福建敖江口表层沉积硅藻空间分布特征

Diatom Distribution in Surface Sediments of Aojiang River Estuary in Fujian, China

摘要:

为探讨福建敖江口表层沉积硅藻空间分布特征，2019年7月对敖江口进行表层沉积硅藻的采样调查，并研究了硅藻与环境因子的关系。结果表明，从13个站点共检出硅藻114种，隶属于39属。硅藻丰度具有从河口向外海先减少后增加的变化特征。聚类分析表明，主要硅藻属种可划分为淡水种组合带和半咸水-咸水种组合带。典型对应分析（CCA）表明，表层海水温度和盐度是影响硅藻分布的主要环境变量。河口区盐度相对较低，主要分布淡水种双面曲壳藻、优美曲壳藻和颗粒沟链藻；外海区北部盐度相对较高，主要分布咸水种流水双菱藻；外海区南部盐度相对较低，主要分布淡水种优美曲壳藻和颗粒沟链藻；滩涂的沉积物较粗，主要分布优美曲壳藻。此外，河口区和外海区南部可能存在一定的水体污染。

Abstract:

To understand the spatial distribution characteristic of diatoms in Aojiang River estuary area, Fujian, surface sediment samples from 13 sites were collected in July 2019, and the relationship between distribution of diatoms and environmental factors was studied. The results showed that there were 114 species of diatoms belonging to 39 genera identified from sediment samples. The abundance of diatoms from estuarine to offshore was firstly decreased and then increased. Cluster analysis showed that the main diatom species could be divided into fresh water assemblage zone and brackish-brackish water assemblage zone. Surface water temperature and salinity were the main environmental variables that affect the distribution of diatoms by canonical correspondence analysis (CCA). The salinity in the estuary area was relatively low, freshwater diatoms, such as Achnanthes biasolettiana, A. delicatula and Aulacoseira granulata were the dominant species. The salinity of northern offshore area of Aojiang River was high, marine diatom Surirella fluminensis was dominant. However, the salinity of southern offshore area was low, the abundance of freshwater diatom Achnanthes delicatula was higher than that in northern area. In addition, it is speculated that there may be some water pollution in estuary and the southern offshore area.