Algal blooms and its economic impact

1. ALGAL BLOOM AND
TOXINS

2. ALGAL BLOOM
phytoplankton
Harmful algal blooms
species
(HABs) refer to a rapid proliferationof
such as dinoflagellates, diatoms, and
cyanobacteria in aquatic ecosystems . HABs are natural phenomena
which pose serious risks to human health, environmental sustainability
and aquatic life due to the production of toxins or the accumulated
biomass.

3. CAUSATIVE ORGANISMS
1.Diatoms
2.Dinoflagellates
3.Cyanobacteria

4. DIATOMS

5. Pseudo-nitzschia spp.

6. Diatoms are unicellular, photosynthetic eukaryotes and include
about 100 species spreading worldwide in both marine and
freshwater.
Diatoms are characterised by a siliceous cell wall (frustule) and
most of them display spines which can physically clog and damage
fish gills, leading to death.

7. Diatoms of the genus Pseudo-nitzschia produce domoic acid, a
neurotoxin and enters into food chain through filter feeding
organisms such as shellfish or finfish.
Domoic acid cause Amnesic Shellfish Poisoning (ASP) in humans
consuming shellfish or crustaceans and the effects include
confusion, short-term memory loss, headache and in severe cases,
death

8. DINOFLAGELLATES

9. Pyrodinium spp. Protoperidinium spp.

10. Prorocentrum spp.

11. Dinoflagellates are microalgae mainly responsible for HABs.
They are mixotrophic.
They consist of two flagella.
Dinoflagellate Toxins (saxitoxins, yessotoxins) can cause significant
diseases in man. These illnesses include Paralytic Shellfish
Poisoning (PSP), Diarrhetic Shellfish Poisoning (DSP), Neurotoxic
Shellfish Poisoning (NPS) and Ciguatera Fish Poisoning (CFP) .

12. Dinoflagellates usually reproduce by asexual fission but sexual
reproduction also occurs in some species determining the
formation of dormant cells called cystis. Cystis, settle to the bottom
sediments, can persist for years and they are considered an
effective strategy for survival through environmental or nutritional
stresses. When favorable environmental conditions, such as
warmer climate and nitrogen runoffs, occur, cystis germinate to
produce HABscausing red tides.

14. HARMFULDINOFLAGELLATEBLOOMS
Gonyaulax polygramma - Cause oxygen depletion
Dinophysis acuta sps - Diarrhetic Shellfish Poisoning (DSP)
Gambierdiscus toxicus, Ostreopsis mascarenensis - Ciguatera Fish Poisoning
Alexandrium acatenella sps - Paralytic Shellfish Poisoning (PSP)
Karenina breve sps - Neurotoxin Shellfish Poisoning (NSP);
Gymnodinium mikimotoi.- Harmful to fish ,shrimp and marine invertebrates
.The cells may cause damage or clog the gills of these animals

15. Alexandrrium acatenella spp.

16. SYMPTOMS
Appearance of gill diseases, annetena rot etc, less appetite, poor growth, bad
molt, soft shell, low survival rate and chance of mass mortality of shrimps.
Gastrointestinal disorders,
Permanent neurological damage.

17. Ceratium spp.

18. CYANOBACTERIA

19. Nostoc Oscillatoria spp..

20. CYANOBACTERIA
Harmful algae , cyanobacteria, sometimes called blue-green algae, produce
cyanotoxins (poisons) that can make people and animals sick and affect the
environment.

21. Microcystins
Cylindrospermopsins
Anatoxin-a
Guanitoxin, formerly known as anatoxin-a(S)
Saxitoxins
Nodularins
Lyngbyatoxins
COMMONCYANOTOXINS

22. Stomach pain, vomiting, or diarrhea
Headache, fever, tiredness, or other general symptoms
Skin, eye, nose, or throat irritation
Neurological symptoms such as muscle weakness or dizziness
SYMPTOMS IN PEOPLE

23. Cyanobacterial bloom formation and persistence is influenced by light
intensity, water temperature, pH, climate change, water flow, water column
stability and anthropogenic modifications of aquatic environment including
nutrient over-enrichment (eutrophication).
WHAT CAUSES CYANOBATERIAL BLOOM ?

24. Eutrophication
Eutrophication, or excessive abundance of nutrients in water bodies,
from agricultural sources (e.g., nitrogen and phosphorus fertilizers),
industrial and domestic waste is a major environmental contributor to
cyanobacterial blooms.

27. Affects
Bad odors from degraded organic matter which cannot be controlled
chlorination in case of drinking water.
Reduction in fish quality causing loss on fishing.
Bathing in lakes that is affected by certain algae causes’ skin irritation and it is
dangerous.
Reduction in concentration of oxygen, particularly at the bottom of the lake
during the end of autumn season and the summer season.

28. N & P - water bodies - algal bloom - consume dissolved oxygen -
depletion of oxygen - at the end of nutrients in water - algae die -
decomposition occurs - no oxygen for aquatic animal - animals
suffocate - death.

29. T O X I N
S
When favorable environmental and climatic conditions concur to induce
harmful algal blooms (HABs), phytoplankton species have the capacity to
produce hazardous toxins that can find their way through levels of food chain
(crustaceans, molluscs) and are subsequently consumed by humans causing
diseases or in the most serious cases, the death.

30. Marine toxins have been classified in five groups according to the effects
they cause to organisms which include:
Paralytic Shellfish Poisoning (PSP),
Diarrhetic Shellfish Poisoning (DSP),
Amnesic Shellfish Poisoning (ASP),
Neurotoxic Shellfish Poisoning (NSP) and
Azaspiracid Shellfish Poisoning (AZP)

34. Cyanobacteria, principally responsible of HABs in freshwater and at lesser
extent in marine environments, are able to produce toxins which are
classified in:
Hepatotoxins that act on liver
Cytotoxins that produce both hepatotoxic and nefrotoxic effects
Neurotoxins that cause injury on the nervous system and
Dermatoxins that cause irritant responses on contact

38. THANK YOU