Scientists have now found several dead zones in the Atlantic Ocean for the very first time. Even though the many species of marine animals are supposedly distributed throughout the world’s oceans, this is not true for some places. Dead zones are regions in the ocean that have less oxygen in the water than other places. Furthermore, these regions have lower salt contents at different depths.
The study was conducted by the Germany GEOMAR Helmholtz Center for Ocean Research, which has lasted nearly a decade. Their most recent observation found that a handful of ocean dead zones have formed in the middle of the Atlantic Ocean. In 2010, a scientist from the study deduced that the salt concentration in the water in some regions was beginning to diminish. Though, they originally believed the measurements were a result of faulty instruments. However, after further tests and measurements, they found that series of dead zones were real.
Dead zones are mainly located in shallow coastal areas. They are caused by chemical run offs from nearby industrial plants and farms into the watershed, which allows algae to grow. When a surplus of algae inhabits an area, it begins to grow faster and suck the oxygen out of the water, called hypoxia. When the algae begins to die off, they are consumed by bacteria and other microorganisms, leading to further oxygen depletion from the metabolic system of the microbes. Although they have been in coastal areas around the world, this is the first time dead zones have been found in the open ocean.
The study stated that a concentrated eddy has created a low-oxygen area. An eddy is known as a whirlpool, unlike those found on the beach, the are much larger in size in the world’s oceans. Scientists observed eddys that were nearly 100 miles wide, going to nearly a depth of 1,000 feet. There is also one that has been found around 60 miles off the coast of Cape Verde near West Africa. In a place that a dead zone forms it makes the area no longer suitable for marine life. Also, if fish and other creatures are forced to migrate to different areas, it could throw off the equilibrium of the ecosystems. Open ocean dead zones move in eddys that create whirlpool-like conditions that rotate the the spin of the Earth. It could also be caused by the weather in the middle of the Atlantic Ocean.
In the past few decades, scientists have located dead zones, including one in the Gulf Mexico that is calculated to be over 5,000 square miles. According to the National Oceanic and Atmospheric Administration (NOAA), this dead zone has caused previous fish die offs.
Since scientists have discovered dead zones in areas of the Atlantic Ocean, they hope that they will unearth more information regarding the formation of the fish-killing eddys. They stated if they can find the reason why they form then they will be able to predict the extinction of key species of marine animals that live in the open ocean.
By Alex Lemieux
Photo by Barnyz – Creativecommons Flickr License