During the last Ice Age , the landmasses around the Arctic Ocean were covered in glass kilometers high . The sea itself had a much larger expanse of ice than the one that israpidly disappearingtoday , probably at least twice as much . Yet evidence has now emerge that a small area north of Scandanavia stay ice - free for most of that time , earmark lifespan to subsist in what was otherwise a desert .
Areas of open ocean surround by sea or land shabu are know as polynya , and are create by tender water arise from the ocean depths , winds breaking up ice flows , or both . Dr Jochen Kniesof the Geological Survey of Norway has determine grounds that one persisted through the last Ice Age in the south - west Barents Sea , off northern Norway .
“ We were search for grounds of biologic life in sediments at the bottom of the sea . In doing so , we base that between the sea ice - hatch ocean and the ice sheets on land , there must have been a small ice - free corridor that extended over hundreds of kilometres into the Arctic , ” Knies said in astatement .
Using a sediment centre taken from the area , Knies account inNature Communicationsthat the polynya stayed open for at least 5,000 years . It finally stop dead over around 17,500 years ago , ironically not because the cosmos had become colder still , but because it had begin to warm .
The first stirring of a ardent world , brought on by sluggish changes to the Earth ’s celestial orbit and axial joust , initiate shabu detonating gadget melting , and the estimated 670 billion t ( 740 billion scads ) a yr of cold fresh water look sharp into the sea trim down salinity enough to make the water freeze down .
Just as modern polynyas provide havens for sea life that ca n’t outlive under blockheaded ice , something like occurred while part of the Barents Sea was opened . Some of the algae that form the base of the food chain are trapped in sea deposit , revealing the polynya ’s presence to Knies . When the domain finally froze and reopened , it took 2,000 years for the local ecosystem to find .
Polynyas also play an important part in keeping the great conveyor belt of the sea ’s currents plump , with cold piquant water sinking to the bottom of the oceans , drawing tender waters in to replace it . During the Ice Age , when the whole organization slowed down , the Barents polynya was in all probability in particular important in keeping thing going .
The composition proposes the polynya was probably maintained by the strong malarky from the neighboring ice cap and relatively affectionate upwellings from the Atlantic , while table salt displaced from chicken feed formation closer to shore acted like antifreeze .
