ALGAL BLOOM?

 ALGAL BLOOM 

Keywords: 

• Alga (singular subject/ noun)
• Algae( plural subject/noun)
• Mycrocystis (alga)
• microcystin( toxin / poison)
• DO: oxygen dissolved in water, generally 4mg/l required to sustain the life in water. 
• Eutrophication (Neutrients enrichment in water bodies ) : The excess of fixed nitrogen builds up in streams and lakes where provides extra food for microorganisms and causes a bloom in the population of algae. The algae population eat up oxygen and eventually, brings the waterbody on the brinks of death.

Algal bloom in river 

Algal bloom( algal pollution) is a condition of excessive sudden  population growth of algae on the surface of water bodies in mat form because of sudden increase of nutrients like nitrogen and phosphorus that leads food chain disturbance in water bodies. Actually microscopic plants( algae) are unicellular, aquatic, roots, and leaves. Algae are required nutrients for growth by the process of photosynthesis; when huge amounts of nutrients obtained suddenly they also increased their population rapidly and covered the surface of water. When they sustained for a  long period of time from few days to few weeks,  water do not have enough sun light below water surface, plants started being decompose by aerobic bacteria that utilize dissolved oxygen of water for decomposition and decomposed organic matters raised up to the surface further thicken the algal blooms mat resulted in decrease in dissolved oxygen in water. These lack of dissolved oxygen (DO), non availability of light, generation of toxins threats to the aquatic life.

In a balance situation algae are grown by using these neutrients and eaten by phytoplankton, phytoplankton are eaten by small fishes, and small fishes are eaten by big fishes  and after getting dead the consumed nutrients returned to the water and created a food chain or neutrients cycle. But, when, additional amount of neutrients are added by outside sources then  blue green algae( un-edible by phytoplankton and fishes) spread rapidly that disturb the natural food chain leads to the death of fishes. Causes sun rays do not penitrate the water. Algal growth may show different colour like green, blue, yellow, brown, red; even in night these may be looked like surface emiting rays. Green algal blooms are formed by an alga is known as Mycrocystis which is found in stagnant or very slow moving water stream, pond, lake etc; that produces neurotoxin like microcystin which is harmful for the aquatic animal. 

Algae are microscopic plants may be both toxic and non toxic; toxic algal blooms are called Harmful algal blooms (HABs).

Example, algal bloom in Ganga river in Benares was a result of algal strains drained into the river from Chunar untapped drains of sewer treatment plant and oxidation pond in Mirzapur district which contained nitrogen and phosphorus mainly that acts as a fertilizers for algae and its bloom growth.

Causes of algal blooms: 

• Suddenly, increase of nutrients (eutrophication) like nitrogen and phosphorus by various sources, are:
• Neutrients rich untreated sewage 
• Synthetic fertilizers used in agriculture 
• Urban water flow 
• Neutrients rich soil erosion 
• Nitrogen and phosphorus getting from atmosphere.
• Drain
• Rain water etc.
• Sun rays
• Navigation erupted neutrients: wastes from ships
• Slow flow of water or static or stagnant water 

Effects:

• Dissolved oxygen (DO) decreased of water 
• Damaged the food chain 
• Fishes getting dea
• Water became toxic 
• Skin rashes or illness on bathing or touching algae 
• Water became unpleasant and non-consumable 
• Biodiversity losses etc
  
  

Measures: 

1. Only treated sewage should be dispose off in water bodies like marine or fresh water 
2. Fertilizers use must decrease in agriculture 
3. Bioremediation technology must be utilized to treat the water
4. Water flow must be increased 
5. Eutrophication should be immediately stop 
6. Water aeration techniques must be use in small ponds  or in lakes 
7. 
   

Green water caused by algal bloom 

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Algae