Sources of particulate organic matter in the Chukchi and Siberian shelves: clues from carbon and nitrogen isotopes  

作　　者：Renming Jia Xinyue Mu Min Chen Jing Zhu Bo Wang Xiaopeng Li A S Astakhov Minfang Zheng Yusheng Qiu 

机构地区：[1]College of Ocean and Earth Sciences,Xiamen University,Xiamen 361005,China [2]V.I.Il’ichev Pacific Oceanological Institute,Far Eastern Branch,Russian Academy of Sciences,Vladivostok 690041,Russia

出　　处：《Acta Oceanologica Sinica》2020年第9期96-108,共13页海洋学报（英文版）

基　　金：The National Natural Science Foundation of China under contract No.41721005;the China Ocean Mineral Resources R&D Association(COMRA)Program under contract No.DY135-E2-2-03;the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology under contract No.2018SDKJ0104-3;the Ministry of Science and Education of Russia Project under contract No.АААА-А17-117030110033-0.

摘　　要：The stable isotopic composition(δ13C andδ15N)and carbon/nitrogen ratio(C/N)of particulate organic matter(POM)in the Chukchi and East Siberian shelves from July to September,2016 were measured to evaluate the spatial variability and origin of POM.Theδ13CPOC values were in the range of−29.5‰to−17.5‰with an average of−25.9‰±2.0‰,and theδ15NPN values ranged from 3.9‰to 13.1‰with an average of 8.0‰±1.6‰.The C/N ratios in the East Siberian shelf were generally higher than those in the Chukchi shelf,while theδ13C andδ15N values were just the opposite.Abnormally low C/N ratios(<4),lowδ13CPOC(almost−28‰)and highδ15NPN(>10‰)values were observed in the Wrangel Island polynya,which was attributed to the early bloom of small phytoplankton.The contributions of terrestrial POM,bloom-produced POM and non-bloom marine POM were estimated using a three end-member mixing model.The spatial distribution of terrestrial POM showed a high fraction in the East Siberian shelf and decreased eastward,indicating the influence of Russian rivers.The distribution of non-bloom marine POM showed a high fraction in the Chukchi shelf with the highest fraction occurring in the Bering Strait and decreased westward,suggesting the stimulation of biological production by the Pacific inflow in the Chukchi shelf.The fractions of bloom-produced POM were highest in the winter polynya and gradually decreased toward the periphery.A negative relationship between the bloom-produced POM and the sea ice meltwater inventory was observed,indicating that the net sea ice loss promotes early bloom in the polynya.Given the high fraction of bloom-produced POM,the early bloom of phytoplankton in the polynyas may play an important role on marine production and POM export in the Arctic shelves.

关 键 词：particulate organic matter carbon isotope nitrogen isotope Chukchi Shelf East Siberian Shelf POLYNYA 

分 类 号：X55[环境科学与工程—环境工程]