Regions in the ocean deep rendered to be uninhabitable by low oxygen levels are called dead zones, according to a study, published in the journal Biogeosceinces.
The discovered dead zone has oxygen levels which are the lowest in the open Atlantic, thus, making it uninhabitable to all marine animal life forms.
Dead zones are created by a multitude of whirling mass of water that move in the west direction, known as eddies.
A researcher and study lead author at GEOMAR, Johannes Karstensen, the Helmholtz Centre for Ocean Research Kiel said, “Before our study, it was thought that the open waters of the North Atlantic had minimum oxygen concentrations of about 40 micromole per liter of seawater, or about one milliliter of dissolved oxygen per liter of seawater.”
Although regarded as low, the above-mentioned composition still allows creatures to thrive in the waters.
In the recently noted dead zone, the measured oxygen level is 20 times lower than previous levels, making this particular region void of any oxygen and uninhabitable for marine life creatures.
The dead zone eddies have sizes of 90 miles in diameter.
The fast spin of the eddies rotation makes it challenging for the water to exchange oxygen at the boundary of the spinning current and the surrounding ocean, according to Karstensen.
The water circulation creates a shallow layer of a few meters at the top of the whirling water which supports intense growth of plants.
Researchers measured the extent of dead zones and analyzed its properties and effect on the local ecosystem.
They discovered that the zoo planktons in eddies linger on the surface by day, instead of hiding to avoid predators in deep waters.
“An aspect related to the ecosystem impact has a socioeconomic dimension, given the few dead zones we observed propagate less than 100 km north of the Cape Verde archipelago, it is not unlikely that an open-ocean dead zone will hit the islands at some point. This could cause the coast to be flooded with low-oxygen water, which put severe stress on the coastal ecosystems and even provoke fish kills and the die-off of other marine life.” Karstensen stated.