Aquatic Biomes: Marine and Freshwater Biomes

What are Aquatic Biomes? How are freshwater biomes different from marine biomes? What is the importance of Aquatic Biomes? Read further to know.

Aquatic biomes, as opposed to land-based terrestrial biomes, exist in and around a body of water.

Aquatic biomes are colonies of creatures that rely on one another and their environment.

Aquatic biomes

Aquatic biomes are water-based biomes. Because water covers 70% of the Earth’s surface, aquatic biomes are an important component of the biosphere.

• They do, however, have less overall biomass than terrestrial biomes.
• Aquatic biomes can exist in both salt and fresh water.
• Around 98 per cent of the water on Earth is salty, with only 2 per cent being fresh.
• The ocean is the principal saltwater biome. Lakes and rivers are examples of major freshwater biomes.
• The word ‘aquatic’ is derived from the Latin word ‘aqua’, which means water.
• So, in a water-based setting, an aquatic ecosystem is a community of species that live together, interact, and to some extent rely on one another.

Aquatic biomes are divided into the following subcategories based on the concentration of salt content.

• Freshwater biomes: Rivers, lakes and ponds.
• Marine biomes: Oceans, Seas, etc.

Aquatic Biome Characteristics

They are distinguished by the following characteristics:

• Being immersed in water
• Being water-based.
• Being a group of living things.
• Having a distinct, more or less self-sufficient community.

Freshwater biomes

Freshwater biomes exist in water with little or no salt. Standing water and running water biomes are examples of freshwater biomes.

The freshwater biome is extremely important in the world, but many people are unaware of its significance. These biomes are made up of tiny bodies of water like creeks, lakes, streams, and rivers. These bodies of water are freshwater and salt-free. There are significant differences between fresh and salted water. Most plants and animals cannot thrive in the absence of freshwater biomes.

Standing Freshwater Biomes

Ponds and lakes are examples of standing freshwater biomes. Ponds are often smaller than lakes and shallow enough that sunlight can reach the bottom. At least some of the water in lakes is too deep for sunlight to penetrate. As a result, lakes, like the ocean, can be classified into zones based on the availability of sunlight for producers.

• The littoral zone is defined as the water nearest to the shore. The water in the littoral zone is generally shallow enough that sunlight can enter and allow photosynthesis to take place. Phytoplankton and plants that float in the water are both producers in this zone.
• The top layer of lake water distant from the coast is known as the limnetic zone. This zone covers a large portion of the lake’s surface, yet it only extends as deep as sunlight can penetrate. This is a maximum distance of 200 metres.
• The profundal zone is the deep water towards the lake’s bottom where no sunlight can reach. Because photosynthesis is impossible, there are no producers in this zone.
• The bottom of the lake receives sunlight near the coast, where the water is shallow, and plants can grow in the sediments. Crayfish, snails, and insects are also found in and around the plants near the coast.

Also Read: Environment and Ecology- Important Terminologies – ClearIAS

Lakes and ponds

Some ponds appear and go. Some have been around for a long time. Because a lake or pond is usually isolated from other bodies of water, not all plants and animals can live in this freshwater biome. They can be found in a variety of settings and on all continents. They might be as small as a few square metres or as large as thousands of square kilometres.

There are many freshwater fish species in lakes and ponds, just as there are many in rivers and streams. They are significant because they provide a fresh source of water for the animals that live nearby.

Wetlands

Wetlands are areas where there is standing water. It can be compared to water-saturated land. Swamps, bogs, marshes, flood plains, and prairie potholes are examples. They can be found all over the world and are frequently found near huge quantities of water such as lakes and rivers.

Wetlands are significant because they prevent flooding by absorbing excess water. They also aid in the purification of water. Hydrophytes are plants that dwell in wetlands. Wetland plants include milkweed, water lilies, grasses, tamarack, sedges, duckweed, cattail, cypress trees, and mangroves.

Wetlands are also home to a variety of amphibians, reptiles, mammals, and birds. Beavers, minks, raccoons, and deer are just a few examples.

Also Read:  Ramsar Sites In India – ClearIAS

Running Freshwater Biomes

Streams and rivers are examples of running freshwater biomes. Streams are often less in size than rivers. Streams can begin as surface runoff, glacial melting, or spring water seeping out of the ground. Water flows downhill if the land is not flat. As it runs across the land, the water joins other streams and finally rivers. The water eventually drains into a pond, lake, or ocean.

Streams and rivers

A river or stream is a body of water that only runs one way. Rivers and streams, unlike ponds and lakes, are always in motion. The temperature at the source is lower than the temperature at the mouth. Streams and rivers can be found all over the world and can traverse thousands of kilometres before joining an ocean. A spring, lake, or snowfall starts the construction of a river or stream and eventually leads to an ocean or other body of water.

Freshwater Biome Creatures

As previously said, the Freshwater Biome provides an ideal habitat for both plants and animals, and many do. These animals and plants thrive because the water is free of the harsh salt present in other locations. The freshwater biome benefits humans as well.
The following animals can be found in the Freshwater Biomes:

• Frogs
• Mosquitos
• Turtles
• Raccoons
• Shrimp
• Crab
• Tadpoles
• Snakes

Plants from the Freshwater Biome

In the freshwater biome, two common plants are grass and sedge. Trees are uncommon in these locations, however they can be observed on occasion. Most of the plants found in freshwater biomes are unrecognisable to most of us.
Some of the plants that can be found in the freshwater biome are:

• Mangroves 
• Spike Rush
• Water Lily
• Cattail
• Bull Rush
• Pickerel Weed

Freshwater ecosystems are composed of land-based water that is constantly cycling and has a low salt content (always less than 5 ppt).

