Effects of Silver Nanoparticles on Denitrification and Associated N2O Release in Estuarine and Marine Sediments

Silver nanoparticles(AgNPs)have been widely used in medicine and consumer products.And it enters the river in dif-ferent ways,then finally converges to the ocean through the estuary.AgNPs polution can affect NO₂?and N₂O production by denitri-fiers in aquatic system.The effects of AgNPs on denitrification activity,nitrogen transformation and nitrous oxide(N₂O)emission were investigated in Dagu River Estuary(DRE)and Jiaozhou Bay(JZB).The results showed that the potential denitrification activity(PDA),NO₃?and NO₂?reduction rates decreased with an increase of AgNPs concentration in DRE and JZB.However,the N₂O ac-cumulation was significantly increased at AgNPs concentrations above 5 mg kg^?1in both areas,and the accumulation rate was greater in estuary than in bay(P<0.05).Moreover,the total bacterial count showed a slightly increasing trend with an increase of AgNPs concentration(P>0.05)in DRE and JZB.Importantly,the relative abundance of narG,nirS and nosZ gene in two areas decreased with the increase of AgNPs concentration,and the negative effect of AgNPs varied in order:nosZ>nirS>narG,inferring that the expression of denitrifying related genes could be significantly and differently inhibited by AgNPs addition.Thus,this study demon-strated that the inhibitory effect of AgNPs on different denitrification process,which may lead to the increase of inorganic nitrogen accumulation and N₂O realease.This study provides a scientific basis for the further studies of AgNPs on the ecological impact mechanism and environmental effects of offshore sedimentary environment.     

Impact of Phenanthrene on Denitrification Activity and Transcription of Related Functional Genes in Estuarine and Marine Sediments

The effects of phenanthrene(Phe)on the denitrification activity and denitrifying genes(narG,nirS and nosZ)were evaluated by dose-response experiments in sediments of Dagu River Estuary(DRE)and Jiaozhou Bay(JZB).The results showed that potential denitrification activity(PDA),N2O,NO3−and NO2−reduction rates of both areas were inhibited with an increase of Phe concentrations.The PDA,N2O,NO3−and NO2−reduction rates of both areas was highest and lowest in the control(DRE:0.453,0.427,7.439 and 3.222mgNkg−1 h−1,JZB:0.592,0.555,8.470 and 3.793mgNkg−1 h−1)and highest Phe amended treatments(DRE:0.069,0.001,4.486,and 1.563 mgNkg−1 h−1;JZB:0.114,0.024,5.527 and 2.200 mgNkg−1 h−1).The inhibition rate of PDA was highest,follow by NO2−reduction and then NO3−reduction.Moreover,with the increasing of Phe concentrations,total bacteria count and the abundance of denitrifying genes were decreased.And N2O accumulation was promoted with the addition of Phe for both areas.Based on the comparison of EC50 values,denitrifiers harboring three genes were more sensitive to Phe than PDA,and denitrifiers harboring nirS gene were more sensitive,followed by nosZ gene,and then narG gene.Furthermore,according to correlation analysis,the relative abundance of denitrifying genes was much more positively correlated with PDA,NO3−and NO2−reduction than total bacteria count.In addition,the denitrification activity and total bacteria count in JZB were more inhibited than that of DRE.This study is useful for understanding the impact of Phe pollution on denitrification in estuary and marine sediments,with profound implications for the management of aquatic ecosystems regarding eutrophication(N-removal)and greenhouse effect.     

红海湾表层沉积物铅、锌污染的判断与分析

以镍作自然参比元素 ,用元素相关图法分析了南海东北部红海湾表层沉积物中铅、锌含量的分布和污染状况。结果表明 :红海湾已经受到人为来源的铅、锌影响 ,但其影响的范围和强度目前尚小 ,仅在湾顶河口浅水区有轻微污染 ,湾中部养殖区、南部自然水域和湾口礁滩护养增殖区尚未受到人为来源的铅、锌影响。元素相关图提供了有关污染区域、污染点、污染物和污染强度等的总信息     

Genotoxic Potential of Copper Oxide Nanoparticles in the Bivalve Mollusk Mytilus trossulus

