Algal bloom and its economic impacts pptx

Algal blooms and its economic impact

1. ALGAL BLOOM AND TOXINS

2. ALGAL BLOOM phytoplankton Harmful algal blooms species (HABs) refer to a rapid proliferation of 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 Diatoms Dinoflagellates 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 HABs causing red tides.

13. HARMFUL DINOFLAGELLATE BLOOMS 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

14. Alexandrrium acatenella spp.

15. 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.

16. Ceratium spp.

17. CYANOBACTERIA

18. Nostoc Oscillatoria spp..

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

20. Microcystins Cylindrospermopsins Anatoxin- a Guanitoxin, formerly known as anatoxin- a(S) Saxitoxins Nodularins Lyngbyatoxins COMMON CYANOTOXINS

21. 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

22. 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 ?

23. 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.

24. 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.

25. 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.

26. TOXINS 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.

27. 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)

28. 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

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