Eutrophication is a process that affects aquatic ecosystems. It can cause algal blooms and nutrient pollution. Listed below are some of the effects of eutrophication. If you’re concerned about eutrophication, it’s important to understand its causes and prevent its effects.
Human-induced eutrophication
While eutrophication is a natural process, human activity has amplified its effects. Large-scale eutrophication affects the quality of water and soils, causing changes in species composition and communities. The effects are already evident, but there are many ways to reduce human-induced eutrophication. For example, restrictions on fertilizer use and improved planning of fertilizer use can reduce the load of nutrients in oceans and lakes. Furthermore, a transition to more sustainable agriculture can also help reduce the threat of eutrophication.
However, further studies are needed to understand the effects of human-induced eutrophication on aquatic organisms. In particular, altered selective pressures may affect genetic variation and alter evolutionary patterns of exposed populations. Moreover, anthropogenic environmental changes often occur faster than natural ones, forcing populations to adapt faster than they would otherwise.
The impacts of eutrophication are more severe in aquatic ecosystems. While eutrophication can enhance aquatic ecosystems, it can negatively affect terrestrial ecosystems. For example, increased nitrate concentrations in soil can change the composition of vegetation. As a result, many plant species may be threatened.
In the UK, a recent assessment of the state of eutrophication in UK waters shows that the problem is largely contained in coastal and estuarine waters. However, the assessment found that a number of water bodies were improving, while others were still suffering from problems. In general, improvements were noted in the amount of nitrogen and phosphorus inputs and oxygen levels.
The main causes of eutrophication are excessive amounts of primary production (PM) in an ecosystem, the resulting excess of nitrogen and phosphorus in an ecosystem, and poor water exchange between land and sea. These factors affect ecosystem health, biodiversity, and ecosystem services. The primary inorganic nutrients that contribute to eutrophication are phosphorus and nitrogen. Both nutrients are largely derived from the land and transferred to the oceans through rivers and rainwater. In extreme cases, eutrophication may result in lower water clarity and reduced oxygen levels.
Overall, the Baltic Sea is improving with regards to eutrophication, although it has not improved in all areas. This could be due to natural variability. While the central Baltic Sea may have experienced a deficiency of oxygen, past nutrient inputs led to an excess of nutrients in the deep waters. In addition, inflow events from the North Sea have also caused intrusions of nutrient-rich deep waters, which can increase the amount of oxygen in receiving areas.
The impacts of eutrophication can be devastating to ecosystems. Regulations often restrict the input of nitrogen and phosphorus to preserve lake quality. In extreme cases, eutrophication can be associated with other types of pollution and lead to ecosystems that are no longer able to support life.
Effects of eutrophication on aquatic ecosystems
Eutrophication, or the presence of excessive nutrients, is a major threat to aquatic ecosystems and is a growing concern. It quickly alters ecological conditions, mostly affecting biodiversity. In some cases, eutrophication can increase species richness, but this is primarily driven by the invasion of non-native species and not by changes in evolutionary dynamics. In lakes, increased nutrient levels also lead to a dramatic shift in phytoplankton communities, where cyanobacteria can dominate.
As ecosystems become more eutrophicated, they can become more vulnerable to species-specific extinctions. For example, eutrophication can affect gene flow, population size, and reproductive isolation. These effects can increase the likelihood of species extinction, and increase its intensity and speed.
Several other effects of eutrophication on aquatic systems include the depletion of dissolved oxygen. The increase of microscopic algae can shade rooted plants on the bottom, compromising the ecological integrity of water bodies. Furthermore, elevated production of algae can cause a higher number of hypoxic events (low dissolved oxygen concentrations), a condition that can further damage ecosystems.
Human activities are one of the major contributors to eutrophication. Chemical nutrients from agricultural lands can enter waterways through point-sources or non-point sources. In addition to agricultural pollution, industrial wastewater from cities can also enter waterways. This means that eutrophication is often a one-way trip.
The effects of eutrophication can range from beneficial effects on plant growth and fish yields to negative effects on ecosystem health and biodiversity. As a result, the entire aquatic ecosystem can change. A diagram below highlights the changes that occur in aquatic ecosystems in the course of eutrophication.
