Moving policy and regulation forward for single-use plastic alternatives

Single-use plastics are often used once or cannot be reused for extended periods. They are widely consumed with the rapid development of social economy. The waste generated by single-use plastics threatens ecosystem health by entering the environment and ultimately restricts sustainable human development. The innovation of sustainable and environmentally friendly single-use plastic alternative materials and the joint participation of governments, enterprises and the public are promising technologies and management approaches that can solve the problem of single-use plastics wastes. The development of single-use plastic alternative products can be promoted fundamentally only by improving relevant legislation and standards, providing differentiated industrial policies, encouraging scientific and technological innovation and expanding public participation.     

“NEW” resource recovery from wastewater using bioelectrochemical systems: Moving forward with functions

Bioelectrochemical systems (BES) have been extensively studied for resource recovery from wastewater. By taking advantage of interactions between microorganisms and electrodes, BES can accomplish wastewater treatment while simultaneously recovering various resources including nutrients, energy and water (“NEW”). Despite much progress in laboratory studies, BES have not been advanced to practical applications. This paper aims to provide some subjective opinions and a concise discussion of several key challenges in BES-based resource recovery and help identify the potential application niches that may guide further technological development. In addition to further increasing recovery efficiency, it is also important to have more focus on the applications of the recovered resources such as how to use the harvested electricity and gaseous energy and how to separate the recovered nutrients in an energy-efficient way. A change in mindset for energy performance of BES is necessary to understand overall energy production and consumption. Scaling up BES can go through laboratory scale, transitional scale, and then pilot scale. Using functions as driving forces for BES research and development will better guide the investment of efforts.

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论我国水生态的保护与修复:任务与对策

本文聚焦我国水生态保护与修复工作,结合长期实践,分析当前的形势和任务,指出了当前要着力解决的水生态问题主要是:在大坝上游,河流变湖库,生境变化导致生物物种变化;水库水流流速变缓,水体自净能力降低,导致富营养化及藻类水华。在大坝下游,清水下泄,冲刷下游河道导致局部河道河势变化较大;水库蓄水使坝下游春季水温下降、秋季水温升高,水温变化过程滞后;水库蓄水导致大坝下游的水文过程改变,水的流量、流速、流态发生变化。在河道(航道)整治工程中,裁弯取直,缩短水流在河道中的停留时间,河岸衬砌和硬化,减少水向沿河堤岸的渗透,在大降水和洪水时易造成涝灾和洪灾。在涉湖工程中,阻隔河湖,填湖造地。在明确存在问题和迫切需求的基础上,提出了切实可行的对策建议。当前水生态保护与修复要围绕一条主线,即"人要发展,鱼要生存"的"人鱼线",要采取"调、控、退、通、改、拆"的综合措施,即生态调度,控制水污染,退建还水、退田还湖,河湖连通,对已建涉水工程进行生态化改造,对在保护区、重点风景名胜区、特有鱼类栖息地修建的小型工程要采取坚决措施拆除,恢复原貌。     

Asexuals looking for sex: conflict between species and mate-quality recognition in sailfin mollies (Poecilia latipinna)

When two closely related species are sympatric the process of species recognition (identifying conspecifics) and mate-quality recognition (increased fitness benefits) can yield a conflict when heterospecifics resemble high-quality conspecifics. Conflict in species versus mate-quality recognition may serve as a possible mechanism for the persistence of unisexual, gynogenetic Amazon mollies (Poecilia formosa). Amazon mollies require sperm from closely related species (e.g., sailfin mollies, P. latipinna) to start embryogenesis but inheritance is strictly maternal. When choosing mates, male sailfin mollies from populations sympatric with Amazon mollies may rely on traits indicating species identity rather than those indicating mate quality. Conversely, males from allopatric populations may rely more on traits indicating mate quality. Previous work has found that male sailfin mollies in sympatry exhibit a significantly greater mating preference for female sailfin mollies over Amazon mollies compared to males in allopatry. In addition, male sailfin mollies prefer to associate with and produce more sperm in the presence of larger conspecific females, which are more fecund. We hypothesized that male sailfin mollies experience a conflict in species recognition and mate-quality recognition in the presence of Amazon mollies that are relatively larger than female sailfin mollies. To test this hypothesis, we paired males from sympatric and allopatric populations with a larger Amazon molly and a smaller female sailfin molly. We scored the number of mating attempts that males directed to conspecific and heterospecific females. Males in most sympatric and allopatric populations demonstrate no clear preference for conspecifics. In addition, we found some evidence for a difference in mating preference between allopatric and sympatric populations with males from allopatry showing a greater heterospecific mate preference. These results indicate a conflict between species and mate-quality recognition. In sympatry this conflict may contribute to the persistence of gynogenetic Amazon mollies.     

