Structure of Answer:

Brief introduction on Dead Zone.

Consequences of spreading of ‘Dead Zones’ on marine ecosystem.

Key points:

• Dead zones are low-oxygen, or hypoxic, areas in the world’s oceans and lakes.
• Because most organismsneed oxygen to live, few organisms can survive in hypoxic conditions.
• That is why these areas are called deadzones.
• Dead zones in the coastal oceans have spread exponentially since the 1960s and have seriousconsequences for ecosystem functioning.

Effects of dead zones on marine ecosystem

• An ocean dead zone is an invisible trap that there is no escaping from for marine life.
• Fish suffer greatly from dead zones because the extreme changes in the oxygen level changes their entire biology.
• Elevated nutrient levels and algal blooms can also cause problems in drinking water in communities nearby and upstream from dead zones.
• Algal blooms can also lead to the death of shore birds that rely on the marine ecosystem for food.