Reassessment of the Ocean-To-Atmosphere Flux of Carbon Monoxide

Carbon monoxide (CO) in the surface sea waters is produced predominantly by photochemical processes, oxidized by micro-organisms and outgassed to the atmosphere. to assess carbon monoxide flux from the oceans to the atmosphere, the photochemical production and microbial oxidation of carbon monoxide in the oceanic mixed-layer was investigated during several oeanographic cruises and in the laboratory. the photoproduction rate of carbon monoxide was found to be well correlated to the concentration of dissolved organic carbon (DOC) in coastal and open ocean surface waters. Taking a global average carbon monoxide production rate of 10 ± 2 nmole litre^-1 (mg DOC hr)^-1 in the surface open ocean water, and 25 ± 7 nmole litre^-1 (mg DOC hr)^-1 in coastal sea water, at cloud-free summer solar noon, the photochemical production of carbon monoxide in the global oceans is estimated to be at a rate of 1200 ± 200 Tg CO y^-1. the microbial carbon monoxide turnover time in the mixed-layer was observed to range from hours in a coastal estuary to 16 days in the Pacific along 1057deg; W in dark incubations. Natural sunlight can largely inhibit the microbial consumption of carbon monoxide in surface water. On a global scale, microbial consumption is responsible for the loss of less than 10% of photochemical produced carbon monoxide in the surface ocean. Field measurements have shown that the net transport of carbon monoxide from the euphotic zone to the underlying deeper ocean water is limited and that the overall life time in surface sea waters is less than 3-4 hours. When combined, these field measurements with the photoproduction and microbial consumption rates obtained, we estimate the oceanic flux to the atmosphere is about 1000 ± 200 Tg CO y^-1, which represents the largest single source of atmospheric carbon monoxide.     

绿灯倒计时信号对驾驶行为的影响

为揭示绿灯倒计时信号对交叉口交通安全的影响,针对不同交通负荷与信号控制方式下的驾驶行为开展研究。选择大连市内的倒计时信号交叉口与非倒计时信号交叉口各2处,开展车辆行驶速度及不良驾驶行为调查。用数理统计方法,对比分析2类交叉口在平峰与高峰时段的车辆行驶速度特性,同时对比分析上述不同条件下闯黄灯及违规变道行为的发生数量。研究表明,绿灯倒计时信号在绿灯时间末期,会诱发一部分驾驶员加速行驶通过交叉口;绿灯倒计时信号在平峰时段对闯黄灯行为数量的影响较小,而对违规变道行为的数量有显著影响。     

反应气氛对绿色合成纳米铁的组分及其活性的影响

成本低廉和无二次污染的"绿色"合成纳米材料是发展原位纳米环境修复技术的前沿研究课题之一.本文以绿茶提取液为还原剂和稳定剂进行"绿色"合成纳米铁,探讨在不同的气氛下"绿色"合成的纳米铁颗粒的主要成分,以期为调控合成纳米铁系材料提供基础研究.首先,利用扫描电子显微镜(SEM)、X射线能谱(EDS)、X射线光电子能谱分析(XPS)和傅里叶变换红外光谱(FTIR)等表征手段对不同反应气氛下合成的纳米铁颗粒的表面微观形貌、尺寸和价态结构进行分析.结果发现,在通入N2情况下,合成的纳米铁颗粒粒径为(84.7±11.5)nm,其主要成分以纳米零价铁为主;在通入空气情况下,合成的纳米铁粒径为(117.8±26.2)nm,其主要成分是纳米零价铁、氧化铁和四氧化三铁的混合物;通入O2时,合成的纳米铁粒径为(141.2±26.3)nm,其主要成分以四氧化三铁为主.其次,评价在不同气氛条件下合成纳米铁颗粒对去除亚甲基蓝(MB)的反应活性.结果表明,在反应温度313 K下降解初始浓度为50 mg·L-1的MB溶液,反应5 min时已达到平衡,通入N2合成的纳米铁降解MB,去除率高达98.7%,而通入O2合成的纳米铁反应效率低,对MB的去除率仅为65.3%.最后,从以上发现提出不同气氛下可以调控"绿色"合成的铁系纳米材料成分,从而导致不同的纳米修复环境中污染物的能力.     

