葛洲坝枢纽下游中华鲟自然繁殖的调查

<正> 中华鲟是一种大型的洄游性鱼类,最大个体达1,100余斤。成熟个体原来由海进入江河,性腺逐渐发育,至翌年秋季在长江上游产卵繁殖。1981年1月,葛洲坝枢纽大江截流,中华鲟的洄游路线受阻,而滞留平坝下江段。在这种情况下,中华鲟的性腺能否继续发育和有无可能在大坝下游自然繁殖的问题,通过两年来的调查研究,已经得到了肯定的回答

葛洲坝水利枢纽兴建后铜鱼繁殖的生态效应

<正> 铜鱼 Coreius heterodon(Bleeker)广泛分布于长江水系,是较典型的河道流水性鱼类。在长江干流中、上游及其主要支流里,它是重要的捕捞对象,在某些地区,其渔捞量终年占总渔获之首位。因其肉味鲜美,含脂量高,被誉为上等食用鱼。1963年易伯鲁等描述了铜鱼卵和胚胎发育特点。60年代初,中国科学院水生生物研究所在长江干流进行家鱼产卵场调查时,

Speciations of Heavy Metals in the Surface Sediments from Xiamen Western Harbor

采用逐级浸出法对厦门西海域6个表层沉积物样品中重金属(Cd、Cr、Cu、Ni、Pb、Zn)的赋存形态进行分析.结果表明:该海域表层沉积物中各重金属元素主要来源于人为输入的各种活性形态,自然输入的残渣态(RES)所占比例较低(10%～20%),在环境条件变化时具有向水相迁移和为水生物所利用的潜在风险性;其中Cu、Cr和Ni的赋存形态以铁锰氧化态(ERO和MRO)和有机物及硫化物结合态(OSM)为主,Pb和Cd则以碳酸盐态(CARB)、铁锰氧化态和有机物及硫化物结合态为主,Zn的各形态所占比例相对比较平均.此次研究对该海域表层沉积物中重金属的赋存形态特征有了基本了解,有助于进一步研究金属元素在近海环境中的迁移和形态转化机制.A sequential extraction procedure was employed to study the chemical speciations of heavy metals in 6 selected surface sediments from Xiamen Western Harbor.The results indicated that Cd,Cr,Cu,Ni,Pb,and Zn in the sediments were predominated(80%~90%) by the geochemically extractable forms,which mainly originated from anthropogenic sources,and least present in residual form(RES).The dominant proportion of Cu,Cr and Ni was ERO(easily reducible oxides),MRO (moderately reducible oxides) and OSM(organic/sulfide matter),and that of Pb and Cd was CARB(carbonate),ERO,MRO and OSM,whereas Zn was evenly distributed.The results of the present study help to provide a deeper understanding to the distribution pattern of such heavy metals and to undertake further research concerning transition mechanisms of pollutants in marine environment.福建省科技攻关课题(2004I001)资

中国被子植物濒危等级的评估

本文基于文献和标本信息收集以及专家提供的数据,运用IUCN濒危物种红色名录方法首次对中国范围内所有已知被子植物进行灭绝风险评估。结果显示,在评估的30,068种被子植物中,灭绝等级(含灭绝、野外灭绝、地区灭绝)共计40种;受威胁等级(极危、濒危、易危)3,363种,受威胁比例为11.18%。从空间分布看,我国受威胁被子植物主要集中分布在西南地区以及台湾、海南等岛屿,且主要分布在中低海拔地区。对受威胁物种的分析结果表明,包括原生植被破坏在内的生境丧失及破碎化是我国被子植物濒危的首要因子,涉及约84.1%的受威胁物种;过度采挖和物种内在系统问题位列致危因子的第二、三位,分别涉及38%和14%的物种。其他的致危因子包括外来入侵种在内的种间竞争、环境污染、自然灾害和全球气候变化等。一个物种的致危因子往往是多方面的。本次评估与2004年红色名录相比,生境变化、实施保护措施及分类学新修订使一些物种的濒危等级发生了变化,这也印证了红色名录是一个动态的系统,需要根据最新信息进行更新,以便为生物多样性保护提供实时准确的基础数据

中国高等植物受威胁物种名录

2008年,环境保护部和中国科学院联合启动了《中国生物多样性红色名录——高等植物卷》的编制工作。通过这项工作,我们依据IUCN濒危物种红色名录标准对中国野生高等植物的濒危状况进行了全面评估,编制了中国高等植物红色名录。2013年9月,该名录以环境保护部、中国科学院第54号公告形式发布,即《中国生物多样性红色名录—

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies