Over the years, the abnormal biological condition has turned in to a widespread Environment hazard. Today, almost every lake in the world has been affected by the phenomenon. Various surveys reveal that over 54% of Asian and 53% of European lakes are eutrophic. The numbers are 48%, 41% and 28% in North American, South American and African lakes. Eutrophication in River Potomac, caused by a dense bloom of Cyanobacteria Causes of Eutrophication: Nutrient pollution such as the release of sewage effluent and run-off from fertilizers into natural waters are among the most common causes of Eutrophication.
The process is however also known to occur naturally in depositional environments due to an accumulation of nutrients or due to a flow of nutrients into systems for short periods of time. Eutrophication may also result due to natural processes in lakes. Researchers and scientists strongly believe that climate changes, regional geology and other external influences may prove to be critical factors in the regulation of the natural productivity of lakes. Several lakes in temperate grasslands are known to show such characteristics.
A reverse process, meitrophication may also result occasionally, which refers to the nutrition deficiency of lakes. Eutrophication in seasonally inundated tropical floodplains can also be common natural phenomena. The Barotse Floodplain of the Zambezi River is a prime example of the issue. The red waters, which are the floodwaters moving down the floodplain at the inception of the rainy season can severely impact fish life because of their hypoxic nature. The process is mostly a function of the quantities of materials such as manure that are picked up by the flood from the plains.
The use of fertilizers, insecticides and other inorganic chemicals only further accelerates the process. Runoff from agricultural and developmental areas, pollution from septic systems and sewers, and other human-related activities greatly influence the flow of organic and inorganic substances into terrestrial and aquatic ecosystems. Atmospheric compounds of nitrogen and phosphorus are also known to play a significant part in Eutrophication. Phosphorus, as a point source pollutant in sewage, may impact the concentration of algae in lakes that grow almost linearly with an increase in concentration of the element.
Prolonged researches in the lake of Ontario indicate that the rate of Eutrophication is strongly related to phosphorous concentrations in the water that has increased drastically over the years. Estuaries, that happen give scope for the natural mingle of the various organic and inorganic nutrients brought by the rivers into the sea, are naturally eutrophic entities. Primary productivity is further enhanced by upwelling in coastal waters. The upwelling process involves conveying the deeper waters that are rich in nutrients on to the surface where the algal systems assimilate them.
Atmospheric anthropogenic fixed nitrogen does also enter the open oceanic surface regularly that is known to can enter the open ocean. A study in 2008 found that this could account for more than a third of non-recycled oceanic nitrogen supply. Subsequently, this amount is also reflected as around three per cent of the total annual marine Eutrophication. Although traditionally only imagined to affect lakes and seas, in more recent studies, we have come to know that semi-enclosed terrestrial ecosystems are equally subjected to similar adverse impacts of eutrophication.
Increased contents of nitrates in soil may lead to adverse changes in vegetation sonata and impact animal life in many areas severely. Eutrophication in terrestrial ecosystems has endangered many plant and animal species. The disrupted orchids of Europe and ecosystems such meadows, bogs and forests are prime examples of the situation. Since these ecosystems are symbolic of species-rich, slowly growing and low nutrient level vegetation, the effect of eutrophication is significantly realized when faster growing competitive vegetation such as tall grasses quickly replace them by making use of unnaturally elevated nitrogen levels in the region.
Common examples are reed grass species overtaking fens and forest undergrowth affected by run-off from nearby fields, where the forest turns into a thick covering of shrubs. Chemical forms of nitrogen are most often of concern with regard to eutrophication because plants have high nitrogen requirements so that additions of nitrogen compounds stimulate plant growth (primary production). This is also the case with increased levels of phosphorus. Nitrogen is not readily available in soil because N2, a gaseous form of nitrogen, is very stable and unavailable directly to higher plants.
Terrestrial ecosystems are mostly enriched in nitrogen through microbial fixation. The process involves the conversion of N2 into compounds such as nitrates. Nitrogen saturated systems, which are the ecosystems receiving more nitrogen than that required by plants, contribute significant amounts of organic and inorganic nitrogen to fresh and salty waters, harnessing a tremendous increase in the levels of eutrophication. Excessive plant growth and decay is the most common effect of eutrophication.
Certain weedy species happen to overtake other vegetation forms and the result is drastically reduced water quality. The exaggerated growth of choking aquatic vegetation called phytoplankton causes what is called the algal bloom, disrupting the normal ecosystem equilibrium. An increased biological oxygen demand (BOD), a term used to describe a situation of extreme oxygen scarcity in water. The water gets cloudy and devoid of oxygen, killing several hundreds of aquatic lives. Decreased biodiversity is the most widespread effect of the process of eutrophication.
Increase in nutrients lead to increased primary production or the algal bloom that in turn, limit the amount of sunlight available to many organisms that dwell at the bottom. Algal blooms may also result in wide swings in the levels of dissolved oxygen. During the days, the quantity of dissolved oxygen is known to increase while darkness brings a great drop in its level. This is mostly because of the respiration of algal systems and other species of the microbial world that largely feed on dead algae.
