URS FLUEELER
The number of these zones rose from more than 400 to around 700 between 2008 and 2019, according to the UN’s second “World Ocean Assessment” on the state of the seas, which was presented in New York on Wednesday. In addition to the Gulf of Mexico and the South China Sea, the Baltic and North Seas are particularly affected.
The phenomenon occurs naturally in some marine regions. One cause is algal blooms. After they die, the algae slowly sink down and are broken down by bacteria that consume oxygen. In this way, huge zones can form in the depths, in which there is hardly any oxygen in the water at times. The entry of nutrients such as nitrogen and phosphorus into the oceans favors such algal blooms.
The UN sees a tendency for the situation to deteriorate further: “It is estimated that man-made nitrogen inputs on the coasts will double in the first half of the 21st century,” says the report. In addition, rising water temperatures would also have a negative impact due to climate change.
UN Secretary General António Guterres called the findings in the report “alarming”: “The pressures from many human activities continue to strain the oceans, destroy important habitats – such as mangrove forests and coral reefs – and hinder their ability to cope with the effects of climate change,” he said Guterres emphasized the role of CO2 emissions, which destroy biological diversity in the seas and threaten coastal areas due to rising water levels.
Meanwhile, the United Nations sees a positive development in the number of incidents involving ships. The accidents on the world’s oceans have decreased significantly in recent years. From 2014 to 2018, an average of 88 ships were “lost” each year, compared to an average of 120 in the previous five years. There has also been progress in reducing air pollution from ship emissions. In addition, incidents with oil leaks are still rare.