Types of Aquatic Ecosystems And Their Adaptations

Types of Aquatic Ecosystems and their Adaptations: Aquatic ecosystem is the water-based counterpart of the terrestrial ecosystem. It is the ecosystem that exists in and around a water body. Although all living organisms are directly or indirectly dependent on water for their survival irrespective of their ecosystem or biome, certain organisms are completely dependent on water as it is their niche or habitat. Such organisms with water bodies as their niche or habitat are called aquatic organisms.

What is an Aquatic Ecosystem?

It is a water-based ecosystem in which different water-based organisms interact with other biotic and abiotic components surrounding them. These water-based organisms are completely dependent on their water-based environment for their food, shelter, reproduction, and other requirements or services. However, the capability of the ecosystem to sustain life will be dependent on the water’s physiochemical characteristics, its quantity of dissolved sediments, levels of dissolved nutrients, etc. factors.

Characteristics of Aquatic Ecosystem

Following are the characteristics of the Aquatic ecosystem;

1. Composed of water i.e. either freshwater or saltwater.
2. Should provide a habitat for a variety of aquatic organisms.
3. The aquatic vegetation or flora should consist of algae and corals.
4. Should be a more or less self-sustained ecosystem.
5. They should be the most productive ecosystem of the plant.
6. They should help and regulate maintaining the hydrological cycle.
7. They should function as pollution filters.

Factors Affecting the Aquatic Ecosystem

The following are the factors that affect the aquatic ecosystem:

1. The extent of distribution of producers depends on the depth at which light can penetrate i.e. the area which has ambient amount of light will have high numbers of producers.
2. The normal concentration of dissolved oxygen in a water body should be 10 ppm by weight or more. If the level goes below 3-4 ppm then the aquatic organisms start to die.
3. Minor changes in the normal temperatures of the water bodies may pose a threat to the survival of aquatic organisms as they have a very narrow tolerance range for temperature.

Types of Aquatic Ecosystem

Freshwater Ecosystem

The type of water ecosystem in which the water has a salt concentration of less than 5 ppt. is called the freshwater ecosystem. This ecosystem covers only 2% of the total water cover of the planet but is the form of water that is required by the terrestrial organisms also along with the aquatic organisms found in it. It is further divided into;

1. Lentic ecosystem (lacustrine ecosystem): The freshwater ecosystem that includes water bodies that are static or still like lakes, and ponds. This type of ecosystem consists of floating or rooted plants and algae as vegetation. Water animals like shrimps, crabs, and some varieties of fish are found. Other than these land animals like snakes, alligators, crocodiles, and amphibians like frogs, and salamanders are also found.
2. Lotic ecosystems (riverine ecosystem): The freshwater ecosystem includes water bodies with rapid flow of water like streams and rivers. They have phytoplankton along with insects like beetles, mayflies, etc., and other species like dolphins, eel, trout, otters, etc.
3. Swamps and Wetlands: The freshwater ecosystem that is partially or fully covered by water like marshes, swamps, and bogs. These areas house wide varieties of organisms like black spruce, water lilies, dragonflies, green heron, northern pike, crocodiles, etc.

Marine Ecosystem

The type of water ecosystem in which the water has a salt concentration of 35 ppt. or above is called a marine ecosystem or saltwater ecosystem. This ecosystem covers 98% of the total water cover of the planet. It has some unique life forms which have adapted to the high salt concentrations. It is further divided into;

1. Ocean ecosystem: Oceans cover more than 70% of the earth’s surface. There are five oceans present i.e. the Indian Ocean, Pacific Ocean, Atlantic Ocean, Arctic Ocean, and Southern Ocean. Out of these, the Pacific Ocean is the largest and the deepest followed by the Atlantic Ocean. Oceans are home to a variety of species like; algae, plankton, crustaceans, corals, sharks, whales, etc.
2. Estuaries: It is the meeting point of a freshwater body and a saltwater body. The water has more salt concentration as compared to freshwater bodies but is diluted as compared to saltwater bodies. These areas receive large quantities of plant nutrients and usually have ambient sunlight so they are more productive due to large quantities of primary producers.
3. Coral reefs: These are formed by the dead remains of the coral polyps that form a shell-like covering of calcium carbonate which after their death forms a network with other such empty shells. This network forms a colony-like arrangement where various kinds of aquatic organisms take shelter. These are found in coastal areas where the water is warm, shallow, clear, receives ambient sunlight, and houses many aquatic organisms. Coral reefs are considered the rainforest of the aquatic system as they are home to the majority of marine biodiversity.
4. Coastal ecosystem: The connecting point between land and water is called the coastal region. These regions have a diverse form of habitats in which the bottom regions are dominated by the huge range of algae, and aquatic plants. The animal species consists mainly of arthropods like insects, crabs, lobsters, etc. along with snails, fishes, etc.

Significance of Aquatic Ecosystem

1. They are the major source of oxygen and are responsible for the huge amounts of carbon removal from the atmosphere. So, the health of the aquatic ecosystem is very critical for the planet.
2. They are home to a huge number of biodiversity acting as valuable biodiversity reservoirs.
3. Water is essential for the survival of the biodiversity present in the land also.
4. They also help in regulating the earth’s temperature and seasons.
5. Aquatic organisms are a huge source of food for terrestrial animals along with humans.
6. They help in nutrient cycling, replenishing groundwater, and providing habitats, and recreational opportunities.