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1.
杭州湾南岸滩涂环境状况及与贝类养殖的关系   总被引:6,自引:0,他引:6  
浙江省慈溪市滩涂环境与贝类养殖的调查结果显示,杭州湾海域水中石油类及无机氮含量介于Ⅱ、Ⅲ类海水水质标准之间,无机磷平均含量超过Ⅳ类海水水质标准。滩涂底质总体上符合海洋沉积物第一类标准,但一些样点多氯联苯(PCBs)超标。分离N2976株细菌,隶属17个属及肠杆菌科的部分属,具有明显的陆源性特点。发现浮游生物71种,主要为硅藻类等广盐性种类,大部分为贝类的主要天然饵料。石油类、Cd、Cr、Hg、Cu及PCBs残留量在一些贝体内不同程度地超过GB18421-2001《海洋生物贝类质量标准》。为有效改良和保育滩涂环境,提高养殖贝类的产量和质量,在揭示滩涂环境与贝类养殖关系的基础上,提出了一些统筹兼顾的措施和建议。  相似文献   

2.
海洋滩涂贝类养殖环境的研究现状   总被引:14,自引:0,他引:14  
薛超波  王国良  金珊 《生态环境》2004,13(1):116-118
随着海洋滩涂贝类养殖业的发展,滩涂贝类养殖环境日趋恶化,生物病原大量滋生,养殖生产受到了严重的阻碍。文章介绍了我国滩涂的分布、类型和资源开发利用状况;结合滩涂贝类养殖生产和发病状况,从微生物学、底栖生态学和污染生态化学等角度,对我国在海洋滩涂贝类养殖环境方而取得的研究成果进行了综述;提出了滩涂贝类养殖环境方面亟需解决的问题。这些问题包括养殖容量的确定、底栖生物生态的研究、健康养殖模式的确立和污染环境的生物修复等。  相似文献   

3.
运用气相色谱-质谱仪(GC-MS)测定海口市售6种贝类中7种指示性多氯联苯(PCBs)含量,评价其污染水平和致癌风险。结果表明,7种指示性PCBs在海口市售海洋贝类中的含量为17.51~47.43 ng·g-1(以干重计),平均含量为32.78 ng·g-1。贝类中指示性PCBs的组成以中、低氯代PCBs为主(三氯-PCBs、四氯-PCBs和五氯-PCBs),其中四氯-PCBs占总PCBs的38.49%。与我国其他相关研究相比,海口市售海洋贝类中PCBs的总含量处于中等水平。成人通过贝类摄入途径暴露指示性PCBs对消费者的5%、50%以及95%致癌风险均小于美国环保局(USEPA)推荐的可接受风险水平,表明海口市售海洋贝类中指示性PCBs对成人消费者的致癌风险处于可接受风险水平。  相似文献   

4.
为了研究贝类养殖对沉积物中汞的分布与不同结合态的影响,2012年5月至2013年5月在胶州湾的红岛、黄岛、胶南以及营海贝类养殖区采集55份沉积物样品,分别用冷原子吸收法和连续提取法测定其总汞及不同结合态汞的含量.研究结果表明,胶州湾贝类养殖区沉积物中总汞含量范围为0.037—0.228 mg·kg~(-1),其中红岛养殖区汞含量最高,超过环境背景值3.2倍.总汞含量在垂直方向上呈从底部到表层增加的趋势,且在沉积物表层富集.通过对比不同区域及不同年代胶州湾表层沉积物总汞含量,发现贝类养殖使得胶州湾养殖区沉积物汞污染程度加重.此外,沉积物中汞主要以残渣态为主,占总汞含量的31.46%,交换态与可溶态所占比例最少,仅占总汞含量的9.06%.几个养殖区域的汞污染程度依次为:红岛营海黄岛胶南,汞的潜在生态风险因子计算结果表明,胶州湾养殖区沉积物存在中等以上的生态风险.  相似文献   

