Aquatic Ecosystem

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

Many lives are undoubtedly supported by water. Furthermore, aquatic creatures are those that can thrive in water. They also rely on water for food, shelter, reproduction, and a variety of other life functions. This particular article will offer you a fair idea of the types of aquatic ecosystems 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 on a water-based environment are known as aquatic organisms.

Water plays a significant role in the management of world-scale ecosystem processes in aquatic systems, connecting the atmosphere, lithosphere, and biosphere by transferring material between them and allowing chemical reactions to occur. Water has unique physicochemical features that reflect the water body's quality. The physicochemical characteristics of an aquatic ecosystem determine how well it functions and how long it can support life forms. In the same way as sediments in terrestrial ecosystems provide substrate, nutrients, and a home for live aquatic resources, sediments in aquatic ecosystems are equivalent to the soil in terrestrial ecosystems. Sediments are significant catalysts in environmental food cycles and the two water quality dynamics.

The quality of sediment has a direct or indirect impact on the functioning of an aquatic ecosystem. The many physicochemical properties of sediment determine its quality. Similarly, the biotic mix of an aquatic environment determines how well it functions. In the aquatic environment, they serve as a trophic level and a source of energy. Fish have a significant ecological role in the whole food web at the trophic level.

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 the aquatic ecosystem are highlighted in this figure below –

• Freshwater or saltwater can be used to make them.

• They serve as a home for a variety of aquatic animals.

• The majority of the vegetation is made up of algae and corals.

• They have a lot of biological diversity, which makes them the most productive and wealthiest ecosystems on the planet.

• They help regulate the hydrological cycle and act as a pollution filter, among other things.

Types of Aquatic Ecosystem

In general, there are two types of aquatic ecosystems, 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. The following categories comprise the marine ecosystem. 

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• 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 the Atlantic is the second largest in terms of size. Also, the Southern Ocean harbors 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, sharks, 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 they stimulate primary production and trap plant nutrients. Some examples of estuaries include – tidal marshes, river mouth, and coastal bays.

• Coral Reefs

These are fondly referred to as the Rain Forest of Oceans as they harbor a wide diversity of aquatic flora and fauna.  A coral reef is an aquatic ecosystem made up of corals that form reefs. Coral polyps are held together by calcium carbonate in the formation of reefs. Stony corals, whose polyps cluster in groups, make up the majority of coral reefs.

The animal phylum Cnidaria includes sea anemones and jellyfish, and coral is part of the class Anthozoa. Corals secrete hard carbonate exoskeletons that support and protect them, unlike sea anemones. Warm, shallow, clear, sunny, agitated water is ideal for most reefs. At the beginning of the Early Ordovician, 485 million years ago, coral reefs displaced the Cambrian's microbial and sponge reefs.

• Coastal Ecosystem 

Coastal ecosystems are formed when land and water meet. The structure, variety, and energy flow of these ecosystems are all unique. The bottom of the coastal environment is dominated by plants and algae. Insects, snails, fish, crabs, shrimp, lobsters, and other animals make up the fauna. It is one of the major aquatic ecosystems and is quite distinct in terms of structure and diversity. The coastal ecosystem is formed in the union of land and water. Coastal ecosystems harbor a variety of plants and algae and serve as a home to snails, shrimps, crabs, lobsters, and fish. 

2. Freshwater Ecosystem

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

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• Swamps and Wetlands

These are marshy areas that are often covered in water and harbor 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. All standing water habitats, such as lakes and ponds, are included in lentic ecosystems. Algae, rooted and floating-leaved plants, and crustaceans like crabs and shrimp live in these habitats. Frogs and salamanders, as well as reptiles like alligators and water snakes, can be found here. Salamanders, frogs, water snakes, and alligators are commonly found in lentic ecosystems. 

• Lotic Ecosystems

These aquatic ecosystems are characterized 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 harbors species like river dolphins, beavers, otters, eel, minnow, and trout. 

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