食蚊鱼(Gambusia afinis)cat、gapdh和gst基因的克隆及其在生态毒理学中的应用

根据Ensembl、Genbank登录的鱼类cat、gapdh和gst基因的CDS序列设计普通PCR扩增引物,寻找食蚊鱼的cat、gapdh和gst基因的c DNA片段,并根据定量引物设计要求设计出相应的SYBR Green I荧光定量RT-q PCR引物,建立了食蚊鱼cat、gapdh和gst基因的SYBR Green I荧光定量RT-q PCR方法。该方法在104~108数量级范围内有良好线性关系(R=0.999~1.000);熔解曲线显示扩增产物特异性良好,均为单一峰值;质粒标准品最高浓度与最低浓度的批内试验变异系数与批间试验变异系数均低于2%。利用该方法监测和评价环境污染物对水生生物的影响,选择了水体中常见典型药物污染物——双氯芬酸,研究其对食蚊鱼抗氧化基因表达的影响。结果表明,雌性食蚊鱼暴露在不同浓度双氯芬酸钠(0.005、0.05、0.5和5 mg·L-1)24 h后,其肝脏cat、gapdh和gst的mRNA呈现显著变化,相对于对照组,在低浓度0.005 mg·L-1时,cat与gst mRNA的表达量均有极显著上升(p0.01),而其它浓度均极显著下降(p0.01)。试验表明该方法具有快速、精确、灵敏度高的优点,可为利用该类小型鱼类的原位污染物的生物监测和生态毒理评价提供有力的技术支持。     

鄱阳湖湿地土壤酶及微生物生物量的剖面分布特征

为探明淡水沼泽湿地土壤微生物功能活性随土壤剖面深度的变化,以鄱阳湖区内典型的苔草湿地土壤为研究对象,选择剖面深度为1 m共5层(0~20、>20~40、>40~60、>60~80、>80~100 cm)的土壤,对土壤酶[Bglu(β-葡萄糖苷酶)、NAG(乙酰氨基葡萄糖苷酶)、Bxyl(β-木糖苷酶)、Phos(酸性磷酸酶)、Phox(酚氧化酶)、Pero(过氧化物酶)]活性、w(MBC)(微生物生物量碳含量)和w(MBN)(微生物生物量氮含量)及土壤理化性质进行研究.结果表明,代表微生物功能活性的土壤酶和w(MBC)、w(MBN)均随着剖面深度的增加而逐渐降低,表层(0~20 cm)土壤中的酶活性和w(MBC)、w(MBN)均显著高于深层土壤.值得注意的是,不同土壤酶活性随着剖面深度的变化规律不一,但总体酶活性在土壤深度为>40~60 cm时达到稳定,并且仍都具有较高活性;表层土壤中w(MBC)为65.58~161.90 mg/kg,w(MBN)为7.39~16.28 mg/kg,二者占所研究剖面土壤总微生物碳氮含量的51%~69%.进一步的相关性分析发现,土壤微生物功能特性与有机质AFDM(去灰分干重)、w(TOC)、w(TN)、含水量及pH存在显著的相关性,其中土壤w(TOC)、w(TN)是影响鄱阳湖湿地土壤微生物数量和活性的最主要因素.研究显示,土壤深度对湿地土壤微生物功能特性及土壤性质具有显著影响,表层土壤中微生物功能活性最高,但湿地深层土壤中仍存在大量的微生物,由微生物参与的代谢活动仍然活跃,深层土壤微生物功能特性不容忽视.      

安铺港表层沉积物中重金属污染现状及潜在生态风险评价

通过对21个表层沉积物样品中的Cu、Pb、Zn、Cd、Cr、Hg、As等7种重金属元素含量进行测定,分析了安铺港沉积物中重金属的空间分布特征及其对港湾生态环境的危害状况。采用重金属单因子污染系数、综合污染指数对其污染程度进行了评价,并采用Hàkanson潜在生态危害系数与潜在生态风险指数法对重金属潜在危害进行了预测。结果表明:安铺港表层沉积物中重金属含量空间离散性较大,总体处于低污染状态,各重金属污染程度依次为Hg > Cd > Pb > As > Zn > Cu > Cr;安铺港潜在生态风险危害总体属于低生态危害范畴,重金属生态危害系数的排序为Hg > Cd > As > Pb > Cu > Cr > Zn;各金属与有机质及相互之间较显著的正相关,其中,Cd与有机质和各金属的相关性略低。     

环境NGO介入环境公益诉讼的必要性和复杂性研究

环境NGO在环保活动中已成为不可忽视的重要力量.随着2015年中国新环保法的颁布,环境NGO已经具备发起环境公益诉讼的主体资格,但由于中国环境NGO自身能力不足,完成诉讼仍存在困难.文章以环境NGO介入环境公益诉讼活动为研究对象,研究了现有环保NGO介入环境公益诉讼的现模式,并分析了环保NGO介入环境公益诉讼的必要性与复杂性,指出要提升NGO介入环境公益诉讼的能力,必须从培育环境公益诉讼意识、加强自身能力改造及破解资金难题等方面着手.     

