生物滞留土壤质地与汇流比对微生物硝化、反硝化过程的影响

生物滞留是工程设计的土壤-植物-微生物共同作用的系统,可有效收集和处理城市地表径流。但是,对城市地表径流氮污染去除变化范围大。由于缺乏直接定量生物滞留反硝化微生物丰度和活性以及工程设计的影响,限制了提高氮去除的工程设计优化。我们在海绵城市建设试点常德选择了15个土壤基质质地和汇流比设计不同的生物滞留设施 (湿式生物滞留和干式生物滞留) ,通过采集土壤基质,测定生物滞留土壤基质反硝化潜势 (DEA) 和硝化潜势 (PN) ,采用qPCR定量硝化基因 (amoA) 和反硝化基因 (narG、napA、nirS、nirK、norB和nosZ) 丰度,研究生物滞留土壤质地与汇流比对微生物硝化与反硝化过程的影响。结果表明,生物滞留土壤质地与汇流比对土壤基质微生物反硝化潜势与反硝化功能基因丰度具有重要的影响。土壤基质为粘壤土和高汇流比设计的湿式生物滞留微生物反硝化功能基因与反硝化潜势显著高于壤土基质与低汇流比的干式生物滞留。湿式和干式生物滞留DEA分别为2.47 mg·kg⁻¹·h⁻¹和0.17 mg·kg⁻¹·h⁻¹,总反硝化功能基因丰度分别为1.80×10⁹ copies·g⁻¹和5.70×10⁸ copies·g⁻¹。土壤基质反硝化菌群与反硝化潜势随基质粘粒含量和汇流比升高而增加。滞水设计或处于饱和淹水状况明显可提高微生物反硝化功能。另外,微生物反硝化功能基因丰度与反硝化潜势也与土壤基质中有机碳和TN呈明显正相关。通过改进生物滞留工程设计可增加反硝化作用并减少氮向受纳水体的输出。本研究结果可为提高城市地表径流氮污染去除效果提供工程案例参考。     

硫酸钛混凝去除无机砷(Ⅲ)的效能

使用硫酸钛作为混凝剂,研究了混凝去除As(Ⅲ)过程中溶液pH值、混凝剂投加量、砷的初始浓度以及阴离子对除砷效果的影响.硫酸钛的水解沉淀物颗粒等电点为pH =5;当pH =6时,水解沉淀物的粒径最大.在pH =5 ～8范围内,As(Ⅲ)的去除率高且基本稳定;而沉淀物颗粒Zeta电位降低较大.说明水解沉淀物Zeta电位对As(Ⅲ)的去除影响不大.混凝剂投加量为2.5 ～10 mg/L时,As (Ⅲ)的去除率随投加量的增加而显著增加;混凝剂投加量大于15 mg/L时,As(Ⅲ)去除率随混凝剂投加量的增加变化趋于平缓.水中阴离子(硅酸根和磷酸根离子)的存在会降低混凝对As (Ⅲ)的去除效率.     

义乌市城镇污水提标处理的环境与经济效益分析

自2014年以来,浙江省义乌市全面推进城镇污水治理工作,在城镇污水提标处理方面开展了诸多实践。以义乌市2015年和2017年施行的污水排放标准为情境要素,结合该市9座污水处理厂实际运行数据及能耗、化学药剂和污染物排放的生命周期环境影响清单数据,模拟分析了义乌市城镇污水提标处理的环境和经济效益。结果表明,义乌市污水提标处理虽然有益于水体污染物减排,但由于既有污水处理厂普遍进水碳源不足,污水二级处理工艺需仰赖增加化学药剂投放来进行强化,使得投入了大量资金的污水提标处理并未能真正有效地解决水体污染问题,而且还会在气候变暖、土壤酸化、土壤生态毒性等方面产生负面影响。进一步地,围绕污水提标处理的强效思路、污水过度处理负面效应的缓解对策、及污水处理经济效益的增收策略进行了展望,以期为义乌市乃至我国构建经济高效、绿色低碳的污水治理模式提供参考。     

