淮南采煤塌陷湖泊浮游植物功能群的季节演替及其驱动因子

在淮南矿区设置潘谢潘集站(PXPJ)、潘谢顾桥站(PXGQ)和潘谢谢桥站(PXXQ)等3个塌陷湖泊站点,分别代表3种典型矿区湖泊水文生态条件,于2013—2014年分4个季度采样并分析了3个湖泊浮游植物功能群组成、季节演替规律及其与环境和生物因子的关系。结果显示,3个湖泊的浮游植物种类可归入16个功能群,其主要优势功能群反映了小型富营养化湖泊水体的生境特征。PXPJ春季S1、X2和Y为主要优势功能群,分别以伪鱼腥藻(Pseudanabaena sp.)、具尾蓝隐藻(Chroomonas caudata Geitler)和卵形隐藻(Cryptomonas ovata Ehr.)为代表种属,随后3个季节C为第1优势功能群,以链形小环藻(Cyclotella catenata)为代表物种。PXGQ春夏秋3个季节中均以伪鱼腥藻为代表的S1功能群占绝对优势地位,冬季向C(以链形小环藻为代表)和D(以尖针杆藻为代表)为主的功能群演替。PXXQ春季X2和Y为主要优势功能群,分别以具尾蓝隐藻和卵形隐藻为代表,夏秋季以伪鱼腥藻为代表的S1功能群占据优势地位,冬季向C(链形小环藻为代表)和E(长锥形锥囊藻为代表)功能群为主的群落结构演替。水温和光照条件是驱动淮南采煤塌陷湖泊浮游植物功能群季节演替的关键环境因子,而营养盐和生物因素是导致3个湖泊功能群组成差异的重要原因。

Seasonal succession of phytoplankton functional groups and their driving factors in the artificial lakes created by mining subsidence in Huainan coal mine areas

Underground coal mining in the Huainan coal mine areas, Anhui, China, has created numerous small artificial lakes, which provide excessive water storage space as well as ecological benefits. Characterization of these freshwater ecosystems might have important implications on ecological rehabilitation and recovery in the mining areas. Phytoplankton community structure can provide important eco-environmental information in different habitats besides playing fundamental roles in trophic structures of the lake ecosystem. This study aimed to classify the phytoplankton community on the basis of functional groups (FGs), which has been reported to be more useful than the traditional taxonomic grouping methods for elucidating the ecological functions of phytoplankton. Three small lakes at the PXPJ, PXGQ, and PXXQ sites in Huainan Panxie coal mine areas were selected as representative research sites considering their ecological conditions, and the phytoplankton community structure and water quality at these sites were assessed from 2013 to 2014. Next, the seasonal succession of phytoplankton FGs related to the biotic and abiotic factors in the three lakes was analyzed. The three lakes have different nutrient contents and levels. The lake at PXPJ is permanently connected with a local river that drains into the lake; thus, it has high nutrient concentration, with an annual average concentration of 0.10 mg/L of total phosphorus (TP) and 1.69 mg/L of total nitrogen (TN). The lake at the PXXQ site has the highest TN concentration of 2.81 mg/L due to seasonal drainage from a local polluted river. The lake at the PXGQ site has the lowest TN concentration of 0.91 mg/L, because it is not connected to any rivers. Moderate amount of phosphorus was detected at the PXGQ and PXXQ sites, with mean values of 0.075 mg/L and 0.045 mg/L, respectively. However, the trophic state index for the three lakes was meso-eutrophic and did not vary considerably across the three lakes. In all, 16 FGs were identified, 11 of which were predominant groups, representing features of typically eutrophic habitats in small lakes. At the PXPJ site, FGs of S1, X2, and Y sites were predominant in spring, with Pseudanabaena sp., Chroomonas caudata Geitler, and Cryptomonas ovata Ehr. as representative species, respectively, whereas C (Cyclotella catenata as a representative) was the first predominant group in summer, autumn, and winter. At the PXGQ site, S1 with Pseudanabaena sp. as a representative was predominant in spring, summer, and autumn, which was then replaced by FGs of C (Cyclotella catenata as a representative) and D (Synedra acus Kützing as a representative). At the PXXQ site, FGs of X2 and Y were the predominant groups in spring, which were succeeded by S1 group in summer and autumn, and then replaced by C (Cyclotella catenata as a representative) and E (Dinobryon bavaricum Imhof as a representative) in winter. Light and temperature were identified as the key environmental factors driving seasonal succession of phytoplankton FGs at the three lakes by using canonical correlation analysis. Nutrient and grazing pressure on phytoplankton could be the main causes for the differences in the community structure among the three sites.