5.
为减少滩涂养殖中的石油烃污染危害、提高水产品的品质,以珠江口滩涂红树林种植–养殖系统耦验示范研究基地A、B两系统的7个红树种植–养殖塘[包括桐花树(Aegiceras corniculatum)、木榄(Bruguiera gymnorhiza)、秋茄(Kandelia candel)、红海榄(Rhizophora stylosa)的单种或组合种植]为对象,采用荧光分光光度法监测了水体、底质及吊养的近江牡蛎(Ostrea rivularis)肉质的石油烃含量.结果表明,牡蛎体内石油烃含量在11.10~29.3 mg/kg之间;与水体中石油烃含量呈正相关(r=0.88),牡蛎能很好地指示水体水质状况.单种或组合种植秋茄、桐花树、木榄、红海榄4种红树植物能有效降低水体石油烃含量,与对照相比降幅为50%~80%;使牡蛎的石油烃含量受到不同程度的影响,与对照相比,红树种植塘牡蛎石油烃含量降幅在20%~60%不等.木榄和桐花树种植塘中,牡蛎中石油烃平均含量分别为11.20 mg/kg、14.13 mg/kg,能达到无公害水产品标准.因此红树种植–养殖塘具有"种植岛基质–红树植物–微生物"的协同效应,通过物理、化学和生物的共同作用降低了水体石油烃的含量,从而提高了养殖生物的品质.  相似文献   

6.
小窑湾双壳贝类筏式养殖对海域环境的影响   总被引:6,自引:0,他引:6  
在对小窑湾海水交换、海域环境现状、底质环境、养殖区生物代谢产生的IN、IP以有浮游植物消长的研究中,首次发现了在没有陆域污染源入海的海湾型双壳贝类筏式养殖区养殖生物产生的IN、IP与浮游植物消长有其独特的平衡关系和制约机制:一方面养殖贝类排泄的IN、IP被浮游植物利用,另一方面贝类摄食又控制了浮游植物的爆发性增殖,同时解释了养殖区水质质量相对较好的原因。  相似文献   

7.
椒江河口滩涂贝类时空分布与环境因子的关系   总被引:1,自引:0,他引:1  
在椒江口两岸共布设6条潮间带采样断面,于2007年10月和2008年1月、4月和7月进行大型底栖动物及环境因子(水温、沉积物温度、沉积物结构、盐度、滩涂宽度、总有机物和油类含量)的调查和测定;运用典范对应方法分析了贝类栖息密度和生物量与各环境因子的关系.结果表明:(1)研究区域共记录到贝类动物23种,其中腹足纲16种,双壳纲7种;(2)贝类柄息密度和生物量季节变化不显著,空间变化显著,平均值分别为610.01 ind m~(-2) 和25.40 g m~(-2);岩头断面中国绿螂的栖息密度和生物餐的季节均值分别可达2 415.28 ind m~(-2) 和110.41 g m~(-2),远高于其他物种;(3)典范对应分析结果显示,滩涂宽度、油类含量、有机质含量和沉积物粒度等环境因子与贝类的分布存在较大相关性.图5表3参28  相似文献   

8.
建立了AutoSPME-GC联用分析无公害海水养殖水环境中8种痕量PCBs的方法,优化了萃取温度,研究了萃取时间、盐度和涂层中PCBs的残留量对萃取方法的影响.该法最低检出限为0.7-1.9ng·μl-1,RSD(n=5)为2.2%-8.2%,回收率为79.8%-108.0%,该法简单、快速,适合海水中PCBs分析.  相似文献   

9.
多氯联苯在土壤中的吸附规律及其影响因素研究   总被引:3,自引:0,他引:3  
崔兆杰  宋善军  刘静 《生态环境》2010,19(2):325-329
为了建立定量描述土壤中多氯联苯(PCBs)迁移规律的数学模型,以采自现代黄河三角洲地区的土壤为研究对象,针对类二噁英类多氯联苯PCB81及阻转类多氯联苯PCB95在土壤中的吸附行为进行了研究,获得了其吸附等温方程并分析了土壤有机质含量、颗粒组成、pH、矿物质含量等特性参数对吸附量的影响。结果表明,PCBs在土壤中的吸附行为符合Langmuir吸附等温方程;PCBs的吸附量与土壤中有机质含量和土壤粘粒含量呈正相关关系,与土壤pH值及土壤矿物质含量无明显相关关系。  相似文献   

