Molecular and cellular biomarker responses to pesticide exposure in juvenile chinook salmon (Oncorhynchus tshawytscha)     

Eder KJ  Leutenegger CM  Wilson BW  Werner I 《Marine environmental research》2004,58(2-5):809-813

  相似文献   

Effects of salinity on sublethal toxicity of atrazine to mummichog (Fundulus heteroclitus) larvae     

Fortin MG  Couillard CM  Pellerin J  Lebeuf M 《Marine environmental research》2008,65(2):158-170

In coastal marshes, fish larvae may be exposed simultaneously to extreme salinities and to atrazine, a widely used herbicide. To assess the effects of salinity on the toxicity of atrazine, newly-hatched mummichog (Fundulus heteroclitus) were exposed to atrazine (0, 5, 50 and 500 microg/L) at three salinities (3, 15 and 35PSU). Whole body cortisol was measured after 24 h. Body length, condition factor, whole body proteins, lipids, residual masses and water contents were assessed after 96 h. Significants effects were found for both condition factor and water content. Condition factors were lower at salinity 3 and 35 compared to near isoosmotic salinity, 15PSU. In addition, atrazine decreased condition factor at 500 microg/L. Reduction in condition was likely due to retardation in axial growth since body length, percentages of proteins or lipids were not affected. In the absence of atrazine, salinity had no effect on the prevalence of dehydrated (81% water) or hyperhydrated (85% water) larvae. In larvae exposed to atrazine, the prevalence of hyperhydrated larvae increased at 3PSU and 5 microg/L atrazine and that of dehydrated larvae increased at 15 and 35PSU and 5 microg/L atrazine. Severity of dehydratation increased with atrazine concentration at salinity 35PSU. Thus, a short-term exposure to environmentally realistic concentrations of atrazine affects osmotic control in mummichog larvae with possible effects on buoyancy, survival and recruitment.  相似文献   

中国区域经济韧性特征与影响因素分析   总被引：2，自引：2，他引：2  

谭俊涛  赵宏波  刘文新  张平宇  仇方道 《地理科学》2020,40(2):173-181

从经济维持性和恢复性2个方面定量化分析中国31省（市）（未包含港澳台数据）应对1997年亚洲金融危机和2008年全球金融危机的经济韧性特征,并对其主要影响因素进行了研究。结果发现：① 在亚洲金融危机中,西部地区的经济维持性较高,中部地区的经济维持性普遍较低;经济恢复性较高的省市主要集中在中部地区,而东部和西部地区经济恢复性较低,经济维持性和经济恢复性呈现一定的负相关。② 各省（市）应对全球金融危机的经济维持性普遍较高,经济维持性较低的区域主要分在东部沿海区域和沿长江经济带地区,而经济维持性较高的区域主要集中在西部地区。③ 在亚洲金融危机中,第二产业表现出了较强的经济韧性,而在全球金融危机中第三产业经济韧性较好。④ 影响2次经济危机中韧性能力的主要因素是不同的,区位条件、人均固定资产投资额和人均GDP的解释力较强,但在2次经济周期中的作用方向不同。  相似文献   

A simple method for locating the fresh water-salt water interface using pressure data   总被引：2，自引：0，他引：2  

Kim KY  Chon CM  Park KH 《Ground water》2007,45(6):723-728

Salt water intrusion is a key issue in dealing with exploitation, restoration, and management of fresh ground water in coastal aquifers. Constant monitoring of the fresh water-salt water interface is necessary for proper management of ground water resources. This study presents a simple method to estimate the depth of the fresh water-salt water interface in coastal aquifers using two sets of pressure data obtained from the fresh and saline zones within a single borehole. This method uses the density difference between fresh water and saline water and can practically be used at coastal aquifers that have a relatively sharp fresh water-salt water interface with a thin transition zone. The proposed method was applied to data collected from a coastal aquifer on Jeju Island, Korea, to estimate the variations in the depth of the interface. The interface varied with daily tidal fluctuations and heavy rainfall in the rainy season. The estimated depth of the interface showed a good agreement with the measured electrical conductivity profile.  相似文献   

The 1974 spill of the Bouchard 65 oil barge: petroleum hydrocarbons persist in Winsor Cove salt marsh sediments     

Peacock EE  Hampson GR  Nelson RK  Xu L  Frysinger GS  Gaines RB  Farrington JW  Tripp BW  Reddy CM 《Marine pollution bulletin》2007,54(2):214-225

Petroleum hydrocarbons persist in salt marsh sediments in Winsor Cove (Buzzards Bay, Massachusetts) impacted from the 1974 spill of No. 2 fuel oil by the barge Bouchard 65. Intertidal sediment cores were collected from 2001 to 2005 and analyzed for total petroleum hydrocarbons (TPHs). TPHs content was greatest (as high as 8.7 mg g(-1) dry weight) in the surface sediments and decreased with distance landward. Select samples were analyzed for polycyclic aromatic hydrocarbons (PAHs) with values as high as 16.7 microg g(-1) for total naphthalenes and phenanthrenes/anthracenes. These remaining PAHs are mainly C(4)-naphthalenes and C(1)-, C(2)-, and C(3)-phenanthrenes/anthracenes revealing preferential loss of almost all of the naphthalenes and the parent compound phenanthrene. Inspection of the data indicates that biodegradation, water-washing and evaporation were major removal processes for many of the petroleum hydrocarbons in the marsh sediments. In addition, historical data and photographs combined with their recent counterparts indicate that erosion has physically removed these contaminants from this site.  相似文献   

Depuration dynamics of oysters (Crassostrea gigas) artificially contaminated by Salmonella enterica serovar Typhimurium     

de Abreu Corrêa A  Albarnaz JD  Moresco V  Poli CR  Teixeira AL  Oliveira Simões CM  Monte Barardi CR 《Marine environmental research》2007,63(5):479-489

