For half a century, 40 percent of the Black sea were uninhabitable, found an international team of scientists from Belgium, Germany, Italy and the United States. This is due to the fact that the layer of sea water saturated with oxygen, since 1955, becoming thinner, and the concentration of phosphorus and nitrogen in the sea, on the contrary, increases.
The scientists collected data about how you changed the Black sea in the period from 1955 to 2015. In particular, they drew attention to a boundary separating a less dense upper layers from the lower more dense. As it turned out, the distance between this boundary and the surface of the water for interested researchers of the period was reduced from 140 to 90 meters. This means that about 40 percent of the previously habitable waters of the Black sea are not more – that the upper layers contain the necessary for underwater life of oxygen.
So far, experts are not ready to confidently answer the question of why the change occurred. However, researchers believe that this may be related to global warming, as well as the fact that for decades as water enters a large number of compounds of nitrogen and phosphorus – a process, according to scientists, is called eutrophication.
Experts believe that if they are correctly analyzed the situation, then once the upper layers may be very thin or even to mingle with the lower, then the living beings that inhabit the Black sea today, whether animals or plants, more so to dwell in it can not.
The results of their study, the scientists presented in the journal Biogeosciences.
We will remind, in February of this year, another group of researchers representing the University of Maryland, expressed concern that in the future, “ecological deserts” may become the Indian ocean. How figured out the experts for 16 years, the number of phytoplankton in the Western part of that ocean decreased by 30 percent, which probably started a whole chain of doubts, which can lead to the destruction of entire ecosystems.