Marine biomes

Marine biomes are bodies of water with salt concentrations that are equivalent to or greater than that of seawater (i.e., 35 ppt or above). Marine ecosystems, which live in salty waters, are the largest of the Earth’s aquatic ecosystems.

As previously stated, freshwater habitats contain less salt than saltwater ones. Marine biomes are aquatic biomes found in the ocean’s saline water.

The three major marine biomes are neritic, oceanic, and benthic. Intertidal zones, estuaries, and coral reefs are examples of marine biomes.

Neritic Biomes

• Neritic biomes are found in ocean water around the continental shelf.
• They extend from the low-tide water line to the continental shelf’s edge.
• Because the water is shallow here, there is enough sunlight for photosynthesis.
• The water is also high in nutrients, which have been washed into it from neighbouring land.
• Because of these favourable conditions, neritic biomes support high concentrations of phytoplankton.
• They generate adequate food for many other creatures, including zooplankton and nekton.
• As a result, neritic biomes have high biomass and diversity.
• Several types of insects and fish live in them. In reality, neritic biomes are home to the majority of the world’s major saltwater fishing locations.

Also Read: Biodiversity Hotspots in India – ClearIAS

Oceanic Biomes

• Oceanic biomes are found beyond the continental shelf in the open ocean.
• Because dissolved nutrient contents are lower away from shore, the oceanic zone has a lower organism density than the neritic zone.
• The oceanic zone is further subdivided into zones based on sea depth.
• The epipelagic zone is defined as the top 200 metres of water, or the depth to which sufficient sunlight may enter for photosynthesis.
• The bathypelagic zone extends from 1,000 to 4,000 metres below sea level. Because sunlight does not penetrate below 1,000 metres, this zone is completely dark.
• Between 4,000 and 6,000 metres below sea level lies the abyssopelagic zone.
• The hadopelagic zone is located in deep ocean trenches beneath 6,000 metres of water.

Also Read : Grasslands: Types, Features, and Significance – ClearIAS

Benthic Biomes

Benthic biomes are found at the ocean’s bottom, where benthos live.Certain benthos, such as sponges, are sessile, meaning they cannot move and reside glued to the ocean floor.Some benthos, such as clams, dig through ocean floor sediments.

The benthic zone is further subdivided dependent on how much below sea level the ocean bottom is.

• The sublittoral zone is the area of the ocean floor near the shoreline that comprises the continental shelf.
• The bathyal zone is the section of the ocean floor that forms the continental slope. It is located between 1,000 and 4,000 metres below sea level.
• The abyssal zone is a section of the deep open ocean’s ocean floor. It ranges between 4,000 and 6,000 metres below sea level.
• In deep ocean trenches, the hadal zone is the ocean bottom below 6,000 metres. The only species known to dwell in this zone are found around hydrothermal vents, where invertebrates like tubeworms and clams can be discovered. For feeding, they rely on minute archaea species.

Intertidal zone

• The intertidal zone is a short strip of land between the high- and low-tide water lines.
• It is also known as the littoral zone.
• The regular passage of the tides in and out is a prominent aspect of this zone.
• This happens twice a day in most places.
• This zone alternates between being underwater at high tide and being exposed to the air at low tide due to tides.
• The high tide brings in coastal water with its heavy supply of dissolved nutrients on a regular basis.
• There is also an abundance of sunshine for photosynthesis.
• Also, the shallow water keeps bigger predators out of the intertidal zone, such as whales and huge fish.

Estuary

• A bay where a river drains into the ocean is known as an estuary.
• It is normally semi-enclosed, which makes it a safe setting.
• The water is nutrient-rich from the river and shallow enough to allow sunlight to penetrate for photosynthesis.
• As a result, estuaries are teeming with marine life.

Coral reef

• A coral reef is an underwater limestone structure formed by corals, which are microscopic invertebrate organisms.
• Coral reefs can only be found in shallow tropical ocean water.
• Corals release calcium carbonate (limestone) to construct an exterior skeleton.
• Corals live in colonies, and the skeletal material accumulates over time to form a reef. Coral reefs are teeming with marine life, including over 4,000 tropical fish species.

Importance of Aquatic Biomes

• The health of aquatic biomes is vital to the general health of the planet.
• The oceans, with their fish, weeds, invertebrates, and mammals, as well as the world’s rivers, lakes, streams, marshes, and ponds, are all important biodiversity reservoirs.
• The waters also help to regulate global temperature and keep carbon out of the atmosphere.
• Whilst we should all try to eat less fish, there is no denying that fish and other aquatic creatures are important food sources for many terrestrial animals (i.e. animals that live on land).
• Aquatic biomes recycle nutrients, purify water, minimise flooding, increase and maintain streamflow, recharge groundwater, and serve as wildlife habitats and recreational areas.
• In addition to contributing to biodiversity and ecological productivity, they serve a variety of services for human populations, including water for drinking and irrigation, recreational activities, and habitat for economically important fisheries.

Conclusion

Around the world, there are many different types of aquatic ecosystems, each of which is home to some wonderful species. Scientists think that because our marine habitats are so vast and enigmatic, they have only documented about 10% of the creatures that live there. Nevertheless, pollution, carbon emissions, and overfishing pose major risks to these aquatic ecosystems. The Great Barrier Reef, one of the world’s natural wonders, is already dying before our eyes. It is vital that we all act now to protect the world’s aquatic ecosystems for future generations. This can be accomplished by reducing emissions, preventing the use of harmful chemicals that can leach into the oceans and rivers, and removing fish from the food chain.

Article Written By: Atheena Fathima Riyas