A sudden rise or aggregation in the population of algae in freshwater or marine water systems is known as an algal bloom. The colouring in the water is mainly caused by the algae’s colours is a common indicator. Algae refers to a wide range of aquatic photosynthetic organisms, including both macroscopic multicellular creatures such as seaweed and microscopic unicellular ones such as cyanobacteria. The term “algal bloom” usually refers to the fast growth of microscopic unicellular algae rather than macro algae. A kelp forest is an illustration of a macroscopic algal bloom. Algal blooms occur when a nutrient, such as nitrogen or phosphorus, enters the aquatic system from multiple sources (for example, fertilizer runoff or other forms of nutrient pollution) and causes excessive algae growth. An algal bloom has an impact on the entire ecosystem.
The consequences range from the beneficial feeding of higher trophic levels to more detrimental impacts such as blocking sunlight from reaching other creatures, depleting oxygen levels in the water, and secreting toxins into the water, depending on the organism. Harmful algal blooms (HAB) are blooms that can affect animals or the environment, especially when the algae release toxins, and can result in fish die-offs, towns cutting off water to inhabitants, or governments having to close fisheries. Eutrophication is the overabundance of nutrients that leads to algae growth and oxygen deprivation.
Toxic Algal Bloom
A harmful algal bloom (HAB) (also known as excessive algae growth) is an algal bloom that harms other creatures by producing natural algae-produced toxins, causing mechanical damage to other organisms, or other methods. HABs are sometimes described as simply those algal blooms that create toxins, and other times as any algal bloom that can cause low oxygen levels in natural environments, killing creatures in both marine and fresh waters. Blooms can endure anywhere from a few hours to several months. When a bloom dies, the bacteria that digest the dead algae consume more oxygen, resulting in a “dead zone” that can kill fish. Neither fish nor plants survive when these zones cover a significant region for an extended period of time. Harmful algal blooms in marine environments are also known as “red tides”.
It’s not always apparent what produces HABs; in some places, they appear to be wholly natural, while in others, they appear to be caused by human activity. There are ties to specific factors like nutrients in some regions, but HABs have been occurring since before humans began to alter the environment. Eutrophication, or an oversupply of nutrients in the water, causes HABs. Fixed nitrogen ( ammonia, nitrates and urea) and phosphate are the two most prevalent nutrients. Industrial pollution agriculture, , excessive fertiliser usage in urban/suburban regions, and associated urban runoff are all sources of excess nutrients. Low circulation and higher water temperature are additional factors.
Effects of Harmful Algal Bloom
Both seaweed and phytoplankton can bloom or develop quickly. Some blooms are dangerous to humans, animals, and the environment. Phytoplankton is responsible for the majority of hazardous blooms that make people and animals sick. When blooms occur, they can affect people, animals, and the environment.
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Toxins are produced (poisons)
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Become overly thick
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Release hazardous gases by depleting the oxygen in the water
Many different forms of phytoplankton can create these dangerous blooms. Most blooms that make people and animals sick are caused by three types of phytoplankton:
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Cyanobacteria are a type of bacteria (also known as blue-green algae)
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Dinoflagellates are a type of dinoflagellate (also known as microalgae or red tide)
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Diatoms are microscopic organisms that live in water (also known as microalgae or red tide)
Prevention of Algal Bloom
It’s a good bet that any chemical or bacteria on the ground will ultimately wash into nearby rivers, either through rain, irrigation, or malfunctioning septic systems, and cause algal blooms. With that in mind, it’s critical to follow the guidelines below to maintain rivers clean.
Use of less lawn chemicals
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Never fertilise before a rainfall is expected.
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Use insecticides and fertilisers only when necessary. Always follow the recommendations and never add more than is required.
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Instead of using traditional chemical fertilisers, consider switching to slow-release and natural organic fertilisers.
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Make sure to use phosphorus-free or low-phosphorus fertilisers, as phosphorus promotes algae growth.
Proper Disposal of Yard Waste
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Keep yard garbage out of the street and out of storm drains and streams. You can either bag it for city pickup, take it to the landfill, or compost or mulch it.
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Compost your yard trash in a compost pile and utilise the nutrient-rich humus in your gardens or potted plants.
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Mulch shrubs and trees with grass clippings or crushed leaves. Mulch aids in weed suppression and moisture retention. Mulch also adds nutrients to the soil by naturally decomposing over time.
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To prevent runoff, cover piles of dirt or mulch used in landscaping tasks.
Conclusion
Algae and cyanobacteria are neither good nor bad on their own. They are crucial to the earth because they provide the oxygen required for life to exist. People, animals, and the environment can be harmed if too much algae or cyanobacteria grows at once or produces toxins. “Nasty blooms” can discolour water, make it smell awful, and make the water or fish taste bad. Because they do not yield toxins, nuisance blooms are usually harmless to humans, pets, and livestock. They can, however, deter people from going to the beach, drinking tap water or eating seafood caught in a continuous bloom.