【摘 要】
：
Microplastics existing widely in different matrices have been regarded as a reservoir for emerging contaminants.Mariculture systems have been observed to host microplastics and antibiotic resistance genes (ARGs).However,more information on proliferation o
【机 构】
：
CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation,Yantai Institute of
论文部分内容阅读
Microplastics existing widely in different matrices have been regarded as a reservoir for emerging contaminants.Mariculture systems have been observed to host microplastics and antibiotic resistance genes (ARGs).However,more information on proliferation of ARGs and metal resistance genes(MRGs) in mariculture system at the presence of microplastics is needed.This study used metagenomic analysis to investigate the distribution of ARGs and MRGs in water and microplastics of a typical mariculture pond.Total 18 types including 174 subtypes of ARGs were detected with the total relative abundances of 1.22/1.25 copies per 16S rRNA copy for microplastics/water.Chloramphenicol resistance genes were the dominant ARGs with the abundance of 0.35/0.42 copies per 16S rRNA copy for microplastics/water.Intergron intI1 was dominant gene among 6 detected mobile genetic elements(MGEs) with the abundance of 75.46/68.70 copies per 16S rRNA copy for water/microplastics.Total 9 types including 46 subtypes of MRGs were detected with total abundance of 5.02 × 102/6.39 × 102 copies per 16S rRNA copy for water/microplastics while genes resistant to copper and iron served as the dominant MRGs.Proteobacteria,Bacteroidetes,and Actinobacteria accounted for 84.2％/89.5％of total microbial community in microplastics/water.ARGs with relatively high abundance were significantly positively related to major genera,MGEs,and MRGs.Microplastics in mariculture system could enrich most of MRGs and some ARGs to serve as potential reservoir for these pollutants.The findings of this study will provide important information on resistance gene pollution at presence of microplastics in the madculture system for further proposing suitable strategy of environmental management.
其他文献
疲劳损伤评估方法(包括时域法和频域法)是结构耐久性设计的重要内容,提高其评估精度和效率具有重要的工程意义.相比时域法而言,频域法计算简便且高效,但精度较低.该研究利用频域Tovo-Benasciutti谱方法(T-B谱方法),并结合高层建筑风致疲劳分析,提出了基于T-B谱方法关键参数包络值的改进方法.首先,以高层建筑顺风向、横风向以及耦合风振疲劳损伤为研究对象,并以时域雨流法为基准,评价了原有两种T-B谱方法的计算精度;其次,基于该方法关键参数的分析结果,利用数值模拟,确定了该参数的包络值;最后,基于该包
Microplastics (MPs) are distributed in the oceans,freshwater,and soil environment and have become major pollutants.MPs are generally referred to as plastic particles less than 5 mm in diameter.They consist of primary microplastics synthesized in microscop
在滑移理论的基础上,通过COMSOL软件建立带有双螺旋线的斜拉索圆柱绕流模型,得到斜拉索的风压力系数和风摩擦系数.忽略斜拉索在横风向上的振动,通过改变风向得到在不同截面下带有双螺旋线的斜拉索受到的气动力,进而求得斜拉索的振动时程曲线及其频谱分析结果.结果 显示,双螺旋线的存在抑制了水线在斜拉索表面的振荡,使得斜拉索在横风向受到的拉索气动力变化范围逐渐缩小,气动力的振荡频率远大于斜拉索的自振频率,降低了水线与斜拉索产生共振的可能性,从而抑制了斜拉索的风雨激振现象.
基于相位传声器阵列在声学风洞中测量了低速空腔流动中主要噪声源的分布特性,提出了一种新的评估气动声源强度的计算方法.通过在空腔前后缘加装锯齿板和阻挡板的方式探索了空腔噪声抑制策略,并且比较了不同措施的降噪效果.结果 表明:低速空腔流动噪声主要来自于剪切层与空腔后壁的相互作用;锯齿板以沿来流方向安装在前缘对空腔噪声控制效果最好,且锯齿越密集,噪声抑制效果越明显;阻挡板对空腔噪声控制效果不理想.
侵彻过载信号包含复杂的信号分量,传统的信号处理方法无法有效提取弹体的侵彻过载特征.提出一种将变分模态分解与盲源分离相结合的侵彻过载信号特征分离方法,首先由变分模态分解将源信号分解成一系列本征模态函数;然后将本征模态函数与源信号组成多维观测信号,对其自相关矩阵进行奇异值分解估计源信号数目,并计算各本征模态函数与源信号的相关系数,根据源信号数目和相关系数,选择相应的本征模态函数与源信号重构多通道观测信号;最后采用特征矩阵联合近似对角化法对多通道观测信号进行盲源分离.与传统信号处理方法相比,该方法能够有效分离出
Plastic pollution has been a legacy environ-ment problems and more recently,the plastic particles,especially those ultrafine or small plastics particles,are widely recognized with increasing environmental and ecological impacts.Among small plastics,microp
针对超声水表在实际工作环境中容易受到噪声干扰从而导致计量精度下降的问题,提出了基于集合经验模态分解(EEMD)的改进小波阈值降噪算法.为了提高降噪效果,对小波阈值降噪算法进行了改进,构造了非线性阈值函数取代传统阈值函数,同时给出了一种分解尺度选择的方法.利用EEMD将流速信号分解为一系列的本征模态函数,通过改进小波阈值降噪算法对本征模态函数进行降噪处理,去除其中的噪声分量,为了验证该算法的适用性,将其与小波阈值降噪算法和时空滤波分析方法进行了比较.试验结果表明,以超声水表流速信号为降噪对象时,基于EEMD
Microplastics are an emerging threat and a big challenge for the environment.The presence of microplastics (MPs) in water is life-threatening to diverse organisms of aquatic ecosystems.Hence,the scientific community is exploring deeper to find treatment a
Microplastics (MPs) are widely present in a variety of environmental media and have attracted more and more attention worldwide.However,the effect of MPs on the interaction between heavy metals and soil,especially in soil solid fraction level,is not well
随着5G时代的到来,地震过程能通过密集分布的摄像头实时记录并快速传输处理,以动态图像的形式更直观地呈现出来.如能从中快速准确的提取地震动参数等数据,将会是地震资料的宝库,弥补地震台站布置密度的不足..通过振动台模拟地震过程,结合图像识别和结构动力学分析方法,提出一种基于图像动态识别技术的地震动参数快速判别方法.通过不同摄像头高度、波形和振动频率下的计算和实测加速度曲线对比分析,多数加速度峰值误差在40％以内,证明该方法具有应用推广价值,能为将来地震动分析工作提供另一层面的解决途径.