Data_Sheet_1_The Structure of the Seasonal Benthic Diatom Community and Its Relationship With Environmental Factors in the Yellow River Delta.docx

Benthic diatoms are the main primary producers and are sensitive to environmental changes in the estuarine ecosystem. Therefore, it is critical to evaluate the impact of environmental stress on the benthic diatom community in the estuarine ecosystem. In this study, the sediment samples from the five sampling sites were collected from the Yellow River Delta in the four seasons, and the abundance of benthic diatoms were determined using the high-throughput sequencing of 18S rRNA genes. The results showed that the motile guild taxa, such as Navicula, Nitzschia, and Amphora, was dominated in the benthic diatom the community throughout the sampling period. The structure of the benthic diatom community was significantly different among seasons (ANOSIM P < 0.01), especially between summer and winter. Redundancy analysis showed that water temperature and the concentrations of silicate, nitrate, ammonium, and pH value are the main driving factors shaping the seasonal assembly of the benthic diatom community. The results will improve knowledge about the benthic diatom community in the estuarine ecosystem and provide a theoretical foundation for estuary environmental management.

底栖硅藻（Benthic diatoms）是河口生态系统中的主要初级生产者，且对环境变化极为敏感。因此，评估环境胁迫对河口生态系统底栖硅藻群落的影响至关重要。本研究于四季期间在黄河三角洲的5个采样点位采集沉积物样本，并通过18S rRNA基因高通量测序技术测定底栖硅藻的丰度。研究结果显示，在整个采样周期内，舟形藻属（Navicula）、菱形藻属（Nitzschia）和双眉藻属（Amphora）等运动型功能群类群为底栖硅藻群落的优势类群。底栖硅藻群落结构在不同季节间存在显著差异（ANOSIM，P<0.01），尤其在夏季与冬季之间差异最为显著。冗余分析（Redundancy analysis）结果表明，水温、硅酸盐浓度、硝酸盐浓度、铵盐浓度以及pH值是驱动底栖硅藻群落季节组装的主要环境因子。本研究结果有助于深化对河口生态系统底栖硅藻群落的认知，并为河口环境管理提供理论依据。