In The Name of Allah The Most Merciful, The Most Beneficent

1. In The Name of Allah The Most Merciful, The Most Beneficent “He who creates everything from nothing and creates all things with the knowledge of what will happen to them”

2. Algal Blooms Presented by Sonia Mehboob Batch V Evening(6)

3. Algal Blooms • What is Algae? • Algal Blooms • Causes of Bloom • Bloom Occurrence • Eutrophication • Harmful Effect • Toxic Bloom • Control

4. What is Algae? • Algae are generally microscopic organisms,are generally thought of as simple aquatic plants which do not have roots,stems or leaves & have primitive methods of reproduction.They are the basic food source for small aquatic animals

6. Algal Blooms • Algal blooms are dense congregations of algae that can form over lakes, dams or streams. OR • When microscopic plants called algae become so thick that they make lake water look like pea soup, the condition is called an algal bloom

8. Causes of Blooms • High nutrient load • Blue-green algal blooms are natural phenomena and while it is not exactly clear what triggers a bloom, excess human sources of nutrients such as fertilisers and sewage certainly can increase the intensity of blooms (i.e. greater number of algae).

9. 2. Thermal stratification • One of the most important factors triggering blue-green algal blooms appears to be a lack of mixing of surface and deeper water layers in a river or reservoir. • In lakes and reservoirs mixing is mainly controlled by wind and temperature. • Through the summer months the surface waters heat up resulting in a warmer top layer and cooler bottom layer which do not mix. In rivers, mixing is mainly caused by flow.

10. 3. Algae Float To Surface • Some blue-green algae can float to the surface under these conditions having access to all the light in the top waters (photic region) and nutrients in the top and bottom waters. • This allows the algae to flourish and bloom. • Some other algae are motile and can swim to the photic region under these conditions.

11. Bloom Occurrence • Under certain conditions, several species of true algae as well as the cyanobacteria are capable of causing various nuisance effects in fresh water, such as excessive accumulations of foams, and discoloration of the water • When the numbers of algae in a lake or a river increase explosively, an algal "bloom" is the result. • Algal blooms are natural occurrences, and may occur with regularity (e.g., every summer), depending on weather and water

12. Blooms generally occur where there are high levels of nutrients present, together with the occurrence of warm, sunny, calm conditions. • However, human activity often can trigger or accelerate algal blooms. Natural sources of nutrients such as phosphorus or nitrogen compounds can be supplemented by a variety of human activities. • For example, in rural areas, agricultural runoff from fields can wash fertilizers into the water.

14. Eutrophication • Concept definition: • A process of pollution that occurs when a lake or stream becomes over-rich in plant nutrient; as a consequence it becomes overgrown in algae and other aquatic plants. • Nitrate fertilizers which drain from the fields, nutrients from animal wastes and human sewage are the primary causes of eutrophication.

15. Harmful Effect These are some diseases caused by HABs • Blooms producing neurotoxic shellfishpoisoning (NSP). These are caused by the dinoflagellate Gymnodinium breve and occur along the coasts of the Gulf of Mexico, and rarely, the southeast Atlantic coast. • Blooms causing paralytic shellfish poisoning (PSP). Various species of the dinoflagellate genus Alexandrium are responsible for PSP in New England, northern California, the Pacific Northwest and Alaska

16. 3. Brown tide" blooms (BTB) caused by very small golden brown algae 4. Blooms which which do not cause illness in humans but result in catastrophic losses of cultured and wild fish, particularly in the Pacific Northwest. Such blooms are caused both by the raphidophyte flagellate Heterosigma akashiwo and by a few species of the diatom genus Chaetoceros, which clog fish gills.

18. Toxic Bloom • Some algae produce toxic chemicals that pose a threat to fish, other aquatic organisms, wild and domestic animals, and humans. • The toxins are released into the water when the algae die and decay.

19. Blooms of toxic species of algae and cyanobacteria can flood the water environment with can cause human illnesses such as gastroenteritis (if the toxin is ingested) and lung irritations • Cause skin irritation to people who swim through an algal bloom. • Toxicity can sometimes cause severe illness and death to animals that consume the biotoxin-containing water.

20. How Do Blue-green Toxins Affect Animals? • When a lake becomes toxic as a result of a blue-green bloom, the only sign of a problem may causes death. • Occasionally, domestic animals such as cattle or dogs may be poisoned if they have no other source of drinking water. • Strains of blue-green algae produce a number of toxins that can be classified into two groups according to their effects on animals

21. Neurotoxins affect the nervous system and cause a rapid death, often within 30 minutes, due to paralysis and respiratory arrest. • The second group, hepato-toxins, affect the liver and cause a slow death, up to 36 hours after drinking the water.

22. How Do Blue-green Algal Toxins Affect People? • Humans are just as susceptible to blue-green toxins as animals, but it is unlikely that people would voluntarily drink much lake water during a bloom because of the objectionable appearance and odour of the water.

23. Precautions • Treat any intense bloom with suspicion • Do not drink water from bloom-infested lakes and reservoirs • Do not swim or wade in water containing concentrated algal material • When at the lake, watch your children carefully • Provide alternative sources of drinking water for domestic animals and pets

24. Control • There are a variety of options for controlling pond algae once it is identified. • Algae growth is stimulated by light penetration in water and the availability of nutrients needed for plant growth, such as carbon, nitrogen and phosphorus. • Light penetration to the soil of the pond bottom occurs in the shallow areas. These shallow areas are where growth of pond algae and weeds typically starts.

25. Carbon and nitrogen are generally abundant nutrients in ponds. The lack of available phosphorus is usually a factor that keeps algae blooms at bay. Ponds that receive loads of nutrients, especially phosphorus, tend to experience chronic problems with algal blooms. • One method of controlling pond algae is to deepen as many shallow areas of the pond as possible so that light does not penetrate to the soil of the pond bottom. Water depths of three feet or more will help to control the start of aquatic weed and algae problems in ponds. • More recently, the use of triploid grass carp, also called white amur, as a means of biological control for pond algae and weeds has received attention