Areas discovered with Extremely Low Levels of Oxygen in tropical North Atlantic

A team of German and Canadian researchers has discovered massive oxygen-sucking eddies. They have found the areas in tropical North Atlantic having extremely low levels of oxygen.

The underlining factor of the discovery is that these dead zones are lowest ever recorded in Atlantic open waters. In eddies, dead zones are created. These are swirling masses of water gradually encountering an island and have the ability to lead to mass fish kills.

A majority of marine animals like fish and crabs cannot survive in these regions, but there are some microorganisms that can survive. When it comes to environmental concern then dead zones are considered as an economic concern for commercial fishing.

Low oxygen concentrations have been linked with low fish yields in the Baltic Sea and other parts of the world. The newly discovered areas have oxygen levels that are 20 times lower than the earlier estimated minimum.

Generally, dead zone are found in inhabited coastlines, as there river take fertilizers and other chemical nutrients into the ocean causing algae bloom. When algae die, they sink to the seafloor and gets decomposed by bacteria using oxygen in the process.

Currents can carry the low-oxygen water away from the coast. "The few eddies we observed in greater detail may be thought of as rotating cylinders of 100 to 150 km in diameter and a height of several hundred metres, with the dead zone taking up the upper 100 metres or so", said study researchers.

As per the team estimation, the oxygen consumption within the eddies are some five times larger than in normal ocean conditions. For the past seven years, the researchers have been carrying out observations in the region off the West African coast.