Eutrophication is phenomenon of the enrichment of aquatic bodies leading to  the luxuriant growth of blue green algae which ultimately results in the deterioration of water quality. The inorganic fertilizers used in the agricultural fields are drained to the rivers by rain water. Besides this, washing of clothes with detergents on the shore of river causes eutrophication as detergents are the source of phoshphate.

Please check the following link for more details

https://www.academia.edu/3012225/Eutrophication_Causative_factors_and_remedial_measures

Dear Mrnka miroslav,

Eutrophication is the enrichment of an ecosystem with chemical nutrients, typically compounds containing nitrogen, phosphorus, or both. Eutrophication can be a natural process in lakes, occurring as they age through geological time. A major problem with the use of fertilisers occurs when they're washed off the land by rainwater into rivers and lakes. The resulting increase of nitrate or phosphate in the water encourages algae growth, which forms a bloom over the water surface. This prevents sunlight reaching other water plants, which then die. Bacteria break down the dead plants and use up the oxygen in the water so the lake may be left completely lifeless.Many factors- Dissolved Oxygen , Nitrate, Phosphorous , Bacteria , pH , Turbidity, Temperature, Salinity , Flow rate.etc.

 The main effects caused by eutrophication can be summarized as follows

1)     Species diversity decreases and the dominant biota changes.

2)     2. Plant and animal biomass increase.

3)     Turbidity increases.

4)     Rate of sedimentation increases, shortening the lifespan of the lake.

5)     Anoxic conditions may develop

Because of the high concentration of organisms in a eutrophic system, there is often a lot of competition for resources and predator pressure. This high degree of competition and the sometimes-high chemical or physical stress make high the struggle for survival in eutrophic systems. As a result the diversity of organisms is lower in eutrophic than in oligotrophic systems.Many ecological effects can arise from stimulating primary production, but there are three particularly troubling ecological impacts: decreased biodiversity, changes in species composition and dominance, and toxicity effects.

1.       Increased biomass of phytoplankton.

2.       Toxic or inedible phytoplankton species.

3.       Increases in blooms of gelatinous zooplankton.

4.       Increased biomassof benthic and epiphytic algae.

5.       Changes in macrophytespecies composition and biomass.

6.       Decreases in water transparency (increased turbidity).

7.       Colour, smell, and water treatment problems.

8.       Dissolved oxygen depletion.

9.       Increased incidences of fish kills.

10.   Loss of desirable fish species.

11.   Reductions in harvestable fish and shellfish.

12.   Decreases in perceived aesthetic value of the water body

.Regards,

Prem Baboo

You already have two great responses.  Eutrophication of flowing streams is generally not a major concern within the national forest areas where most of my experience has been over my career.  Of course there may be temporary conditions of eutrophication and accumulation of organics of wetlands and non-flowing waters at times.  Conditions brought on by drought or extreme events.  One factor I would suggest is sunlight, streams or flowing waters, when open to sunlight as well as the nutrients and other factors suggested are much more apt to have dense plant growth.  Another factor are fine stream substrates that tend to allow plant or periphyton growth, and possibly the added roughness of vegetation accumulations that would further reduce stream velocities also favor algal growths.  I would guess also that aggrading or braided streams with excess sediments and nutrients also might favor conditions for eutrophication.  As stream facets fill with sediment, conditions increasing are able to support organic growth and accumulation.  River meanders that have lost regular channel connectivity (sloughs) may also eutrophy more quickly, as the properties of flowing systems have been compromised.  Streams with roughly annual bankfull channel scouring and velocities that support coarse substrates, more dissolved oxygen and low to moderate temperatures are unlikely to eutrophy.  But I do not live or work in conditions where nutrient loading of flowing streams has been extreme.  If plant growth invade and overtake channels, a variety of physical, chemical and biological changes occur in how streams respond and process water, sediment, nutrients, habitat, etc. 

Thanks for answers. But I still have a little mish-mash about factors that affect fluid water and that affect lakes. And how this factors affect fluid water? E.g. how the temperature influence the fluid water.

Dear Mrnka miroslav,

again Good Question, 

Water eutrophication is one of the most challenging environmental problems in the world. Adequate temperature and favourable other environmental factors, and  microbial activity and biodiversity. Water eutrophication may occur rapidly when all of these conditions are favorable.In shallow water, increased frequency of disturbance could increased the P release from the sediment, especially at high temperature.Temperature and salinity are the two important factors to induce alga bloom. Alga bloom always occurs at temperature between 23 °C and 28 °C, salinity between 23% and 28%. The variation of temperature and salinity also affect algal bloom, and an important condition for algal bloom is that temperature increases and salinity decreases faster than ever in short time. From the conception of ecology, exquisite change of temperature may cause the subrogation of biological communities, thus leading to algal bloom when other environment conditions are adequate (Wang et al.,Statistical analysis shows that the influence of temperature on algal growth rate is the largest, followed by salinity and their interaction. The process of sporangium pullulating is hypersensitive to temperature. When under adequate temperature, it can bourgeon largely and alga bloom will form very fast. Change of salinity is also influenced by the concentration of nutrition. Research shows that salinity is negatively related with NO3 −-N, and PO4 3−-P, but positively related with NH4 +-N, and however, it is not very related with NO2 −-N. In addition, average temperature in winter is highly relative with the beginning growth time of Gymnodinium, but whether it has universality to all algae still needs to be studied. In the Vistula Lagoon, salinity gradient was determined as an important factor (along with water temperature and predation by young herring) that defined the dynamics of zooplankton abundance and biomass in this estuary. The pH changes in these ponds are governed by the amount of free carbon dioxide, carbon trioxide, and bicarbonate (Kant and Raina,  Inflow nutrient concentration, inflow volume and inflow water temperature show very regular and reasonable impacts on the quality of lake water reported that monsoons served as a flushing mechanism in two ways:

1.        They reduced seasonal eutrophication by nutrient enrichment in summer,

2.       They prevented long-term (annual) accumulation of organic matter in the sediments due to nutrient enrichment in the region.

The researchers used 48 tanks in north-western England which simulated shallow lake communities. They studied the effects of warming by 4°C (which is the high emission scenario for the temperature increase during a hundred years period) and the effects of two levels of nutrient loading relevant to current degrees of eutrophication. Levels of nutrients, oxygen and pH, as well as phytoplankton, fish and plants, were also studied. During the experiment the highest temperatures at noon reached 21°C in unheated shallow lakes and 25°C in heated lakes. They did not drop below about 3°C in either. The study demonstrated that warming increased the concentration of soluble phosphate in the water. It also increased total plant biomass, but surprisingly reduced the amount of phytoplankton.Blue-green algae, which cause noxious blooms in lakes and estuaries (Figure 1), are favored both by increased nutrients and higher water temperature.Lakes with warmer water will have higher densities of fish species that eat zooplankton, the microscopic animals that normally feed on and control algae. A particular kind of zooplankton (Daphnia) that is very effective in controlling algae is most susceptible to being eaten by fish, and it is also highly sensitive to warming water (Figure 2).Eutrophication reduces the ability of zooplankton to control algae because it leads to dominance by blue-green algae, which is harder to feed on and digest. As a result, climate change and eutrophication together will limit the ability of zooplankton to control algae, reinforcing the potential for harmful blooms.

https://www.researchgate.net/post/How_does_temperature_affect_eutrophication?_tpcectx=profile_questions

Thank you for complete information. Can I discuss something about it in private?

Dear Mrnka miroslav,

Always welcome,Yes, you can discuss privately.

hi

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