Table 1.

Location and description of marine regions and rivers, and regional means ± SD of δ¹³C values in dissolved inorganic carbon (DIC), ocean dissolved CO₂, POC_water, POC_ice and POC_riv

Marine regions	Description	Regional mean ± SD (n = number of observations)				References
		δ13C‐DIC (‰)	δ13C‐CO2 (‰)	δ13C‐POCwater (‰)	δ13C‐POCice (‰)
Outer shelves
South Iceland	Atlantic influenced	1.3 ± 0.2 (n = 560)	−9.3 ± 0.2 (n = 560)	−19.9 ± 3.3 (n = 4)	NA	Becker et al. (2016); Key et al. (2015); Sarà et al. (2007); Schmittner et al. (2013); Young et al. ( 2013)
Norwegian sea	Atlantic influenced	1.4 ± 0.4 (n = 183)	−10.0 ± 0.4 (n = 183)	NA	NA	Bauch et al. (2015); Becker et al. (2016); Key et al. (2015)
Southeast Greenland	Atlantic influenced	1.3 ± 0.1 (n = 267)	−9.9 ± 0.2 (n = 267)	NA	NA	Becker et al. (2016); Key et al. (2015)
Hudson bay	Atlantic influenced; fresh water influenced	NA	NA	−24.7 ± 1.3 (n = 19)	NA	Kuzyk et al. (2010)
Bering sea	Pacific influenced	1.3 ± 0.6 (n = 11)	−9.8 ± 0.8 (n = 11)	−23.9 ± 0.7 (n = 62)	−21.5 ± 0.9 (n = 2)	Guo et al. (2004); Lin et al. (2014); Lovvorn et al. (2005); Schmittner et al. (2013); Smith et al. (2002); Young et al. (2013); Zhang et al. (2012)
Gulf of Alaska	Pacific influenced	0.8 ± 0.2 (n = 50)	−10.3 ± 0.3 (n = 50)	NA	NA	Schmittner et al. (2013); Young et al. (2013)
Inflow shelves
Barents sea	Atlantic influenced	1.0 ± 0.4 (n = 10)	−10.3 ± 0.5 (n = 10)	−23.7 ± 1.6 (n = 12)	−19.3 ± 2.6 (n = 12)	Becker et al. (2016); Søreide et al. (2006); Tamelander et al. (2006, 2009)
Svalbard	Northwest of the Barents sea inflow shelf	1.3 ± 0.4 (n = 17)	−10.0 ± 0.4 (n = 17)	−24.5 ± 0.9 (n = 12)	−23.0 ± 0.7 (n = 6)	Becker et al. (2016); Søreide et al. (2006, 2008); Tamelander et al. (2009)
Svalbard fjords	Fresh water influenced; Northwest of the Barents sea inflow shelf	NA	NA	−26.5 ± 1.2 (n = 11)	NA	Hallanger et al. (2011); Kuliński et al. (2014)
Chukchi sea	Pacific influenced	0.8 ± 0.5 (n = 21)	−10.8 ± 0.7 (n = 21)	−22.7 ± 0.1 (n = 36)	NA	Bauch et al. (2015); Iken et al. (2010); Ivanov et al. (2012); Zhang et al. (2012)
Interior shelves
Siberian coast	Fresh water influenced; consists of the East Siberian sea	NA	NA	−24.5 ± 0.5 (n = 7)	NA	Iken et al. (2010); Ivanov et al. (2012)
Beaufort sea	Fresh water influenced; North American coast	NA	NA	−26.7 ± 2.2 (n = 43)	−26.4 ± 0.5 (n = 8)	Connelly et al. (2015); Forest et al. (2010); Iken et al. (2005); O'Brien et al. (2006); Parsons et al. (1989); Zhang et al. (2012)
Outflow shelves
Fram strait	Northeast of Greenland	1.3 ± 0.4 (n = 102)	−10.5 ± 0.4 (n = 102)	NA	NA	Bauch et al. (2015); Becker et al. (2016)
North‐East Water Polynia	Recurring mesoscale areas of open water within areas of pack ice (Sakshaug, 2004); Northeast of Greenland	NA	NA	−27.7 ± 0.6 (n = 3)	−18.6 ± 0.2 (n = 3)	Hobson et al. (1995)
North Water Polynia	Recurring mesoscale areas of open water within areas of pack ice (Sakshaug, 2004); North Baffin bay	NA	NA	−21.9 ± 0.6 (n = 30)	−17.7 ± 3.5 (n = 20)	Hobson et al. (2002); Tremblay et al. (2006)
Canadian archipelago	Complex straits and channels, terrestrial influence	NA	NA	−25.9 ± 1.4 (n = 21)	−18.9 ± 2.3 (n = 9)	Roy et al. (2015)
Arctic basins
Arctic oceanic basins	Includes Amundsen, Nansen and Canadian basins	1.0 ± 0.2 (n = 134)	−11.1 ± 0.2 (n = 134)	−26.3 ± 1.6 (n = 88)	−22.1 ± 2.4 (n = 9)	Bauch et al. (2015); Brown et al. (2014); Griffith et al. (2012); Ivanov et al. (2012); Kohlbach et al. (2016); Schubert and Calvert (2001); Søreide et al. (2006); Tamelander et al. (2009); Zhang et al. (2012)

Riverine regions	Description			δ13C‐POCriv (‰)		References
Siberian rivers	Includes the large rivers of Lena, Ob and Yenisei and smaller rivers of Kolyma, Indigirka, Yana, Olenek, Vakina and Mezen	NA	NA	−29.5 ± 2.1 (n = 237)	NA	Holmes et al. (2018); Lobbes et al. (2000)
North American rivers	Consists of the large rivers of Mackenzie and Yukon, as well as the smaller rivers surrounded the Hudson Bay (Figure 1)	NA	NA	−29.5 ± 1.7 (n = 146)	NA	Goni et al. (2000); Holmes et al. (2018); Kuzyk et al. (2010)