江苏陆地海岸线绿潮藻种类组成及分布特征

2012年12月—2013年5月对江苏启东蒿枝港至连云港西大堤长约730 km岸线内的69个岸滩堤坝站点进行了绿潮藻种类组成及数量分布调查.结果表明:绿潮藻出现的站点占总设置站点的26.09%,出现绿潮藻岸线长度约占整个江苏调查岸线长度的22.83%;岸滩上绿潮藻主要生长在沿岸石堤、养殖围坝和植被较浅相对稀疏的草滩上,绿潮藻种类组成主要有浒苔(Ulva prolifera)、曲浒苔(Ulva flexuosa)和缘管浒苔(Ulva linza).1—3月浒苔为主要优势种,4—5月曲浒苔为主要优势种,缘管浒苔在历次调查中其湿重生物量均很低.5月岸滩上固着绿潮藻量约36.7 t,不及海上飘来附着在岸滩上绿潮藻量的1/10,岸滩上固着绿潮藻中浒苔的量约为同期海上飘来浒苔湿重生物量的0.6%,岸滩堤坝不会是引起绿潮暴发的主要源头.     

Water chemistry controlled aggregation and photo-transformation of silver nanoparticles in environmental waters

The inevitable release of engineered silver nanoparticles (AgNPs) into aquatic environments has drawn great concerns about its environmental toxicity and safety. Although aggregation and transformation play crucial roles in the transport and toxicity of AgNPs, how the water chemistry of environmental waters influences the aggregation and transformation of engineered AgNPs is still not well understood. In this study, the aggregation of polyvinylpyrrolidone (PVP) coated AgNPs was investigated in eight typical environmental water samples (with different ionic strengths, hardness, and dissolved organic matter (DOM) concentrations) by using UV–visible spectroscopy and dynamic light scattering. Raman spectroscopy was applied to probe the interaction of DOM with the surface of AgNPs. Further, the photo-transformation and morphology changes of AgNPs in environmental waters were studied by UV–visible spectroscopy, inductively coupled plasma mass spectrometry, and transmission electron microscopy. The results suggested that both electrolytes (especially Ca^2 + and Mg^2 +) and DOM in the surface waters are key parameters for AgNP aggregation, and sunlight could accelerate the morphology change, aggregation, and further sedimentation of AgNPs. This water chemistry controlled aggregation and photo-transformation should have significant environmental impacts on the transport and toxicity of AgNPs in the aquatic environments.     

下凹式绿地在降雨径流控制中的应用研究

下凹式绿地具有蓄渗雨水、削减洪峰流量、净化雨水、防止土壤侵蚀等优点,且投资少,是一种能同时满足环境、生态、经济等多重效应的新型雨水利用措施;它的应用将有效缓解城市水资源匮乏和降雨地表径流造成的面源污染,同时能在一定程度上防止城市内涝.在介绍下凹式绿地对降雨径流控制的基础上,着重综述了下凹式绿地对雨水的蓄渗、净化作用及其设计方面的研究进展.     

Environmental Equity and the Role of Public Policy: Experiences in the Rijnmond Region

This Φ Ψ study of environmental equity uses secondary quantitative data to analyze socioeconomic disparities in environmental conditions in the Rijnmond region of the Netherlands. The disparities of selected environmental indicators—exposure to traffic noise (road, rail, and air), NO₂, external safety risks, and the availability of public green space—are analyzed both separately and in combination. Not only exposures to environmental burdens (“bads”) were investigated, but also access to environmental benefits (“goods”). Additionally, we held interviews and reviewed documents to grasp the mechanisms underlying the environmental equity situation, with an emphasis on the role of public policy. Environmental equity is not a priority in public policy for the greater Rotterdam region known as the Rijnmond region, yet environmental standards have been established to provide a minimum environmental quality to all local residents. In general, environmental quality has improved in this region, and the accumulation of negative environmental outcomes (“bads”) has been limited. However, environmental standards for road traffic noise and NO₂ are being exceeded, probably because of the pressure on space and the traffic intensity. We found an association of environmental “bads” with income for rail traffic noise and availability of public green space. In the absence of regulation, positive environmental outcomes (“goods”) are mainly left up to market forces. Consequently, higher-income groups generally have more access to environmental “goods” than lower-income groups.     

