渤海3个河口区底栖硅藻群落的时空变化特征

底栖硅藻是河口泥滩系统中的重要初级生产者，其群落结构的时空变化可显著影响到河口底栖动物生产力。本研究选取渤海区域的大辽河口、汉沽河口和黄河口为研究对象，分析了泥滩中底栖硅藻群落结构的季节变化特征(2014?2016年)与空间差异，并探讨了环境因素的影响作用。结果表明，3个河口区底栖硅藻多样性和生物量高峰均出现在秋季，优势种存在显著季节演替特征；在空间上，大辽河口和汉沽河口的底栖硅藻生物量显著高于黄河口。底栖硅藻群落结构与多种环境因子的相关性分析表明，温度和营养盐浓度变化对底栖硅藻群落的季节性特征影响显著；河口沉积物的粒径、潮差与径流量可能是造成底栖硅藻群落空间差异的重要因素，黄河口较低的底栖硅藻生物量显著受限于较粗的沉积物粒径和显著的磷限制。

Temporal and spatial variations of benthic diatom communities at three estuaries in the Bohai Sea

Benthic diatoms are important primary producers in estuarine mudflat system, and the spatial and temporal changes in the communities can significantly impact the productivity of benthic fauna in the estuary. In this study, the ecological parameters in the estuaries of Daliao River, Hangu River and Huanghe River along the Bohai Sea coastline were surveyed and the related environmental factors were discussed, aiming to understand the seasonal variations and spatial differences of benthic diatom communities. The results showed that the species diversity index and absolute abundance of benthic diatoms were the highest in autumn, and the dominant species displayed obviously seasonal succession. The diatom absolute abundance in the estuaries of Daliao River and Hangu River were significantly higher than that of Huanghe River Estuary. The coarser sediments and significant phosphorus limitation in the Huanghe River Estuary are main reasons for the low diatom abundance. The correlation analysis between the benthic diatom communities and environmental factors indicated that the changes of temperature and nutrient concentration have significant effects on the seasonal pattern of the benthic diatom communities, while the sediment size, tidal range and runoff of the three estuaries are more important to explain spatial differences.