Seasonal variations of siliceous microplankton fluxes and radiolarian assemblages linked to environmental conditions in Prydz Bay polynya, Eastern Antarctica

Frontiers in Marine Science

Marine Science

Yongming Sun¹  Jun Zhao²  Zhengbing Han²  Ji Hu²  Jian Ren²  Jianming Pan³  Gaojing Fan⁴  Rujian Wang⁵  Haifeng Zhang⁶ 

[1] College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao, China;Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China;Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China;Ocean College, Zhejiang University, Zhoushan, China;Key Laboratory of Polar Science, MNR, Polar Research Institute of China, Shanghai, China;State Key Laboratory of Marine Geology, Tongji University, Shanghai, China;State Key Laboratory of Marine Geology, Tongji University, Shanghai, China;Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China;

关键词: Prydz Bay;    siliceous microplankton flux;    radiolarian assemblage;    seasonal variation;    polynya;    primary productivity;    Ice Shelf Water;   

DOI  :  10.3389/fmars.2023.1135900

 received in 2023-01-02, accepted in 2023-03-20,  发布年份 2023

来源: Frontiers

【 摘 要 】

Siliceous microplankton is an effective proxy for connecting modern and past marine environments; however, radiolarians have been understudied in Prydz Bay, Eastern Antarctica. This study investigated the changes in the siliceous microbiota fluxes and radiolarian assemblages captured in a 1-year time-series sediment trap (February 2014 to February 2015, ~490 m water depth) in the polynya of Prydz Bay. The results exhibited the strong seasonality in the radiolarian assemblages and the fluxes of radiolarians, diatoms, silicoflagellates and sponge spicules, with low numbers in winter and high numbers in summer. Seasonal variations in the sea ice and plankton community were critical in these patterns. The total radiolarian flux (TRF) displayed three peaks with higher flux than the annual average TRF over the year, all of which occurred in summer. These TRF peaks were mainly driven by seasonal fluctuations of sea ice, primary productivity, grazing pressure caused by phytophagous zooplankton and resuspension of small radiolarians in the surface sediments induced by modified Circumpolar Deep Water (mCDW) intrusion onto the shelf. There were also two notable low-TRF stages, mainly related to full sea-ice coverage and high grazing pressure. Two dominant assemblages were recognized by means of Q-factor analysis. Dominant assemblage one was composed of three small-sized taxa, Antarctissa sp., Phormacantha hystrix and Plectacantha oikiskos, which could be used as a proxy for primary productivity in the Marginal Ice Zone (MIZ) in Prydz Bay. Dominant assemblage two was composed of Antarctissa strelkovi and Antarctissa denticulata, with A. strelkovi dominating. The high flux and high relative abundance of A. strelkovi marked the extension of Ice Shelf Water (ISW) to the shelf area in Prydz Bay. These findings will provide new insights and reliable proxies for modern and paleoceanographic research in the Southern Ocean.

【 授权许可】

Unknown   
Copyright © 2023 Zhang, Wang, Han, Sun, Fan, Zhao, Hu, Ren and Pan