Scientists recently detected some "dead zones" located at the North Atlantic ocean that can cause massive fish kills, claims new research.

These dead zones in the world's oceans possess extremely dangerously low levels of oxygen where most marine animals such as fish and crustaceans cannot thrive within these regions and only a few micro organisms can subsist. 

Like Us on Facebook

Although there are no immediate harmful impacts to the environment, these zones can still affect commercial fishing industries on an economic level. One example is that very low concentrations are linked to a decrease in fish yields expecially in the Baltic Sea. 

Researchers from Germany and Canada are now studying this dead zone some 700 kilometers off the Western Africa coast where the lowest level of oxygen ever detected in the Atlantic are found.

According to lead author Johannes Karstensen of GEOMAR, the Helmholtz Centre for Ocean Research Kiel, Germany, prior to this study, scientists have estimated that there are minimum oxygen concentrations in the North Atlantic of 40 micromole per liter of seawater which is about one milliliter of oxygen per liter in seawater.

Even if these oxygen concentrations are low, majority of fish can still survive in the ocean. However, this new study says that these dead zones possess 20 times lower oxygen content that prior estimates, which makes them all the more devoid of oxygen which is truly unsuitable for most marine creatures.

These dead zones are created especially near inhabited coastlines where river runoffs carry fertilizers and other chemicals into the ocean that generate more algal blooms. These algae die eventually and when they decompose, their bacteria consumes oxygen in the process similar to Lake Erie.

This new study explores the first dead zone formation in the ocean where they are unique as they form within eddies that are large whirlpools in the ocean. Karstensen says that the eddies the team had observed were rotating cylinders that are 100 to 150 kilometers in diameter and are 700 meters deep as the dead zone occupies the first 100 meters of these whirlpools in the open ocean.

Using satellite data, the team took measurements of oxygen levels and plant growth. These dead zones only had 0.3 milliliters of oxygen per liter of seawater, where normal waters have 100 times higher oxygen content.

Scientists are worried that these dead zones can damage coastal ecosystems leading to mass fish kills and mass die offs of other marine species. This study is published in the journal Biogeosciences, an open access journal of the European Geosciences Union (EGU). 

Tagsdead zones, Atlantic Ocean, dead zones atlantic ocean, mass fish kills, mass die offs