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1.
为了解三峡库区鱼类群落结构现状,于2017~2019年对三峡库区干流和9条重要支流开展鱼类种类组成调查,于2018年对库尾木洞、库中云阳和库首巫山干流江段开展渔业资源调查,同时结合历史资料进行了分析.共采集到鱼类149种,隶属于10目25科92属,其中长江上游特有鱼类30种,外来物种20种,喜流水鱼类67种,喜静缓流鱼类82种.研究表明:总物种数与水库运行前相比持平,但组成发生了较大变化;土著种和喜流水性鱼类显著减少,外来种增多;小型鱼类在资源量中占据优势,大中型鱼类资源退化;喜流水鱼类仅在库尾渔获物中占据优势,库中和库首江段渔获物以喜静缓流鱼类为主;干流特有种种类数和资源量均显著下降,支流仍分布有较多特有鱼类;外来种在库中和库首渔获物中占据一定比例,其大量繁衍和发展可能给该水域土著种的生存带来负面影响.三峡库区蓄水过程显著影响了鱼类群落结构.  相似文献   

2.
为掌握金沙江下游巧家江段产漂流性卵鱼类繁殖状况,为金沙江下游鱼类资源保护提供科学依据,于2017~2018年5~7月对金沙江下游巧家江段进行鱼类早期资源调查。结果表明,至少有14种(亚种)鱼类在金沙江下游江段繁殖,其中包括产漂流性卵鱼类12种,长江上游特有鱼类7种。两年调查期间,估算产漂流性卵鱼类的产卵量分别为6 949.73×10~4 ind和11 056.17×10~4 ind,其中长江上游特有鱼类产卵量分别为3 861.44×10~4 ind和5 338.16×10~4 ind。监测期间累计出现5次产卵高峰(2017年2次,2018年3次),合计产卵量为7 942.02×10~4 ind,占两年产卵总规模的42.67%。采用Pearson相关系数对鱼卵径流量与水环境因子进行分析,2018年水温与鱼卵径流量极显著正相关(P0.01),圆口铜鱼、长薄鳅和中华金沙鳅等特有鱼类产卵高峰均出现在流速增长期。产卵场范围为巧家县至攀枝花市江段,2017年主要产卵场分别为巧家县、会泽、会东和皎平渡4个江段;2018新增加了武定江段。与历史调查结果比较,本次调查长江上游特有鱼类种类数量相对增多,产卵总量变化不显著,产卵江段相对更为分散。建议加强巧家江段产漂流性卵鱼类早期资源研究,尤其是特有物种人工繁殖技术研究,同时科学适宜地开展水利工程生态调度。  相似文献   

3.
长江干流典型区域河流生境健康评价   总被引:1,自引:0,他引:1  
河流生境是河流生态系统中的重要组成部分,是维持河流健康的重要因素。河流生境健康的准确评估可以为河流生态系统的保护与修复提供重要依据。针对长江干流生境特点,从河流物理生境形态、河流岸边带生境和水环境特征3个方面选取了10个指标,构建了长江干流生境评价的指标体系。基于该评价体系,在2017年8~9月对长江干流的金沙江下游、三峡库区、长江中下游3个典型区域的127个调查断面进行河流生境综合评估。结果表明:金沙江下游、三峡库区、长江中下游河流生境综合指数(RHI)分值的分别为133.9、124.6、130.8,总体评价等级均为“良”。水流情势、受人类活动干扰是金沙江下游生境变化的主要驱动因子,河岸渠化硬化、河岸植被覆盖、河岸植被带宽则是三峡库区和长江中下游生境变化的主要驱动因子。建议长江上游区域强化水生生物重要栖息地完整性保护,中下游区域加强岸边带、洲滩的生态修复,恢复江湖连通性,构建长江流域生态廊道和生物多样性保护网络。  相似文献   

