According to a study by a team of scientists from GO2NE ('Global Ocean Oxygen Network'), a new working group created in 2016 by the Intergovernmental Oceanographic Commission of the United Nations, there are more and more "dead zones" in the oceans, it is that is, regions where there is hardly any oxygen.
The oceans not only produce much of the oxygen we breathe, but It is an essential element for marine life itself.
The decrease in ocean oxygen is between the most serious effects of human activities on the Earth's environment. The problem is that scientists expect oxygen to continue to fall even outside these areas as the Earth warms.
As noted Vladimir Ryabinin, executive secretary of the International Oceanographic Commission that formed the GO2NE group:
Approximately half of the oxygen on Earth comes from the ocean. However, the combined effects of nutrient loading and climate change greatly increase the number and size of 'dead zones' in the open sea and coastal waters, where oxygen is too low to support most of life. Marine.
Minor oxygen decreases can hinder growth in animals, hinder reproduction and cause disease or even death. It is also possible that they trigger the release of hazardous chemicals such as nitrous oxide, a greenhouse gas up to 300 times more powerful than carbon dioxide.
Coral reefs can also be consumed without enough oxygen. In another study published in Science, an international team of scientists has measured the increasing rate of coral bleaching in places throughout the tropics over the past four decades, which evidences its destruction.
Before the 1980s, mass bleaching of corals was unheard of. For example, the Great Barrier Reef has now been bleached four times since 1998. According to the author Andrew Baird:
Coral bleaching is a response to stress caused by the exposure of coral reefs to high ocean temperatures. When the bleaching is severe and prolonged, many of the corals die. It takes at least a decade to replace even the fastest growing species.