珠江口无瓣海桑(Sonneratia apetala)湿地中浮游动物构成及富营养化评价

STRUCTURE OF ZOOPLANKTON AND EUTROPHICATION EVALUATION IN SONNERATIA APETALA WETLANDS IN THE ZHUJIANG(PEARL)RIVER ESTUARY

选择珠江口南沙区两处典型的以大面积人工种植红树植物无瓣海桑(Sonneratia apetala)为主的感潮河涌,进行湿地区域中的浮游动物研究。于2011年5月和11月对开放性河涌湿地14涌(A区)和封闭性河涌湿地19涌(B区)中的浮游动物进行调研,从种类数和丰度、污染指示种和优势种、营养指数E和污染指数A等方面对浮游动物进行群落结构和功能的分析,并以此对湿地水质和无瓣海桑的净化能力进行评价。结果表明,B区林内原生动物总丰度可达106ind/L数量级,7种丰度优势种均为纤毛虫类,优势种哑铃中缢虫(Mesodinium rubrum),1种赤潮原生动物种类,单种丰度在春秋两季可达1.8×105ind/L、5.1×105ind/L。桡足类、枝角类在春季B区林内丰度最高,分别可达576ind/L和46ind/L,显示春季可能为其繁殖季节。轮虫相对不耐污染生境。指数E和指数A均远高于判断阈值。提出了二项浮游动物的富营养判断标准和二条原则。据此判断,B区湿地存在极重的有机污染现象,主要可能与无瓣海桑林内凋落物量较大或根系分泌物的作用且林内水流不畅有关。

Structure of zooplankton was studied in two selected tidal channels planted with mangrove tree Sonneratia apetala in Nansha District in the Zhujiang （Pearl） River estuary to analyze the purification function of mangrove wetlands. The species composition and abundance, pollution indicator and dominant species of zooplankton was investigated in the open 14th channel （area A） and enclosed 19th channel （area B） in the two constructed wetlands in spring （May） and autumn （November） of 2011, and the eutrophication index E and pollution index A were calculated, so that water quality and puri- fication capacity of S. apetala were evaluated. Results showed that abundances of protozoa could reach to level ×106 ind/L; seven dominant species were all ciliates; the dominant species of protozoa was Mesodinium rubrum, a red tide protozoan with highest abundance in BI 1.8×105 ind/L in spring and 5.1×105 ind/L in autumn. Copepoda and Cladocera were maxi- mum in abundance in B1 576 ind/L and 46 ind/L in spring, respectively; and it was estimated that spring was the reproduc- tion season. Rotifera was intolerant of the habitat. Index E and index A were all much higher than the threshold value. Two eutrophication judgment standards and two judgment principles of zooplankton were proposed. Based on these, area B was heavily polluted and this maybe related with the litter amount and the root exudates of S. apetala as well as the hydrologi- cal conditions.