A aquatic ecosystem is an ecosystem in a body of water. Community organisms that depend on each other and in their environment live in aquatic ecosystems. The two main types of aquatic ecosystems are marine ecosystems and freshwater ecosystems.
Video Aquatic ecosystem
Type
Marine
The marine ecosystem covers about 71% of the earth's surface and contains about 97% of the planet's water. They produce 32% of the world's net primary production. They are distinguished from freshwater ecosystems by the presence of dissolved compounds, especially salts, in water. Approximately 85% of the dissolved materials in seawater are sodium and chlorine. Sea water has an average salinity of 35 parts per thousand (ppt) of water. The actual salinity varies among different marine ecosystems.
Marine ecosystems can be divided into many zones depending on the depth of water and coastline features. The ocean zone is a wide open part of the ocean where animals such as whales, sharks and live tuna. The benthic zone consists of substrate under water where many live invertebrates. The intertidal zone is the area between high and low tides; in this image is called the litoral zone. Other near-shore zones may include estuaries, salt marshes, coral reefs, lagoons and mangrove swamps. In water, hydrothermal holes can occur where chemosynthetic sulfur bacteria form the basis of the food web.
Classes of organisms found in marine ecosystems include brown algae, dinoflagellates, corals, cephalopods, echinoderms, and sharks. Fish captured in marine ecosystems are the largest source of commercial food derived from wild populations.
Environmental concerns about marine ecosystems include the non-sustainable exploitation of marine resources (eg overfishing of certain species), marine pollution, climate change, and coastal development.
Freshwater
Freshwater ecosystems cover 0.78% of the Earth's surface and inhabit 0.009% of its total water. They produce nearly 3% of net primary production. Freshwater ecosystems contain 41% of the world's known fish species.
There are three basic types of freshwater ecosystems:
- Lentika: slow moving water, including ponds, ponds, and lakes.
- Lotik: water that moves faster, such as streams and rivers.
- Wetlands: areas where the soil is saturated or stagnant for at least some time.
Lentic
The lake ecosystem can be divided into zones. One common system divides the lake into three zones (see figure). The first, the litoral zone, is a shallow zone near the coast. This is where wetland plants take root. Offshore is divided into two further zones, open water zone and deep water zone. In open water zones (or photon zones), sunlight supports photosynthetic algae, and the species that eat them. In the deep water zone, sunlight is not available and the food web is based on the incoming detritus of the litoral and photon zones. Some systems use other names. The offshore area can be called a pelagic zone, the photon zone can be called the limnetic zone and the pharmacy zone can be called the profundal zone. Inland from the litoral zone can also often identify riparian zones that have plants that are still affected by the presence of lakes - these can include the effects of windfalls, spring floods, and winter ice damage. The production of the lake as a whole is the production of plants growing in the litoral zone, combined with the production of plankton growing in open water.
Wetlands can be part of the lentik system, since they form naturally along the shores of the lake, the area of ​​wetlands and littoral zones depend on the slope of the shoreline and the number of natural changes in water levels, within and between years. Often dead trees accumulate in this zone, either from beach livelihood or timber transported to the site during floods. These wooden ruins provide an important habitat for nesting fish and birds, and protect the shoreline from erosion.
Two important subclasses of the lake are ponds, which are usually small lakes that are interconnected with wetlands, and water reservoirs. Over a long period of time, the lake, or bay in it, can gradually be enriched by nutrients and slowly filled with organic sediments, a process called succession. When humans use watersheds, the volume of sediments entering the lake can accelerate this process. The addition of sediment and nutrients to the lake is known as eutrophication.
Ponds
The pond is a small body of fresh water with shallow plants and water, swamps, and water. They can be subdivided into four zones: vegetation zone, open water, bottom sludge and film surface. The size and depth of the pool often varies greatly with time of year; many ponds are generated by spring floods from the river. The food web is based both on free-floating algae and on aquatic plants. There are usually a variety of aquatic life, with some examples including algae, snails, fish, beetles, water insects, frogs, turtles, beavers and muskrats. The top predators may include large fish, storks, or crocodiles. Because fish are the main predators in amphibian larvae, the ponds dry out annually, thereby killing the resident fish, providing an important refuge for amphibian breeding. A pond that dries fully every year is often known as a vernal pool. Some ponds are produced by animal activity, including crocodile and beaver ponds, and this adds an important diversity to the landscape.
Lotic
The main zone in the river ecosystem is determined by the river bottom gradient or by the current velocity. The faster moving turbulent water usually contains a greater concentration of dissolved oxygen, which supports greater biodiversity than slow-moving pool waters. These differences form the basis for the division of rivers into upland and lowland rivers. River food bases in riparian forests mostly come from trees, but a wider stream and those without a canopy get most of their food bases from algae. Anadromous fish is also an important source of nutrients. Environmental threats to rivers include loss of water, dams, chemical pollution and introduced species. Dams produce negative effects that continue to flow in the watershed. The most important negative effects are the reduction of spring floods, which damage the wetlands, and sediment retention, leading to the loss of delta wetlands.
Wetlands
Wetlands are dominated by vascular plants that have adapted to saturated soil. There are four main types of wetlands: swamp, swamp, fen, and swamp (both swamp and marsh are mud types). Wetlands are the most productive natural ecosystems in the world due to the proximity of water and soil. Therefore they support a large number of plant and animal species. Because of their productivity, wetlands are often converted into dry land with dikes and waterways and used for agricultural purposes. The construction of embankments and dams, has negative consequences for individual wetlands and entire watersheds. Their proximity to lakes and rivers means that they are often developed for human settlements. Once settlements are built and protected by embankments, the settlements then become vulnerable to land subsidence and increased flood risk. The Louisiana coast around New Orleans is a famous example; The Danube Delta in Europe is another.
