Siliceous micro- and nanoplankton fluxes over the Northwind Ridge and their relationship to environmental conditions in the western Arctic Ocean

• Published in: Deep Sea Research Part I: Oceanographic Research Papers
• Main Authors: Ren, Jian, Chen, Jianfang, Li, Hongliang, Wiesner, Martin, Bai, Youcheng, Sicre, Marie-Alexandrine, Yao, Zhixiong, Jin, Haiyang, Zhuang, Yanpei, Li, Yangjie
• Other Authors: Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: Beaufort Gyre; Pacific water inflow; Sea ice; Northwind Ridge; Chukchi Sea; Sediment trap; Diatoms; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Arctic; Arctic Ocean; Chukchi; Phytoplankton
• Online Access: https://hal.science/hal-03414876; https://hal.science/hal-03414876/document; https://hal.science/hal-03414876/file/Ren_DSRI_Arctic%20silic%20micro%20fluxes_Manuscript-pre-proof.pdf; https://doi.org/10.1016/j.dsr.2021.103568

International audience Over the last decades the western Arctic Ocean has undergone unprecedented environmental changes. However, long-term marine phytoplankton in situ observations are still rare and therefore insufficient to fully characterize evolutionary trends. This study investigate diatom flux and composition in sediment trap material collected in the Northwind Ridge, western Arctic Ocean from August 2008 to September 2009. Our data show that Chaetoceros resting spores are the predominant species accounting for >40% of the diatom composition. The sea ice diatom group, which includes Fossula arctica, Fragilariopsis cylindrus and F. oceanica, dominates the rest of the assemblage throughout the observation period. While the diatom fluxes in winter are extremely low, higher values are found in summer, with summer 2009 flux values being twice as high as in 2008. High total mass and diatom fluxes in summer 2009 are attributed to the intertwined effect of a weakened Beaufort Gyre, strengthened Pacific Water Inflow (PWI) and distribution pattern of the sea ice. Enhanced values of coastal diatoms and terrigenous proxies in summer 2009 are in agreement with intensified PWI. Sea ice diatoms and sea ice biomarker IP 25 fluxes are both high during the sea ice melting season and significantly correlated (r 2 = 0.64, p < 0.01). Our data also suggest that sea ice diatoms are prone to selective dissolution in the water column and sediments, implying biases on diatom assemblages and subsequently on paleoceanographic reconstructions.