长江中游干流浮游动物空间分布
SPATIAL DISTRIBUTION OF ZOOPLANKTON IN THE MAIN STEM OF THE MIDDLE YANGTZE RIVER
-
摘要: 2016年10月对长江中游干流5个江段(宜昌、荆州、岳阳、武汉、湖口)开展了以轮虫、桡足类、枝角类为代表的浮游动物调查, 共检测到浮游动物23种, 隶属13科14属, 其中轮虫16种, 桡足类4种, 枝角类3种。各调查江段比较显示, 湖口江段浮游动物物种数最多, 为9种, 岳阳江段浮游动物物种数最少, 为5种, 宜昌、荆州、武汉江段物种数接近。武汉江段浮游动物密度最高, 为(10.94±5.81) ind./L, 湖口江段次之, 宜昌、岳阳和荆州段密度接近。轮虫为优势类群, 密度为(3.41±0.21) ind./L, 其中曲腿龟甲轮虫、尖尾疣毛轮虫和螺形龟甲轮虫为优势种。桡足类密度为(0.75±0.07) ind./L, 多为无节幼体。枝角类密度最低。武汉江段浮游动物生物量最高, 湖口江段次之, 其他3个江段相当。与长江干流其他江段调查结果相比, 此次调查的各江段浮游动物群落呈现较低的物种多样性。Spearman相关系数分析显示, 浮游动物生物量和多样性均与叶绿素a浓度呈显著正相关(P<0.05)。Abstract: To better understand zooplankton distribution and its relationship with the physical-chemical factors in middle Yangtze River, we collected 20 zooplankton samples from segments at Yichang, Jingzhou, Yueyang, Wuhan and Hukou in October, 2016. A total of 23 species that belong to 13 families and 14 genera were identified, among which 16 species belong to Rotifera, 4 to Copepoda and 3 to Cladocera. Among the five segments, the highest number of zooplankton species was detected at Hukou (9 species), while the lowest was at Yueyang (5 species). The average density at Wuhan (10.94±5.81) ind./L was higher than that at Hukou and the other segments. Rotifers (3.41±0.21) ind./L were dominant in the zooplanktonic community, and Keratella valga, Synchacta atylata and Keratella cochlearis were the dominant species. The average density of copepods (mainly nauplius) was (0.75±0.07) ind./L. Cladocera had the lowest average density. Similarly, the zooplankton biomass at Wuhan was also higher than that at Hukou and the other three segments. Comparing with studies at other segments of Yangtze River, we detected lower zooplankton diversity in our investigation. Spearman correlations indicated that the biomass and diversity of zooplankton were significantly and positively correlated (P<0.05) to chlorophyll a.