what is the mechanism of eutrophication?

Answer 1

Natural eutrophication is the process by which lakes gradually age and become more productive. It normally takes thousands of years to progress. However, humans, through their various cultural activities, have greatly accelerated this process in thousands of lakes around the globe. Cultural or anthropogenic "eutrophication" is water pollution caused by excessive plant nutrients. During the 1960's, Lake Erie was undergoing rapid cultural eutrophication and was the subject of much concern.
Humans add excessive amounts of plant nutrients (primarily phosphorus, nitrogen, and carbon) to streams and lakes in various ways. Runoff from agricultural fields, field lots, urban lawns, and golf courses is one source of these nutrients. Untreated, or partially-treated, domestic sewage is another major source. Sewage was a particular source of phosphorus to lakes when detergents contained large amounts of phosphates. The phosphates acted as water softeners to improve the cleaning action, but they also proved to be powerful stimulants to algal growth when they were washed or flushed into lakes.

The excessive growth, or"blooms", of algae promoted by these phosphates changed water quality in Lake Erie and many other lakes. These algal blooms led to oxygen depletion and resultant fish kills. Many native fish species disappeared, to be replaced by species more resistant to the new conditions. Beaches and shorelines were fouled by masses of rotting, stinking algae. A means to control this problem became a paramount need.

Using small, natural lakes as experimental systems, scientists at the ELA were able to add various combinations of nutrients and determine which of the major plant nutrients (carbon, nitrogen, phosphorus) was the key to controlling cultural eutrophication in lakes.

Answer 2

Eutrophication is the natural process of accumulation of excessive nutrient in a lotic ecosystem like pond.
It happens due to run off of chemicals from land with rain water, wind.etc..
It results in excessive growth of sea weeds and algae and
Increase in BOD(biological oxygen demand)

Answer 3

Eutrophication is frequently a result of nutrient pollution such as the release of sewage effluent into natural waters (rivers or coasts) although it may also occur naturally in situations where nutrients accumulate (e.g. depositional environments) or where they flow into systems on an ephemeral basis (e.g. intermittent upwelling in coastal systems). Eutrophication generally promotes excessive plant growth and decay, favors certain weedy species over others, and is likely to cause severe reductions in water quality . In aquatic environments, enhanced growth of choking aquatic vegetation or phytoplankton (that is, an algal bloom) disrupts normal functioning of the ecosystem, causing a variety of problems.

Human society is impacted as well: eutrophication decreases the resource value of rivers, lakes, and estuaries such that recreation, fishing, hunting, and aesthetic enjoyment are hindered. Health-related problems can occur where eutrophic conditions interfere with drinking water treatment. Although traditionally thought of as enrichment of aquatic systems by addition of fertilizers into lakes, bays, or other semi-enclosed waters (even slow-moving rivers), terrestrial ecosystems are subject to similarly adverse impacts.

Increased content of nitrates in soil frequently leads to undesirable changes in vegetation composition and many plant species are endangered as a result of eutrophication in terrestric ecosystems, e.g. majority of orchid species in Europe. Ecosystems (like some meadows, forests and bogs that are characterized by low nutrient content and species-rich, slowly growing vegetation adapted to lower nutrient levels) are overgrown by faster growing and more competitive species-poor vegetation, like tall grasses, that can take advantage of unnaturally elevated nitrogen level and the area may be changed beyond recognition and vulnerable species may be lost. Eg. species-rich fens are overtaken by reed or reedgrass species, spectacular forest undergrowth affected by run-off from nearby fertilized field is turned into a thick nettle and bramble shrub.

Eutrophication was recognized as a pollution problem in European and North American lakes and reservoirs in the mid-20th century. Since then, it has become more widespread. Surveys showed that 54% of lakes in Asia are eutrophic; in Europe, 53%; in North America, 48%; in South America, 41%; and in Africa, 28%..

Answer 4

Q1 B) passive by actuality that antibodies are on the instant presented to the little one devoid of little one contemporary technique any exposure to antigen. Q2 D) The secondary reaction facilitates new antigens to be ordinary speedier. Q3 C) grows, divides, and differentiates extra. On touch with antigen B cellular differentiates into plasma cells and produces antibodies. this fall D) autoimmune by actuality it somewhat is against bodies very own antigens so because it somewhat is continually risky. Q5 D. Helper T cells they administration the intensity of the immune reaction.

Answer 5

Eutropication refers the gradual increase of nutrient concentration in water bodies. this is considered as one kind of water pollution since it is not good for that ecosystem.

mechanism
normally water bodies such as lake, ponds and tanks receives water through runoff produced by excess rainfall. this runoff water dissolves allnutrient elements while passing over soils. Natural soil contain very less amount of nutrients.

but in modern days, due to increased fertilization of agricultural lands eutropication of near by ponds take places frequently.
once the ponds get rich in nutrients it will increase the algal and other plant biota first. because of abundant plant biota, the related animal biota such as fishes anf others growth increases subsequently.

once this happens, the limited disolved oxygen decreases drastically and leads to death of living organisms one by one. finally all living organisms will die shortly and the colour of the lake become balck and foul odour develops.

by Mani,
Dept of soil,
TNAU

Answer 6

increase in the organism in water bodies that consumes the water body oxygen which led to its oxygen decline

Answer 7

http://rds.yahoo.com/_ylt=A0geu630BOtFChMA.whXNyoA;_ylu=X3oDMTE2MjE1ZmJzBGNvbG8DZQRsA1dTMQRwb3MDMQRzZWMDc3IEdnRpZANGODczXzgw/SIG=11vteh7ge/EXP=1173116532/**http%3a//en.wikipedia.org/wiki/Eutrophication