This Ocean Invaded Its Neighbor Earlier Than Anyone Thought

It's the middle of the world. The Atlantic. The warm and salty Atlantic waters were gently flowing into the northern part of the planet. The boundary between the polar ocean and the warmer Atlantic was held together by the nature of the ice on top, freshwater in the middle and salty water at the bottom of the ocean.

When the larger ocean began flowing faster than the polar ocean could accommodate, the distinction between the layers was weakened and the waters were turned into something closer to the Atlantic. The process of Atlantification is a part of the reason the ocean is warming faster than any other ocean.

Yueng-Djern Lenn, a physical oceanographer at Bangor University in Wales, said that it was not a new invasion of the Arctic. The properties of the north are changing.

Satellites offer some of the clearest data on the changes in the sea ice. The climate of the ocean may have changed in the past, but their records only go back 40 years.

Tommaso Tesi is a researcher at the Institute of Polar Sciences-CNR, Italy.

Dr. Tesi and colleagues were able to archive 800 years of historical changes in the waters of the North Pole with the help of yard-long cores from the seafloor. Their analysis showslantification began at the beginning of the 20th century. Since 1900, the temperature in the northern part of the planet has warmed by 2 degrees. The discrepancy that the authors say may reveal gaps in the estimates is that this early Atlantification did not appear in existing historical climate models.

Dr. Tesi said it was a bit unnerving because they rely on these models for future climate predictions.

The findings were described as "remarkable" by a researcher at the Tromso campus of the University of Norway.

Information on long-term changes in the hydrography of the ocean is needed.

The Kongsfjorden is a glacier fjord in the east end of the Fram Strait, which is a gateway between the Norwegian archipelago of Svalbard and Greenland.

The researchers dried the layers after slicing up the core. The process of sifting out and identifying the samples foraminifera took a long time.

The image is.

The fjord at the far eastern end of the Fram Strait is called Kongsfjorden and is home to a sediment core.

When foraminifera die, their shells accumulate in the layers of the ocean. Scientists can glean the properties of the past oceans by analyzing the chemistry of the shells of the creatures that are present in the sample.

The original idea was to reconstruct the oceanographic conditions of a region that contained both the Atlantic and the Arctic oceans. The researchers noticed a huge increase in the concentration of foraminifera that preferred salty environments, far earlier than anyone had documented.

An oceanographer at the University of Cambridge and an author on the paper said that it was quite a lot of surprises.

The researchers could assemble a chronology of the past climate in a few years. The year 1916 was when coal mining began in Kongsfjorden. The foraminiferal shift occurred just before this marker, so the researchers thinklantification began around 1907.

The researchers compared the data from their paleoclimate model with other models to see if they overlap, and found no sign of the early Atlantification. There are a number of possible reasons for the absence, such as an underestimation of the role of freshwater mixing in the Arctic or the region's sensitivity to warming.

The current rapid Atlantification is largely driven by the melting of the sea ice in the north. It is too soon after the start of the industrial revolution for us to have accumulated excess heat in the planetary system.

The reasons behind the early Atlantification are not known. The whole system is more sensitive to greenhouse gases if human influences are the cause.

The accelerated Atlantification of recent decades may have made theArctic Ocean more sensitive to natural warming. Is it possible that we destabilizing a system that was already shifting? Dr. Tesi said so.

The mystery of any paleoclimate model is difficult to explain. The doctor said that none of them were there.

This is not true of corals in the Fram Strait. The long-lived animals record changes in climate and other parameters. Dr. Tesi wants to study the corals in the strait to see if they can offer insight into the Atlantic's attempt to take over the Arctic.