You might think a ocean dead zone is where the ocean abruptly ends or where there is no life in a part of it. An ocean dead zone is where ocean life cannot survive but it is almost always not a natural occurrence. An ocean dead zone is where the oxygen concentrations are very low. This oxygen deficiency condition is called hypoxia and and is caused by a mixture of biological factors and chemical and physical factors. Because of the lack of oxygen, marine animals are forced to move out of these areas or ones that cannot die. Even though it is called a dead zone, bacteria thrive in these places feeding on the food produced in the upper layer of water. Hypoxia is a natural occurrence but in the last 50 years, this condition is starting to affect many coastlines rapidly due to the increase in human activities polluting nature. These pollutants have thrown coastal ecosystems out of balance resulting in the expanding of ocean dead zones. This will only result in a threading environment for humans and marine animals.