SF6 and CFC12 in the water column during POLARSTERN cruise PS106/2 (ARK-XXXI/1.2)

• Main Authors: Heuzé, Céline, Sahlin, Sara, Tanhua, Toste, Stöven, Tim, Andrée, Elin
• Format: Dataset
• Language: English
• Published: PANGAEA 2021
• Subjects: after Stöven (2011); Arctic; Arctic Ocean; ARK-XXXI/1.2; Bottle number; CFC12; chemistry; CTD/Rosette; CTD-RO; Date/Time of event; DEPTH; water; Event label; Freon-12 (dichlorodifluoromethane); LATITUDE; LONGITUDE; physical oceanography; Polarstern; Pressure; PS106_53-1; PS106_56-1; PS106_67-3; PS106_69-4; PS106_73-4; PS106_74-1; PS106_75-1; PS106_78-1; PS106_80-6; PS106_83-1; PS106_85-1; PS106/2; Quality flag; SF6; Station label; Sulfur hexafluoride; Svalbard; tracers
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.929650; https://doi.org/10.1594/PANGAEA.929650

Dissolved gases that act as passive transient tracers have become increasingly popular in physical oceanography for determining the age of a water mass as well as its circulation. In particular, chlorofluorocarbon CFC12 and Sulfur Hexafluoride SF6 are most adapted for comparatively deep water masses that may be several decades old. We here present the full depth concentrations of CFC12 and SF6 from samples collected in June-July 2017 as part of the Polarstern expedition PS106.2 (ARK-XXXI/1.2) ”SiPCA” north of Svalbard, from the shelf to the Nansen abyssal plain. During selected casts, up to ten samples were collected from the Niskin (as first sample collected upon opening of the Niskin). All Niskin bottles had been cleaned with isopropanol beforehand. Samples were collected by connecting a 300 ml glass ampoule to the Niskin tap via an airtight stainless steel system. We let the ampoule fill three times for rinsing, screwed the system shut after the fourth filling, and immediately put the ampoule in icy cold water. These ampoules were flame sealed immediately after collection, one at a time, so that the last sample was sealed at worst a few hours after the cast. The samples were analysed on land in the months that followed the expedition, at the GEOMAR Helmholtz Zentrum für Ozeanforschung, according to the method described in Stöven (2011). These concentrations will now contribute both to local studies of the Svalbard shelf break and its ecosystem, but also to our understanding of the large scale circulation of deep water masses in the Arctic Ocean.