By Badal Yadav M.F.Sc (fish nutrition and feed technology ) KUFOS

1. SUBJECT:-SOIL AND WATER QUALITY MANAAGEMENT (AQC502)(2+1)
TOPIC:- ALGAL BLOOM AND THEIR CONTROL
SUBMITTED BY
BADAL YADAV
M.F.Sc. (FNFT)
ROLL NO.~ AQC-2021-21-03

2. What is an Algae bloom?
The term algae encompass most types of aquatic photosynthetic organisms, including
macroscopic, multicellular organisms such as seaweed and small, single-celled organisms
such as cyanobacteria.
An algal bloom is a rapid increase or aggregation in the algae population of freshwater or
marine water systems and is often identified by water discolouration of their pigments.
A kelp forest is an example of a macroscopic algal bloom.
Algal blooms are the result of a nutrient, such as fertilizer runoff nitrogen or phosphorus,
entering the water environment and causing excessive algae growth.

3. TYPES OF ALGAL BLOOM
Algal blooms occur when environmental conditions allow explosive growth of
phytoplankton that create very dense clouds of these organisms (blooms) which can
change the color of ocean water.
These blooms are often called 'red tides.' However, red tides are not always "red,"
and furthermore, they really have nothing to do with the tides.
There are three kinds of bloom: Red, Brown, and Green.

4. Harmful algal blooms
Blooms which can injure animals or the ecology are called “Harmful algal
blooms" (HAB).
A harmful algal bloom (HAB) occurs when toxin-producing algae grow
excessively in a body of water.
Harmful algal blooms (HABs) represent a natural phenomena caused by a mass
proliferation of phytoplankton (Cyanobacteria, diatoms, dinoflagellates) in
waterbodies.
HABs are a type of algae that grows quickly and forms blooms, where the algae
grows to cover most or all of the lake or pond, often resulting in a colored scum
on the surface. HABs are most prevalent in nutrient rich waters when the
weather is hot and calm.

5. What are the Causes of Algae Bloom?
 Excess of Nutrients
 Presence of Dead Organic Matter
 High Temperatures
 Slow Moving Water

6. What Causes Algal Bloom?
Impact of Algal bloom: Human Health
 Direct exposure to toxic algae.
 Drinking, accidentally swallowing or swimming in water
affected by a harmful algal bloom can cause serious health
problems including:
 Rashes
 Stomach or liver Illness
 Respiratory Problems
 Neurological Effects
When disinfectants used to treat drinking water react with toxic
algae, harmful chemicals called dioxins can be created.
These byproducts have been linked to reproductive and
developmental health risks and even cancer.

7. Impact of Algal bloom: Environmental
● Harmful algal blooms sometimes create toxins that can kill fish and other
animals. After being consumed by small fish and shellfish, these toxins move
up the food chain and hurt larger animals like sea lions, turtles, dolphins,
birds, manatees, and fish.
● Even if algal blooms are not toxic, they can hurt aquatic life by blocking out
sunlight and clogging fish gills.
● Nutrient pollution can create dead zones, areas in water with little or no
oxygen where aquatic life cannot survive.

8. WHAT IS ALGAL
TOXIN
¨ algal toxins are organic molecules
produced by a variety of algae in marine,
brackish and fresh waters.
¨ they are a problem in fisheries when
they are produced in sufficient
quantities, with sufficient potency, to kill
cultured organisms, decrease feeding
and growth rates, cause food safety
issues, or adversely affect the quality of
the product.

9. ¨COMMON TYPES OF ALGALPOISONING
¨NSP – neurotoxic shellfish poisoning.
¨ PSP _ paralytic shellfish poisoning.
¨ ASP _ amnesic shellfish poisoning.
¨ DSP _ diarrhoetic shellfish poisoning.
¨ all are caused by toxins synthesized by dinoflagellates , except
for ASP , which is produced by diatoms of the genus
pseudonitzschia

10. NeurotoxicShellfishPoisoning
NSP is a disease caused by the consumption of molluscan shellfish
contaminated with brevetoxins; these are a group of more than ten
natural neurotoxins produced by the marine dinoflagellate, Karenia
brevis (formerly known as Gymnodinium breve).
NSP causes a range of signs and symptoms, both neurological and
gastrointestinal.

11. Paralyticshellfishpoisoning
Paralytic Shellfish Poison (PSP) is a naturally occurring marine biotoxin such as
neurotoxin chiefly saxitoxin that is produced by microscopic algae, such as
Dinoflagellates species known to produce this toxin include Gymnodinium
catenatum, Alexandrium catenella.
Bivalve molluscan shellfish such as clams, mussels, oysters and scallops can
accumulate Paralytic Shellfish Poison.

12. AmnesicShellfishPoisoning
Amnesic shellfish poisoning (ASP) is an illness caused by consumption of shellfish that contain
the marine biotoxin called domoic acid. In mammals, including humans, domoic acid acts as
a neurotoxin, causing permanent short-term memory loss, brain damage, and death in severe
cases.
This toxin is produced naturally by marine diatoms belonging to the genus Pseudo-nitzschia and
the species Nitzschia navis-varingica.
Although human illness due to domoic acid has only been associated with shellfish, the toxin
can bioaccumulate in many marine organisms that consume phytoplankton, such as anchovies
and sardines.