The State of Santa Catarina produces the greatest quantity of edible mollusks in Brazil. To guarantee sanitary qualify, mollusk cultures should be monitored for contamination by pathogenic microorganisms. A self-purification or "depuration" system that eliminates Salmonella enterica serovar Typhimurium contamination from oysters has been developed and evaluated. The depuration process occurred within a closed system, in which 1000 L of water was recirculated for 24 h. The water was sterilized with ultraviolet (UV) light, chlorine, or both together. Oysters (Crassostrea gigas) artificially contaminated with S. typhimurium were harvested every 6 h. Samples of oyster tissue were excised and both the presence and numbers of bacteria were determined. Combined UV light and chlorine treatments resulted in total elimination of bacteria within 12 h. Polymerase chain reaction detected bacteria in water exposed to the three treatments. This pioneering study is the first of its kind in Brazil and represents a major contribution to commercial mollusk culture in this country.  相似文献   

基于旅游者视角下的鄂西圈旅游竞争力影响因素研究     

郭清霞  秦张平  樊冬平 《世界地理研究》2012,(2):136-143

本文选取旅游者的微观视角为研究的切入点,对鄂西生态文化旅游圈(鄂西圈)旅游竞争力影响因素进行了实证研究,发现直接对该区域旅游竞争力起作用的是市场需求状况和区位条件,而区域旅游资源、旅游支持因素、区域旅游管理都通过市场对该区域的旅游竞争力起间接作用;同时通过路径分析得到了相关因素之间以及相关因素对区域旅游竞争力的影响程度,其中市场需求的影响系数最大。最后提出了提升鄂西圈旅游竞争力的一些建议。  相似文献   

安庆沿江退耕还湖18年的湿地土壤生物化学性质研究     

张平究  赵永强  孟向东 《湿地科学》2012,10(3):299-305

以安庆沿江农田不同退耕还湖方式——低坝高网式水产养殖和湿地自然恢复区的湿地土壤为研究对象,并以邻近的水田和旱地土壤作为参照,研究退耕还湖后湿地土壤生物化学性质变化.结果表明,退耕还湖18a(1991～2009年)后,在湿地自然恢复区,湿地土壤(深度为0～30 cm)微生物量碳含量、土壤磷酸酶活性和过氧化氢酶活性增大,土壤脲酶活性和蔗糖酶活性减小;由水田退耕18a的湿地亚表层土壤(深度为15～30 cm)脲酶活性和表层土壤(深度为0～15 cm)过氧化氢酶活性与由旱地退耕18a的湿地无明显差异,由水田退耕18a的湿地表层土壤脲酶活性和亚表层土壤过氧化氢酶活性、表层和亚表层土壤微生物量碳含量、蔗糖酶活性和磷酸酶活性都明显高于由旱地退耕18a的湿地.退耕还湖18a后,进行低坝高网式水产养殖的湿地土壤微生物量碳含量、土壤脲酶活性、蔗糖酶活性和磷酸酶活性减小,而过氧化氢酶活性增大;由水田退耕18a的湿地表层和亚表层土壤微生物量碳含量与由旱地退耕18a的湿地无明显差异,由水田退耕18a的湿地表层和亚表层土壤脲酶活性、表层土壤蔗糖酶活性和亚表层土壤磷酸酶活性明显高于由旱地退耕18a的湿地,而其亚表层土壤蔗糖酶、表层土壤磷酸酶、表层和亚表层土壤过氧化氢酶活性均显著低于由旱地退耕18a的湿地.天然湿地土壤微生物量碳含量、土壤脲酶活性、蔗糖酶活性和磷酸酶活性明显低于已退耕还湖的湿地和参照农田土壤.退耕还湖后,湿地的不同利用方式及其历史利用方式影响湿地土壤生物化学性质;湿地土壤有机质等养分含量和水文条件变化是导致湿地土壤生物化学性质变化的主要原因.  相似文献   

合肥市PM10 输送轨迹分类研究   总被引：8，自引：2，他引：6  

石春娥  姚叶青  张平  邱明燕 《高原气象》2008,27(6)

应用聚类分析的方法,对2001—2005年合肥市逐日72 h后向轨迹按季节分类,结合PM10日均浓度观测资料,分析了不同输送轨迹与该地区PM10浓度之间的关系。结果表明:不同方向后向轨迹所对应的PM10平均浓度有明显不同;最高PM10平均浓度对应的后向轨迹在春、秋和冬季都是来自西北方向,它们与季节平均的相对距平分别为44%,20%和31%;夏季为东北方向,与季节平均的相对距平为20%;其次为本地轨迹,各季的相对距平分别为5%,16%,18%和17%。根据分析得出合肥地区6组易于出现高浓度PM10的后向轨迹及对应的天气形势,并简要分析了其特征。气溶胶的远程输送主要发生在自由大气层,区域输送主要发生在边界层内。合肥地区大气污染事件超过50%与远程输送有关。移动快的气团不一定对应低浓度的PM10。  相似文献   

"5.12"汶川特大地震重灾区地面气温特征分析     

何光碧  张利红  张平  屠妮妮  李跃清 《高原山地气象研究》2008,28(2):55-61

本文利用1961-2007年逐日地面气温资料、1971-2000年整编地面气温资料,以及2006年1月1日-2008年4月30日的逐时地面气温资料,采用统计方法,对汶川特大地震重灾区进行气温的气候特征分析,较系统和全面地得到汶川“5.12”特大地震重灾区气温的日、旬、月、年变化以及极端气温特征,为该地区抗震救灾和灾后重建提供气象服务支撑。  相似文献