Algal bloom
An algal bloom is a rapid increase in the population of algae in a water body, often resulting in dense, visible accumulations of green, red, or brown coloration on the water’s surface. These blooms typically occur in freshwater or marine environments and are most commonly driven by excess nutrients—particularly nitrogen and phosphorus—from agricultural runoff, wastewater discharge, or other sources of pollution. Warm temperatures, sunlight, and stagnant water conditions can further promote bloom formation.
While not all algal blooms are harmful, some produce toxins that can pose serious risks to aquatic life, animals, and humans. These are known as harmful algal blooms (HABs) and can lead to fish kills, contaminated drinking water, and closures of recreational or commercial fisheries. Even non-toxic blooms can disrupt ecosystems by blocking sunlight, reducing oxygen levels in the water, and altering food chains.
Monitoring and managing algal blooms is a major concern for environmental and public health agencies. Strategies include reducing nutrient pollution, improving land-use practices, and using satellite imaging or field sensors to detect blooms early. As climate change and human activity continue to affect water quality and temperature, algal blooms are becoming more frequent and widespread, highlighting the need for sustainable water management practices.