4.
为研究金沙江干流浮游植物群落结构及其时空分布特征,于2017~2018年春秋两季对干流14个断面进行调查分析。调查结果显示:金沙江干流水域共分布浮游植物8门100种(含变种),主要由硅藻(56%)、蓝藻(22%)、绿藻(11%)组成,浮游植物密度变化范围为0.019 3×10~6~0.341 0×10~6cells/L,浮游植物生物量变化范围为0.016~0.434 mg/L,各江段存在显著性差异。Shannon多样性指数变化范围1.168~2.519,Pielou均匀度指数变化范围为0.559~0.876,Margalef指数变化范围为1.573~3.36,各江段多样性指数变化各异,金沙江干流水环境综合评价为中污染状态。等级聚类和排序结果表明,2017、2018年的春秋两季样本点群落均分为3组。上中下游在不同季节、年份里表现出不同程度的相似性,由于不同断面的环境差异造成了浮游植物群落的时空差异。时间上,金沙江干流浮游植物群落结构上每个季节演替明显,既有延续也有交替;空间上,采样点从上游至下游浮游植物群落越均匀旺盛,具有较明显的空间趋异性,聚类和排序较好的揭示了金沙江干流各江段浮游植物分布组成、种类数量和生境的相似性。  相似文献   

5.
为了解金沙江二期工程白鹤滩、乌东德水库蓄水前,金沙江下游产漂流性卵鱼类产卵场现状,2016~2018年在皎平渡江段使用弶网对产漂流性卵鱼类早期资源开展调查。结果显示:金沙江下游皎平渡江段产漂流性卵鱼类有7种,其中长江上游特有鱼类5种,分别为中华金沙鳅(Jinshaia sinensis)、长薄鳅(Leptobotia elongata)、圆口铜鱼(Coreius guichenoti)、长鳍吻鮈(Rhinogobio ventralis)和红唇薄鳅(Leptobotia rubrilabris)。2016~2018年产漂流性卵鱼类产卵量分别为2 140.0×104、2 189.9×104、2 486.2×104粒,产卵场主要分布在元谋县、永仁县、平地镇、金江镇和格里坪镇5个江段。金沙江下游皎平渡以上江段产漂流性卵鱼类产卵规模较大,但在二期工程蓄水后部分江段将成为淹没区,其产卵繁殖活动将会受到一定程度的影响。针对研究结果,建议对乌东德库尾以上干支流流水江段开展生境保护和修复。  相似文献   

6.
为了解白鹤滩蓄水运行前黑水河下游鱼类资源的现状、受到的主要威胁及其保护措施,于2014年1~12月在黑水河下游干支流江段采用电捕法进行了渔获物调查。结果显示:12个月共调查发现鱼类28种,隶属于3目8科23属,其中喜流水生境、产粘沉性卵、以着生藻类或/和底栖动物为食物的鱼类种类较多;调查区域鱼类个体规格普遍较小,其中齐口裂腹鱼Schizothorax prenanti、短体副鳅Paracobitis potanini、红尾副鳅Paracobitis varigatus、短须裂腹鱼Schizothorax wangchiachii、前鳍高原鳅Triplophysa anterodorsalis、中华纹胸鮡Glyptothorax sinense和凹尾拟鲿Pseudobagrus emarginatus为调查区域的主要经济鱼类;上半年和下半年的渔获物结构在统计学上差异显著(R=0.81,p=0.1%0.05),鱼类在金沙江干流和黑水河下游之间的相互迁徙比较明显;CPUE呈现先波动下降然后逐月上升的趋势,其中10月份的CPUE最低;丰度生物量比较曲线显示2014年各月的渔获物结构均处于严重干扰状态。黑水河下游河道采砂以及过度捕捞是白鹤滩蓄水前影响黑水河下游鱼类资源的主要因素,建议通过控制采砂的江段、采砂的时间以及全面禁捕保护该区域的鱼类资源。  相似文献   

