崂山近岸浮游植物群落结构季节变化及其环境影响因素

Seasonal Variations in the Phytoplankton Community Structure and Their Environmental Impact Factors in the Offshore Area of Laoshan,Qingdao

为了解山东省青岛市崂山近岸海域浮游植物群落结构变化特征及其与环境因子的关系,于2016~2017年的春、夏、秋3个季节在该海域设置15个监测站位进行调查,并同步监测海区环境因子。结果显示,共检出浮游植物2门31属69种。其中,硅藻门(Bacillariophyta)为绝对优势门类,共25属60种,甲藻门(Pyrrophyta)有6属9种。调查海区浮游植物细胞丰度变化范围为(732.10~1142.19)×10^4 cell/m^3,平均为937.15×10^4 cell/m^3。浮游植物细胞丰度季节变化明显,2016年最高峰出现在秋季;2017年最高峰出现在夏季;空间分布上,春、夏2个季节呈现由北向南递减的趋势。浮游植物群落结构特征指数分析结果显示,调查海域浮游植物的多样性指数和丰富度指数均较好,表明该海域浮游植物群落结构比较稳定。聚类分析结果显示,春季浮游植物细胞丰度季节变化不大,2016和2017年相似性高达70%左右,但夏、秋季的浮游植物细胞丰度季节变化较大,相似性仅为40%左右,这主要与环境因子变化有关。浮游植物群落结构与环境因子相关性分析表明,浮游植物细胞丰度平均值与化学需氧量(COD)的相关系数最高,最高值为0.536,其次与之相关的双因子组为pH与COD、COD与无机氮(DIN)、溶解氧(DO)与COD。因此,崂山近岸海区浮游植物细胞丰度的关键限制因子为COD、pH、DIN和DO。

To explore the seasonal variations in the phytoplankton community structure and their relationship with environmental factors in the offshore area of Laoshan,we designed 15 monitoring stations and made six investigative voyages in the spring,summer,and autumn during 2016~2017 while monitoring other environmental factors simultaneously.We detected 69 species belonging to 31 genera and two phyla of phytoplankton,most of which belong to temperate coastal species.Diatoma was the dominant phylum comprising 25 genera and 60 species,and dinoflagellates comprised 6 genera and 9 species.The seasonal variations in the dominant species were obvious.The most dominant species were Coscinodiscus oculus-iridis,Coscinodiscus asteromphalus,and Ceratium fusus.The total number of phytoplankton ranged from 732.10×10^4 to 1142.19×10^4 cell/m^3,with an average of 937.15×10^4 cell/m^3.The number of phytoplankton cells changed significantly during the year.The highest peak in 2016 appeared in autumn and the second highest peak in summer;the highest peak in 2017 appeared in summer and the second highest peak in autumn.The spatial distribution showed a decreasing trend from north to south,and the high-value areas appeared in Wanggezhuang Bay,Nanyao River,and Shilaoren Beach.The diversity and abundance of phytoplankton in the surveyed area are at a high level,and the phytoplankton community structure in this area is relatively stable,indicated by the analysis of the phytoplankton community structure index.The result of cluster analysis showed that the interannual variations in phytoplankton cell abundance are unobvious in spring,and the similarity is approximately 70%both in 2016 and 2017.However,the interannual variations in phytoplankton cell abundance are relatively obvious in summer and autumn,and the similarity is only approximately 40%,which is mainly related to environmental factors.The correlation analysis between phytoplankton community structure and environmental factors showed that the correlation coefficient between cell abundance average and COD is the highest(0.536)and the two factors that were most related to environmental factors were pH and COD,COD and DIN,and DO and COD.Therefore,the key limiting factors for phytoplankton cell abundance in the offshore area of Laoshan are COD,pH,DIN,and DO.