Pujari Laxman, Wu Chao, Kan Jinjun, Li Nan, Wang Xingzhou, Zhang Guicheng, Shang Xiaomei, Wang Min, Zhou Chun, Sun Jun
Research Center for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, China.
Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin, China.
Front Microbiol. 2019 Jul 5;10:1501. doi: 10.3389/fmicb.2019.01501. eCollection 2019.
Phytoplankton are the basis of primary production and play important roles in regulating energy export in marine ecosystems. Compared to other regions, chromophytic phytoplankton are considerably understudied in the Bay of Bengal (BOB). Here, we investigated community structure and spatial distribution of chromophytic phytoplankton in the BOB by using RuBisCO genes (Form ID L). High throughput sequencing of L genes revealed that diatoms, cyanobacteria (Cyanophyceae), Pelagophyceae, Haptophyceae, Chrysophyceae, Eustigamatophyceae, Xanthophyceae, Cryptophyceae, Dictyochophyceae, and Pinguiophyceae were the most abundant groups recovered in the BOB. Abundances and distribution of diatoms and Pelagophyceae were further verified using quantitative PCR analyses which showed the dominance of these groups near the Equator region ( < 0.01) where upwelling was likely the source of nutrients. Further, redundancy analysis demonstrated that temperature was an important environmental driver in structuring distributions of Cyanophyceae and dominant chromophytic phytoplankton. Morphological identification and quantification confirmed the dominance of diatoms, and also detected other cyanobacteria and dinoflagellates that were missing in our molecular characterizations. Pearson's correlations of these morphologically identified phytoplankton with environmental gradients also indicated that nutrients and temperature were key variables shaping community structure. Combination of molecular characterization and morphological identification provided a comprehensive overview of chromophytic phytoplankton. This is the first molecular study of chromophytic phytoplankton accomplished in the BOB, and our results highlight a combination of molecular analysis targeting L genes and microscopic detection in examining phytoplankton composition and diversity.
浮游植物是初级生产的基础，在调节海洋生态系统中的能量输出方面发挥着重要作用。与其他区域相比，孟加拉湾（BOB）中色素浮游植物的研究相当不足。在此，我们通过使用核酮糖-1,5-二磷酸羧化酶/加氧酶（RuBisCO）基因（形式ID L）来研究孟加拉湾色素浮游植物的群落结构和空间分布。L基因的高通量测序显示，硅藻、蓝细菌（蓝藻纲）、褐藻纲、定鞭藻纲、金藻纲、真眼点藻纲、黄藻纲、隐藻纲、网柱藻纲和平藻纲是在孟加拉湾中发现的最丰富的类群。使用定量PCR分析进一步验证了硅藻和褐藻纲的丰度和分布，结果显示这些类群在赤道附近地区占主导地位（<0.01），上升流可能是那里营养物质的来源。此外，冗余分析表明温度是构建蓝藻纲和优势色素浮游植物分布的重要环境驱动因素。形态学鉴定和定量证实了硅藻的主导地位，同时也检测到了我们分子表征中缺失的其他蓝细菌和甲藻。这些形态学鉴定的浮游植物与环境梯度的皮尔逊相关性也表明，营养物质和温度是塑造群落结构的关键变量。分子表征与形态学鉴定相结合，提供了色素浮游植物的全面概况。这是在孟加拉湾完成的首次色素浮游植物分子研究，我们的结果强调了针对L基因的分子分析与显微镜检测相结合在研究浮游植物组成和多样性方面的作用。