典型农业活动区土壤重金属污染特征及生态风险评价

联合野外采样和室内分析,以典型农田土壤为研究对象,分析土壤中重金属Cr、Ni、Cu、Zn、Cd、Pb、As和Hg的含量及污染特征,并采用单因子污染指数法、内梅罗污染指数法及潜在生态危害指数法,对农田土壤进行生态风险评价,同时利用主成分因子分析法,提取出3主因子,分析土壤重金属可能来源。结果表明,研究区农田土壤各重金属含量均高于背景值,表层污染程度高于底层;各重金属单因子污染指数对应污染等级均为清洁,内梅罗污染指数为0.46,污染等级为安全。潜在生态风险评估结果显示,研究区土壤重金属污染的潜在生态风险危害程度为中等,各重金属的潜在生态危害程度依次为Cd> Hg> As> Cu> Pb> Ni> Cr> Zn。主成分因子分析显示,研究区土壤中Hg、As和Cr主要由工业污染源贡献,土壤中Cd、Pb的污染主要来源于不合理的农业生产活动和居民生活,Ni、Zn和Cu与自然成土过程密切相关。综合评价表明,尽管研究区农田土壤目前重金属污染情况较轻,未达到警戒水平,但由于城市化的发展及长期现代化农业耕作活动造成农田土壤重金属的富集,因此,增强农田土壤安全性生产管理、严控土壤污染源与推行标准农业生产是十分必要的。     

气候变化对长江源地区高寒草甸生态系统的影响

近十几年来,长江源区气候暖干化趋势明显,冰川退缩、湖泊萎缩、草场退化、土地沙漠化、水土流失等环境问题日益严重。高寒草甸是长江源地区主要的植被类型之一,在全球变化影响下,以耐低温寒冷的嵩草属（Kobresia）植物为建群种的高寒草甸将面临更严重的生态胁迫。以长江源地区高寒草甸生态系统为研究对象,采用国际通用的生物地球化学模型模拟高寒草甸生物量、生产力和土壤有机质等的动态变化,并综合考虑人类活动对生态系统生产力和营养元素生物地球化学循环的影响,探讨了全球气候变化对高寒草甸生态系统可能造成的影响。     

基于生态和社会经济约束的区域土地整治潜力评价研究

准确评价区域耕地整治、农村居民点整治、废弃地复垦和未利用地开发4种类型的土地整治潜力是实现区域统筹规划和保障粮食安全的重要前提。通过选取能反映区域四种土地整治类型内在和外在潜力的指标因素,引入生态安全和社会经济双重制约条件,结合层次分析法和约束条件评价模型对研究区域生态安全和经济社会约束下的土地整治综合潜力开展定量评价,并采用K-Means聚类方法进行潜力分区。研究结果表明:高生态安全和经济发展水平条件能提高区域土地整治潜力水平,反之则制约土地整治潜力水平,同时根据约束条件的土地整治潜力评价结果将研究区域划分为土地整治高潜力区、较高潜力区、一般潜力区和低潜力区,与无约束条件下的土地整治潜力评价结果相比,该分区结果更加符合当地实际情况。该研究一方面可为生态文明建设背景下的土地整治潜力评价提供新方法,另一方面可为新一轮土地整治统筹规划提供有效的依据和参考。     

Developments in the Framing of Climate Change as a Public Health Issue in US Newspapers

News media are major channels for the transmission of information to the public and deliver news about the latest developments regarding health issues such as climate change. How the media frame such information may enhance public understanding and enable appropriate responses by individuals and communities. This study follows up on previous research examining media portrayals of climate change in US newspapers from 1 January 2007 to 31 December 2008. Here, we content analyze 270 news stories on climate change as a public health issue from five US newspapers between 1 January 2011 and 31 December 2012. Findings indicate that the total number of articles about climate change declined while emphasis on the public health dimension of climate change increased. The types of generic news frames (i.e., dramatic/substantive) most frequently used did not considerably change across the two time periods, however. To explain this, we discuss ways in which people may assess and spark change in news framing of public issues to better reach and influence a range of audiences.     

