Scientists from the Institute for Marine Research in Tromso, Norway have identified rapid and dramatic climatic changes in the northern Barents Sea. According to researchers, this region is losing the features of the Arctic sea and may soon become part of the Atlantic climate system. In turn, this is likely to have a detrimental effect on local natural ecosystems where ice-dependent animals live and commercial fishing is carried out. An article by scientists was published in the journal Nature Climate Change.
The Barents Sea consists of two regions with different climatic regimes. The north has a cold climate and ice-related ecosystems, while the south is dominated by mild Atlantic conditions. This separation occurs due to the fact that warm and salty waters of the Atlantic enter one part of the sea, while the other contains the fresher and colder waters of the Arctic, which every year under the pressure of the former recede to the north.
Scientists believe that the main role in this process is played by the disturbance of the stratification of water layers due to a decrease in the amount of fresh water entering the sea during ice melting. In a normal cycle, when the ice sheet melts, the ocean surface receives cold fresh water, which creates the conditions for new ice sheets to form next winter. The same ice protects the Arctic layer from direct contact with the atmosphere, and also compensates for the influence of the deep Atlantic layers, preserving stratification.
If there is not enough melt water, stratification begins to be disrupted, and warming and an increase in salinity of the entire water column starts a positive feedback loop that reduces the ice cover and, accordingly, contributes to an even greater shift in the stratification of layers, allowing deep warm waters to rise higher and higher. Scientists cite a general decrease in the amount of ice cover in the Arctic due to global warming as the reason for the decrease in the flow of melt water.
The researchers conclude that the depletion of fresh melt water triggered a chain of events that ultimately led to the emergence of a "hot spot" in the Arctic. However, the changes are likely to be irreversible, and the Barents Sea will soon inevitably become part of the Atlantic climate system. Such transformations took place only during the last ice age.