13. DiarrhoeticShellfishPoisoning
Diarrhetic shellfish poisoning is caused from the ingestion of toxin-contaminated bivalve
shellfish and crustaceans.
Eating shellfish contaminated with diarrhetic shellfish toxins ( akodoic acid,
dinophysistoxins and pectenotoxins) causes severe gastrointestinal problems.
Symptoms can begin within 30 minutes to 15 hours.
Acute GI symptoms predominate including nausea, vomiting, watery diarrhea, abdominal
pain. Symptoms last up to 3 days.

15. CONTROL OF ALGAL BLOOM
The presence of cyanobacteria is a severe and global problem. When it comes to
lakes or bigger ponds.
While some methods are environmentally unfriendly (Algaecides), other methods
are expensive (Aeration).
To treat and control the growth of algae, the following four main methods.
 Chemicals
 Aeration
 Mixing
 Ultrasound

16. CHEMICALS
 Chemical intervention involves treating the water with a
variety of additives, such as alum, lanthanum, or any
other products that precipitate or sequester the ionized
orthophosphates.
 Algaecides., herbicide for algae can also be used.
Advantages
Effective if the entire surface is treated.
Disadvantages
Algaecides are expensive and need frequent dosing. They must
be used with care, as they can cause algal cell rupture. This
triggers the release of toxins into the water.

17. Aeration
It’s crucial to maintain healthy levels of
dissolved oxygen in a pond or any other water
body.
Oxygen helps break down decaying vegetation
and other nutrients in water.
Microorganisms help break down the silt at the
bottom. Aerobic and anaerobic bacteria both
contribute to decomposition.
Advantages
Aeration is an environmentally-friendly technique
that rejuvenates water bodies. It increases the oxygen
level in water. Aeration systems can help avoid
chemicals and create a healthy ecosystem. It can be
used for large ponds.
Disadvantages
High costs for maintenance and labor, intense energy
use. Aeration doesn’t directly kill the algae, therefore
it’s not always efficient. It requires treating the entire
water surface.

18. MIXING
 The main function of mixers in a reservoir is destratification, which is a process in which the water
is mixed to eliminate stratified layers (Epilimnion, Metalimnion, Hypolimnion) and make it less
favorable for algae growth in certain layers.
 Advantages
Artificial circulation causes less environmental damage chemicals. It’s generally more effective in
deep reservoirs (mean depth >15 m).
 disadvantage
The mixing or circulation of water is often the high maintenance.

19. ULTRASOUND
 Ultrasound waves create a sound layer in the top layer of the water. The sound layer has a direct
impact on the buoyancy of the algae.
 The algae cells will sink to the bottom and are unable to photosynthesize and eventually die due to a
lack of light.
 Advantages
Controlling algae with ultrasound is a well-known method that’s been used for decades. It’s a proven effective solution for
green and blue-green algae species. Also, what make it truly great is that it’s environmentally friendly; it’s safe for the
aquatic life and for the ecosystem.
 Disadvantages
Must cover the entire surface of the lake. Each spatial spot must be treated to achieve full efficiency

20. ¨ FLOATING ARTIFICIAL WETLANDS
¨Plants are placed on
floating mats and placed
in the water.
¨ As the plants grow,
they filter excess
nutrients from the water,
helping to prevent an
algae bloom.
¨ When the plants
mature, they need to be
switched out with young
plants in order for the
process to continue

21. DIRECT NUTRIENT REMOVAL
¨ When the food that the
algae feeds on is taken away
in order to control the algae
growth, it is called direct
nutrient removal
¨ These are two main
products that do this:
¨ Alum ¨ Phoslock
¨ Both of
these products
remove
phosphorus
from the
water.

22. IN INDIA
• ¨RESEARCHERS HAVE FOUND
TOXIC BLOOM HAS INCREASED
AROUND 15 PRESENT OVER THE
12 YEARS IN INDIA SEAS.
• ¨ THERE WAS 80 HARMFUL
BLOOM RECORDED BETWEEN THE
1998-2010 IN INDIAN WATER
• ¨ RESEARCH DATA WAS
GENERATED BY- K.B
PADMAKUMAR & V.N SANJEEVAN (
CENTER FOR MARINE LIVING
RESOURCES & ECOLOGY, KOCHI
• ¨ FIRST RECORDED OBSERVATION
ON ALGAL BLOOM IN INDIA WAS
IN 1908.

23. REFERENCES
• FRESHWATER HARMFUL ALGAL BLOOMS 101 | NRDC
• ALGAL BLOOM – CAUSES, HARMFUL EFFECTS AND TYPES
(VEDANTU.COM)
• ¨ HTTP://DNR.WIGOV/LAKES/BLUEGREENALGAE
• ¨ HTTPS//WWW.EPA.GOV/NUTRIENTPOLLUTION/EFFECTS
• HTTPS://WWW.SLIDESHARE.NET/JAYANTTIPLE/ALGAL-
BLOOM