Seasonal and spatial variability of sea ice and phytoplankton biomarker flux in the Chukchi sea (western Arctic Ocean). (February 2019)

• Record Type: Journal Article
• Authors: Bai, Youcheng; Sicre, Marie-Alexandrine; Chen, Jianfang; Klein, Vincent; Jin, Haiyan; Ren, Jian; Li, Hongliang; Xue, Bin; Ji, Zhongqiang; Zhuang, Yanpei; Zhao, Meixun
• Is Part Of: Progress in oceanography. Volume 171(2019)
• Page Start: 22
• Page End: 37
• Publication Date: 2019-02
• Subjects: Sea ice -- Biomarkers -- Chukchi sea -- Sediment trap -- IP25 -- HBI-III -- PIIIIP25; Oceanography -- Periodicals; 551.4605
• DOI: 10.1016/j.pocean.2018.12.002
• Languages: English
• ISSNs: 0079-6611

Abstract

Highlights: First report on HBI-III and PIII IP25 in sinking particles in the western Arctic Ocean. HBI-III in sinking particles suggests ice edge rather than ice-free production of this compound at our site. Sedimentary IP25 shows a positive correlation with HBI-III. Sedimentary PB IP25 and PIII IP25 both exhibit a linear relationship with spring sea ice cover. Abstract: Sediment traps were deployed at 870 m water-depth from August 2008 to September 2009 at station DM in the Chukchi Sea (western Arctic Ocean) in an area covered by sea ice in winter to determine seasonal fluxes of HBIs and phytoplankton sterols in order to improve our understanding of sea ice proxies. HBI-III fluxes and PIII IP25 are for the first time documented in the Arctic Ocean to evaluate their significance for paleoclimate reconstructions. Highest mass fluxes were found from mid-July 2009 to September 2009 contrasting with low values during all other months (i.e., December 2008 to early July 2009). Indeed, during the winter months IP25 was not detected but increased by a factor of nine over summer 2009 reflecting sea ice algae and pelagic phytoplankton production at the sea ice edge. High HBIs and low sterol fluxes at the end of summer 2008 are consistent with the complete melting of sea ice and post-bloom conditions. We found that HBI-III was more abundant in the early stage of sea ice retreat that characterizes the marginal ice zone. These sea ice biomarkers were also measured in surface sediments across a wide range of sea ice cover in the western Arctic region. Higher IP25 values were found in the southeastern Chukchi Sea and decreased westwards where sea ice conditions are less severe. Stronger positive linear relationship were found between the sea ice proxy indexes PB IP25 and PIII IP25 and spring sea ice concentrations than with IP25 in agreement with earlier findings from other Arctic and sub-Arctic regions.