What is dead zone and what is its cause?

A dead zone refers to an area in a body of water where oxygen levels are so low that most marine life cannot survive, leading to decreased biodiversity. This phenomenon is primarily caused by nutrient pollution, particularly from agricultural runoff containing fertilizers, which leads to excessive algal blooms. When these algae die and decompose, the decomposition process consumes oxygen, creating hypoxic (low-oxygen) conditions. Dead zones are commonly found in coastal areas and can significantly impact local fisheries and ecosystems.