Background The invasiveness of Spartina alterniflora Loisel.into the estuarine coastal wetlands has impacted the stability of soil organic carbon,as well as the functional genes of soil microorganisms.However,the mech...Background The invasiveness of Spartina alterniflora Loisel.into the estuarine coastal wetlands has impacted the stability of soil organic carbon,as well as the functional genes of soil microorganisms.However,the mechanisms by which S.alterniflora invasion affects soil organic carbon,especially at the micro-level,is still unclear.Therefore,this study compared the differences in soil carbon cycling(C-cycling)functional genes between invaded and native areas during the cold season,as well as the changes in microbial communities involved in differential functional genes'expression.Results Our results showed that in salt marsh wetlands dominated by Suaeda salsa(L.)Pall.,invasion by S.alterniflora negatively impacts soil microbial biomass carbon(MBC)and reduces the diversity of C-cycling functional genes.The invasion species significantly increased the relative abundance of carbon fixation genes,while decreasing the relative abundance of carbon degradation genes.Additionally,the differential genes-expressing microbial communities exhibited notable differences across groups.At the class level,both generalist taxa(e.g.,Gammaproteobacteria,Deltaproteobacteria)and specialist taxa(e.g.,Nitrospiria,Flavobacteriia)collectively influenced the abundance of C-cycling functional genes.Correlation and hierarchical partitioning analyses revealed that the increased soil carbon fixation capacity was closely associated with increased soil organic carbon(SOC)and decreased MBC,whereas the decline in soil carbon degradation capacity was linked to higher soil electrical conductivity(EC)and a lower C:P ratio.Conclusions Our study filled a gap in research during the cold season and revealed that the invasion of S.alterniflora significantly impacts both soil C-cycling functional genes and their expressing microbial communities,thereby potentially affecting the soil organic carbon of salt marsh wetland ecosystems.展开更多
目的针对模糊C-均值聚类图像分割方法存在的对初始值敏感及抗噪性能差的问题,提出一种结合基因表达式编程与空间模糊聚类的图像分割方法。方法首先,利用基因表达式编程算法对图像进行初次分割,即将聚类中心编码成染色体,通过适应度评价...目的针对模糊C-均值聚类图像分割方法存在的对初始值敏感及抗噪性能差的问题,提出一种结合基因表达式编程与空间模糊聚类的图像分割方法。方法首先,利用基因表达式编程算法对图像进行初次分割,即将聚类中心编码成染色体,通过适应度评价引导搜索获得优化的聚类中心;然后在隶属度计算中引入空间函数,以初次分割结果作为初始值,使用空间模糊聚类对图像进行二次分割。结果对加噪的合成图像和Berkeley图像的分割实验显示,本文方法在聚类划分系数(VPC)、聚类划分熵(VPE)和峰值信噪比(PSNR)等评价指标上总体性能优于经典的模糊C-均值聚类和空间模糊C-均值聚类分割算法,其中VPC值平均高出0.062 4和0.061 1,VPE值平均降低0.117 0和0.101 1,而PSNR值平均提升了约13.312 1 d B和3.308 4 d B;在对Berkeley图像库中的6幅图片的分割实验显示,本文方法对图像分割的VPC值均在0.93以上,相比两种对比方法平均提高0.157 6和0.013 3,VPE值保持在0.1附近,均低于对比方法,PSNR值平均提高2.896 3 d B和1.934 4 d B;在多目标分割实验上,随着聚类数目增加,3种方法的分割性能均有下降,但本文方法性能曲线最为平缓,受聚类数目的影响最小。虽然本文方法所需的运行时间略有增加,但求解所需的迭代次数却极大地减少。结论本文提出的图像分割方法具有很强的抗噪性、更高的分割精度和稳定性,适用于需要更精确结果、对时间要求不高的分割场景。展开更多
基金supported by the Key R&D Program of Zhejiang Province(2023C02004,2023C02015)the National Natural Science Foundation of China(42277283,42090060)+1 种基金the Fundamental Research Funds for the Central Universities(226-2022-00139)Ningbo Welfare Science and Technology Plan Project(No.2022S118)
文摘Background The invasiveness of Spartina alterniflora Loisel.into the estuarine coastal wetlands has impacted the stability of soil organic carbon,as well as the functional genes of soil microorganisms.However,the mechanisms by which S.alterniflora invasion affects soil organic carbon,especially at the micro-level,is still unclear.Therefore,this study compared the differences in soil carbon cycling(C-cycling)functional genes between invaded and native areas during the cold season,as well as the changes in microbial communities involved in differential functional genes'expression.Results Our results showed that in salt marsh wetlands dominated by Suaeda salsa(L.)Pall.,invasion by S.alterniflora negatively impacts soil microbial biomass carbon(MBC)and reduces the diversity of C-cycling functional genes.The invasion species significantly increased the relative abundance of carbon fixation genes,while decreasing the relative abundance of carbon degradation genes.Additionally,the differential genes-expressing microbial communities exhibited notable differences across groups.At the class level,both generalist taxa(e.g.,Gammaproteobacteria,Deltaproteobacteria)and specialist taxa(e.g.,Nitrospiria,Flavobacteriia)collectively influenced the abundance of C-cycling functional genes.Correlation and hierarchical partitioning analyses revealed that the increased soil carbon fixation capacity was closely associated with increased soil organic carbon(SOC)and decreased MBC,whereas the decline in soil carbon degradation capacity was linked to higher soil electrical conductivity(EC)and a lower C:P ratio.Conclusions Our study filled a gap in research during the cold season and revealed that the invasion of S.alterniflora significantly impacts both soil C-cycling functional genes and their expressing microbial communities,thereby potentially affecting the soil organic carbon of salt marsh wetland ecosystems.
文摘目的针对模糊C-均值聚类图像分割方法存在的对初始值敏感及抗噪性能差的问题,提出一种结合基因表达式编程与空间模糊聚类的图像分割方法。方法首先,利用基因表达式编程算法对图像进行初次分割,即将聚类中心编码成染色体,通过适应度评价引导搜索获得优化的聚类中心;然后在隶属度计算中引入空间函数,以初次分割结果作为初始值,使用空间模糊聚类对图像进行二次分割。结果对加噪的合成图像和Berkeley图像的分割实验显示,本文方法在聚类划分系数(VPC)、聚类划分熵(VPE)和峰值信噪比(PSNR)等评价指标上总体性能优于经典的模糊C-均值聚类和空间模糊C-均值聚类分割算法,其中VPC值平均高出0.062 4和0.061 1,VPE值平均降低0.117 0和0.101 1,而PSNR值平均提升了约13.312 1 d B和3.308 4 d B;在对Berkeley图像库中的6幅图片的分割实验显示,本文方法对图像分割的VPC值均在0.93以上,相比两种对比方法平均提高0.157 6和0.013 3,VPE值保持在0.1附近,均低于对比方法,PSNR值平均提高2.896 3 d B和1.934 4 d B;在多目标分割实验上,随着聚类数目增加,3种方法的分割性能均有下降,但本文方法性能曲线最为平缓,受聚类数目的影响最小。虽然本文方法所需的运行时间略有增加,但求解所需的迭代次数却极大地减少。结论本文提出的图像分割方法具有很强的抗噪性、更高的分割精度和稳定性,适用于需要更精确结果、对时间要求不高的分割场景。
基金National Key Basic Research Program of China(No.2013CB956601,2013CB956000)National High Technology Research and Development Program of China(863 Program,No.2012AA061401)National Natural Science Foundation of China(No.41471202,41171201,41230750,41430856)
