algal bloom

Definition-1. An Algal bloom is rapid increase or accumulation in the population of algae(typically microscopic) in an aquatic system.2. A rapid increase in no of algae usually caused by a change in flow, light, temp. or nutrient levels of water in which it lies.

It may occur in freshwater as well as marine environments.

The freshwater and ocean blooms have been found to be anthropogenic, directly caused by nutrient pollution of nitrogen and phosphates from agriculture and intensive animal farming fertilizers, and household cleaning products.

Algal blooms are of national concern, problem for ecosystem and human society. They are often green, but they can also be other color such as yellow brown or red, depending on species of algae.

Health damage range from cell damage to organism mortality through such mechanisms as toxin production & localised condition of low oxygen

Detrimental effects of Harmful algal bloomToxins:- The most well known HAB toxins are cigutera fish

poisoning(dinoflagellate) neurotoxic(Gymnodium breve) & paralytic shellfish poisoning(Genus-Alaxandrium) Cynobacteria poisonig:- Anabaena & microcystis sp.

Blue-green algae HABs in freshwater, lakes and ponds, occur when specific types of photosynthetic bacteria (cyanobacteria or blue-green algae) form blooms (visible, dense build-ups).

Under certain conditions, these may produce neurotoxins & hepatotoxins.

• Blue-green algae HABs may be short-lived, appearing and disappearing in hours, or long-lived, persisting for several weeks, depending on the weather and the characteristics of the lake.

They spoil water quality when present in large number by producing odour or thick Scum. they can make drinking water smell and taste bad. They can make recreational area unpleasant. Dense bloom can block sunlight killing Other plants and animal when algae decompose. They may use up oxygen in the water and cause Fish kills.

Some cyanobacteria can produce TOXINS that are among the most Powerful natural poison known these toxins have NO ANTIDOTES.

These toxins are poisonous to human and may be deadly to livestock, pets & fishes.

WHAT CAUSES ALGAL BLOOM?

The development and proliferation of algal bloom likely result from a combination of environment al factors including below:-

1. NUTRIENTS:- the main nutrient contributing to algal bloom are phosphorus and nitrogen.

Runoff and soil erosion from fertilized agriculture areas and lawns and sewage effluents are the major sources of phosphorus and nitrogen.

2. LIGHT :- algae populations are diminished when they are exposed to long periods of high light intensity (photo-inhibition) but have optimal growth when intermittently exposed to high light intensities.

Continued…3. TEMPERATURE:- Early blue–green algal blooms usually develop during the spring when water temperature is higher and there is increased light. The growth is sustained during the warmer months of the year. Water temperatures above 25°C are optimal for the growth of Cyanobacteria. 4. STABLE CONDITIONS :- Most of blue–green algae prefer stable water conditions with low flows, long retention times, light winds and minimal turbulence; other prefer mixing conditions and turbid environments.5. TURBIDITY:- Turbidity is caused by the presence of suspended particles and organic matter (flows) in the water column. When turbidity is low, more light can penetrate through the water column. This creates optimal conditions for algal growth. In return, growing algae create a turbid environment.

EFFECT OF HAB’s

EFFECTS OF ALGAL BLOOM China- lake ERIE, a mat of three inches thick green algae clung into the beach & contaminates drinking water .

Dal lake , is pruned to algal outbreakDue to high level of nutrient, sewageAnd waste in lake particularly in summer.

Costal region of India is also affected by Bloom.

MANAGEMENT PRE DISASTER:-1. Aware the people about harmful effects

of algal bloom.2. Develop techniques for sample collection

of water for pre control.3. Identify & gather knowledge about

harmful species of algae.4. Proper management of nutrient and

judicious use of potassium and nitrogen fertilizer.

DURING & AFTER DISASTERMechanical- Involves use of filters, pumps,

barriers(curtains, floating bloom) to remove or exclude HAB’s cells, dead fish.

Biological- Use of organism( virus, bacteria, parasites, zooplankton)

Physical:- USE OF MICROPRESSURE :- According to research of Florida

International university ,in Miami it has found that ultra sound of 640 kilohartz create micro pressure which kills algae.

• CHEMICAL CONTROL:- To check growth of algae

Trimazine is used. (trade name is Tekazine 50)

Submitted to:-Sh. J. L. SALAM(course teacher)

Submitted by:- ANCHAL SAHANE AVINASH PATEL BHUMIKA

YADAV BRIJESH

PATRE B.Sc.”Ag” 3rd

year

THANK YOU