There is a concern over the increase in harmful algal booms in the sea waters of India. What could be the causative factors for this phenomenon ? 1. Discharge of nutrients from the estauraries. 2. Run-off from the land rung the monsoon. 3. Upwelling in the seas. Select the correct answer from the codes given below :

Harmful Algal Blooms (HABs) in Indian coastal waters are driven by several synergistic factors. First, the discharge of nutrients from estuaries, such as the Kochi and Mandovi-Zuari systems, introduces high levels of nitrogen and phosphorus from sewage and industrial waste, triggering eutrophication [2]. Second, monsoonal runoff significantly contributes to this phenomenon by washing agricultural fertilizers and land-based pollutants into the sea, which correlates with increased HAB species density [2]. Third, coastal upwelling—a natural process where deep, nutrient-rich waters rise to the surface—provides the essential nutrients required for rapid phytoplankton proliferation. These factors, combined with rising sea surface temperatures and optimal salinity, create the ideal conditions for blooms to intensify along both the Arabian Sea and the Bay of Bengal coasts. Therefore, all three factors—estuarine discharge, monsoon runoff, and upwelling—are causative agents for HABs in India.

Sources

1. [1] https://www.sciencedirect.com/science/article/abs/pii/S0278434317306477
2. [2] https://pmc.ncbi.nlm.nih.gov/articles/PMC3354478/