Waste Management in Guangdong Cities: The Waste Management Literacy and Waste Reduction Preferences of Domestic Waste Generators

A questionnaire survey was conducted in 2002 on 1365 households in two prefectural-level cities in the Pearl River Delta, Jiangmen and Zhongshan. Three groups of issues are covered in this paper: 1) waste management literacy, concerns, and public participation; 2) waste recycling practices and the potential for waste avoidance; and 3) public environmental literacy. This study confirms findings from previous surveys and provides new information on important issues such as imposing monetary charges on waste and environmental activities, littering, source separation programs (SSPs), and public participation and expectations in local waste management. Saving up recyclable materials for redemption in waste depots is commonly practiced in mainland China regardless of the level of development of a city, although at the household level, high-income families tend to place less value on the revenues to be gained from redemption than lower income groups do. Data from the previous and the present studies indicate that such voluntary but largely economically driven waste recovery behavior diverts at least 10% of the household waste from the waste stream. Although uncompensated SSP is less appealing in the two cities than compensated SSP, it was found that when the median per capita income of a city reaches RMB2000 per month, a high participation rate for uncompensated waste recovery is more likely to occur. Education and income levels are the chief factors affecting littering behavior and the potential for waste avoidance. Contrary to general belief, the local Chinese community is active in microwaste management. The concern, however, is over the inability of the grassroots bureaucracy to deal with rising expectations for waste collection services and neighborhood cleanliness.     

Adaptive introgression as a resource for management and genetic conservation in a changing climate

Current rates of climate change require organisms to respond through migration, phenotypic plasticity, or genetic changes via adaptation. We focused on questions regarding species’ and populations’ ability to respond to climate change through adaptation. Specifically, the role adaptive introgression, movement of genetic material from the genome of 1 species into the genome of another through repeated interbreeding, may play in increasing species’ ability to respond to a changing climate. Such interspecific gene flow may mediate extinction risk or consequences of limited adaptive potential that result from standing genetic variation and mutation alone, enabling a quicker demographic recovery in response to changing environments. Despite the near dismissal of the potential benefits of hybridization by conservation practitioners, we examined a number of case studies across different taxa that suggest gene flow between sympatric or parapatric sister species or within species that exhibit strong ecotypic differentiation may represent an underutilized management option to conserve evolutionary potential in a changing environment. This will be particularly true where advanced‐generation hybrids exhibit adaptive traits outside the parental phenotypic range, a phenomenon known as transgressive segregation. The ideas presented in this essay are meant to provoke discussion regarding how we maintain evolutionary potential, the conservation value of natural hybrid zones, and consideration of their important role in adaptation to climate.     

Identifying Reefs of Hope and Hopeful Actions: Contextualizing Environmental, Ecological, and Social Parameters to Respond Effectively to Climate Change

Abstract:  Priorities for conservation, management, and associated activities will differ based on the interplay between nearness of ecosystems to full recovery from a disturbance (pristineness), susceptibility to climate change (environmental susceptibility [ES]), and capacity of human communities to cope with and adapt to change (social adaptive capacity [AC]). We studied 24 human communities and adjacent coral reef ecosystems in 5 countries of the southwestern Indian Ocean. We used ecological measures of abundance and diversity of fishes and corals, estimated reef pristineness, and conducted socioeconomic household surveys to determine the AC of communities adjacent to selected coral reefs. We also used Web-based oceanographic and coral mortality data to predict each site's ES to climate warming. Coral reefs of Mauritius and eastern Madagascar had low ES and consequently were not predicted to be affected strongly by warm water, although these sites were differentiated by the AC of the human community. The higher AC in Mauritius may increase the chances for successful self-initiated recovery and protective management of reefs of this island. In contrast, Madagascar may require donor support to build AC as a prerequisite to preservation efforts. The Seychelles and Kenya had high ES, but their levels of AC and disturbance differed. The high AC in the Seychelles could be used to develop alternatives to dependence on coral reef resources and reduce the effects of climate change. Pristineness weighted toward measures of fish recovery was greatest for Kenya's marine protected areas; however, most protected areas in the region were far from pristine. Conservation priorities and actions with realistic chances for success require knowledge of where socioecological systems lie among the 3 axes of environment, ecology, and society.