Fig 1. Modern oceanography and core location.

(A) Summer surface temperatures (World Ocean Atlas 2018 (WOA 18), April-September) in the northern North Atlantic. The white star indicates the core location of GS15-198-33 on the northwestern Icelandic Shelf. The location of the major ocean currents is indicated with the arrows. (B) North to South hydrographic section of modern summer temperatures [19] across the core location showing warmer NIIC waters overlying cold Arctic/Polar intermediate waters (AIW) in the deep troughs. EIC: East Iceland Current; NIIC: North Iceland Irminger Current. (C) Cross-section of stable isotopes of dissolved inorganic carbon (δ¹³C of DIC in ‰ VPDB) in the seawater samples analysed over the entire water column collected during ice2ice I cruise in July 2015. The sampling locations are shown in the insert. Ocean data view was used for creating the maps [20].