10.
浙江省沿海地区四种贝类中砷的形态及含量分布   总被引:6,自引:0,他引:6  
唐健  李士敏 《环境化学》2006,25(2):236-237
贝类等海产品中砷的含量比其它食品高,因为贝类不同程度地具有富集砷的能力.通过检测它的组织污染程度能反映水体环境的化学物质变化.贝类中砷的形态多种多样,包括无机砷和有机砷,有机砷包括甲基砷、二甲基砷、砷甜菜碱、砷胆碱等,通常是低毒或者无毒的,而无机砷的毒性远大于有机砷.因此,考察海洋食品中砷的限量主要是检测其无机砷的含量.  相似文献   

11.
Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación  相似文献   

12.
Protected areas (PAs) are often implemented without consideration of already existing PAs, which is likely to cause an overrepresentation of certain biophysical conditions. We assessed the representativeness of the current PA network with regard to the world's biophysical conditions to highlight which conditions are underprotected and where these conditions are located. We overlaid terrestrial and marine PAs with information on biophysical conditions (e.g., temperature, precipitation, and elevation) and then quantified the percentage of area covered by the PA network. For 1 variable at a time in the terrestrial realm, high temperature, low precipitation, and medium and very high elevation were underrepresented. For the marine realm, low and medium sea surface temperature (SST), medium and high sea surface salinity (SSS), and the deep sea were underrepresented. Overall, protection was evenly distributed for elevation across the terrestrial realm and SST across the marine realm. For 2 variables at a time, cold and very dry terrestrial environments had mostly low protection, which was also the case for low SST and low and medium SSS across most depths for marine environments. Low protection occurred mostly in the Sahara and the Arabian Peninsula for the terrestrial realm and along the Tropic of Capricorn and toward the poles for the marine realm. Although biodiversity measures are of prime importance for the design of PA networks, highlighting biophysical gaps in current PAs adds a frequently overlooked perspective. These gaps may weaken the potential of PAs to conserve biodiversity. Thus, our results may provide useful insights for researchers, practitioners, and policy makers to establish a more comprehensive global PA network.  相似文献   

13.
Summary The adaptation of defensive secretions to their target organisms was examined for the abdominal gland secretions ofBledius furcatus, B. spectabilis andB. arenarius. Therefore the target organisms of the secretion of theseBledius species (i.e. their predators) had to be identified. At the collection sites examined these were the earwigLabidura riparia, the antCataglyphis bicolor, the flyLispe candicans, different carabids of the generaPogonus, Dichirotrichus, Dyschirius, Bembidion andCalathus and the wading birdsHaematopus ostralegus andCalidris alba. The secretion of the abdominal glands contains the toxin ptoluquinone dissolved in either-dodecalactone and 1-undecene (B. furcatus andB. spectabilis) or in octanoic acid and octyloctanoate (B. arenarius). The ratio of these solvents is species-specific. Application experiments using some of the natural insect predators (L. riparia, C. bicolor, Pogonus, Di. gustavii, Dyschirius) revealed that these solvent ratios provided a more effective deterrent than other possible ratios. Thus by combining the solvents in certain ratios, the capability of cuticular penetration and therefore the effectiveness of the defensive secretions are adapted to their natural targets.  相似文献   

14.
The politics of development includes subtexts of choice, as underpinned by community consensus (or lack of it), against the larger backdrop of a liberal democracy, with its intricate power structures that influence the choice of concepts and often lead to complicity rather than consent. A dilemma exists between the understanding of field-level practitioners and that of academics, whose understandings of progress differ. Progress can (and often does) imply long-term change across generations whereas development is often more a matter of crisis management and delivering tangible results to end-users. This makes it a bone of contention across political systems, irrespective of local or global dynamics. Development can emerge as a tool to be wielded for power and further political mileage at the expense of progress. Progress cannot be studied as a counterpoint to development as the sense of history is often missing in development interventions. Development tends to be piecemeal as its very logic often stems from the rationale of power. This is not to suggest, however, that development is only about politics; it is definitely more than the politics of everyday life and involves all of civil society that requires its critical and immediate attention. In this sense, it has become a priority for politicians with an underlying agenda designed to out-manouevre dissent and all statements of protest.  相似文献   

