Date: 25/01/2023

Relevance: GS-3: Environmental Pollution & Degradation.

Key Phrases: Harmful Algal Blooms(HABs), Red Tide, In situ Sampling, National Aeronautics and Space Administration (NASA), Tick Tick Bloom, Blue or Green Blooms, Red Tides.

Why in News?

• The National Aeronautics and Space Administration (NASA) is offering cash prizes for help in finding algal blooms in satellite images.
• The competition, named "Tick Tick Bloom," is asking participants to look at satellite images of inland water bodies and to classify algal blooms based on severity if they are present.
• NASA is looking to use this competition to train computers to recognise the signs of algal blooms in satellite images, making it easier to detect and monitor these blooms on a large scale.

Algae:

• Algae are a group of plants that are usually found in water. Like all plants, algae have a pigment called chlorophyll that they use to turn sunlight into food.
• Algae can be found in all types of waters, including salt water, fresh water, and brackish water (a mix of salt and fresh water).
• Algae can be grouped into two categories, seaweed and phytoplankton.
  • Seaweed are large plants made up of many cells
  • phytoplankton are small, single-celled plants.

What are algal blooms?

• Algal blooms are mass growths of microscopic algae or phytoplankton, usually caused by an influx of nutrients.
• When these blooms occur in inland water bodies, they can cause damage to marine ecosystems due to the blocking of sunlight and depletion of oxygen in the water.

Types of phytoplankton cause most blooms:

• Cyanobacteria (blue-green algae):
  • Blooms of cyanobacteria are more commonly seen in fresh water but sometimes can be found in salt water or brackish water.
  • Even though cyanobacteria are a type of bacteria, they do not cause harm by infecting people or other animals. Instead, cyanobacteria can cause harm by making toxins or growing too dense which can be dangerous to humans and wildlife.
  • Cyanobacterial algal blooms can multiply very quickly in warm, nutrient-rich environments, often creating visible blue or green blooms.
• Dinoflagellates and diatoms:
  • Dinoflagellates and diatoms cause most saltwater blooms of public health concern.
  • Blooms caused by dinoflagellates and diatoms are called algal blooms. Dinoflagellates and diatoms are two different types of phytoplankton and are most often found in salt water or brackish water, including in estuaries.
  • Harmful algal blooms of dinoflagellates or diatoms are often called red tides because they can make the water appear red.
  • Dinoflagellates and diatoms can cause harm to people and animals by making toxins or growing too dense.

Factors Responsible for Algal Bloom:

• Nutrient enrichment: Levels of nutrients such as phosphorus and nitrogen increase in water. Nutrient pollution sources include:
  • Fertilizer (for example, from home lawns and agricultural land)
  • Sewage from people and animals
  • Run-off from cities and industrial buildings
• Increase in water temperature: Blooms are more likely to happen in summer or fall but can occur any time of year.
• Turbidity change: When turbidity is low, light can shine through the water easily. This helps phytoplankton grow.
• Changes in the local ecology: Ecology is how organisms interact with the environment and with each other.
• Climate change: Climate change also plays a role in the formation of algal blooms. Rising water temperatures and changes in precipitation patterns can create conditions that are more favorable for certain types of algae to grow. NASA has stated that the effect of climate change on marine environments likely makes harmful algal blooms form more often.

Anthropogenic Factors:

• In addition to these factors, algal blooms can also be caused by human activities. For example, the overuse of fertilizers in agriculture can lead to excess nutrients flowing into water bodies, creating the ideal conditions for a bloom.
• Similarly, discharge of sewage into water bodies can also contribute to algal blooms by providing an excess of nutrients for the algae to grow.
• Once an algal bloom has formed, it can have a number of negative impacts on the ecosystem.
• The blooms can block sunlight from reaching the water, leading to the death of aquatic plants and animals.
• They can also consume oxygen in the water, leading to the suffocation of fish and other aquatic life.

Harmful Impact of Algal Blooms:

• According to experts, these blooms can block sunlight from reaching the rest of the aquatic ecosystem beneath the surface, and take away oxygen and nutrients from other organisms.
• Nutrient pollution can create ocean dead zones in water with little or no oxygen, where aquatic life cannot survive. Also known as hypoxia, these areas are caused by algal blooms consuming oxygen as they die and decompose. This can result in the massive deaths of aquatic life.
• The toxins can lead to flu-like symptoms, skin irritation, abnormal breathing, gastrointestinal symptoms, and even paralysis in humans.
• Seizures and death may occur in pets, due to their smaller mass. These toxins can also lead to neurological problems in wild animals, causing unusual behaviours.

Mitigation:

• Proper Sewage Treatment:
  • In a bid to limit the presence of nitrogen and phosphorus in water, there is a need to treat sewage water using the recommended waste treatment procedure – the five-step process that ensures optimal treatment.
• Ultrasound Bloom Treatment:
  • This technology focuses on ultrasonic sound waves in water bodies to look for algal blooms and to control their growth if discovered – reducing algae growth by up to 90%. All this is tried and tested, and thus, no harm comes upon aquatic life as it is 100% environmentally friendly with the added advantage of low operational costs.
• Green infrastructure:
  • Adding green roofs, planting trees, and building gardens of rain-absorbing plants all capture rainwater before it flows into waterways.
• Smart water policies and conservation:
  • Protecting wetlands, which act as natural filters to improve water quality, capture runoff, and enhance biodiversity, is also vital.
• Monitoring, mitigation, and collaboration:
  • Improved monitoring and increased research into HABs are also much needed. There is no nationwide system for collecting data on and responding to HABs, and the type of information available on HABs in individual states varies greatly. Improved methods of communication to the public, across organizations, and among states could speed up emergency response to HABs, reducing harm to the environment, wildlife, and people.

Conclusion:

• As per NASA, manual water sampling, or “in situ” sampling, is generally used to monitor cyanobacteria in inland water bodies.
• In situ sampling is accurate, but time intensive and difficult to perform continuously.
• Ultimately, more accurate and more timely detection of algal blooms helps keep both the human and marine life that rely on these water bodies safe and healthy.

Source: The Hindu

Mains Question:

Q. What do you understand about algal bloom? Discuss the factors responsible for the algal bloom as well as the measures for its mitigation. (150 words)