Copper oxide nanoparticles(CuO-NPs) are among the most widely used metal oxide nanoparticles,which increases the chance of their being released into the marine environment.As the applications of these particles have increased in recent years,their potential impact on the health of marine biota has also increased.However,the toxicological effects of these NPs in the marine environment are poorly known.In the present study,the DNA damaging potential of CuO-NPs in the marine eastern mussel Mytilus trossulus was evaluated and compared to that of dissolved copper exposures.Genotoxicity was assessed by the single cell gel electrophoresis(comet) assay in mussel gill and digestive gland cells.The results showed that copper in both forms(CuO-NPs and dissolved copper) was accumulated to different extents in mussel tissues.The mussel exposed to the dissolved copper attained higher concentrations of copper in the gills than in the digestive gland.In contrast to these results,it was found that CuO-NPs could induce much higher copper accumulation in the digestive gland than in the gills.A clear and statistically significant increase in DNA damage was found in both tissues of the Cu-exposed group compared to the control mussels.Our results indicated that the CuO-NP exposure produced remarkable effects and increased DNA damage significantly in mussel gill cells only.It should be noted that the digestive gland cells were prone to accumulation following CuO-NPs when compared to the gill cells,while the gill cells were more sensitive to the genotoxic effects of CuO-NPs.These results also suggested the need for a complete risk assessment of engineered particles before its arrival in the consumer market.     

LED光照对螺旋藻生长及锌富集的影响

采用LED光照技术研究光照波长、照度和光照时间对螺旋藻生长及锌生物富集作用的影响。结果表明,不同波长LED光照下螺旋藻生物量增长的顺序为红光(655~665 nm)蓝光(465~475 nm)绿光(522~532 nm)黄光(570~580 nm),与对照组比,光照14 d生物量增加为红光组13.97%,蓝光组10.12%,绿光组1.44%,黄光组则减少2.88%;不同波长LED光照对螺旋藻锌富集作用的影响顺序为黄光绿光蓝光红光,实验8 d螺旋藻锌含量趋于稳定,与对照组比,黄光组增加43.73%,绿光组增加23.98%,蓝光组增加14.29%,红光组增加9.04%。以LED红光做光源,在照度0~10 000 lx范围内,螺旋藻生物量与照度成正相关;在照度0~8 000 lx范围内,螺旋藻锌含量与照度正相关;在光照时间0~6 h内,螺旋藻生物量和锌含量均随LED红光光照时间增加而增大。     

The Variation of Microbial(Methanotroph) Communities in Marine Sediments Due to Aerobic Oxidation of Hydrocarbons

Methanotrophs in marine sediments and overlying water attenuate the emissions of methane into the atmosphere and thus play an important role for the global cycle of this greenhouse gas. However, gas released from natural hydrocarbon seeps are not pure methane but commonly mixed hydrocarbons. Currently, how methanotrophic bacteria behave in the co-presence of methane and heavier hydrocarbons remains unknown. In this paper, the bacteria were cultured aerobically in fresh sediment samples(collected from Bohai Bay in eastern China) at 28℃ under the atmospheres of pure methane and methane + ethane + propane mixed gas, respectively. The prevailing terrigenous n-alkanes and fatty acids in the original sediment samples varied consistently after incubations, confirming the proceeding of aerobic bacterial activities. The real-time quantitative PCR assay and sequencing of the 16 S rRNA and particulate methane monooxygenase(pmo A) genes revealed the changes of microbe communities to a methanotroph-dominating structure after incubations. Particularly, after incubations the family Methylococcaceae(type I methanotrophs) became dominant with proportions higher than 40%, whereas Methylocystaceae(type II methanotrophs) nearly disappeared in all incubated samples. Moreover, the species of methanotrophs from the samples treated with pure methane were dominated by Methylobacter luteus, whereas Methylobacter whittenburyi took the predominant proportion in the samples treated with mixed gas. The phenomenon suggests that some methanotrophs may also utilize ethane and propane. Collectively, this study may help to gain a better understanding of the effects and contributions of microbial activities in marine hydrocarbon seep ecosystems.     

Effect of Temperature on the Acoustic Reflection Characteristics of Seafloor Surface Sediments

Because the sound speeds of seawater and seafloor sediment both increase with temperature,the influence of tempera-ture on the bottom reflection characteristics of seafloor sediments needs to be investigated.Based on the calculation of the temperature-controlled experimental measurement data of typical seafloor surface sediment samples,the temperature-dependent acoustic characteristics,including acoustic impedance,acoustic impedance ratio between surface sediment and seawater,and reflection coefficient,were analyzed.The effective density fluid model was used to analyze and explain the reflection coefficient variation of surface sediments with temperature and predict the dispersion characteristics.Results show that the acoustic impedance of the seabed sediment increases with temperature,whereas the acoustic impedance ratio and acoustic reflection coefficient slightly decrease.The acoustic impedance,acoustic impedance ratio,and acoustic reflection coefficient of sandy,silty,and clayey sediments vary similarly with tem-perature variation.Moreover,the influence of temperature on these acoustic characteristics is independent of detection frequencies.     

