Where there is hardly any oxygen, there is no life – and this also applies to the oceans. According to the United Nations, there are now more than 700 death zones in the world’s oceans. The reason is the death of algae. And climate change.
New York (AFP) The number of so-called death zones in the world’s oceans has increased dramatically, according to a United Nations report. These are areas of the sea that are very poor in oxygen, and where life is hardly possible.
The number of these areas increased from more than 400 to about 700 between 2008 and 2019, according to the United Nations’ Second World Ocean Assessment, which was presented in New York. In addition to the Gulf of Mexico and the South China Sea, the Baltic and North Seas are particularly affected.
This phenomenon occurs naturally in some marine areas. One reason is algal blooms. After they die, the algae slowly sink and are decomposed by bacteria that consume oxygen. In this way, huge areas can form at the depths, sometimes where there is hardly any oxygen in the water. The entry of nutrients like nitrogen and phosphorous into the oceans aids algal blooms.
The United Nations sees the situation deteriorating further: “It is estimated that the human-made input of nitrogen to the coasts will double in the first half of the twenty-first century,” the report says. In addition, rising water temperatures will also have a negative impact due to climate change.
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