7.
基于2013~2017年金沙江干流攀枝花江段的鱼类资源监测数据,分析了观音岩水电站蓄水前后该江段的鱼类群落结构特征及变化情况。5年共监测到鱼类65种,长江上游特有鱼类共20种,5年均监测到的鱼类有12种,其中11种为喜流水性鱼类。各年度鱼类多样性指数呈现一定波动。ABC曲线及W统计表明2013和2014年鱼类群落结构未受到扰动,但在观音岩水电站蓄水运行后受到严重干扰。CA和NMDS分析显示鱼类群落可以分为两组,组I包括2013和2014年,组II包括2015、2016和2017年,one-way ANOSIM显示这2组在统计学上没有显著性差异。对聚类结果进行SIMPER分析结果显示,在观音岩水电站运行后,产漂流性卵的鱼类丰度明显降低,如圆口铜鱼、长鳍吻鮈等。因此,为了更好地保护攀枝花段的鱼类资源,应采取包括就地或迁地保护、生态调度和人工繁殖放流的针对性措施。  相似文献   

8.
2014~2016年在岷江下游干流开展了4次鱼类资源调查,共采集到鱼类71种(亚种),隶属于3目11科51属,其中包括长江上游特有鱼类16种。不同调查江段鱼类组成相似性指数分析结果显示,宜宾和乐山江段相似性指数最低,70%;宜宾和屏山江段相似性指数最高,9219%。岷江下游干流江段主要经济鱼类为鲤(Cyprinus carpio)、光泽黄颡鱼(Pelteobaggrus nitidus)和瓦氏黄颡鱼(Pelteobagrus vachelli),在岷江下游整个江段渔获物中各占1610%、1396%和1232%。对调查到的71种鱼类产卵类型进行分析结果显示,产粘性卵鱼类和漂流性卵鱼类分别占渔获物总重量的6828%和2707%。不同调查时间和不同江段多样性指数存在差异,其中5~7月份调查到的鱼类多样性指数高于10~12月份调查结果;乐山和犍为江段间鱼类均匀度Pielou指数存在显著差异(P<005)。从调查结果看,岷江下游干流段鱼类种类丰富,渔获物数量较高,但受岷江下游梯级开发的影响,资源前景不容乐观,需加强保护措施。  相似文献   

9.
岷江下游产漂流性卵鱼类早期资源现状   总被引:1,自引:0,他引:1  
为了解岷江下游干流江段产漂流性鱼类早期资源状况,于2016和2017年的5月7日~7月30日在岷江下游干流江段进行鱼类早期资源调查。调查发现:产漂流性卵鱼类18种,其中长江上游特有鱼类8种,分别是小眼薄鳅(Leptobotia microphthalrna)、长薄鳅(Leptobotia elongate)、红唇薄鳅(Leptobotia rubrilaris)、异鳔鳅鮀(Xenophysogobio boulengeri)、裸体异鳔鳅鮀(Xenophysogobio nudicorpa)、四川华鳊(Sinibrama taeniatus)、中华金沙鳅(Jinshaia sinensis)和短身金沙鳅(Jinshaia abbreviata)。主要产卵场有喜捷镇、高场镇和蕨溪镇3处。小眼薄鳅和长薄鳅的产卵规模相对较大,分别为652.75×10~6粒或尾和368.01×10~6粒或尾。典型对应分析结果显示,鲢(Hypophthalmichthys molitrix)和草鱼(Ctenopharyngodon idellus)产卵时断面流量相对增大,透明度相对降低;吻鮈(Rhinogobio typus)产卵期间江水透明度相对较高;随着流速增加,中华金沙鳅(Jinshaia sinensis)和短身金沙鳅(Jinshaia.abbreviata)卵漂流密度均相应增加。  相似文献   

10.
三峡大坝的阻隔,造成鱼类生境片段化,为了解三峡船闸对上下游鱼类的连通性,研究三峡船闸过鱼能力,于2009年6月、2012年2月、2017年2月和2018年2月三峡船闸检修期间,对闸室及廊道进行鱼类调查,分析鱼类组成、多样性和群落结构变化.研究结果显示:历次调查共采集鱼类6目10科32属39种,其中长江上游特有鱼类4种、鲟类2种(匙吻鲟和杂交鲟);鳖、贝氏鳖、鳊、瓦氏黄颡鱼4种鱼类出现频率较高,分别占各次采集鱼类总尾数的98.78%、96.55%、68.14%和91.10%;23种鱼类可能具有通过船闸的能力,其中9种鱼类能顺利通过船闸或可在船闸内定居;大银鱼、太湖新银鱼等弱游泳能力鱼类在船闸也有分布,推测早期仔鱼等也可以通过船闸到达下游江段,达到上下资源交流的目的.该研究为发挥船闸的生态功能提供现实依据.  相似文献   

