为探究南水北调中线工程蓄水后新水域环境对鱼类群落的影响,采用eDNA宏条形码技术(environmental DNA metabarcoding)首次对密云水库鱼类群落结构及多样性的时空变化特征进行了分析,并结合生态位宽度Shannon-Winner(B_(i))和重叠Pianka...为探究南水北调中线工程蓄水后新水域环境对鱼类群落的影响,采用eDNA宏条形码技术(environmental DNA metabarcoding)首次对密云水库鱼类群落结构及多样性的时空变化特征进行了分析,并结合生态位宽度Shannon-Winner(B_(i))和重叠Pianka指数(Q_(ik))研究了鱼类种群间的相互作用、共生共存及生态位分化的响应过程。结果表明:本次调查密云水库共检出86个鱼类物种eDNA信息,隶属14目21科68属,有3个鱼类eDNA信息仅注释到科、属级分类水平;鱼类主要栖息于水库底层(61.63%),以肉食性(43.02%)和杂食性(26.74%)摄食类型为主;PCoA分析显示,密云水库各采样点鱼类群落结构无显著性差异(P>0.05),Alpha多样性各项指数也无显著性差异(P>0.05);主要鱼类生态位宽度为1.15~9.25,均为中生态和广生态位种,其中,生态位重叠指数Q_(ik)>0.6的种对有517对,约占总种对数的14.15%;与历史资料相比,鲢(Hypophthalmichthys molitrix)、鳙(Aristichthys nobilis)、鲫(Carassius auratus)、鲂(Megalobrama terminalis)和鲤(Cyprinus carpio)等增殖放流鱼类仍为水库主要经济鱼类。研究表明,蓄水后营底栖、以肉食性和草食性为主要生活策略的水库鱼类对环境的适应能力较弱,且彼此之间竞争明显。展开更多
The depositional fluxes of atmospheric polonium-210 were measured at one site in Xiamen from August 2001 to March 2002. With predominant marine air mass, the depositional fluxes of atmospheric polonium-210 ranged from...The depositional fluxes of atmospheric polonium-210 were measured at one site in Xiamen from August 2001 to March 2002. With predominant marine air mass, the depositional fluxes of atmospheric polonium-210 ranged from 0.01 to 0.09 Bq/（m^2· d）, with an average of 0.04 Bq/（m^2 · d）. The seasonal pattern showed elevated polonium-210 fluxes in summer and autumn rather than in winter. Atmospheric depositional fluxes of polonium-210 showed a good correlation with beryllium-7 （r^2 =0. 85） and lead-210 fluxes （r^2 =0.71 ）, indicating their similar removal mechanism from atmosphere. The relationship between the polonium-210 depositional fluxes and the precipitation amount demonstrated that the precipitation dominates the polonium-210 removal from the atmosphere. The observed high activity ratios of polonium-210 to lead-210 indicated the occurrence of excess polonium-210 in coastal atmosphere, which may originate from marine surface waters either by indirect （foam）, or mare likely, direct （ air - sea exchange） input of marine bingenic material into the atmosphere. This source is even more important than the in situ decay of lead-210.展开更多
基金This research was supported by the National Natural Science Foundation of China under contract No.90411016the National Key Basic Research Special Foundation Program of China under contract No.2005CB422305China 0cean Mineral Resources Research and Development Association Foundation under contract Nos DY105-02-04 and DY105-02-01.
文摘The depositional fluxes of atmospheric polonium-210 were measured at one site in Xiamen from August 2001 to March 2002. With predominant marine air mass, the depositional fluxes of atmospheric polonium-210 ranged from 0.01 to 0.09 Bq/（m^2· d）, with an average of 0.04 Bq/（m^2 · d）. The seasonal pattern showed elevated polonium-210 fluxes in summer and autumn rather than in winter. Atmospheric depositional fluxes of polonium-210 showed a good correlation with beryllium-7 （r^2 =0. 85） and lead-210 fluxes （r^2 =0.71 ）, indicating their similar removal mechanism from atmosphere. The relationship between the polonium-210 depositional fluxes and the precipitation amount demonstrated that the precipitation dominates the polonium-210 removal from the atmosphere. The observed high activity ratios of polonium-210 to lead-210 indicated the occurrence of excess polonium-210 in coastal atmosphere, which may originate from marine surface waters either by indirect （foam）, or mare likely, direct （ air - sea exchange） input of marine bingenic material into the atmosphere. This source is even more important than the in situ decay of lead-210.
