Marine organisms need oxygen to survive and if there is deficiency of oxygen demand it causes that area as a dead zone which also lead to a nutrient pollution in Marine water ecosystem.
1. climate change: temperature increases and water becomes warm and lighter and lose the ability to hold oxygen and restrict the distribution of oxygen into the water.
2. Eutrophication: It creates hypoxic condition in water due to algae bloom.
3. Nutrient pollution: surplus of nutrients from agricultural run off, usage of fertilizers ,sewage through this enters into the water body and consume oxygen which leads to less oxygen supply.
4. Pollution: Other than nutrient pollution heavy metals, chemicals, oil skills, industrial waste, domestic waste, can also pollute marine ecosystem and creates dead zone areas.
example , Mexico experiences one of the largest dead zone globally due to nutrient rich to run out from the Mississippi River basi
Dead zones in Marine ecosystem requires efforts to reduce pollution eutrophication climate change and need to improve water quality through proper waste water management good environmental policies and mindful agricultural practices.