Wood carbon content of tree species in Eastern China: interspecific variability and the importance of the volatile fraction

Data on the mass density and carbon content of tree organs, and in particular stem wood, are essential for accurate assessments of forest carbon sequestration. However most available data, including that for East Asia, has neglected the volatile C fraction. Wood samples were collected and assayed for C content from 14 native tree species in Jilin Province, NE China. C content showed statistically significant variation among species, ranging from 48.4% to 51.0%. The volatile C fraction was non-negligible, averaging 2.2%, and showed high variation among species. As found in prior studies, wood C content was appreciably higher in conifer than hardwood (angiosperm) species (50.8+/-0.1% vs. 49.5+/-0.2%, respectively). Wood carbon density (gC/cm(3)) showed very high inter-specific variation, due mainly to differences in wood specific gravity. Our analyses, in conjunction with recently published data from North America, indicate a global mean value of 47.5+/-0.5% wood C content exclusive of volatile C; the widely used 50% figure corresponds more closely to total wood C inclusive of the volatile fraction. Failure to include volatile C or to use species- or higher-taxon-specific C content values in forest C assessments is likely to introduce biases on the order approximately 4-6%. In addition, the stocks and flows of the volatile C fraction in wood are in themselves an important and sorely neglected aspect of forest C processes likely to be strongly impacted by harvests and other management practices.     

中国旅游业绿色发展效率时空演变特征及影响机理

绿色发展是旅游业可持续发展理念的重要组成部分,是旅游业奉行以人为本、生态至上和全面发展的新价值观。在梳理旅游业绿色发展概念及内涵基础上,构建旅游业绿色发展效率评价体系,运用SBM-Undersirable模型、核密度估计、空间马尔科夫链等方法,探讨2008—2018年中国31个省（市、自治区）旅游业绿色发展效率（TGDE）时空演化特征及影响机理。研究发现：（1）时间和空间变化方面,TGDE总体处于中等偏下水平,时间上呈“W”型变化形态,“下降—上升—调整”阶段特征显著;空间呈“东—中—西”递减分布,内部差异为西部地区>东部地区>中部地区,低、中、高效率由“金字塔”向“菱形”结构转变,高效率地区集中于东部沿海,中等效率多分布于中西部地区,低效率位于胡焕庸线两侧。（2）动态演进方面,TGDE始终存在两极分化现象,但区域协调性逐步增强,具有较强平稳性,难以实现跨越式发展,空间向上转移省份比较集中,以中西部为主,向下调整省份较少,且存在明显的空间溢出效应,溢出影响具有不对称性。（3）影响机理方面,总体上,经济水平、产业结构、政府规制、教育水平和旅游资源影响因子与TGDE间存在显著的正向关系,对外开放程度的作用不显著,但各因子的影响程度、作用机理及条件具有较强地域性。     

农业生产转型及其环境效应的研究进展与展望

农业绿色转型已经成为乡村振兴与农业农村深化改革的关键路径,亟待探索农业生产转型与其环境效应的耦合关系与机制,从而推进农业的高质量发展。近年来,学者们基于不同的空间尺度,对农业生产转型及其环境效应的过程、格局、机理与优化调控开展了广泛探讨。为系统梳理该方面研究的相关进展,识别出相应的研究不足,本文采用文献分析与系统归纳相结合的方法,分析了农业生态环境问题的识别、测度与成因等方面的研究态势,从关键要素的视角解析了农业生产转型对生态环境影响的研究进展,并对农业经济增长与农业面源污染和农业生产转型与农业生态效率的相互关系进行了总结。研究指出：未来农业生产转型及其环境效应研究应加强从系统科学的视角解读二者的互馈关系,并关注二者互馈响应的区域异质性,深化基于土地系统科学视角的耕地利用转型的环境影响研究,通过多学科交叉融合加强对中国特色“小农”生产方式转型所引发的环境问题的微观机理探析。