光合细菌对养殖水质及凡纳滨对虾抗病力的影响

在凡纳滨对虾养殖环境中人工引入不同浓度的光合细菌,监测氨氮、亚硝酸氮、化学需氧量的变化,15d后测定凡纳滨对虾的AKP、POD、PO、SOD、抗菌、溶菌活力,以及不同光合细菌浓度下凡纳滨对虾的成活率与体重增长率,研究光合细菌对水质和凡纳滨对虾抗病力的影响。结果表明,引入光合细菌可显著降低水体化学需氧量、氨氮含量,并抑制亚硝酸盐氮的产生,提高凡纳滨对虾的抗病力。当光合细菌投放浓度为3×103/mL时,水体中化学需氧量、氨态氮、亚硝酸盐氮含量的均值分别比对照组降低31.59%、43.42%、52.20%,差异显著(P<0.05);对虾的AKP、POD、PO、SOD、抗菌、溶菌活力分别比照组提高31.92%、72.29%、55.56%、31.61%、39.07%、69.51%,差异显著(P<0.05);成活率,体重增长率分别比对照组提高18.67%、34.03%,差异显著(P<0.05)。     

BACKGROUND STUDY ON NON-RESIDUAL PHASE OF ELEMENTS IN CHANGJIANG AND HUANGHE ESTUARINE SEDIMENTS

Analysis of Zn, Cu, Pb, Co, Cr, Li, Ni, K, Al, Fe extracted by 1 mol/L HCl or 0.5 mol/LHCl/H_2O_2, showed concentrations of Zn, Cu, Pb, Co, Cr, Fe, Ni were significantly correlated with Li, Al,K, and clay. Two methods are used to indicate the background value of the non-residual phase of elementsin sediments, and are the same as the methods used to indicate the background value of totalconcentrations in sediments. The first method uses correlograms and regression equations,the second usesthe mean element concentrations normalized with grain size. Li, Al, K can be used as reference elements to determine the background value of Zn, Cu, Pb, Co,Cr, Ni, Fe, while the clay concentration's correlation with some extractable concentrations can be used tocalculate the background value of the non-residual phase of elements as a percentage of clay concentrationin the sediments. Based on this study, the concept of using the background value of the non-residualphase of elements to compare the pollution level in differ     

山东省典型地区地质灾害野外科学观测效果初探

重点选取山东省具有代表性的典型地质灾害易发区：济南市历城区阁老滑坡、青岛崂山区青山滑坡以及临沂市城区岩溶塌陷易发区,进行地质灾害野外科学观测和预警预报研究,并提出下一步研究方向,以期提高山东省预警预报的可信度和准确度,并将其作为地质灾害自动化观测的试验点和示范点在全省推广应用。     

溶藻弧菌对凡纳滨对虾血清中一氧化氮及氧自由基的影响

对凡纳滨对虾注射浓度为1×105、1×106、1×107mL-1的溶藻弧菌悬液,在注射后4、12、24、48、72和120 h于腹血窦取血,测定其血清中一氧化氮(NO)、丙二醛(MDA)含量,以及一氧化氮合酶(NOS)、超氧化物岐化酶(SOD)活力。结果表明,注射溶藻弧菌后,凡纳滨对虾血清中NO含量及NOS活力显著高于对照组,且NOS活力最大值出现时间较NO早;而SOD活力先升高后下降,MDA含量在SOD活力开始下降后逐渐升高,说明一氧化氮系统对凡纳滨对虾感染的溶藻弧菌有清除作用,并能在一定程度上对损伤过程中生成的氧自由基产生作用。     

Adverse Effect of TiO_2 Nanoparticles on Antioxidant System and Antitumor Activities of Macroalgae Gracilaria lemaneiformis

