These environments harbour numerous species of insects such as beetles, mayflies, stoneflies and several species of fishes including trout, eel, minnow, etc. Apart from these aquatic species, these ecosystem also include various mammals such as beavers, river dolphins and otters.

Lentic Ecosystems: They include all standing water habitats. Lakes and ponds are the main example of Lentic Ecosystem. The word lentic mainly refers to stationary or relatively still water. These ecosystems are home to algae, crabs, shrimps, amphibians such as frogs and salamanders, for both rooted and floating-leaved plants and reptiles including alligators and other water snakes are also found here.

Wetlands: Wetlands are marshy areas and are sometimes covered in water which have a wide diversity of plants and animals. Swamps, marshes, bogs, black spruce and water lilies are some examples in the plant species found in the wetlands. The animal life of this ecosystem consists of dragonflies and damselflies, birds such as Green Heron and fishes such as Northern Pike.

Marine Aquatic Ecosystem

Marine ecosystem covers the largest surface area of the earth. Two third of earth is covered by water and they constitute of oceans, seas, intertidal zone, reefs, seabed, estuaries, hydrothermal vents and rock pools. Each life form is unique and native to its habitat. This is because they have adaptations according to their habitat. In the case of aquatic animals, they can’t survive outside of water. Exceptional cases are still there which shows another example of adaptations (e.g. mudskippers). The marine ecosystem is more concentrated with salts which make it difficult for freshwater organisms to live in. Also, marine animals cannot survive in fresh water. Their body is adapted to live in salt water; if they are placed in less salty water, their body will swell (osmosis).

Ocean Ecosystems: Our planet earth is gifted with the five major oceans, namely Pacific, Indian, Arctic, and Atlantic Ocean. Among all these five oceans, Pacific and the Atlantic are the largest and deepest ocean. These oceans serves as a home to more than five lakhs aquatic species. Few creatures of these ecosystem includes, shellfish, Shark, Tube Worms, Crab Small and large ocean fishes, turtles, crustaceans, blue whale, reptiles, marine mammals, seabirds, plankton, corals and other ocean plants.

Coastal Systems: They are the open systems of land and water which are joined together to form the coastal ecosystems. The coastal ecosystems have a different structure, and diversity. A wide variety species of aquatic plants and algae are found at the bottom of the coastal ecosystem. The fauna is diverse and it mainly consists of crabs, fish, insects, lobsters snails, shrimp, etc.

Plants and animals in an aquatic ecosystem show a wide variety of adaptations which may involve life cycle, physiological, structural and behavioural adaptations. Majority of aquatic animals are streamlined which helps them to reduce friction and thus save energy. Fins and gills are the locomotors and respiratory organs respectively. Special features in freshwater organisms help them to drain excess water from the body. Aquatic plants have different types of roots which help them to survive in water. Some may have submerged roots; some have emergent roots or maybe floating plants like water hyacinths.

Stay tuned with BYJU’s to learn more about the Ecosystem, its types and their habitat.


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Cactus plant is best suited for growth in _______.