The changes in nutrient levels affect the behavioural and physical structure of some species. For example, the presence of a dense mat of filamentous algae around male stickleback nests results in smaller territorial areas and reduced aggression among males. The increased density of nests also indicates greater reproductive ability of the males.
Increased turbidity reduces the amount of light reaching the surface of a lake, which reduces its effectiveness as a source of energy for the organisms. As a result, eutrophication can lead to the extinction of endemic species.
Animal feeding operations also contribute to eutrophication. These operations dump high-nitrogen concentrations into surface waters, which in turn causes recurring algal blooms. While this process is natural and has existed for millennia, the use of fertilizers and sludge has increased the rate of eutrophication.
As a result of eutrophication, many lakes have experienced severe ecological changes. A major change in plankton communities is the rise of small-bodied zooplankton. These organisms exhibit anti-herbivorous traits, resulting in a resegregation of plankton communities. In addition, the biomass of planktivorous fish tends to be positively related to nutrient levels. Furthermore, planktivores become more dominant in nutrient-enriched lakes.
Moreover, eutrophication can lead to an increase in algal growth, which causes dense mats of plants. This can restrict boat mobility and hamper recreational opportunities.
Control measures
One of the most important factors in preventing eutrophication is public involvement. Increasing public awareness about the issue is critical to the success of policies designed to protect water resources. Public awareness can be achieved by promoting programs that encourage recycling, waste elimination, and rational use of water.
However, reducing P inputs alone cannot prevent eutrophication. Increasing human population and agricultural production will likely increase P inputs. Therefore, it is crucial to evaluate the effectiveness of different approaches to controlling eutrophication. Using multiple lines of evidence, limiting P inputs can effectively control eutrophication.
Control measures for eutrophication must be tailored to the type and size of lakes affected. For example, a large lake may not be suited to large-scale chemical treatments. Therefore, case studies of specific lake sizes can provide important information to regulators. In addition, case studies add weight to the results of whole-lake experiments.
Managing runoff from farms is another key element to preventing eutrophication. By increasing ground cover, farmers can prevent runoff of nutrients. In addition, buffer zones near roads and farms can prevent nutrients from traveling too far into the water. However, the effects of atmospheric nitrogen pollution can extend well beyond these buffer zones.
In addition to causing environmental degradation, eutrophication can also affect human health and economic activity. It can reduce the quantity of fish and shellfish available, and can increase water treatment costs. Further, it can affect the appearance of a water body and affect its quality.
Eutrophication is an important environmental issue around the world. China’s Lake Taihu is an example of a large, shallow eutrophic lake. A large-scale ecological engineering experiment was recently implemented in Meiliang Bay on the lake. This large-scale experiment focused on minimizing the amount of nutrients entering the lake.
The term eutrophication comes from the Greek word eutrophos, which means “nutrient-rich.” In plain English, eutrophication causes the concentration of nitrate in the water, which supports the growth of algae and other aquatic plants. Eventually, the water becomes eutrophic, leading to the formation of a dead zone and the killing of fish.
Control measures for eutrophication also include reducing phosphorus and other nutrients entering a lake. Agricultural and urban sewage systems are two of the primary contributors to the lake’s nutrient pollution. In addition, wetlands and buffer zones around water systems could limit nutrient releases to the lake. Additionally, the efficient use of lake water could help reduce domestic water usage.
The emergence of eutrophication as a concern was first noted in the mid-20th century. This was followed by breakthrough research conducted in the Experimental Lakes Area in Ontario, Canada. In the 1970s, this research used a whole-lake approach to study freshwater. The results of the study disproved the detergent industry’s claim that carbon control was necessary to curb eutrophication. Moreover, the results also called into question the validity of the small-scale experiments that supported the detergent industry’s claims.
In addition to controlling phosphorus and nitrogen, control measures for eutrophication must also consider other factors, such as the intensity of human activities. The intensity of human activity affects the amount of nutrients in the water and how effectively these nutrients influence algae growth.