15.
As landscapes continue to fall under human influence through habitat loss and fragmentation, fencing is increasingly being used to mitigate anthropogenic threats and enhance the commercial value of wildlife. Subsequent intensification of management potentially erodes wildness by disembodying populations from landscape-level processes, thereby disconnecting species from natural selection. Tools are needed to measure the degree to which populations of large vertebrate species in formally protected and privately owned wildlife areas are self-sustaining and free to adapt. We devised a framework to measure such wildness based on 6 attributes relating to the evolutionary and ecological dynamics of vertebrates (space, disease and parasite resistance, exposure to predation, exposure to limitations and fluctuations of food and water supply, and reproduction). For each attribute, we set empirical, species-specific thresholds between 5 wildness states based on quantifiable management interventions. We analysed data from 205 private wildlife properties with management objectives spanning ecotourism to consumptive utilization to test the framework on 6 herbivore species representing a range of conservation statuses and commercial values. Wildness scores among species differed significantly, and the proportion of populations identified as wild ranged from 12% to 84%, which indicates the tool detected site-scale differences both among populations of different species and populations of the same species under different management regimes. By quantifying wildness, this framework provides practitioners with standardized measurement units that link biodiversity with the sustainable use of wildlife. Applications include informing species management plans at local scales; standardizing the inclusion of managed populations in red-list assessments; and providing a platform for certification and regulation of wildlife-based economies. Applying this framework may help embed wildness as a normative value in policy and mitigate the shifting baseline of what it means to truly conserve a species.  相似文献   

16.
Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.  相似文献   

17.
Abstract: In the United States, as elsewhere, a growing debate pits national energy policy and homeland security against biological conservation. In rural communities the extraction of fossil fuels is often encouraged because of the employment opportunities it offers, although the concomitant itinerant workforce is often associated with increased wildlife poaching. We explored possible positive and negative factors associated with energy extraction in the Greater Yellowstone Ecosystem (GYE), an area known for its national parks, intact biological diversity, and some of the New World's longest terrestrial migrations. Specifically, we asked whether counties with different economies—recreation (ski), agrarian (ranching or farming), and energy extractive (petroleum)—differed in healthcare (gauged by the abundance of hospital beds) and in the frequency of sexual predators. The absolute and relative frequency of registered sex offenders grew approximately two to three times faster in areas reliant on energy extraction. Healthcare among counties did not differ. The strong conflation of community dishevel, as reflected by in‐migrant sexual predators, and ecological decay in Greater Yellowstone is consistent with patterns seen in similar systems from Ecuador to northern Canada, where social and environmental disarray exist around energy boomtowns. In our case, that groups (albeit with different aims) mobilized campaigns to help maintain the quality of rural livelihoods by protecting open space is a positive sign that conservation can matter, especially in the face of rampant and poorly executed energy extraction projects. Our findings further suggest that the public and industry need stronger regulatory action to instill greater vigilance when and where social factors and land conversion impact biological systems.  相似文献   

18.
Summary Acanthoscelides obtectus (Say) is one of the most damaging pests of kidney beans,Phaseolus vulgaris L. worldwide. However, aromatic plants from the families Lamiaceae, Lauraceae, Myrtaceae and Poaceae can protect kidney beans by direct or delayed insecticidal effect, through increased adult mortality and inhibition of beetle reproduction (both oviposition and adult emergence). The efficiency of hydrodistillated and intact plants fromThymus vulgaris andT. serpyllum, Mentha piperata, Rosmarinus officinalis, Satureia hortensis, Eucalyptus globulus, Laurus nobilis, Origanum vulgare, andCymbopogon nardus was compared. For both extracts,Origanum vulgare had the best effect. The insecticidal effect was induced by more than the essential oils because no significant difference was noticed between distilled and intact plants extract. Inhibition of reproduction was particularly important. These results suggest that lipidic as well as non lipidic, allelochemicals, such as phenolics, or non-protein amino-acids, or flavonoids may be involved in the toxicity of aromatic plants to this beetle.  相似文献   

19.
A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.  相似文献   

20.
Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.  相似文献   

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