Berings hav påverkas av Atlanten

Unlike the Atlantic and Pacific, the upper waters of the Eurasian Arctic Ocean get warmer as they get deeper. The top of the ocean is typically covered by sea ice. Below this is a layer of cool freshwater, followed by a deeper layer of warmer, saltier water delivered to the Arctic from the Atlantic by ocean currents.

The layers are held in place as a result of differences in water salinity. The cool freshwater is less salty than the warmer Atlantic water and so is more buoyant. Therefore, warmer, saltier water sinks below the fresher top layer. In between, a steep salinity gradient forms. This is known as a “halocline”.[1]

Källa: https://www.carbonbrief.org/explainer-how-atlantification-is-making-the-arctic-ocean-saltier-and-warmer

This, in turn, causes the ocean to mix together, drawing more Atlantic heat up towards the surface. This “Atlantification” can, in turn, cause more ice to melt from below, says Tsamados:

“By removing the ice, you are essentially taking off the blanket from on top of the Arctic Ocean and causing it to wake up. This turns the ocean from very calm to something more dynamic.”

I oceanerna finns gott om ‘Argos-dykare‘ som driver med havsströmmar och mäter olika parametrar som varierar med väder och förskjuts av klimatförändringar. Här finns mer om dem: https://urminsynvinkel.wordpress.com/2020/01/19/argo-dykare-i-oceanerna/

Argos måste kunna nå ytan för att kontakta satelliter, rapportera position och ladda upp mätdata. Under havsis används därför en annan taktik, bojar som är förankrade på isytan, färdas upp och ner längs linor och följer isens rörelser. Dessa kallas ‘Ice-Tethered Profiler’ (ITP) och beskrivs här: https://www.whoi.edu/website/itp/overview

Det finns ytterligare tecken på att Berings hav ‘Atlantifieras’ utöver forskarnas mätvärden:

A study published in 2018 found that black-legged kittiwakes – a seabird which feeds in the Barents Sea and Svalbard archipelago – have shifted their diets to incorporate more Atlantic fish species over the last decade. The study authors wrote that the seabirds could be seen as “messengers of Atlantification”.

[1] In oceanography, a halocline (from Greek hals, halos ‘salt’ and klinein ‘to slope’) is a subtype of chemocline caused by a strong, vertical salinity gradient within a body of water. Because salinity (in concert with temperature) affects the density of seawater, it can play a role in its vertical stratification. https://en.wikipedia.org/wiki/Halocline