Gu Bowei, Huang Hungchia, Zhang Yizhe, Li Ran, Wang Lei, Wang Ying, Sun Jia, Wang Jianning, Zhang Rui, Jiao Nianzhi, Xu Dapeng
State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Institute of Marine Microbes and Ecospheres, Xiamen University, Xiamen, China.
Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, China.
Front Microbiol. 2022 Feb 7;13:797638. doi: 10.3389/fmicb.2022.797638. eCollection 2022.
Ciliates are pivotal components of the marine microbial food web, exerting profound impacts on oceanic biogeochemical cycling. However, the temporal dynamics of ciliate assemblages on a short time scale in the highly fluctuating estuarine ecosystem remain largely unexplored. We studied changes in the ciliate community during a short time frame in the high salinity waters (>26) of a subtropical estuary. Ciliate abundance, biomass, size and oral diameter structure, and community composition fluctuated considerably and irregularly over a few days or even a few hours. Spearman correlations and the generalized linear model revealed that heterotrophic prokaryotes (HPs) and viral abundances drove the dynamics of ciliate abundance and biomass. The structural equation model further identified a major path from the high-fluorescence content virus (HFV) to HPs and then ciliates. Given the substantial correlation between salinity and HPs/HFV, we proposed that the response of HPs and HFV to salinity drives the dynamics of ciliate biomass. Additionally, the Mantel test showed that phytoplankton pigments such as Lutein and Neoxanthin, phosphate, and pigmented picoeukaryotes were key covariates of the ciliate community composition. This study demonstrated the highly changing patterns of ciliate assemblages and identified potential processes regulating ciliate biomass and community composition on short timescales in a subtropical, hydrographically complex estuary.
纤毛虫是海洋微生物食物网的关键组成部分，对海洋生物地球化学循环有着深远影响。然而，在高度波动的河口生态系统中，纤毛虫群落的短期时间动态在很大程度上仍未得到探索。我们研究了亚热带河口高盐度水域（>26）短时间内纤毛虫群落的变化。纤毛虫的丰度、生物量、大小和口直径结构以及群落组成在几天甚至几小时内都有相当大且不规则的波动。斯皮尔曼相关性分析和广义线性模型表明，异养原核生物（HPs）和病毒丰度驱动了纤毛虫丰度和生物量的动态变化。结构方程模型进一步确定了从高荧光含量病毒（HFV）到HPs再到纤毛虫的一条主要路径。鉴于盐度与HPs/HFV之间存在显著相关性，我们提出HPs和HFV对盐度的响应驱动了纤毛虫生物量的动态变化。此外，Mantel检验表明，叶黄素和新黄质等浮游植物色素、磷酸盐以及有色素的微微型真核生物是纤毛虫群落组成的关键协变量。这项研究展示了纤毛虫群落的高度变化模式，并确定了在亚热带、水文复杂的河口短时间尺度上调节纤毛虫生物量和群落组成的潜在过程。
