Table 1.

Four sea-ice cores retrieved vertically from different fast ice blocks were cut into three subsections and were respectively named ‘upper’, ‘middle’, and ‘bottom’ from top to bottom. Depths of ice core subsections, filtered volumes of melted ice core subsections, salinities of melted ice core subsections, the numbers of particles (> 30 μm) on filters, abundances of MPs N_mp (> 30 μm), abundances of cellulosic particles (> 30 μm) N_c, abundances of other organic particles (> 30 μm) N_o, and abundances of inorganic particles (> 30 μm) N_io.

Sample code	Depth (cm)	Vol. (mL)	Sal. (PSU)	N (particles/filter)	Nmp (particles/L)	Nc (particles/L)	No (particles/L)	Nio (particles/L)
Core-1_upper	0–15.5	414.5	2.5	402	10	29	116	815
Core-1_middle	15.5–31	411.8	2.1	129	9	6	75	222
Core-1_lower	31–43	333.2	4.0	66	33	24	57	84
Core-2_upper	0–13	430.7	3.7	453	32	263	53	705
Core-2_middle	13–26	437.8	3.1	56	5	21	25	78
Core-2_lower	26–36	252.2	3.6	91	20	8	44	289
Core-3_upper	0–18	554.4	3.1	167	9	42	33	217
Core-3_middle	18–33	526.5	2.4	273	36	192	41	249
Core-3_lower	33–48	478.9	3.3	102	19	11	60	124
Core-4_upper	0–15	341.8	1.3	277	24	49	146	592
Core-4_middle	15–30	404.2	2.0	189	0	23	117	327
Core-4_lower	30–50	652.6	2.4	560	60	172	206	420