Algal bloom

What is algal bloom, causes of algal bloom, effect of algal bloom etc

1. Presentation on Algal bloom Presented by: Devarshi ranjan M.F.Sc - I st year College of fisheries, dholi Rpcau , pusa , bihar

2. Content Algal bloom Harmful algal bloom Effect of algal bloom Impact of algal bloom Name of some harmful algal bloom Control methods of algal bloom

3. Algal bloom An algal bloom is a rapid increase in the population of algae in an aquatic system. Algal blooms may occur in freshwater as well as marine environments. Result of an excess of nutrients ( paricularly p and n). Their growth is harmful for other plant and organisms.

4. Harmful algal blooms A harmful algal blooms is an algal bloom that causes negative impacts to aquatic organisms via production of natural toxins, mechanical damage to aquatic organism. Harmful algal blooms are often associated with large-scale marine mortality events and have been associated with various types of shellfish poisonings and also fin fishes and other aquatic organisms.

5. Causes of algal bloom Eutrophication Upwelling High temperature Presence of dead organic material Large mass of water Higher carbon dioxide levels Extreme storm

6. Eutrophication Eutrophication is the process in which a water body becomes overly enriched with nutrients( phosphorus and nitrogen), leading to plentiful growth of simple plant life . The excessive growth (or bloom) of algae and plankton in a water body are indicators of this process . Eutrophication is considered to be a serious environmental concern since it often results in the deterioration of water quality and the depletion of dissolved oxygen in water bodies . Eutrophic waters can eventually become “dead zones” that are incapable of supporting life .

7. Source of nutrients Fertilizers runoff Untreated sewage Detergents containing phosphorus Industrial discharge of waste.

8. Effect of Huge Biomass of Algae in Eutrophic Waters The excessive growth of algae in eutrophic waters is accompanied by the generation of a large biomass of dead algae . These dead algae sink to the bottom of the water body where they are broken down by bacteria, which consume oxygen in the process . The overconsumption of oxygen leads to hypoxic conditions (conditions in which the availability of oxygen is low) in the water . The hypoxic conditions at the lower levels of the water body lead to the suffocation and eventual death of larger life forms such as fish.

9. Upwelling Upwelling is a process where deeper colder nutrient rich water comes to the surface through the push of surface winds. It is very productive water bodies for fisheries. But it can be harmful when harmful algal blooms are developed in these water bodies due to high nutrient availability.

10. High temperature As depletion of ozone layer is happening due to global warming and this reason is a major factor behind tremendous growth in algal bloom. Appropriate temperature is needed for proper growth of algal bloom. As high temperature leads to rapid decompositions of the nutrients like nitrogen, phosphorus and these decomposed nutrients become easy for algal bloom to use up and grow rapidly.

11. Presence of dead organic material There are so many varieties of bacteria which are present in water bodies as well as in the atmosphere. These bacteria lead to the growth of algae bacteria like all other bacteria. As nutrients in water along with dead organic matter leads to increase in growth of algal bloom. Large mass of water Large mass of water is needed for growth of algal bloom. As less disturbance in water propagation leads to tremendous growth of algal bloom.

12. Higher carbon dioxide Algae need carbon dioxide to survive. Higher levels of carbon dioxide in the air and water can lead to rapid growth of algae, especially toxic blue-green algae that can float to the surface of the water . Extreme storm By extreme storm the various nutrients reached into water bodies which is helpful for algal production.

13. Impact of algal bloom Human health Direct exposure of toxic algae: By drinking water Accidentally swallowing of water Swimming in affected water bodies H armful algal bloom can cause serious health problems including: Rashes Stomach or liver illness Respiratory problems Neurological effects Algal blooms produce toxins harmful to humans and marine life

14. Environmental Harmful algal blooms sometimes create toxins that can kill fish and other animals. When these algal blooms are consumed by small fishes and shellfishes then toxin move up the food chain and largely effect the aquatic life. It is also block the sunlight and also cause gill chocking of fish. Nutrient pollution can create dead zones area in water with little or no oxygen where aquatic life cannot survive. Over 166 deads zones have been documented nationwise , affecting water bodies like the Chesapeake Bay and the Gulf of Mexico. The Gulf of Mexico dead zone is the largest in the United States, measured to be 5840 square miles in 2013.

15. Economy Drinking water costs: Nitrates and algal blooms in drinking water sources can drastically increase treatment costs. So cost of drinking water will increase . Tourism losses: The tourism industry losses close to $ 1 billion each year, mostly through losses in fishing and boating activities.

16. Commercial fishing and shellfish losses: Annual losses to these industries from nutrient pollution are estimated to be in the tens of millions of dollars.

17. Some HAB’s Redtides - Neurotoxic shellfish poisoning Cyanobacteria (blue-green algae) Ciguatera- Gambierdiscus toxicus

18. Red tides Red tide is a phenomenon caused by algal blooms  during which algae become so numerous that they discolor coastal waters mainly red color . (hence the name "red tide "). The algal bloom may also deplete oxygen in the waters and/or release toxins that may cause illness in humans and other animals.