Effect of chimneys on indoor air concentrations of PM10 and benzo[a]pyrene in Xuan Wei,China

This paper reports the effect of chimneys in reducing indoor air pollution in a lung cancer epidemic area of rural China. Household indoor air pollution concentrations were measured during unvented burning (chimneys blocked) and vented burning (chimneys open) of bituminous coal in Xuan Wei, China. Concentrations of particulate matter with an aerodynamic diameter of 10 μm or less (PM₁₀) and of benzo[a]pyrene (BaP) were measured in 43 homes during normal activities. The use of chimneys led to significant decreases in indoor air concentrations of particulate matter with an aerodynamic diameter of 10 μm or less (PM₁₀) by 66% and of benzo[a]pyrene (BaP) by 84%. The average BaP content of PM₁₀ also decreased by 55% with the installation of a chimney. The reduction of indoor pollution levels by the installation of a chimney supports the epidemiology findings on the health benefits of stove improvement. However, even in the presence of a chimney, the indoor air concentrations for both PM₁₀ and BaP still exceeded the indoor air quality standards of China. Movement up the energy ladder to cleaner liquid or gaseous fuels is probably the only sustainable indoor air pollution control measure.     

Continued decline of an Atlantic cod population: how important is gray seal predation?

The continental shelf ecosystem on the Eastern Scotian Shelf (ESS) has experienced drastic changes. Once common top predators are a small fraction of their historical abundance, and much of the current community structure is now dominated by pelagic fishes and invertebrates. Embedded within this food web, Atlantic cod and gray seal populations have recently exhibited nearly opposite trends. Since 1984, cod populations have decreased exponentially at a rate averaging 17% per year, whereas gray seals have continued to increase exponentially at a rate of 12%. We reexamined the impact of gray seals on Atlantic cod dynamics using more than 30 years of data on the population trends of cod and gray seals while incorporating new information on seal diet and seasonal distribution. The closure of the cod fishery over 10 years ago allowed for a better estimation of natural mortality rates. We quantified the impact of seals on ESS cod by (1) estimating trends in seal and cod abundance, (2) estimating the total energy needed for seal growth and maintenance from an energetics model, (3) using estimates of the percentage of cod in the total diet derived from quantitative fatty acid signature analysis (QFASA) and of the size-specific selectivity of cod consumed (derived from otoliths collected from fecal samples), and (4) assuming a gray seal functional response. Uncertainties of the model estimates were calculated using the Hessian approximation of the variance-covariance matrix. Between 1993 and 2000, cod comprised, on average, < 5% of a gray seal's diet. Our model shows that, since the closure of the fishery, gray seals have imposed a significant level of instantaneous mortality (0.21), and along with other unknown sources of natural mortality (0.62), are contributing to the failure of this cod stock to recover.     

曝气器工业化性能测试研究

对7种曝气器产品分别进行了单盘耐用性生产试验、单盘清水充氧性能试验以及对在大生产试验期间的服务面积、供气量、阻力变化、停气后阻力变化、曝气强度等方面进行了测试对比工作。试验表明,中微孔曝气器的各种性能指标明显优于大孔曝气器,可显著提高混合液中氧的吸收率。     

Population Structure and Cryptic Evolutionary Units in the Alligator Snapping Turtle

The alligator snapping turtle (  Macroclemys temminckii ) is a long-lived, slow-growing chelydrid turtle found in Gulf of Mexico drainages from Florida to Texas (U.S.A.). Populations are thought to be depleted throughout the range due in part to an increased harvest in the 1960s through 1980s. To identify population and evolutionary units, 420 base pairs were sequenced within the mitochondrial DNA control region of 158 specimens from 12 drainages. Results indicate substantial phylogeographic structuring and strong population-level separations among river drainages. Eight of 11 haplotypes were observed to be river-specific, providing diagnostic markers for most drainages. Three partitions are resolved in the mtDNA genealogy, corresponding to the eastern, central, and western portion of the species' range. These separations coincide with recognized biogeographic provinces. The population structure by river system indicates that many drainages are distinct management units, with the Suwannee River lineage possibly deserving special attention, based on the criterion of genetic distinctiveness. The partitioning of M. temminckii into river-specific populations illustrates the management framework and conservation challenges that apply to a broad array of riverine species. Drainage-specific molecular markers may be used to identify the geographic origin of turtle products in the marketplace.