Recently, the widespread use of TiO_2 nanoparticles(nano-TiO_2) has attracted the global concern regarding their adverse effects to aquatic organisms. Nanoparticles may get to the aquatic environments and harm the growth of algae. This paper presents the studies of nano-TiO_2 concentrations influence on the photosynthetic characteristics, antioxidant system and antitumor activity of marine macroalgae Gracilaria lemaneiformis after exposed to 0, 5, 10, 20 or 40 mg L-1 of nano-TiO_2. Results showed that the photosynthetic pigment content of G. lemaneiformis obviously decreased and the antioxidant defense system was significantly disturbed after exposure to nano-TiO_2. Compared with control, the maximum level of malondialdehyde showed 3.3-fold increase for 15 days exposure to nano-TiO_2. The activity of superoxide dismutase and catalase enhanced obviously by 1.10-2.24-fold. The aqueous extract of G. lemaneiformis(AEGL) possesses anticancer activity against HepG2 liver cancer cells proliferation and the 48 h-cell inhibition exceeds 35%. But the toxicity of nano-TiO_2 would inhibit the anticancer activity of AEGL. When G. lemaneiformis was exposed to nano-TiO_2, the effect of the aqueous extract of G. lemaneiformis on the cell inhibition, reactive oxygen species production, apoptosis, cycle arrest of HepG2 cells significantly lessened, and which were linearly associated with nano-TiO_2 exposure concentration. Those results further confirmed that nano-TiO_2 can inhibit the anticancer activity of G. lemaneiformis. The results in this work imply that macroalgae can be an effective biomarker of nano-TiO_2 contaminant, and can be useful indicator to evaluate ecological effects of increasing pollutants in marine ecosystem.     

典型深街谷内树木空间配置对行人呼吸高度处气流的影响

为揭示树木的不同空间配植方案对行人呼吸高度气流的影响,本文将树木视为均匀多孔介质,通过附加源项法从空气动力学角度用CFD模拟了H/W=2的典型深街谷几何内4种树木配植情景,实验表明,不同空间配置下树木对街谷内行人呼吸高度处局地气流的影响强弱在空间分布模式上差异悬殊：① 均匀种植的树木对街谷内行人呼吸高度的气流起到阻碍作用,不均匀种植则有效提升街谷的整体流速。4种空间配植方案下树木对气流的影响程度不同,阻碍作用从大到小的顺序为均匀间距8 m（Spa8m）>均匀间距6 m（Spa6m）>均匀间距20 m（Spa20m）>不均匀配植（Non-uniform）;对应的平均气流增强指标顺序为$\bar{D}_{spa8}$（-19.31%）<$\bar{D}_{spa6}$（-16.14%）<$\bar{D}_{spa20}$（-10.73%）<$\bar{D}_{non-uniform}$（1.25%）。② 对比不均匀和均匀的种植方案,不均匀植树的街谷内部行人呼吸高度的气流流速比其对照案例（均匀植树Spa8m方案）整体增强了106.49%。街谷中部不种树,在街谷两端配置树木并预留足够的自由空间的不均匀植树方案,能够让角涡渗入街谷中部,促使街谷内部的垂直漩涡和两端的水平角涡运动,增强湍流和垂直交换,有效减少了街道两端“风口效应”和街道中部“风影效应”的区域,改善了整个街谷行人呼吸平面的风环境。④ 合理空间配置的树木能够改善街谷内部的行人风环境。街谷内行人呼吸高度处的气流对局地条件很敏感,树木的局部配置（空间簇集、密度）将引起强烈的空间变化。在既有城市建筑布局条件下,如何通过谨慎的景观设计,利用树木等城市绿化措施有效地改善城市的行人风环境,缓解污染扩散、疾病传播等问题,本文的方法可提供一定的参考。     

华南地区典型种植园地遥感分类研究

华南地区种植园地广泛分布,类型混杂多样,导致园地分布信息难以正确获取,为农业管理造成了较大困难。本研究基于Landsat8 OLI数据,通过数据融合、特征优化,应用随机森林算法构建面向对象的种植园地分类规则集,对华南地区典型经济作物香蕉、柑橘、葡萄、蒲葵、海枣、番木瓜和火龙果等进行类别识别,同时对比贝叶斯分类法、K最邻近分类法、支持向量机法、决策树分类法的分类效果。结果表明：数据融合会在一定程度上影响分类结果精度;植株形态、光谱特征接近,种植期交错是影响华南地区典型园地分类精度的重要原因;以中分辨率影像为数据源,面向对象的随机森林算法应用于种植园地分类研究总体精度可达88.05%,Kappa系数0.87,可以有效区分华南地区典型种植园地类别;相比于其他算法,随机森林算法在分类精度、可靠性和稳定性上具有一定优势,可为园地作物生长监测和种植管理提供科学依据。     

我国典型城市生态问题的现状与对策

当前我国的环境污染已从陆地蔓延到近海水域．从地表水延伸到地下水,从一般污染物扩展到有毒有害污染物。发达国家在不同发展阶段出现的生态环境问题．我国却在近20年间集中爆发出来,生态问题的严重性已经不仅仅在于排污总量的增加和生态破坏范围的扩大．而是生态与环境问题变得更加复杂,威胁和风险更加巨大。     

