Fig. 1.

Map showing the geographical positions of the 12 sampling stations in the Central Arctic Ocean (CAO). White circles indicate the eight stations where ice brine (IB) samples were collected and green circles indicate the four stations where immediate sub-ice seawater (SW) samples were collected. Station 12 is located at the geographic North Pole. The background map was extracted from the International Bathymetric Chart of the Arctic Ocean (IBCAO) Version 3.0 [120]. The borders of the CAO large marine ecosystem (white line) were defined by the PAME Working Group of the Arctic Council [121]