Scientists are sounding the alarm. A recent study, published in the journal Science and conducted by the Smithsonian Environmental Research Center, reveals the alarming and worrying situation of these ocean areas lacking oxygen. In half a century, the number of dead zones has quadrupled. These zones in the ocean reflect a low oxygen level, or even nonexistent. In the long run, this expansion could lead to a massive marine life extinction.

Disastrous consequences on marine and human life

These dead zones are fatal for plant and animal marine life. The oxygen level is so low that animals die asphyxiated. In addition, fish seeking to get around these zones reduce the size of their habitat and become easier prey in for their predators. The depletion of oxygen also causes a proliferation of nitrous oxide-emitting microbes (a more powerful greenhouse gas than CO2), triggers diseases on marine life and disrupts their reproductive system.

But marine life is not the only one concerned. According to the National Center for Scientific Research (CNRS), “the survival of humanity is at stake.” For example, researchers point out that all activities related to artisanal fishing could stop if the lack of oxygen affects their area. Knowing that almost half of the Earth’s oxygen comes from the oceans makes the situation as worrying for the planet than it is for its inhabitants.

Human activity being the cause

Originally, dead zones result from the natural phenomenon of marine currents. But if their number has explodes it is mainly because of human activity. The deoxygenation of the oceans comes primarily from global warming which increases the water temperature and lower its oxygen’s level. Now, the higher the water temperature is, the more marine animals breathe quickly and consume oxygen…

Near the coast, where the number of dead zones has increased ten-fold since 1950, chemical spills, fertilizers and wastewater are pointed out. These discharges into the ocean cause a large proliferation of algae which also consume a large amount of oxygen.

To fight against the multiplication of dead zones, researchers behind the study recommend a massive agricultural fertilizers use reduction and a strong diminution of greenhouse gases emission. They also encourage the creation of protected marine areas to save the most vulnerable species and monitor oxygen levels in all the oceans of the world.

A little-known effect of the human footprint that could have irreversible consequences …