Types of Aquatic Ecosystem and its Adaptations

May 17, 2023, 16:45 IST

The collection of all the organisms living in a region, their surroundings, and the interactions between them form the complete ecosystem. These ecosystems can be broadly divided into two categories

• Terrestrial ecosystem - Consists of the organisms living on the land and their surroundings.
• Aquatic ecosystem - Consists of all the organisms living underwater and their surroundings.

The organisms that are living and utilize resources are called biotic components of the ecosystem and the physical surrounding which supports life including air, water, and soil are called abiotic components. In this article, we will discuss the aquatic ecosystem in detail.

Introduction to Aquatic Ecosystem

70% of the Earth's surface is covered with water forming giant water bodies including lakes, seas, and oceans. All organisms require water for performing their metabolic activities and therefore, first life originated under water. Water contains all the dissolved nutrients, and gasses like oxygen and provides ambient conditions for the survival of life. All these organisms living inside water and their surroundings are a part of the Aquatic ecosystem.

Phytoplanktons are the smallest microscopic organisms found in water bodies that undertake photosynthesis and make their own food. These are consumed by zooplanktons which are slightly bigger microscopic animals. Large plants and animals are also found in the aquatic ecosystem including whales which are the largest living mammals.

Also, check - Animals Nervous System

Types of Aquatic Ecosystem

Depending upon the type of water body, the ecosystem, and the environment also varies. Oceans and seas have salty water whereas lakes and rivers have freshwaters. Both these environments give rise to totally different types of plants and animals. The two main types of aquatic ecosystems include:

• Marine ecosystems

Saltwater organisms living in seas and oceans are included in Marine ecosystems. Most of the large fishes, like sharks and whales are adapted to the ocean ecosystem.

The deep water organisms are included in Ocean ecosystems while the organisms living at the edges where land meets the ocean are a part of the coastal ecosystem.

These organisms have special adaptations which allow them to adjust to hyperosmotic conditions i.e. in highly concentrated salt water. The deep water regions are often devoid of sunlight but still many organisms are found on the ocean floor most of which are bioluminescent (light emitting).

• Freshwater ecosystem

The water bodies having fresh water like lakes, rivers, and ponds are included in this type of ecosystem. These plants and animals are not as large as marine organisms because more nutrients are washed away into the seas and oceans. However, these organisms also show a wide variety and can be categorized into subgroups depending upon their habitat in the water body.

• Lentic ecosystems

The water bodies where the water is stagnant and does not move much are included in the Lentic ecosystem. Ponds and Lakes are primary examples and contain free-floating plants and amphibians like frogs and reptiles.

• Lotic ecosystem

Running water comprises the Lotic ecosystem where the water currents drive the movement of the organisms. Primary examples are Rivers, Streams and Springs. Mainly submerged plants are found in these ecosystems with several varieties of insects, fishes, and certain mammals like river dolphins.

• Wetlands

The Wetlands include land habitats that are partially or fully covered by water bodies. These regions are highly productive due to the extra nutrition provided by water bodies and high moisture content. The Wetlands show the highest diversity in freshwater ecosystems having animals like insects, birds, mammals, and even fish.

Examples

• Freshwater ecosystem - Plants like Lily, Duckweed, Water hyacinth, and Spinach, and animals like frogs, beavers, freshwater fishes, algae, crabs, dragonflies, and birds like Green Herons.
• Marine ecosystem - Plants like kelp, diatoms, seaweed, corals, and animals like sharks, whales, dolphins, zooplanktons and phytoplanktons, turtles, and many more are found here.

Aquatic Ecosystem: FAQs

Q1. How is an aquatic ecosystem different from a terrestrial ecosystem?

Ans. In an Aquatic ecosystem, the oxygen remains dissolved in water and organisms extract it directly from water while in a terrestrial ecosystem, free oxygen is present in the atmosphere and can be inhaled through the respiratory organs.

Q2. Can aquatic animals survive without water?

Ans. Some amphibians are adapted to survive on both land and water but most aquatic animals like fishes, whales, and sharks cannot survive without water.

Q3. Which adaptation allows fishes to live in water?

Ans. Fishes have specialized gills that allow them to breathe underwater and extract oxygen directly from the water. These gills allow fish to remain underwater.

Q4. What are the components of Aquatic ecosystems?

Ans. Aquatic ecosystems include biotic components which are living like plants and animals and abiotic components which are non-living like water and rocks.