Aquatic ecosystem
An aquatic ecosystem is a specific type of ecosystem found within bodies of water, encompassing both the plants and animals that inhabit these areas. Covering approximately 70 percent of Earth’s surface, aquatic ecosystems are classified into two main categories: saltwater and freshwater. Saltwater ecosystems, such as oceans and coral reefs, have high salinity and feature diverse habitats including intertidal, pelagic, benthic, and abyssal zones, each supporting unique biological communities. Freshwater ecosystems, which include lakes, rivers, and wetlands, are characterized by low salt concentrations and contain varying habitats, such as the warm littoral zone and the deeper, colder profundal zone.
These ecosystems are interdependent, relying on a balanced flow of energy that begins with sunlight, is harnessed by producers like algae, and is transferred through consumers to decomposers. However, aquatic ecosystems face significant threats from pollution, chemical disturbances, and biological invasions, all of which can disrupt their delicate balances and, consequently, human health. The importance of maintaining healthy aquatic ecosystems is underscored by their role in providing drinking water and food sources. Restoration efforts are ongoing, with scientists employing technology and legislation to safeguard these vital environments.
Aquatic ecosystem
An aquatic ecosystem is an ecosystem that exists in a body of water. An ecosystem refers to the plants and animals in a particular area. All parts of an ecosystem rely on each other for survival. About 70 percent of Earth's surface contains aquatic ecosystems, and about 30 percent contains terrestrial ecosystems, or land-dwelling ecosystems. Aquatic ecosystems can be classified as either saltwater or freshwater ecosystems.
Saltwater ecosystems exist in bodies of water such as oceans and salt marshes that contain high amounts of salt. Freshwater ecosystems exist in bodies of water with little or no salt, such as ponds, swamps, and bogs. Saltwater and freshwater ecosystems are home to different types of animal and plant life. Pollution and other environmental damage can endanger aquatic ecosystems.
Energy Flow in Ecosystems
An ecosystem must be balanced in order for the plants and animals within it to survive. If one plant or animal species within an ecosystem is disturbed, the flow of energy is disrupted, and the entire ecosystem becomes unbalanced.
The basic structure of an ecosystem's energy flow is as follows:
- Sunlight is absorbed as energy by producers such as algae.
- Producers are eaten by consumers, or animals.
- Consumers die and decompose, turning into fungi or bacteria.
- Decomposers release minerals into their environment.
- Minerals nourish water and soil where producers live.
- Producers feed off nutrients and the cycle begins again.
Types of Aquatic Ecosystems
Aquatic ecosystems are primarily of two types: saltwater and freshwater. Organisms living in a saltwater ecosystem cannot survive in fresh water and vice versa.
Saltwater ecosystems, also called marine ecosystems, exist in bodies of water with a high salt content, such as oceans, coral reefs, lagoons, and estuaries. Saltwater ecosystems contain an array of aquatic and subaquatic organisms. The larger of the aquatic ecosystems, saltwater ecosystems have several different zones, or habitats, which include the intertidal zone, pelagic zone, benthic zone, and abyssal zone.
Different species of plants and animals live in each zone. The intertidal zone is a shallow region where the tide meets the land. Organisms such as crabs, mussels, seaweed, and barnacles live in the intertidal zone. The pelagic zone is part of the open ocean upper region, which is where most swimming fish, or nektons, live. Turtles, whales, and sharks also live in this zone. The benthic and abyssal zones are part of the open ocean lower region, which is the darkest, coldest area of the ocean. The benthic zone is populated by benthos, or bottom dwellers, such as eels, shrimp, and lobster. Other organisms found in the benthic zone include bacteria, fungi, sponges, sea anemones, and worms. Bottom dwellers eat algae and decayed matter off the ocean floor. Just beneath the benthic zone is the abyssal zone, the deepest region of the ocean. The water in this zone is only around three degrees Celsius and highly pressurized. Unlike the benthic zone, the abyssal zone is nutrient-deficient, so very few organisms live there.
Freshwater ecosystems exist in bodies of water with low concentrations of salt, such as lakes, ponds, streams, rivers, and wetlands. Lakes and ponds are isolated bodies of water and therefore contain a limited diversity of species. However, plant life such as algae and animals such as snails, clams, fish, and amphibians can survive in the littoral zone of lakes and ponds. This is the warmest zone because it absorbs heat from the sun. The region below the littoral zone, the limnetic zone, accommodates mostly plankton, which plays an important role in the ecosystem's food chain because it is a major source of food for fish. Lakes and ponds also have a deep region called the profundal zone that can get as cold as four degrees Celsius.
Aquatic Ecosystem Dangers
Aquatic ecosystems are vulnerable and their balance can be disturbed in many ways. Physical disturbances such as a rise in water temperature can put some of the organisms within the ecosystem at risk. Chemical disturbances such as toxic waste are also a danger to aquatic ecosystems. Acid rain can change the chemical properties of an aquatic ecosystem, making it more acidic, which harms the life within it. Biological disturbances such as the introduction of non-native plants and animals also threaten aquatic ecosystems.
People need aquatic ecosystems to be healthy in order to stay healthy themselves. We drink water from lakes and rivers and eat fish from various bodies of water. If these bodies of water become contaminated, the life within them may also become contaminated. Therefore, pollution, such as medical refuse and animal waste, not only threatens aquatic ecosystems but human life as well. Contamination is also responsible for urban beach closures and water treatment problems.
Fortunately, scientists are able to restore some aquatic ecosystems by using technology to closely monitor them. Preventative measures such as environmental legislation can also help ensure that aquatic ecosystems remain healthy.
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