Aquatic Ecosystem: Understanding Curious Ecosystem Facts For Kids

Akinwalere Olaleye
Feb 20, 2023 By Akinwalere Olaleye
Originally Published on Nov 09, 2021
Edited by Katherine Cook
Fact-checked by Vikhaash Sundararaj
Underwater coral reef and fished in blue ocean.

An ecosystem consists of all living creatures as well as the natural environment in which they reside.

There are two types of ecosystems, aquatic ecosystems, and terrestrial ecosystems, both of which act as a habitat for several species. Aquatic ecosystems cover 70% of the earth, while terrestrial ecosystems only cover 30% of the earth's surface.

The well-being of aquatic systems is directly proportional to the survival of human beings. As one increases, the other increases automatically. Many times we fail to understand how dependent we are on aquatic ecosystems.

Activities like fishing and crystallization have been in practice for a very long time. This is why human beings take the contributions of ecosystems lightly.

Apart from the purification of air and water, maintaining soil, providing food, and regulating temperature and climate, the contribution of ecosystems to the tourism industry is also huge. Did you know, alterations to the environment can cause stress on aquatic ecosystems. Continue reading to know more about such amazing things.

Once you have finished reading this article, check out our other articles on cuttlefish facts and apex predator lifespan.

What is in an aquatic ecosystem?

An ecosystem is a stretch of land that sustains all forms of life, including plant life, animal life, and other organisms combined with the environment in which they exist.

All organisms are interlinked with one another in the form of food chains or webs and energy flow. An aquatic ecosystem is one that exists in a water body. Oceans, lakes, rivers, streams, estuaries, and wetlands are the seven aquatic ecosystems. They are categorized under two major systems, freshwater ecosystems and marine ecosystems.

Freshwater Ecosystems: Freshwater ecosystems are lakes, ponds, streams, wetlands, and rivers. All water bodies that have low salt levels or concentrations, which are lower than 1%, fall under this category.

They are home to over 100,000 aquatic species. Freshwater systems are one of the most valuable resources on the planet.

Freshwater ecosystems act as a bridge between people and the resources they need for survival. Groundwater and surface waters are the only freshwater sources that humans have.

The freshwater ecosystems are divided into three categories, namely lentic, lotic, and wetlands, based on the temperature, pH and other factors. Lentic refers to the slow-moving or standing waters such as pools, reservoirs, lakes, and ponds. Pond ecosystems provide four variations in habitats.

Based on the temperature, depth, and several other conditions, they are categorized as shore habitats, surface film habitats, open water habitats, and bottom water habitats. Each of them is home to different plants and animals.

Lotic refers to quick-moving water bodies such as rivers and streams. Wetlands are land areas covered by shallow water such as marshes, swamps, and bogs.

Marine Ecosystems: Marine ecosystems include water bodies with high salt levels, like oceans and seas. Salt concentration can vary depending on the region, but the usual salinity is 35 parts per notation of water. These systems are the world's largest aquatic ecosystems.

They are filled with a wide variety of plants and animals. We depend on these organisms to a great extent. Marine ecosystems are broadly classified into two categories.

They are the benthic zone and the oceanic zone. The division was made based on the coastline and depth.

Benthic zone is the lowest level of a marine system. This biological area is primarily arid. It is composed of a sediment surface and the water areas above it.

The species that dwell in this area are known as benthos. Because of the depths, it usually has low temperatures that may drop from 35.6-37.4 F (2-3 C) . The organisms found in this area play an important role by transferring nutrients across sediment layers and the sea or ocean surface.

The area of the ocean or seawater that extends further than the continental slope is called the oceanic zone. Areas with a water level lower than 660 ft (200 m) also come under this category.

This zone is divided into four subzones: the sunlight zone, the twilight zone, the midnight zone, and the abyssal zone. The sunlight zone is the top surface that receives direct sunlight.

It is sometimes referred to as the photic zone, the euphotic zone, and the epipelagic zone. The twilight zone is the area lying right below the sunlight zone of a marine body of water where there is no or little sunlight.

The midnight zone is the zone, also known as the bathyal zone, that is inhabited by predators and scavengers. Sunlight does not reach the icy waters of this zone.

The abyssal zone is the deepest zone and is 14,000 ft (4267.2 m) deep. Producing light is an adaptation developed by organisms that live in this region.

Urban runoff, agricultural and environmental pollution have degraded the water quality of freshwater ecosystems and marine ecosystems. Estuaries are most affected by runoff.

How important is an aquatic ecosystem?

Aquatic ecosystems are very essential to maintain ecological balance. They support plant life, animal life, and human life. Even a slight change in the aquatic system can affect all these species to a great extent.

Recycle Nutrients: For plants and animals to grow, nutrients are required. Herbivores get nutrients from plants and carnivores get their energy from herbivores. Primary producers derive their energy from the surrounding ecosystems. Nitrates, minerals, and phosphates available in nature act as a source of energy to primary producers. Therefore, aquatic ecosystems are essential.

Water Purification: By eliminating contaminants from surface waterways, wetlands can enhance the quality of the water. When the water reaches a wetland through a stream channel or surface runoff, it spreads out and runs through closely packed plants.

The force of flow is decreased, which allows harmful particles in the water to sink to a marsh surface. The roots of plants also remove sediments from runoff, rivers, and streams.

Plants absorb nutrients that contribute to algal blooms when the water from streams flows through wetlands and other shallow regions. Algae produces a lot of chemical compounds that affect the health and survival of humans as well as the earth's health.

Habitat: Aquatic ecosystems act as a habitat for wildlife and several aquatic species. There are 228,450 species in the ocean. Freshwater environments are crucial for the survival of many animal species, including several fish species.