化学品足迹:概念、研究进展及挑战

化学品污染被联合国环境规划署列为影响人类生存与发展的全球重大环境问题之一。为实现可持续的化学品管理,需定量评价产品生命周期内由化学品排放造成的生态影响。然而,当前的化学品风险评价指标体系往往指向零碎的危害性或毒性终点,未能综合出整体性指标来定量表征生态系统所承受的损害,亦不能衡量人类活动排放的化学品总量与环境承载容量的相对大小。作为环境足迹一员,化学品足迹继承了"足迹"指标的特点,可定量表征生态系统受化学品影响的程度,并结合生态阈值及环境承载容量,有助于评价人类活动对环境可持续性的影响,有望成为公众、企业、决策者及利益相关者之间相互交流的重要工具。本文概述了化学品足迹的基本概念及其发展历程,介绍了现有的化学品足迹计算方法及其应用于不同空间尺度下的案例研究,讨论了化学品足迹研究中存在的问题与挑战,并对其应用前景进行了展望。     

Moving towards sustainable development: rhetoric,policy and reality of ecological agriculture in China

Past decades have witnessed the rise of sustainable agriculture movements throughout the world. In parallel with this international trend, ecological agriculture (with essential goals of food security, rural employment, poverty alleviation, natural resource management and environmental protection) has been advocated as a workable approach for the realization of sustainable agriculture in China. Two decades of ecological agricultural development have shown that it not only gained legitimacy at the senior policy level but also became a focus of scientific research in fields such as ecological economics, ecology, and agricultural and environmental sciences. However, this endeavour is hardly known in the West and little attention has been paid so far to examining the broader politico-economic and sociocultural contexts within which it has evolved. This paper attempts to provide a general review of the emerging background, development history, policy initiatives and recent tendencies of ecological agriculture. In addition, the extant problems and potential contributions of this alternative practice to China's sustainable agricultural development are discussed. The purpose of this study is to identify the gap between the policy rhetoric and practical implementation of Chinese ecological agriculture and therefore to facilitate its moving towards sustainable development.     

Chemical composition of Leptocythere psammophila (Crustacea: Ostracoda) as influenced by winter metabolism and summer supplies

Leptocythere psammophila is well known for the ecophenotypic variations of the ornamentation of its carapace. To test the respective influences of the environmental parameters on its ornamentation, 41 living specimens were collected in the Baltic Sea, the North Sea and in the English Channel during spring, summer and winter (April 1987, September and December 1988). The carbonate carapaces of these specimens were analyzed by means of electron microprobe. Thirteen elements were detected. Statistical comparisons of means and variances were performed using classical F and t-tests. Data were submitted to Normalized Principal Component Analysis and Discriminant Analysis. There are no significant differences between chemical composition of the carapaces from the different stations. However, the variability of Baltic Sea specimens is lower than that of other stations. Nonetheless, strong and significant differences appear when samples are gathered by season. The chemical composition of summer individuals is controlled by variations in water salinity and in fine grain terrigenous sediment supply. The composition of winter samples is related to the incorporation of Mg. In the case of spring specimens, both these factors have to be considered. Discriminant analysis between winter and non-winter samples sets correctly 84% of the individuals. The wrongly classified specimens are interpreted as ostracods that did not molt during the season of sampling. By attributing them to their possible season of molting, the result of the Normalized Principal Component Analysis improves. Differences in ornamentation are slight. They occur between the samples from the Baltic Sea and those from the other stations. The former have larger and less numerous punctations and lack the smooth surface in the anteroventral part of the carapace. The punctation diameter is more variable during summer than during spring. In the range of environments investigated, ornamentation of the carapace of L. psammophila seems unaffected by the seasonal environmental variations whereas its composition exhibits strong differences.     

Chemical recognition of queen cells by honey bee workersApis mellifera (Hymenoptera: Apidae)

Summary Honey bee workers are able to nurse or to destroy and thus to recognize the capped queen cells containing a pupa. Fatty acid esters, especially methyl oleate, methyl palmitate and ethyl oleate were found in significant amounts on the queen pupal cuticle. Methyl oleate, the major component, along with smaller amounts of methyl linoleate and methyl linolenate, were involved in the recognition of queen cells by workers. In natural conditions of the colony, queen cells containing a paraffin pupal lure with methyl oleate were accepted 5.9 days by workers, releasing about 1.8 queen pupa equivalents during that period, when control cells (without ester) were kept only 2.1 days. Although these esters are non specific to honey bees, they are of great importance in social regulation of the honey bee colony.