长江口及东海夏季小型底栖动物丰度和生物量变化  

Abundance and biomass of meiofauna in the Yangtze Estuary and East China Sea in summer,with special reference to changes over the past ten years

作　　者：史本泽 于婷婷[1,2] 徐奎栋[1] 

机构地区：[1]中国科学院海洋研究所,青岛266071 [2]中国科学院大学,北京100049

出　　处：《生态学报》2015年第9期3093-3103,共11页Acta Ecologica Sinica

基　　金：国家重点基础研究发展计划(973)(2011CB403604);中国科学院知识创新工程重要方向(KSCX2-EW-Z-5)

摘　　要：2012年7月,对长江口及东海海域的小型底栖动物类群组成、丰度、生物量的空间分布及其与沉积环境的关系进行了调查研究。该研究海域夏季小型底栖动物的丰度和生物量总体上自北向南递减,在长江口以东的海域由近岸向外海增加,至约45 m等深线达到最高,然后向深水区减少。其小型底栖动物的丰度和生物量分别为(1203±191)个/10 cm2和(723±171)μg干重/10 cm2,略高于同一海域春季和秋冬季的数量,但明显低于以往夏季的数量,这可能与本年度该海域沉积物中叶绿素a含量明显偏低有关。在小型底栖动物11个主要类群中,自由生线虫在丰度上占绝对优势(94.1%),其次是桡足类(2.7%)和涡虫类(1.2%)。线虫在生物量上也是最优势类群(62.1%),其次是多毛类(18.8%)、桡足类(8.3%)和涡虫类(6.1%)。Spearman相关分析表明,小型底栖动物的生物量、桡足类和涡虫的丰度均与沉积物中有机氮含量呈负相关;多毛类的丰度与盐度、叶绿素a呈显著正相关;而线虫与所测环境因子未见任何相关关系。BIOENV分析显示,与小型底栖动物各类群的丰度相关性最高的环境因子组合为盐度、沉积物含水量和有机氮含量。研究发现,近10年该海域小型底栖动物的丰度呈总体下降趋势;而且,小型底栖动物的垂直分布随时间推移趋向于向沉积物表层聚集,一定程度上显示沉积环境趋于恶化。通过对近岸和外海两个站位的702条线虫生物体积的测算,获得两个站位线虫的平均个体干重分别为0.186μg/个体和0.281μg/个体,两站位平均为0.214μg/个体,与2009年秋冬季相邻两站位的0.213μg/个体非常接近,但各站位的线虫个体干重变化相对较大。该结果一方面反映了我国当前普遍采用的0.4μg/个体系数高估了线虫的生物量,另一方面显示季节和站位差异影响了线虫个体的大小。The assemblage composition and distribution of meiofauna in the Yangtze Estuary and East China Sea were investigated using samples collected from 16 stations（ from 26°N to 32°N,121°E to 126°E） in July 2012. Generally,both the abundance and biomass of meiofauna decreased from the northern to the southern sea area,increased from the inshore to the offshore area,peaked along the about 45 m isobathymetric line,and then decreased to the offshore area. The meiofaunal abundance amounted to（ 1206 ±189） ind /10 cm2,and the biomass reached（ 729 ±170） !g dwt /10 cm2. The standing crops of meiofauna were slightly higher in the summer season than those from the same area in spring and in winter,but distinctly lower than those in summer（ June 2003）. The low standing crops were likely associated with the low food supply,as indicated by the low sediment chlorophyll-a concentration,though no close relationship was observed. Among the eleven main meiofaunal groups sorted,nematodes represented the most abundant group,accounting for 94. 1% of the total abundance,followed by copepods（ 2. 7%） and turbellarians（ 1. 2%）. In terms of biomass,nematodes and polychaetes accounted for 62. 1% and 18. 8%,respectively,followed by copepods（ 8. 3%） and turbellarians（ 6. 1%）. Spearman correlation analysis showed that the biomass of meiofauna and the abundance of copepods and turbellarians were respectively negatively correlated to the sediment organic nitrogen content,the polychaete abundance was positively correlated with sediment chlorophyll-a concentration and bottom water salinity,while there was no correlation between the nematode standing crops and any environmental factors. BIOENV analysis indicated that the combination of bottom water salinity,sediment water content and total organic nitrogen content best correlated with the meiofaunal communities. Generally,the abundance of meiofauna decreased over the past ten years. Our study revealed a tendency of the meiofauna congregating from the lower to the up

关 键 词：长江口 东海 小型底栖动物 线虫 丰度 生物量 

分 类 号：Q958.8[生物学—动物学]