The Gulf of Mexico’s shame is its ever-growing oxygen-depleted “dead zone” radiating for 8,776 square miles from the mouth of the Mississippi river, an area large enough to blanket the state of New Jersey. The largest hypoxic area in the western hemisphere, the Gulf of Mexico’s aquatic graveyard has fallen to a paltry third place worldwide compared with those in the Baltic Sea and the newly confirmed zone in the Arabian Sea.
The scientific definition of a “dead” or “hypoxic” zone is an aquatic area containing less than two parts per million of oxygen. Although hypoxic zones can occur naturally, such zones have become a worldwide problem. According to the Smithsonian Environmental Research Center, some 500 coastal areas exhibit oxygen-depletion since the 1950’s. Prior to that time period, only 50 had fit this definition.
Scientists long suspected a hypoxic area lurked below the Arabian Sea but failed to research the theory due to pirate traffic and other life-threatening geopolitical issues. A surreptitious evaluation was conducted by scientists from England’s University of East Anglia of Norwich via underwater robots that proved their suspicions correct. The Arabian Sea’s dead zone is seven times the size of the Gulf of Mexico’s.
At 63,000 square miles, the size of Florida, the Arabian Sea hypoxic zone now stands as the world’s largest. Number two is Europe’s 23,000 square mile dead zone stretching from Poland to Finland.
The Baltic and Gulf of Mexico zones have similar causes: agricultural runoff. As for the cause of the largest dead zone in the world, the answer is not as straightforward.
Semi-enclosed within the Gulf of Oman, the Arabian Sea experiences very little movement causing its waters to grow stagnant. Scientist Zouhair Lachkar of NYU Abu Dhabi and other researchers have concerns that warming seas are causing this zone to expand. Lachkar explains that the Arabian Sea dead zone appears to be stuck in a cycle where warming seas are depleting the oxygen supply which in turn is reinforcing the warming. This warming cycle combined with the excess fertilizer and sewage that gets dumped into the Gulf of Oman have potential to perpetuate this problem.
Although the study done by UEA did not offer any solutions, this issue is one that will take multiple nations working together to make a difference. From creating better management of agricultural and sewage runoff to reducing carbon emissions, these are certainly complex and often controversial undertakings to tackle. But these issues are worth confronting when the livelihood and survival of humans and wildlife that rely on these oceans are at stake.