辽河三角洲湿地表层沉积物渗透系数的研究

该文利用圆盘渗透仪,对辽河三角洲湿地4种不同的生境进行渗透系数的测定,并对4种生境的渗透系数进行老人分析比较,作出辽河三角洲湿地渗透系数的分布状况图。从图上可以看出,辽河三角洲湿地渗透系数值最大值为（3.2~3.4）×103cm/s,平均值为1.5×103cm/s。     

生物滤料对翘嘴红鲌生长、水质及细菌变化的影响

在实验池投放一定数量的生物刷和生物球等生物滤料,研究其对翘嘴红鲌生长、池塘水质及细菌变化等的影响。结果表明:与对照池相比,实验池翘嘴红鲌生长有增加趋势,对池塘水温、pH、DO、TP、H2S等指标无显著影响(P>0.05),但是在30 d时水体COD显著降低(P<0.05);在90 d时NH4-N显著降低(P<0.05);在60 d和90 d时NO2-N显著降低(P<0.05);与对照池相比,在30 d时实验池水样与生物球中异养菌的数量显著增加(P<0.05);在30、60 d时,实验池生物刷中异养菌的数量显著增加(P<0.05);在90 d时实验池水样、生物球、生物刷氨化细菌、反硝化细菌的数量显著增加(P<0.05);实验池水样、生物球分别在30、90 d时弧菌数量显著降低(P<0.05)。表明生物滤料可增加池塘的异养菌、氨化细菌、反硝化细菌数量,降低水体弧菌数量,一定程度上改善养殖水体,促进鱼体生长。     

红海湾底质硫化物的分布和变化

根据南海区半封闭型海湾规模化养殖技术研究的需要,对红海湾底质硫化物进行了研究。用碘量法分析的结果表明：红海湾底质中硫化物含量的区域分布极不均匀,呈北部河口区＞虾池＞鱼湾＞中部＞南部自然水域＞礁滩区的特点。虾池、鱼的硫化物含量清淤前分别为清淤后的8.4、3．6倍;湾南部硫化物含量春季明显高于夏季,其余区域的两季差异不明显。46份样品中约13％、28％分别超过国内外评价标准,超标测站位于河口和清淤前的虾池、鱼。礁滩护养增殖区、南部自然水域、湾中部牡蛎养殖区和清淤后的虾池、鱼尚未见硫化物的污染。     

松嫩平原含水层沉积物特征及其对砷赋存态分布的影响

松嫩平原西部地区为中国砷中毒区域,含水层沉积物特征及砷赋存态对地下水砷迁移、转化的影响并不清楚。在对研究区高砷区与低砷区钻孔沉积物进行取样的基础上,运用激光粒度分析、Tessier五步提取法和Keon分步提取法分别确定了不同深度沉积物的粒度分布和不同赋存态砷含量,系统研究了沉积物的水力传导系数、不同赋存态砷的分布及其与高砷地下水形成的关系。结果表明:沉积物5种赋存态砷(包括可交换态、碳酸盐吸附态、铁/锰氧化物吸附态、有机物或硫化物吸附态和基质态)中,铁/锰氧化物吸附态砷含量最高,并且砷含量与铁、锰含量呈明显正相关性;高砷区钻孔沉积物铁/锰氧化物吸附态砷质量分数为(1.18~6.11)×10-6,低砷区为(0.67~2.60)×10-6;高砷区钻孔沉积物以粉砂、黏土为主,水力传导系数介于0.004~0.027m·d-1,低砷区钻孔沉积物以细砂、中砂为主,水力传导系数介于0.005~0.2m·d-1;沉积物中粉砂或黏土含量越多,则沉积物颗粒越小,其水力传导系数越低,各赋存态砷含量越高,因此,高砷区低水力传导系数有利于还原环境的形成。通过地下水的循环,高砷含水层沉积物的淋滤作用和铁/锰氧化物的还原性溶解形成了研究区高砷地下水。     

考洲洋底质中硫化物的含量与分布

1 999年 2月和 8月对考洲洋底质硫化物状况进行了调查。结果表明 :考洲洋底质中的硫化物含量在 1 3 7～ 2 2 8 7mg·kg- 1(干重 ,下同 )之间 ,平均值为 1 2 8 2mg·kg- 1。其含量呈养殖区 >河口入海区>近湾口区非均匀分布。丰水期间底质硫化物含量略高于枯水期的。底质硫化物含量与底质有机质含量和化学耗氧量的呈正相关关系。以全国海岸带污染调查关于底质硫化物含量标准 (3 0 0mg·kg- 1)比较 ,硫化物含量未出现超标现象 ;与其它海湾比较 ,其含量高于海南的安游湾而低于或远低于深圳湾、红海湾、衙前湾、南澳湾和雷州湾以及厦门西海域和大连湾