11.
十一五期间中央环境保护专项资金下达近91亿元,为我国环境污染防治和监管基础能力建设提供了强有力的资金保障。随着财政资金使用改革的不断深入,财政部和环保部对中央环境保护专项资金的管理已从过去以评审为中心转变为以绩效为中心,无论在资金投向、分配方式、过程管理、绩效评估等方面都紧密围绕环境绩效这一中心开展。本文在对十一五期间中央环境保护专项资金资金分配总体情况总结归纳的基础上,分析了资金分配方式制约绩效发挥的主要问题,以改革创新资金分配方式、提高环境绩效为目的,对中央统筹法、项目申报法、因素分配法等三种分配方式提出了若干改革优化的建议。  相似文献   

12.
Refrigerants used in refrigerators are an important source of ozone depleting substances released into the atmosphere, and can have a significantly negative effect on the hole in the ozone layer. But most-emission of refrigerants is man-made, unreasonable and needless. Since in most emission cases the refrigerants are contained in the refrigerators, we can retrieve them by some technique that changes the 'manual emission' into manual retrieving. To promote the retrieval action and diminish the pollution, society can use economic, administrative and technical countermeasures, which can create a 'good-cycle' both 'harnessing pollution and earning income simultaneously', reinforce the motive of retrieving, and retrieve most proportion of refrigerants used by'all refrigerators. This 'good-cycle' method can be easily promoted, and also a valuable way to promote other forms of environmental protection. The three countermeasures have almost no social cost, even no cost at all.  相似文献   

13.
Abstract

Refrigerants used in refrigerators are an important source of ozone depleting substances released into the atmosphere, and can have a significantly negative effect on the hole in the ozone layer. But most emission of refrigerants is man-made, unreasonable and needless. Since in most emission cases the refrigerants are contained in the refrigerators, we can retrieve them by some technique that changes the ‘manual emission’ into manual retrieving. To promote the retrieval action and diminish the pollution, society can use economic, administrative and technical countermeasures, which can create a ‘good-cycle’ both ‘harnessing pollution and earning income simultaneously’, reinforce the motive of retrieving, and retrieve most proportion of refrigerants used by all refrigerators. This ‘good-cycle’ method can be easily promoted, and also a valuable way to promote other forms of environmental protection. The three countermeasures have almost no social cost, even no cost at all.  相似文献   

14.
The results of more than 1 yr of air monitoring inside and outside of five homes in each of two communities are presented for SO2, NO2, mass respirable particles, SO4, Al, Br, Cl, Mn, Na, and V. Outdoor measurements across the home site in each city are consistent with proximity to outdoor sources. Looking across indoor residential sites in each city, the home appears to alter outdoor concentrations in several ways. Indoor level of SO2, SO4, Mn, and V are lower than those measured outdoors. These constituents are thought generally to result from outdoor sources. The other constituents studied are at times found in excess within homes. In some cases the source or sources of excess concentration of a particular constituent could be identified; often, however, the source of excess indoor concentration could not be identified.  相似文献   