This is essential for them to thrive. Freshwater habitats support 41% of the world's fish species. Human beings are also dependent on aquatic ecosystems for drinking water, electricity, and water for irrigation.

Aquatic systems have been affected by human activities like deforestation and overfishing. Deforestation exposes the bare surface of earth, which causes soil erosion.

It also transfers the soil nutrients into streams and other freshwater systems, creating an imbalance. Overfishing reduces the number of fish species and their population, which also affects other animals that depend on these fish species, creating an imbalance within the systems. Draining the water systems has a direct effect on aquatic biodiversity.

What is an example of an aquatic ecosystem?

There are many different types of aquatic ecosystems. Here is a list of some of the most common ones:

Lakes: A lake is one of the freshwater ecosystems. It is a large area filled with standing or slow-moving water surrounded by land.

There are two types of lakes, natural lakes and artificial lakes. A natural lake does not have an outlet and is formed by erosion, for example Lake Michigan.

An artificial lake is one that is created by humans with an outlet. It is formed by constructing reservoirs or dams. A piece of land is dug out and filled with water by diverting a river flow, for example Lake Mead, Arizona-Nevada.

This lake is mainly built for the generation of hydroelectric power. There are several other types of lakes, including tectonic lakes, solution lakes, shoreline lakes and glacial lakes.

Ponds: Ponds are a subclass of lakes and the simplest aquatic ecosystems. They are much smaller than lakes and are shallow. A pond is a small water body. It can either be created naturally or artificially. In the natural process, it is created when depression is filled by other water sources.

Estuaries: Estuaries are areas where ocean water gets mixed up with freshwater, forming brackish or mild saltwater. It is known by other names like lagoon, bay, slough, and sound.

Since it is partly open, the water circulation in and out of estuaries is constant such as Chesapeake Bay. There are four kinds of estuaries, coastal plain estuaries, tectonic estuaries, bar-built estuaries, and fjord estuaries.

Oceans: An ocean is a fast-moving body of saltwater. Oceans trap 98% of water in the world. Oceans are widely spread and cover 71% of the earth's surface. There are five main oceans in the world, the Indian Ocean, Pacific Ocean, Atlantic Ocean, Artic Ocean, and Antarctic Ocean.

Rivers: Rivers are flowing or fast-moving bodies of water that flow into oceans, ponds, and lakes. Rivers act as a natural drainage system.

There are several types of rivers, some of them are the perennial river, episodic river, underground river, and tributary river, such as the Mississippi River. Did you know, the Roe River in Montana, United States is the smallest river in the world and the Nile River is the largest?

Wetlands: A wetland differs greatly from all other aquatic ecosystems. It is a land area covered by water either permanently or seasonally. Marshes, swamps, bogs, and fens are the four basic types of wetlands such as Pantanal (largest tropical wetland.) A wetland purifies and replenishes water, aiding in water purification.

Coral Reefs: Coral reefs are a part of the underwater ecosystems. Just like wetlands, coral reefs are also a distinct part of the aquatic ecosystem. Coral reefs are made up of a thin layer of calcium carbonate or limestone. The basic layers of coral reefs are made of coral skeletons.

What makes up a healthy aquatic ecosystem?

Healthy aquatic ecosystems are dependent on a wide range of environmental conditions.

Diversity Of Life: A healthy aquatic ecosystem must have a wide variety of organisms to carry out various processes like the nutrition cycle and water purification to keep it from collapsing and ensuring that the flow of energy is not interrupted. It must serve as a home to wildlife.

Space: For the aquatic ecosystems to remain healthy, they need space. Beach habitats, for example, face erosion from the sea.

Hawaii's beaches are deteriorating owing to urban expansion and shoreline obstacles such as quays and sea walls. Sand erosion due to human activities like agricultural waste deposition and urban runoff coupled with developments has critically damaged the beaches in Oahu. Almost 25% of the beaches in Oahu have lost their importance because of such destructive practices.

Loss of sand has a direct effect on space and habitat. All of this is essential to provide a protective habitat.

Water Quality: Salinity determines the types of animals and plant species in aquatic systems. If the water is not of high quality, it won't be able to support organisms, which means it is just waste. In the same way, excess nutrients in water can also cause health problems.

A balance of the quality, salinity, and nutrient levels is very essential to maintain a healthy ecosystem. Marine creatures can be harmed by trash or marine debris.

The oxygen flow is restricted when there are more pollutants and chemicals in the water. It also impedes the penetration of sunlight. An optimal flow of oxygen and good sunlight is essential for organisms to thrive.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for the Aquatic ecosystem: Understanding curious ecosystem facts for kids, then Why not take a look at what is the shortest book in the Bible?

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Written by Akinwalere Olaleye

Bachelor of Arts specializing in English Literature

Akinwalere Olaleye picture

Akinwalere OlaleyeBachelor of Arts specializing in English Literature

As a highly motivated, detail-oriented, and energetic individual, Olaleye's expertise lies in administrative and management operations. With extensive knowledge as an Editor and Communications Analyst, Olaleye excels in editing, writing, and media relations. Her commitment to upholding professional ethics and driving organizational growth sets her apart. She has a bachelor's degree in English Literature from the University of Benin, Edo State. 

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Fact-checked by Vikhaash Sundararaj

Bachelor of Fine Arts specializing in International Business

Vikhaash Sundararaj picture

Vikhaash SundararajBachelor of Fine Arts specializing in International Business

With a background in International Business Management, having completed his degree at the University of Hull. Vikhaash has volunteered with 'Teach For India' to help students create a monthly newsletter. In his free time, he enjoys sports and was the assistant captain of his school's hockey team. He has also gained marketing experience through an internship at Decathlon Sports India.

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