19. Species in the United States that release these harmful toxins include: Alexandrium fundyense  - found along the Atlantic coast from the Canadian Maritimes to southern New England Alexandrium catenella  - found along the Pacific coast from California to Alaska Karenia brevis  - found in the Gulf of Mexico along the west coast of Florida

20. Poisoning caused by red tide Paralytic Shellfish Poisoning (PSP)  - This disease is caused by the production of saxitoxin by the  Alexandrium  species. It is common along the Atlantic and Pacific coasts in the US and Canada. Poisoning occurs when one ingests shellfish contaminated with PSP toxins causing disruption of nerve function and paralysis. Extreme cases may result in death by asphyxiation by respiratory paralysis . Diarrhetic Shellfish Poisoning (DSP)  - This disease is caused by the  Dinophysis  species. It generally occurs in Japan and Europe, but it has also been found in other countries such as Canada, the US, Chile, New Zealand, and Thailand. Symptoms of DSP include diarrhea , nausea, vomiting, abdominal pain, and cramps. DSP is generally not lethal.

21. Amnesic Shellfish Poisoning (ASP)  - This disease, which has been found along the eastern Canadian coast, is caused by domoic acid producing planktonic and benthic algae, including  Pseudo- nitzschia pungens  forma.  Pseudo- nitzschia multiseries  and  Amphora coffaeformis . It can also be found in soft shell clams and blue mussels infected by  Pseudo- nitzschia delicatissima . Gastric and neurological symptoms include dizziness, disorientation and memory loss.

22. Cyanobacteria (blue-green algae) Cyanobacteria produce a toxin which is known as cyanotoxins . The production of cyanotoxins includes risks to human and animal health . Depending on the concentration in the aquatic environment, they can cause severe poisoning, produce chronic diseases such as cancer, and even lead to death.  Cyanotoxins are thus an important group of chemical compounds, from the point of view of ecotoxicology, toxicology, and environmental chemistry. Three classes of cyanotoxins are hepatotoxins , neurotoxins, dermatotoxins .

23. Main toxins from cyanobacteria Cyanotoxins Genera of main producers Hepatotoxins Microcystins Anabaena ,  Planktothrix ,  Nostoc ,  Anabaenopsis Nodularins Nodularia Cylindrospermopsins Cylindrospermopsis raciborskii ,  Aphanizomenon ovalisporum ,  Aphanizomenon zflos-aquae Neurotoxins Anatoxin -a Anabaena ,  Aphanizomenon ,  Planktothrix Anatoxin -a(s) Anabaena Saxitoxins Dinoflagellates :  Alexandrium ,  Pyrodinium ,  Gymnodinium   Cyanobacteria :  Anabaena circinalis ,  Aphanizomenon sp .,  Aphanizomenon gracile ,  Cylindrospermopsis raciborskii ,  Lyngbya wollei

24. Dermatotoxins Lyngbyatoxin -a Lyngbya Aplysiatoxin Lyngbya ,  Schizothrix ,  Planktothrix ( Oscillatoria ) Lipopolysaccharides (LPS) Cyanobacteria in general

25. Ciguatera- Gambierdiscus toxicus Ciguatera fish poisoning (or ciguatera) is an illness caused by eating fish that contain toxins produced by a marine microalgae called  Gambierdiscus toxicus . People who have ciguatera may experience nausea, vomiting, and neurologic symptoms such as tingling fingers or toes. They also may find that cold things feel hot and hot things feel cold. Ciguatera has no cure. Symptoms usually go away in days or weeks but can last for years. People who have ciguatera can be treated for their symptoms.

26. Control method Physical controls Chemical controls Biological controls

27. Physical controls Aeration Mechanical mixing Surface skimming Ultrasound

28. Aeration Aeration Air is pumped into a pond or lake from an aeration device placed on the bottom. This forms plumes of air that disrupt the stratification of the body of water and limit the nutrients the algae can get.  Drawback - Proximity limit of mechanical devices

29. Mechanical mixing This mixes the water, disrupting the stratification and limiting nutrients to the algae. Drawback - Proximity limit of mechanical devices

30. Surface skimming By using oil skimmers, the algae can be removed . Drawback - High labor cost

31. Ultrasound Ultrasound Ultrasonic waves of a particular frequency are used to kill the algae by destroying their cellular structure . Drawback - Transmitter could be blocked; Need reprogramming for different types of algae

32. Chemicals controls Algaecides Barley straw Coagulation

33. Algaecides Copper sulfate , copper citrate, and other copper based products  Potassium permanganate Chlorine Drawback - Harmful to the environment

34. Barley straw Barley Straw Bales of barley straw are placed in the water . When exposed to sunlight and oxygen, the straw produces a chemical that stops algae growth.  Drawback - Cannot produce chemical without sunlight; Occupy space

35. Coagulation Coagulation Chemicals are introduced into the water that makes the algae coagulate and fall to the bottom of the pond or lake . At the bottom, the algae has no access to light, oxygen, or other critical resources, eventually dies . Drawback - Current ways of applying the solution are not efficient and effective

36. Biological controls Increasing grazing organisms Floating artificial wetland

37. 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 . Drawback - Occupy space; Need effort for planting and switching to young plants

38. Increasing grazing pressure By increasing the growth of zooplankton, plants, and other organisms that feed on algae, it will be less likely for algae to experience a bloom . This can be done by removing fish that feed on these organisms.  Drawback - May introduce new risks

39. Thank you