Not only does the newly created anaerobic condition bring an end to countless aquatic lives, it provides ample scope for the growth of bacteria such as Clostridium botulinum that produce toxins lethal to all possible life f Toxic compounds produced in the algal blooms may enter the food chain and cause severe damage to aquatic and terrestrial life forms, either directly or otherwise. Freshwater algal blooms are known to pose a threat to livestock and cattle. Toxins released by these algal blooms are consumed by shellfish, subsequently entering human food chain. Marine animals can also fall prey to such eutrophic bio-toxins.
The ciguatera, a predator fish that consumes the algae and relays the toxin on to humans, is an appropriate example. Eutrophication is gradually taking the shape of a major environmental concern to the world. Management strategies and a mitigation plan such as the following might prove to be an important weapon in combating and controlling disaster. Reducing input of nutrients into the water bodies: Undoubtedly, the most obvious reason for the process of eutrophication is the input of nitrogen and phosphorous compounds into the various fresh and salt water bodies.
Apart fro the compounds of these two elements, control of particulate as well as dissolved carbon inputs into the water might be an important consideration. Reducing urban, agricultural, suburban and atmospheric sources and the use of nutrient interceptors such as buffers and wetlands are aspects of the plan. Sources such as sanitary sewer overflows, municipal and industrial treatment plants, storm sewer systems and construction sites come under urban and suburban sources of nutrient production.
Municipal and industrial treatment plants that implement advanced treatment technologies including several physical and bio-chemical methodologies need to be established and developed. Chemical addition with primary clarification and biological nutrient removal are the primitive examples of these processes. These methods are known to remove major proportions phosphorous and nitrogen from wastewater. If the filtration of phosphorous is accomplished through chemical addition and biological treatment processes, nitrogen removal is largely governed by the nitrification and de-nitrification processes.
Nutrient inputs can also be reduced through education. The use of modern street sweepers, bio-retention, use of permeable membranes in constructional processes, Causing effective vegetative uptake are only some of the newly adopted practices that in many ways decrease the levels of eutrophication in our water bodies. Non-point pollution is an important cause of eutrophication. The natural runoff into the various water bodies is a prime factor in the formation of algal blooms.
If the flow of these inorganic and organic pollutants into the water can be prevented or at least be minimized, the control of eutrophication will only be a small step away. Building riparian buffer zones has been a wise step I this direction. These zones are interfaces between flowing water bodies and the surface and are mostly built near waterways, objected to accomplish an effective pollutant-filtration process. Building these buffer zones in domestic farms and roads has also proved to be a productive step in preventing nutrients entering into the water bodies.
Appropriate steps to suppress the nutrients from Onsite Wastewater and septic Systems can also be significant steps in our mitigation plan. The use of septic tanks and filter beds on residential property are practical instances. Recirculation sand filters and up-flow filters can remove nearly 80 percent of the total nitrogen loads. Drip irrigation is yet another method to reduce these nutrient levels in the discharge further. However, the proper maintenance and management of previously existing technologies still remains the most effective and important policy.
Apart from these primary mitigation strategies, the following are some other aspects of our plan that can significantly reduce eutrophication and its effects: The following is a list of methods that can be used to control eutrophication: ¢ Vegetation plantation along streambeds to curb erosion and enhance the proper absorption of nutrients. ¢ Control of the amount ad proper timing of fertilizer and insecticide application. ¢ Control of runoff from feedlots. ¢ Proper Lawn and Landscape Care. ¢ Proper Wildlife care and Pet Waste control. ¢ Strategies to reduce nutrient entrance from agricultural Sources.
¢ Design and manufacture of newer tools for cultivators that would effectively reduce the levels of nutrient flow from agricultural lands. ¢ Application of Incentive-based Strategies to regulate a proper execution and practical implementation of the plan and its objectives. ¢ Reducing Atmospheric Loads through in depth research and application. ¢ Watersheds and Adaptive Management strategies. ¢ Providing federal and governmental support to encourage advanced research and studies in the field of pollution control and waste management. ¢ To strengthen the foundation of the issue; to educate the young children.
There are numerous challenges and obstacles for these programs to be executed effectively and successfully. Therefore they have to be tackled in a very wide perspective. It is incredible to expect the workforce to work honestly and sincerely at all levels of the industry. Bribery and red-tapes are major challenges to the implementation of such a plan. However we make the laws and rules strict, there has to be an honest and sincere effort by each member and related official at each level of execution, starting from the farmer who cultivates I his lands to the ministry officials who will eventually control and direct the plan.
The plan would look more incredible and unachievable if proper support, cooperation and understanding is not associated with the plan. There needs to be a global support. Every government of the world must actively support the plan and take innovative measure to implement the plan. Its the civilian who must awaken his knowledge and expertise to successfully tackle the possible outcomes of the disruption of the plan that would eventually not only result in the mass destruction of the natural habitat of millions and millions of aquatic animals and sea birds but his own life as well.It is with these efforts that the rate at which our environmental heritage is being squandered can be slowed down.
References: Selman, Mindy (2007) Eutrophication: An Overview of Status, Trends, Policies, and Strategies. World Resources Institute Martin, A. ; G. D. Cooke (1994). Health risks in eutrophic water supplies. Lake Line 14: 2426 Rodhe, W. 1969 Crystallization of eutrophication concepts in North Europe. In: Eutrophication, Causes, Consequences, Correctives. National Academy of Sciences, Washington D. C. , Standard Book Number 309-01700-9, 50-64.