Overfishing has depleted fish-stocks the world over. Subsidies and lack of enforcement of sustainability measures drive the fishing industry to deplete the very stocks on which its existence depends, while climate interference and global contamination are leaving oceans so hypoxic (oxygen deprived) they cannot support marine life. At least 405 such ‘dead zones’ have been identified across the globe.

According to a NASA report, hypoxia is so extreme in some areas, that total anoxia (zero oxygen availability) can be found, allowing for no animal life to exist. In the Mississippi River delta, feeding into the Gulf of Mexico, it is thought that agricultural waste is creating a glut of nutrients for phytoplankton, which leaves excess organic matter for bottom-dwelling bacteria to feed on.

“When the fertilizer reaches the ocean, it just becomes more nutrients for the phytoplankton, so they do what they do best: they grow and multiply. Which leads to more organic matter reaching the bottom, more bacterial respiration, and more anoxic bottom water.” The water becomes anoxic because bacteria use oxygen and give off carbon dioxide, depleting the oxygen other life forms require to sustain life.

We need responsible, enforceable agricultural waste policies, clean water regulations, oceanic industry controls, and international consensus to put an end to these harmful outcomes of unchecked industrial farming, fish production and fossil-fuel use, all of which contribute to or feed back into the vicious cycle of oxygen depletion in the world’s oceans.

It’s clear from what’s taking place in the Gulf of Mexico that we need to find a way to operate as a civilization without threatening the health of the oceans, but how can we best change policy on the use of agricultural chemicals, the dumping of industrial waste, the management of landfills, and the harvesting of fossil fuels, to ensure that we are not putting toxic chemicals into the marine environment?