Maps Aquatic ecosystem
Function
Aquatic ecosystems perform many important environmental functions. For example, they recycle nutrients, purify water, reduce floods, recharge ground water and provide habitat for wildlife. Aquatic ecosystems are also used for human recreation, and are very important for the tourism industry, especially in coastal areas.
The health of aquatic ecosystems is degraded when the ability of the ecosystem to absorb stress has been exceeded. Stress in aquatic ecosystems can be the result of physical, chemical or biological changes from the environment. Physical changes include changes in water temperature, water flow and light availability. Chemical changes include changes in nutrient loading rates of biostimulators, substances that consume oxygen, and toxins. Biological changes include excessive taking of commercial species and introduction of exotic species. The human population can impose excessive pressure on aquatic ecosystems. There are examples of excessive pressure with negative consequences. Consider three. The environmental history of the Great Lakes of North America illustrates this problem, specifically how various pressures, such as water pollution, over-harvesting and invasive species can combine. The Norfolk Broadlands in the UK illustrates a similar decline with pollution and invasive species. Lake Pontchartrain along the Gulf of Mexico illustrates the negative effects of various pressures including the construction of embankments, felling of swamps, invasive species and saltwater intrusions.
Abiotic characteristic
An ecosystem consists of biotic communities that are structured by biological interactions and abiotic environmental factors. Some important abiotic environmental factors of aquatic ecosystem include substrate type, water depth, nutritional level, temperature, salinity, and flow. It is often difficult to determine the relative importance of these factors without a rather large experiment. There may be a complicated feedback loop. For example, sediment can determine the presence of aquatic plants, but aquatic plants can also trap sediments, and add sediment through peat.
The amount of dissolved oxygen in the body of water is often a key substance in determining the level and type of organic life in water bodies. Fish require dissolved oxygen to survive, although their tolerance to low oxygen varies between species; in extreme low oxygen cases some fish even resort to swallow air. Plants often have to produce aerenchyma, while the shape and size of leaves can also be altered. Conversely, oxygen is fatal for many types of anaerobic bacteria.
Nutritional levels are important in controlling the abundance of many species of algae. The relative abundance of nitrogen and phosphorus can determine which species of algae dominate. Algae are a very important food source for aquatic life, but at the same time, if they become abundant, they can cause fish to decline when they rot. The same abundance of algae in coastal environments such as the Gulf of Mexico produces, after decay, the hypoxic water region known as the dead zone.
The salinity of water bodies is also a determining factor in the types of species found in water bodies. Organisms in marine ecosystems tolerate salinity, while many freshwater organisms are not tolerant of salt. Salinity levels at the estuary or delta are important controls on the type of wetlands (fresh, medium, or brackish), and related animal species. Upper-built dams can reduce spring flooding, and reduce sediment loads, and therefore can lead to saltwater intrusion in coastal wetlands.
Freshwater used for irrigation purposes often absorbs salt levels that are harmful to freshwater organisms.
Biotic Characteristics
Biotic characteristics are mainly determined by the organisms that occur. For example, wetland plants can produce thick canopies that cover large areas of sediment - or snails or swans can graze from vegetation leaving large mud. The aquatic environment has relatively low oxygen levels, forcing adaptation by the organisms found there. For example, many wetland plants must produce aerenchyma to bring oxygen to the roots. Other biotic characteristics are more subtle and difficult to measure, such as the relative importance of competition, mutualism or predation. There are more cases where predation by coastal herbivores including snails, geese and mammals seems to be the dominant biotic factor.
Autotrophic organism
Autotrophic organisms are producers that produce organic compounds from inorganic materials. Algae use solar energy to produce biomass from carbon dioxide and perhaps the most important autotrophic organism in the aquatic environment. The shallower the water, the greater the contribution of biomass from rooted and floating vascular plants. These two sources combine to produce remarkable production of estuaries and wetlands, because these autotrophic biomass are converted into fish, birds, amphibians and other aquatic species.
Bacteriosynthetic bacteria are found in benthic marine ecosystems. The organism is capable of feeding on hydrogen sulfide in water derived from volcanic vents. The large concentrations of animals that feed on these bacteria are found around volcanic vents. For example, there is a giant tube worm ( Riftia pachyptila ) with a length of 1.5 m and a 30 cm long ( Calyptogena magnifica) shell. Heterotrophic organism
Heterotrophic organisms consume autotrophic organisms and use organic compounds in their bodies as a source of energy and as a raw material for creating their own biomass. Euryhaline organisms are tolerant of salt and can survive in marine ecosystems, whereas intenohalin species or salt intolerance can only live in freshwater environments.
See also
- Aquatic plants
- Freshwater
- Hydrobiology
- Marine ecosystem
- Stephen Alfred Forbes - co-founder of aquatic ecosystem science
- Metabolic flow
- Terrestrial ecosystem
Note
References
External links
- Aquatic Ecosystems in the Canadian Environment
- Aquatic Bioma
- Fish Collecting Device as a Registered Observatory of the pelagic ecosystem (FADIO) - IRD Video Channel
Source of the article : Wikipedia
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