Shrub patches often support the colonizers particularly under stressful and/or disturbed environments.The intensities of stresses and disturbances on mountains are often related to an elevation gradient and are decrea...Shrub patches often support the colonizers particularly under stressful and/or disturbed environments.The intensities of stresses and disturbances on mountains are often related to an elevation gradient and are decreased by shrub patches(canopy and litter).We aim to clarify these relationships by using shrub patches at different elevations on a volcano.We monitored all shoots in plots established inside and outside of patches of Salix reinii(Salicaceae)and their related environments,such as temperature,light,moisture and chemistry,at three elevations on Mount Koma(1131 m a.s.l.),northern Japan,from early spring in 2005 to summer in 2006.The patch structures were evaluated by area,branch density and litter thickness.The structures of shrub patches did not differ among the elevations.The patches increased the diversity of rare species,by an overall increase in plant species richness.The moisture,nitrogen and phosphate contents in the patches were higher than outside of patches.The effects of shrub patches on the cohabitants were overall positive,although the effects were negative on seedling abundance,shoot survival and flowering.These results suggest that the growth patterns of shrub patches determine the plant community structures and facilitate plant diversity.展开更多
Nitrogen pollution is an increasingly severe worldwide problem because of drainage of nitrogen-containing wastewater and intensive application of nitrogen-containing fertilizers. Denitrification, a key process in nitr...Nitrogen pollution is an increasingly severe worldwide problem because of drainage of nitrogen-containing wastewater and intensive application of nitrogen-containing fertilizers. Denitrification, a key process in nitrogen cycles, is commonly employed for nitrogen removal in engineered wastewater treatment systems. Biological denitrification is performed by denitrifying microbes(bacteria) that use nitrate as terminal electron acceptor. Better understanding the functions of diverse microbial populations in denitrification-based wastewater treatment systems, and the interactions of these populations with operating environments, is essential for improving both treatment performance and system stability. Recent advances in "meta-omics"(e.g., genomics, transcriptomics, proteomics, metabolomics), other molecular biology tools, and microbiome analysis have greatly enhanced such understanding. This minireview summarizes recent findings regarding microbial community structure and composition, key functional microbes and their physiology, functional genes involved in nitrogen cycle, and responses of microbes and their genes to changes of environmental factors or operating parameters, in denitrification processes in wastewater treatment systems. Of particular interest are heterotrophic denitrification systems(which require alternative organic carbon sources) and the autotrophic denitrification systems(which do not require an external carbon source). Integrated microbiome and-omics approaches have great future potential for determination of optimal environmental and biotechnological parameters,novel process development, and improvement of nitrogen removal efficiency and system stability.展开更多
基金supported in part by Ministry of Education,Culture,Sports,Science and Technology of Japan and Japan Society for the Promotion of Science.
文摘Shrub patches often support the colonizers particularly under stressful and/or disturbed environments.The intensities of stresses and disturbances on mountains are often related to an elevation gradient and are decreased by shrub patches(canopy and litter).We aim to clarify these relationships by using shrub patches at different elevations on a volcano.We monitored all shoots in plots established inside and outside of patches of Salix reinii(Salicaceae)and their related environments,such as temperature,light,moisture and chemistry,at three elevations on Mount Koma(1131 m a.s.l.),northern Japan,from early spring in 2005 to summer in 2006.The patch structures were evaluated by area,branch density and litter thickness.The structures of shrub patches did not differ among the elevations.The patches increased the diversity of rare species,by an overall increase in plant species richness.The moisture,nitrogen and phosphate contents in the patches were higher than outside of patches.The effects of shrub patches on the cohabitants were overall positive,although the effects were negative on seedling abundance,shoot survival and flowering.These results suggest that the growth patterns of shrub patches determine the plant community structures and facilitate plant diversity.
基金supported by the projects of National Key Research and Development Program of China (2016YFD0501409)
文摘Nitrogen pollution is an increasingly severe worldwide problem because of drainage of nitrogen-containing wastewater and intensive application of nitrogen-containing fertilizers. Denitrification, a key process in nitrogen cycles, is commonly employed for nitrogen removal in engineered wastewater treatment systems. Biological denitrification is performed by denitrifying microbes(bacteria) that use nitrate as terminal electron acceptor. Better understanding the functions of diverse microbial populations in denitrification-based wastewater treatment systems, and the interactions of these populations with operating environments, is essential for improving both treatment performance and system stability. Recent advances in "meta-omics"(e.g., genomics, transcriptomics, proteomics, metabolomics), other molecular biology tools, and microbiome analysis have greatly enhanced such understanding. This minireview summarizes recent findings regarding microbial community structure and composition, key functional microbes and their physiology, functional genes involved in nitrogen cycle, and responses of microbes and their genes to changes of environmental factors or operating parameters, in denitrification processes in wastewater treatment systems. Of particular interest are heterotrophic denitrification systems(which require alternative organic carbon sources) and the autotrophic denitrification systems(which do not require an external carbon source). Integrated microbiome and-omics approaches have great future potential for determination of optimal environmental and biotechnological parameters,novel process development, and improvement of nitrogen removal efficiency and system stability.
