Question

10) Describe with details how the dead zone in the Gulf of Mexico forms.

Answer 1

Formation of Dead zone in gulf of Mexico:
1.Basically in Gulf of Mexico a dead zone of oxygen depleted waters forms every summer in response to nutrient runoff containing nitrogen and phophorus from agricultural lands, sewage and Mississippi river watershed.
As these nutrients primarily in combination with sunlight and warm water trigger algal blooms. But as nutrients get depleted the algae get die further these are decomposed by bacteria .
2. Due to this aquatic life get affected as oxygen levels in the bottom of water drops to the level so that aquatic lives get affected. It will become deadly for many marine organisms.
Dead zones results from process of
eutrophication:
i. Algal blooms that is accumulation of algae due to nutrients overloading, Massive nutrients runoff

ii.Ecological hypoxia (oxygen depletion) cause of fish kill

iii. Microorganisms decomposes dead and decaying matter uses more dissolved oxygen
iv. Dissolved oxygen get depleted
v. Entire ecosystem get affected which depend on oxygen for survival
Nutrient overloading and algal blooms leads to eutrophication which reduces benthic biomass and biodiversity.
This all lead to formation of Dead sea inGulf of Mexico which is major source area for seafood industry but due oxygen depletion fish get killed.
3 . The dead zone that form in the year 2019 is was smaller as predicted it will no larger than 1900 square miles (4921 square km) by 2035.