The contributions of refractory particulate organic matter in the Chukchi Sea, Arctic Ocean

Abstract

To investigate the lability of the particulate organic matter (POM), samples were collected from euphotic zone in the Chukchi Sea during summer 2017. Potential temperature and dissolved inorganic nitrogen within euphotic zone decreased toward northern Chukchi Sea. Based on hydrological and nutrient conditions, stations are divided into two zones: southern part (Stns. 2, 3, and 6) and northern part of Chukchi Sea (rest of stations). Statistical analysis of the quantitative and qualitative characteristics of the POM pointed to differences between the stations. Total proteins contributed to 43.8% (± 5.1%) of POM in the southern part and low (29.0 ± 6.4%) in the northern part, whereas carbohydrates accounted for more than half (55 ± 5.8%) in the north area. Hydrolyzable proteins, lipids, and carbohydrates accounted for 31.0%, 79.0%, and 34.2% of each compound in the southern part, but for 64.1%, 53.8%, and 79.7% in the northern part, respectively. These results revealed that lipids were more rapidly altered or mineralized in the southern part, whereas carbohydrates are largely used as sources of energy for higher trophic levels in the northern part of the Chukchi Sea.