15.
The proposed conversion from gasoline powered automobiles to diesel powered vehicels has prompted the Environmental Protection Agency to evaluate the potential health effects associated with exposure to diesel emissions. At present, there is no direct epidemiological link between this exposure and human health. Therefore, a research program was constructed to compare the health effects associated with diesel emissions with those from other emission sources for which epidemiological information was available. The emission sources chosen were cigarette smoke, roofing tar, and coke oven. An additional comparative emission source which was a gasoline catalyst engine. Respirable particles from a variety of combustion sources have the potential of being carcinogenic and mutagenic. The objective of these studies was to determine the relative biological activity of the organic material adsorbed on these particles in both in vitro mutagenesis and in vitro and in vivo bioassays. The organic extracts from the following series of emission sources were quantitatively bioassayed in a matrix of tests for their carcinogenic and mutagenic activity: (1) a light-duty Oldsmobile diesel 350 engine; (2) a heavy-duty Caterpillar diesel engine; (3) a light-duty Nissan engine; (4) a Volkswagen Rabbit diesel engine; (5) cigarette smoke; (6) roofing tar; (7) coke oven; and (8) a gasoline catalyst Mustang. The test matrix consisted of the following bioassay: reverse mutation in Salmonella typhimurium; mitotic recombination in Saccharomyces cerevisiae; DNA damage in Syrian hamster embryo cells (SHE); sister chromatid exchange in CHO cells; gene mutation in L5178Y mouse lymphoma cells, Balb/c 3T3 mouse embryo fibroblasts and CHO cells; viral enhancement of SHE cells; oncogenic transformation in Balb/c 3T3 cells; and skin tumor initiation in SENCAR and C57 black mice. The results of this test matrix are discussed.  相似文献   

16.
Harbour seals (Phoca vitulina) and harbour porpoises (Phocoena phocoena) are top predators in the North Sea and consequently accumulate a variety of pollutants in their tissues. Concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and their hydroxylated metabolites (HO-PCBs and HO-PBDEs) were measured in serum of wild harbour seals (n = 47) and captive harbour porpoises (n = 21). Both species exhibit long life spans and do not have extreme situations, such as complete fasting during periods of lactation, in their annual cycles. For PCBs, concentrations in adult males were slightly higher than in juveniles and lowest in juvenile females. For PBDEs, juveniles have higher levels than adult males and females, probably as a consequence of lactational transfer. However, differences between these age–gender groups were not statistical significant, indicating that individual variation was limited within each species, even without knowing the feeding status of the animals. Body condition, particularly emaciation, has a major influence on the levels of chlorinated and brominated contaminants in serum. Profiles of PCBs were CB 153 > CB 138 > CB 187 > CB 180 and CB 153 > CB 138 > CB 149 > CB 187 > CB 180 for harbour seals and porpoises respectively. For PBDEs, BDE 47 was the predominant congener followed by BDE 100 and 99 in both species. In harbour seals, concentrations of sum PCBs (median: 39,200 pg/ml) were more than 200 times higher than levels of sum PBDEs (median: 130 pg/ml) and almost 10 times higher than concentrations of sum HO-PCBs (4350 pg/ml). In harbour porpoises, concentrations of sum PCBs (median: 24,300 pg/ml) were about 20 times higher than concentrations of PBDEs (median: 1300 pg/ml). HO-PCBs were detected in only 4 harbour porpoises and this at very low concentrations. Naturally-produced MeO-PBDEs were only found in harbour porpoises at concentrations ranging from 120 to 810 pg/ml. HO-PBDEs were not found in any species. In general, harbour seals accumulate less compounds and have mostly lower concentrations than harbour porpoises possibly as a result of a better developed metabolism.  相似文献   

17.
The widespread use of brominated flame-retarded products in the last two decades has resulted in an increasing presence of bromine in thermal processes such as waste combustion and accidental fires. Brominated and brominated-chlorinated dibenzodioxins and dibenzofurans (PBDDs/PBDFs, PXDDs/PXDFs) are micropollutants of concern arising from such processes. The present review aims to evaluate the relevance of these compound classes in actual thermal processes. Four categories of thermal processes are discussed in this respect according to their potential for PBDD/PBDF and PXDD/PXDF generation: thermal stress, pyrolysis/gasification, insufficient combustion conditions and controlled combustion conditions. Under thermal stress situations, as they may occur in production or recycling processes, PBDDs/PBDFs precursors like polybrominated diphenylethers (PBDE) can have a relevant potential for PBDD/PBDF formation via a simple elimination. Under insufficient combustion conditions as they are present in, e.g. accidental fires and uncontrolled burning as well as gasification/pyrolysis processes, considerable amounts of PBDDs/PBDFs can be formed from BFRs, preferably via the precursor pathway. In contrast, under controlled combustion conditions, BFRs and PBDDs/PBDFs can be destroyed with high efficiency. The relevance of de novo synthesis of PXDDs/PXDFs is discussed for this condition.Providing a basis for the understanding of PXDD/PXDF formation in actual thermal processes, the present paper also summarises the formation pathways of brominated and brominated-chlorinated PXDDs/PXDFs from brominated flame retardants (BFRs) investigated during laboratory thermolysis experiments. Relevant mechanistic steps for PBDD/PBDF formation from brominated precursors are discussed including elimination reactions, condensation steps and debromination/hydrogenation reactions.In addition, chlorination/bromination and halogen exchange reactions are briefly discussed with respect for their relevance on the final distribution of PBDDs/PBDFs, mixed chlorinated PXDDs/PXDFs and PCDDs/PCDFs resulting from thermal processes.  相似文献   

