Algal Bloom

Ravi Shankar

B.F.Sc. 3rd year

Content

• Intodution

• HAB’S

• In india

• World wide effect of HAB’s

• Reasons of increasing HAB’s

• Images of some Algal Bloom

• Some sps. of HABs

• Cyanobacteria

• Effect of algal bloom.

• Control method

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. Typically only one or a few phytoplankton species are involved and some blooms may be recognized by discoloration of the water resulting from the high density of pigmented cells.  

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.

HABs 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 .

In India • Researchers have found toxic bloom has increased

around 15 percent over the 12 years in indian 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 (centre for marine living resources &

Ecology,kochi)

1st recorded observation on algal bloom in india was in 1908.

Worldwide Effects of HAB’sWorldwide Effects of HAB’s

Light penetration levels in water decrease altering photosynthesis rate.

Algal blooms may be harmful to seagrass and coral reef ecosystems and the connected food webs.

Shellfish may accumulate algal toxins by feeding on the toxic phytoplankton resulting in fish kills, marine mammal distress, human illness and possible death.

Reasons for Increase in HAB’sReasons for Increase in HAB’s

Global climate changes producing wider ranges for some species.

Human contributions of increased nutrients and pollution in coastal waters and also fresh waters.

Changes in local ecosystems that may allow exotic species to thrive if introduced.

Continue..

Upwelling.

Formation of mud banks.

Nutrients discharge on sea or fresh water through river.

Images

Freshwater algal blooms A red tide

Some HAB’s

• Cyanobacteria (blue-green algae)

• Redtides - neurotoxic shellfish poisoning

• Ciguatera-Gambierdiscus toxicus

• Alexandrium

• Gymnodium

• Dynophysis

• Coolia monotis

• Prorocentrum lima.

Cyanobacteria (blue-green algae)

• Cyanobacteria, also known as blue-green algae.

• Grow in any type of water and are photosynthetic

• Cyanobacteria live in all types of water like Fresh water marine & brackish water.

• They usually are too small to be seen, but sometimes can form visible colonies, called an algal bloom.

• Cyanobacteria have been found among the oldest fossils on earth and are one of the largest groups of bacteria. Cyanobacteria have been linked to human and animal.

Cyanobacterial blooms and how they form

• Within a few days, an bloom of cyanobacteria can cause clear water to become cloudy.

• The blooms usually float to the surface and can be many inches thick, especially near the shoreline.

• Cyanobacterial blooms can form in warm, slow-moving waters that are rich in nutrients.

• Blooms can occur at any time, but most often occur in late summer or early fall.

• Cyanobacterial bloom looks like - foam, scum, or mats on the surface of fresh water lakes and ponds.

• The blooms can be blue, bright green, brown, or red and may look like paint floating on the water.

• Some blooms may not affect the appearance of the water. As algae in a cyanobacterial bloom die, the water may smell bad.

Harmful effect of algal bloom

• Changes in levels of chemicals such as nitrogen and phosphorus from fertilizer, in the water.

• Algal blooms can deplete the oxygen and block the sunlight that other organisms need to live.

• And some can produce toxins that are harmful to the health of the environment- plants, animals, and people etc.

• Aquaculture industries.

Control method

• Biological- Bacteria(Gymnodinium mikimotoi ), Virus, Bivalves, zooplankton etc.

• Chemical- Copper sulfate, Alum etc.

• Physical

Thank You