What happens to aquatic life as a result of excessive algal blooms caused by nutrient pollution?

Excessive algal blooms, often fueled by nutrient pollution from sources such as agricultural runoff or wastewater discharge, lead to decreased oxygen levels in aquatic environments. When these blooms occur, they can block sunlight from reaching underwater plants, which impairs photosynthesis and reduces the oxygen they produce. When the algae eventually die and decompose, the decomposition process consumes a significant amount of dissolved oxygen in the water.

This reduction in oxygen levels can create hypoxic or anoxic conditions, which are detrimental to fish and other aquatic organisms. Many aquatic species, particularly those that require higher oxygen levels, can suffocate or become stressed due to this lack of oxygen, leading to declines in their populations and biodiversity. This oxygen depletion is a critical issue in environments affected by algal blooms and is a primary factor contributing to the negative impacts on aquatic life.