18.
城镇化对经济波动具有重要影响,过快和过慢均不利于经济的平稳发展。我国经济新常态客观上要求实施新型城镇化战略,关键是积极稳妥推进城镇化,科学控制城镇化水平和速度。以宏观经济稳定为目标,确定最优城镇化规则,诊断当前城镇化水平和速度,可为落实新型城镇化,稳定宏观经济提供决策参考。本文建立了附加城镇化变量的后顾型宏观经济模型,利用最优控制理论求解基于宏观经济波动最小化的最优城镇化水平和速度决定规则,实证结果表明:我国人口城镇化速度主要对宏观总需求产生影响,而土地城镇化速度既影响总需求也影响总供给;最优城镇化速度规则对总产出缺口负反馈,对通胀缺口正反馈。在此基础上,进一步模拟了1990-2013年间最优人口城镇化、土地城镇化水平以及相应的总产出和通胀波动情况,模拟结果显示:最优城镇化水平和速度规则具有逆经济周期的特征,为保持经济平稳发展,经济过度繁荣时城镇化应减速,经济衰退时应加速城镇化,我国历史上城镇化速度和水平存在较大的优化空间;最优城镇化水平和速度规则会小幅度降低城镇化进程和总产出的平滑性,但会大幅度抑制通胀波动,总体来看使总福利损失下降约三分之一;当前我国人口城镇化水平超前速度过快,土地城镇化水平偏低速度过慢。建议"十三五"期间,政府应该根据宏观经济波动情况适当控制人口城镇化速度,加快推进土地城镇化,提高土地城镇化水平和质量,同时应制定相应的财政政策和货币政策以促进最优城镇化规则发挥其降低宏观经济波动功能。  相似文献   

19.
探矿权资产化、证券化是我国改革探矿业投融资体制,解决探矿业资金瓶颈问题的关键。本文从制度建设、机构投资者的发展状况等方面分析了我国初步推行探矿权资产化、证券化的有利条件.指出了探矿权资产化、证券化的三种模式。并以基金模式和股权模式为例提出了实施探矿权资产化、证券化的步骤设想。  相似文献   

20.
中国工业化进程与能源矿产供需均衡的研究   总被引:2,自引:0,他引:2  
工业化与能源需求的均衡关系及解决工业化进程中能源供需失衡的战略途径是中国工业化进程中需要探讨的重大问题.文章运用协整技术,就1990-2008年间中国工业化进程与能源需求协整关系的检验,认为中国工业化与能源需求增长具有长期稳定的均衡关系,能源需求将继续保持增长,能源利用效率也将持续提高.然而工业化进程中重工业化高能耗结构特征与能源低效利用并存的困境以及能源供需矛盾不利于能源供需平衡的平稳发展.我国应适应工业化进程的基本规律,转变能源消费方式;走新型工业化道路,适当限制低附加值产业发展,鼓励产业向离附加值、低能耗、高技术产业转移;在实现能源开发利用技术进步和创新的同时.有效利用国内外能源资源;建立能源应急机制等战略途径来实现工业化进程中能源供需平衡发展.  相似文献   

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