Fish feces affect the structure and function of aquatic ecosystems,and they are affected by the functional fish organizations.In this research,Ctenopharyngodon idellus,Hypophthalmichthys molitrix,and Cyprinus carpio w...Fish feces affect the structure and function of aquatic ecosystems,and they are affected by the functional fish organizations.In this research,Ctenopharyngodon idellus,Hypophthalmichthys molitrix,and Cyprinus carpio were selected to study the effects of different functional fish organizations on the fractal characteristics of fecal micro-structure by scanning electron microscopes(SEM),particles(pores)and cracks analysis system(PCAS).The results showed that fish feces pores mainly consisted of medium pores(cumulative pore number,97%)classified by the International Union of Pure and Applied Chemistry(IUPAC).The grain area fractal dimension D_(1) and the pore-number and pore-size fractal dimension D_(2) were 1.94-1.96 and 2.07-2.19,respectively.The distribution of fish feces pores was very close to the Sierpinski carpet structure,which is the basic fractal construction methods widely used to describe the fractal of pore surface distribution.D_(1)(1.96)and D_(2)(2.19)of Hypophthalmichthys molitrix were the maximum values of the three functional organizations.Combining with the habit of fish,it is inferred that the feces of H.molitrix,the finer the feed and the faster the swimming of fish,the higher the content of feces clay,the larger the fractal dimension of feces,the easier it is to decompose feces,and the high the content of nutrients and organic matter to release into the water.It is demined that fish functional organizations affected the fractal characteristics and the stability of fish feces in water.This study is helpful for further research on water quality prediction and the impact of functional fish organizations on the structure and function of the ecosystem.展开更多
联合国2030年可持续发展目标(Sustainable Development Goals,SDGs)为全球可持续发展提供了新的评价框架和远景目标,但目标间关系的复杂性决定了17个发展目标无法同时实现、同时执行,关注可持续发展目标间相互独立、相互依赖的综合性质...联合国2030年可持续发展目标(Sustainable Development Goals,SDGs)为全球可持续发展提供了新的评价框架和远景目标,但目标间关系的复杂性决定了17个发展目标无法同时实现、同时执行,关注可持续发展目标间相互独立、相互依赖的综合性质已经成为当前的研究热点。文章基于目标间的复杂性质,在回顾既有文献的基础上,发现协同和权衡是分析目标间关系的主要概念,庞大的目标体系也存在多种潜在的结构类型;同时,目标的主观性取舍、数据的来源和质量、评估理论和方法的应用、跨学科和部门的合作以及国家间的异质性都会影响目标间关系的研究。文章认为,精确定义目标间关系类型最需要的还是认识论层面的指导。从可持续发展经济学的角度出发,研究提出了一个区分目标间关系类型的分析模型,用目标间存在的基本关系类型,即协同和权衡,拓展了可持续性科学中有关强可持续性和弱可持续性的分析框架。以整合性为目的,理论上可持续发展目标间关系应该包括四种类型:共存关系、替代关系、包含关系、互补关系。同时,研究呼吁将协同和权衡关系纳入可持续性科学的分析框架,强调应从强可持续性的视角来理解和检验目标间关系;建议对可持续发展目标进行结构上的降维处理,最好的目标间关系应该是结构类型中的平衡。展开更多
基金financial support from the National Natural Science Youth Foundation of China(No.32002443)the Natural Science Foundation of Shandong Province(No.ZR2021QD 149)。
文摘Fish feces affect the structure and function of aquatic ecosystems,and they are affected by the functional fish organizations.In this research,Ctenopharyngodon idellus,Hypophthalmichthys molitrix,and Cyprinus carpio were selected to study the effects of different functional fish organizations on the fractal characteristics of fecal micro-structure by scanning electron microscopes(SEM),particles(pores)and cracks analysis system(PCAS).The results showed that fish feces pores mainly consisted of medium pores(cumulative pore number,97%)classified by the International Union of Pure and Applied Chemistry(IUPAC).The grain area fractal dimension D_(1) and the pore-number and pore-size fractal dimension D_(2) were 1.94-1.96 and 2.07-2.19,respectively.The distribution of fish feces pores was very close to the Sierpinski carpet structure,which is the basic fractal construction methods widely used to describe the fractal of pore surface distribution.D_(1)(1.96)and D_(2)(2.19)of Hypophthalmichthys molitrix were the maximum values of the three functional organizations.Combining with the habit of fish,it is inferred that the feces of H.molitrix,the finer the feed and the faster the swimming of fish,the higher the content of feces clay,the larger the fractal dimension of feces,the easier it is to decompose feces,and the high the content of nutrients and organic matter to release into the water.It is demined that fish functional organizations affected the fractal characteristics and the stability of fish feces in water.This study is helpful for further research on water quality prediction and the impact of functional fish organizations on the structure and function of the ecosystem.
文摘联合国2030年可持续发展目标(Sustainable Development Goals,SDGs)为全球可持续发展提供了新的评价框架和远景目标,但目标间关系的复杂性决定了17个发展目标无法同时实现、同时执行,关注可持续发展目标间相互独立、相互依赖的综合性质已经成为当前的研究热点。文章基于目标间的复杂性质,在回顾既有文献的基础上,发现协同和权衡是分析目标间关系的主要概念,庞大的目标体系也存在多种潜在的结构类型;同时,目标的主观性取舍、数据的来源和质量、评估理论和方法的应用、跨学科和部门的合作以及国家间的异质性都会影响目标间关系的研究。文章认为,精确定义目标间关系类型最需要的还是认识论层面的指导。从可持续发展经济学的角度出发,研究提出了一个区分目标间关系类型的分析模型,用目标间存在的基本关系类型,即协同和权衡,拓展了可持续性科学中有关强可持续性和弱可持续性的分析框架。以整合性为目的,理论上可持续发展目标间关系应该包括四种类型:共存关系、替代关系、包含关系、互补关系。同时,研究呼吁将协同和权衡关系纳入可持续性科学的分析框架,强调应从强可持续性的视角来理解和检验目标间关系;建议对可持续发展目标进行结构上的降维处理,最好的目标间关系应该是结构类型中的平衡。
