北仑河口海域小型硅藻群落结构及其与环境因子的关系

北仑河口地处亚热带-热带地区,气候温暖湿润,是我国北部湾沿岸与越南交界的一个重要入海河口。于2008年3、5、8和11月分别采集该海域小型浮游硅藻,同时测定水温、盐度等水体参数,以及氮、磷、硅等18项水化学指标,分析了小型硅藻群落结构变化与环境因子之间的关系。该河口区的小型硅藻主要由纤细翼鼻状藻Proboscia alata f.gracillima、拟旋链角毛藻Chaetoceros pseudocurvisetus、细弱海链藻Thalassiosira subtilis、中华齿状藻Odontella sinensis和菱形藻Nitzschiasp.等优势种类组成,并且存在明显的季节性演替。应用典范对应分析,发现影响北仑河口硅藻群落结构的主要环境因子为温度、盐度、N、Si、Hg和悬浮体质量浓度等,且不同季节的主控因素有所差异。菱形藻对温度和Cu、As、Zn和Hg等重金属的耐受性较强。纤细翼鼻状藻适宜于生长在水体透明度高的海域,悬浮体质量浓度以6.27 mg.L-1以下为宜。拟旋链角毛藻受Cr的影响较大,高含量的Cr会限制其生长。而细弱海链藻和中华齿状藻对Hg的耐受性较强。

Relationship between diatom community structure and environmental factors in Beilun River Estuary

Beilun River is located in the warm and humid subtropical-tropical regions and is an important estuary in the Beibu Gulf coast adjacent to Vietnam.We carried out a field investigation in 2008,and found that the diatom community is mainly composed of Probosica alata f.gracillima,Chaetoceros pseudocurvisetus,Thalassiosira subtilis,Odontella sinensis and Nitzschia sp.These dominant species showed significant seasonal variation.By means of CCA analysis,we found that temperature,salinity,N,Si,Hg and suspension were the main environmental factors which influence diatom community structure.The influencing factors in different seasons varied.Nitzschia sp.had strong tolerance to temperature,Cu,As,Zn and Hg.Probosica alata f.gracillima preferred to grow in clear waters,preferably the suspension concentration no more than 6.27 mg·L-1.Chaetoceros pseudocurvisetus were greatly influenced by Cr,and high levels of Cr would limit its growth.Thalassiosira subtilis and Odontella sinensis had strong tolerance to Hg.