Introduction of 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.
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.
(Image will be Uploaded soon)
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.
Freshwater Ecosystem
This aquatic ecosystem covers less than 1% of the earth’s surface and is broadly divided into – wetlands, lentic and lotic ecosystems.
(Image will be Uploaded soon)
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
FAQs on Aquatic Ecosystem
1. What is an aquatic ecosystem?
An aquatic ecosystem is a community of organisms that live and interact with each other and their environment within a water-based setting. These ecosystems are broadly defined by their abiotic factors, such as water chemistry, sunlight penetration, and temperature, and their biotic factors, which include all living organisms like plants, animals, and microbes.
2. What are the major types of aquatic ecosystems?
Aquatic ecosystems are primarily divided into two major types based on salinity:
- Freshwater Ecosystems: These have low salt concentrations. They are further classified into lotic (moving water like rivers and streams) and lentic (still water like lakes, ponds, and wetlands).
- Marine Ecosystems: These are saltwater environments and are the largest type of ecosystem on Earth. They include oceans, coral reefs, and estuaries.
3. What are the key components that structure an aquatic ecosystem?
The structure of an aquatic ecosystem is determined by its biotic and abiotic components. Abiotic components include non-living factors like sunlight, temperature, water pH, and nutrient availability. Biotic components include all living organisms, which are often categorised as:
- Producers: Organisms like phytoplankton and aquatic plants that produce their own food.
- Consumers: Animals that feed on other organisms, such as zooplankton, fish, and mammals.
- Decomposers: Bacteria and fungi that break down dead organic matter, recycling nutrients back into the ecosystem.
4. Why are aquatic ecosystems so important for the environment?
Aquatic ecosystems provide essential ecological services. They play a critical role in the global water cycle, help in nutrient recycling, purify water by filtering pollutants, and recharge groundwater. Furthermore, they are vital habitats for a vast diversity of species and are crucial for regulating the Earth's climate.
5. How is a typical food chain structured in an aquatic ecosystem like a pond?
In a typical pond ecosystem, the food chain begins with producers like phytoplankton and algae, which use sunlight for photosynthesis. These are eaten by primary consumers (herbivores) like zooplankton and small insects. Small fish (secondary consumers) then eat the zooplankton, and larger fish or birds (tertiary consumers) prey on the smaller fish, forming multiple trophic levels.
6. What is the main difference between a freshwater and a marine ecosystem?
The primary difference lies in the salinity, or salt content, of the water. Freshwater ecosystems, like rivers and lakes, have a very low salt concentration (typically less than 1%). Marine ecosystems, such as oceans, have high salt concentrations (around 3.5% on average). This fundamental difference in chemistry dictates the types of species that can survive in each environment, as organisms must have specific adaptations for osmoregulation.
7. How do abiotic factors like sunlight and temperature limit life in deep ocean ecosystems?
Sunlight and temperature are major limiting factors in deep oceans. Sunlight only penetrates the upper layer of water, known as the photic zone, where photosynthesis can occur. Below this, in the aphotic zone, there is no light, so no plant life can grow. Organisms here rely on organic matter sinking from above or chemosynthesis. Similarly, the water temperature drops drastically with depth, slowing down metabolic rates and requiring special adaptations for survival in the cold, high-pressure environment.
8. What is thermal stratification in a lake and why is it important?
Thermal stratification is the layering of lake water during summer and winter due to temperature differences, which affects water density. A typical lake in a temperate region stratifies into three layers: the warm upper layer (epilimnion), a middle layer where temperature changes rapidly (thermocline), and the cold, dense bottom layer (hypolimnion). This layering prevents the mixing of water and nutrients, leading to oxygen depletion in the hypolimnion. Seasonal turnover, or mixing, is crucial for redistributing oxygen and nutrients throughout the lake.
9. Why are estuaries considered one of the most productive types of aquatic ecosystems?
Estuaries, where freshwater rivers meet the saltwater ocean, are highly productive for several reasons. They receive a constant supply of nutrients from the river and the ocean, creating a nutrient-rich environment. The shallow water allows for ample sunlight penetration, supporting high rates of photosynthesis by plants and algae. This combination of factors supports a rich biodiversity and makes estuaries critical nursery grounds for many marine species.
