During several austral summers covering a 13 year period, we collected a random sample of body feathers from chicks of 11 sympatric species of Procellariiform (wandering albatross Diomedea exulans -79 individuals in total-, black-browed albatross Thalassarche melanophris - 51-, grey-headed albatross T. chrysostoma - 58 -, light-mantled sooty albatross Phoebetria palpebrata - 34 -, northern giant petrel Macronectes halli - 59 -, southern giant petrel M. giganteus - 60 -, white-chinned petrel Procellaria aequinoctialis - 39 -, blue petrel Halobaena caerulea - 19 - , Antarctic prion Pachyptila desolata - 19 -, South Georgian diving petrel Pelecanoides georgicus - 2 - and common diving petrel P. urinatrix - 6 -) to analyse Delta15N and Delta13C.

Samples of snow, sea ice, seawater (0.5 m and 5 m depths) and meltponds were collected from two ice-covered stations located in the Barents Sea (81 N), during the "Nansen Legacy Q3" summer cruise of the Norwegian research vessel Kronprins Haakon on 26-28 August 2019. Perfluoroalkyl substances (PFAS) concentrations, salinity and stable oxygen isotopes were measured in all samples to determine sources and environmental fate of PFAS during late summer. NERC ENVISION Doctoral Training Centre (NE/L002604/1). NERC and the German Federal Ministry of Education and Research (BMBF) funded Changing Arctic Ocean program EISPAC project (NE/R012857/1). The Nansen Legacy research is funded by the Research Council of Norway (# 276730).