Fig. 1

Maps of the sampling stations over the a Chukchi Shelf and b Bering Shelf. In map a, the blue dotted stations were sampled for hydrographic and hydro-chemical measurements, and all of them were located east of 169°W. Two subsections could be divided with one south–north orientation starting from Sta. R01, while the other stretches northeasterly from Sta. R02 to near Pt. Hope. Among the hydrographic stations, four (open circles) were collected for anaerobic incubations and three (open triangles) were adopted from the literature, which were sampled for measurements of primary productivity during the same cruise (see “Denitrification vs anammox within the Chukchi Shelf water”). In map b, the blue dotted stations were sampled for hydrographic and hydro-chemical measurements. Among the hydrographic stations, only BL12, BL13, and BL15 (open circles) were collected for anaerobic incubations