Algal Bloom Impact

An algal bloom off the coast of California has caused sea lions to exhibit unprecedented aggression towards humans due to exposure to a marine neurotoxin (domoic acid) from Pseudo-nitzschia algae.

About Algal Blooms

Algae are microscopic organisms found in salt water, fresh water, and brackish water, using photosynthesis to generate energy from sunlight.
Toxin-Producing Algae: Certain types of algae can produce toxins that harm people, animals, fish, and other parts of the ecosystem.

What is a Harmful Algal Bloom (HAB)?:

A harmful algal bloom occurs when toxin-producing algae grow excessively, creating visible blooms in green, blue-green, red, or brown colors.

Causes of Algal Bloom

Environmental Factors: Conditions like warmer water temperatures, high light intensity, salinity changes, and altered pH can stimulate excessive algal growth.
Nutrient Overload: Runoff carrying fertilizers, sewage waste, and other pollutants provides excess nutrients that trigger algal blooms.
Climate Change Impact: Rising global temperatures and changes in water currents have increased the frequency and intensity of HABs.

Types of Algal Blooms and Their Impact

Organism	Water Type	Bloom Color	Toxin	Health Effects
Alexandrium sp.	Saltwater	Red or brown	Saxitoxins	Gastrointestinal issues, neurological symptoms like muscle weakness
Cyanobacteria	Freshwater	Blue-green	Cylindrospermopsin	Nausea, vomiting, diarrhea, liver damage
Gambierdiscus	Saltwater	Orange	Ciguatoxins	Gastrointestinal problems, stomach pain
Karenia brevis	Saltwater	Red	Brevetoxins	Muscle cramps, seizures, respiratory problems, paralysis
Pseudo-nitzschia	Saltwater	Red or brown	Domoic acid	Vomiting, seizures, diarrhea, confusion, memory loss
Microcystis	Freshwater	Blue-green	Microcystin	Liver damage, gastrointestinal illness

Impact of Algal Blooms On Ecological Balance

Oxygen Depletion: HABs deplete oxygen levels in water bodies, leading to fish and aquatic life deaths.
Light Blockage: Dense blooms block sunlight, affecting photosynthesis for deeper aquatic plants.
Marine Animal Deaths: Toxins from HABs cause illness and death in fish, dolphins, sea lions, and other marine creatures.
Food Chain Disruption: Accumulated toxins in marine organisms impact higher predators and overall marine biodiversity.

Impact On Human Health

Toxin Exposure: Humans can be exposed by consuming contaminated seafood, swimming in, or breathing near affected waters.
Severe Illnesses: Health issues include vomiting, diarrhea, memory loss, seizures, respiratory problems, and even paralysis.
Vulnerable Populations: Children, the elderly, and communities relying heavily on seafood face higher health risks.
Business Losses: Fisheries, recreational activities, and tourism sectors suffer major revenue losses due to waterway closures and health advisories.

Also Read
UPSC Daily Editorials	UPSC Daily Current Affairs
Daily Current Affairs Quiz	Daily Main Answer Writing
Check Out Previous Years Papers From PW Store	UPSC Test Series
Check Out UPSC NCERT Textbooks From PW Store	Check Out UPSC Modules From PW Store