There is a certain type of sea ice called pancakes.

Pancake ice forms, for example, in winter in the Greenland Sea: it starts with needle-shaped ice crystals forming in the water column. Due to the high wave energy, these do not form a closed ice sheet but only small 1 to 5 metre wide discs - the so-called pancakes. These are raised at the edges due to the constant impacts against each other.

The special thing about pancake ice is that when the water freezes, most of the salt remains in the liquid seawater, increasing its density.

The rapid growth rate of the pancake ice and thus the rapid increase in salinity in the surface water is crucial for the rapid sinking of the water (convection current) in the Greenland Sea and thus also for maintaining the thermohaline circulation.

In the centre of the Greenland Sea there is an entrance to the deep sea, which is of crucial importance for the entire ocean circulation. This area is not even as large as a thousandth of the area of the world's oceans and yet it is the big motor: the density of the cold seawater is increased by the salt and sinks.

The sinking water causes complete horizontal and vertical mixing (ventilation). In this way, gases such as carbon dioxide are transported into the depths. The oceans can thus store large quantities of carbon dioxide.

There are climate models that predict a decrease in convection in the Greenland Sea and thus a cooling of the western European climate.

Source:

Farewell to the ice: a wake-up call from the Arctic, ed. Peter Wadhams. Berlin, Heidelberg: Springer, 231-54. doi.org/10.1007/978-3-662-60662-9_11 last accessed 18 January 2023). P. 235 ff.