丰水期赣江流域着生藻类群落结构及其与水环境因子的关系

着生藻类在水质监测与水生态健康评价中发挥着重要作用。以江西最大的河流赣江为研究对象,对赣江丰水期着生藻类群落结构及其与环境因子的关系进行研究。选取53个点位对赣江全流域进行着生藻类群落结构的调查研究,共鉴定着生藻3门42属175种,其中硅藻门有23属151种,绿藻门有9属12种,蓝藻门有10属12种。硅藻门舟形藻属为丰水期赣江流域着生藻类优势属,该属生物密度百分比为14.080%。下游着生藻类以硅藻门桥弯藻属和舟形藻属为优势属,该属生物密度百分比分别为13.088%和12.935%;中游着生藻类以硅藻门桥弯藻属为优势属,该属生物密度百分比为12.849%;上游着生藻类以硅藻门异极藻属为优势属,该属生物密度百分比达10.150%。通过蒙特卡罗显著性检验发现,赣江流域下游总氮、溶氧、叶绿素a和电导率对着生藻类有显著影响,中游主要海拔、流速、河宽和总磷对着生藻类有显著影响,上游总氮、河宽、浊度和流速对着生藻类有显著影响。将其与着生藻类群落结构进行冗余分析(RDA),结果发现影响下游着生藻类群落结构的主要水环境因子为叶绿素a和电导率,影响中游、上游着生藻类群落结构的主导水环境因子分别是海拔和总氮。可见赣江流域丰水期下游和上游的着生藻类群落可在一定程度上反映水质状况,中游着生藻类群落结构主要反映的是流域地貌因子。

Community Structure of Periphytic Algae and Their Relationship to Water Environmental Factors in Ganjiang River Basin During the High Water Period

Abstract：In the large high-productive river basin, periphytic algae are the base of the food web for many organisms in the natural ecosystem, and now have been played an important role in monitoring the water quality and assessing the health of aquatic ecosystem in order to manage the river watershed. In the present study, the structure of periphytic algae community and its relationship with water environmental factors were explored throughout the Ganjiang River basin, the largest river in Jiangxi. Fifty-three sampling sites were chosen for the investigation of the periphytic algae community in Ganjiang River during the high water period. Results showed that a total of 175 periphytic algaespecies were identified in Ganjiang River, belonging to 42 genera of 3 phyla. There were 151 species of Bacillariophyta, 12 species of Chlorophyta and 12 species of Cyanophyta in the river, respectively. Navicula was the dominant genus in Ganjiang River basin, occupied 14.080% of periphytic algae genera density. Cymbella and Navicula were the dominant genus in the downstream of Ganjiang River basin, occupied 13.088% and 12.935% of the genera density, respectively. Cymbella was the dominant genus in the midstream, occupied 12.849% of the genera density. Gomphonema was the dominant genus in the upstream, occupied 10.150% of the genera density. The Monte Carlo significance test results showed that the periphytic algae in downstream was significance affected by total nitrogen (TN), dissolved oxygen (DO), Chlorophyll a and conductivity. The periphytic algae in r midstream was significance affected by altitude, velocity, river width, and total phosphorus (TP). The periphytic algae in upstream was significance affected by TN, river width, turbidity and velocity. Redundancy analysis (RDA) was applied to reveal the relationship between periphytic algae community and water environmental factors. Results showed that Chlorophyll a and conductivity were the main factors for periphytic algae communities in the downstream. Altitude and TN were the main factors for periphytic algae communities in the midstream and upstream, respectively. It could be suggested that the water quality was reflected by the community structure of periphytic algae to some extent in the downstream and upstream, but not for the midstream.