Making ends meet, in the household and on the planet

Policy-making in relation to sustainable development is usually at the national (or, in relation to climate change, the global) level, yet the consumption it seeks to modify takes place at the household level. If households all ‘made ends meet’ in the same way then the much-relied upon notion of per capita consumption would be valid and we could rely on ‘top-down’ modelling to guide policy. Cultural Theory, however, predicts that there are five socially viable ways of making ends meet, and that all of them will be found (in varying proportions) within any nation. This prediction has been tested on a sample of 220 British households and shown to be well supported. Top-down modelling, it is argued, has to give way to a constructive interplay between the reflexive policy-maker and a plurally responsive citizenry. This revised version was published online in August 2006 with corrections to the Cover Date.     

Hydrogen and oxygen isotope studies of metamorphic fluid-rock interactions in the Dabie Mountains

Hydrogen and oxygen isotope studies were carried out on mineral separates from high to ultrahigh pressure metamorphic rocks at Huangzhen and Shuanghe in the eastern Dabie Mountains, East China. The δ¹⁸O values of eclogites cover a wide range of −5‰ to+9‰, but the δD values of micas fall within a narrow range of −85% to −70‰. Both equilibrium and disequilibrium oxygen isotope fractionations were observed between quartz and the other minerals, with reversed fractionations between omphacite and garnet in some eclogite samples. The δ¹⁸ O values of −5‰ to −1‰ for some of the eclogites represent the oxygen isotope compositions of their protoliths which underwent meteoric water-rock interaction prior to plate subduction. The preservation of oxygen isotope heterogeneity in the eclogites implies a channelized flow of fluids during progressive metamorphism caused by rapid subduction. Retrograde metamorphism has caused oxygen and hydrogen isotope disequilibria between some of the minerals, but the fluid for retrograde reactions was internally buffered in the stable isotope compositions. Project supported by the Chinese Ministry of Science and Technology (Grant No. 95-Pre-39), the National Natural Science Foundation of China (Grant Nos. 49794042, 49473173 and 49453003) and the Chinese Academy of Sciences (Grant No. KZ951-A1-401-5)     

溶解氧对低洼盐碱地鱼塘物质循环的影响

对黄淮海平原低洼盐碱地鱼塘中溶解氧与物质循环之间的关系进行了初步研究. 结果表明池塘水体中的溶解氧含量取决于水体中藻类的光合作用及其它生物的耗氧作用扰动的方式时间可显著改变水体中溶解氧的含量. 池塘水体中异养细菌的数量变动除与水体中的有机物质含量等有关外与水体中溶解氧的含量密切相关. 尤其在底泥中这种变化更加明显. 池塘水体中的氨化作用强度磷的转化强度明显地呈现出受水体中的溶解氧含量影响. 当水体中的溶解氧含量增加时导致细菌的现存量及活性的增加使得氨化作用强度磷的转化强度也显著增加这种情况在底泥中表现的更加明显. 池塘水体中反硝化作用强度反硫化作用强度的变化则与水体中溶解氧含量的变化相反. 当水体中溶解氧的含量减少时水体中的反硝化作用强度反硫化作用强度反而大大增加. 这种作用在底泥中表现得也非常明显.     

pH胁迫对菲律宾蛤仔(Ruditapes philippinarum)耗氧率、排氨率、免疫和抗氧化酶活性以及组织形态的影响

随着人类工业迅速发展, CO2大量排放,引起了海洋的酸化效应,不仅导致了全球气候变暖,也严重危害了海洋生物的生态健康。以菲律宾蛤仔(Ruditapes philippinarum)为研究对象,研究pH变化对菲律宾蛤仔耗氧率、排氨率、鳃组织结构以及鳃和内脏团的免疫、抗氧化酶活性的影响。将菲律宾蛤仔置于酸化海水(pH 6.4、7.1和7.7)中,以自然海水(pH 8.1)为对照。结果表明:耗氧率和排氨率随着pH的升高或降低而降低,在pH=8时达到最大值; 6.4酸化组蛤仔鳃组织结构损伤严重,鳃丝间距扩大,纤毛黏合;鳃组织碱性磷酸酶(AKP)第42天所有酸化组活性显著高于对照组(P<0.05),所有酸化组溶菌酶(LZM)和酸性磷酸酶(ACP)活性显著低于对照组(P<0.05), 7.7酸化组超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)活性和总抗氧化能力(T-AOC)显著高于对照组(P<0.05),所有酸化组丙二醛(MDA)含量显著低于对照组(P<0.05);内脏团7.1和7.7酸化组LZM活性显著高于对照组(P<0.05),...     

北部湾防城港东湾白骨壤潮滩近底层动力响应台风作用的耗散过程

揭示极端天气影响的红树林潮滩潮流能量耗散过程是理解生物海岸演变及滨海湿地生态修复工程的核心内容。以北部湾防城港东湾白骨壤红树林潮滩为例,基于声学多普勒流速仪（ADV）获取区域2020年8月连续6天的水动力和白骨壤红树林下垫面植被实测数据,分析白骨壤潮滩近底层动力响应台风“森拉克”的耗散过程。结果表明：1）正常天气涨、落潮期间,自光滩到白骨壤红树林林内近底层湍流动能变化具有潮汐不对称性特征。涨潮期间光滩—白骨壤红树林边缘、白骨壤红树林边缘—林内潮流挟沙能量分别通过泥沙沉降以及搬运泥沙两种方式沿程消耗,落潮期间潮流挟沙能量主要以泥沙净沉降的方式消耗。2）白骨壤通过其潮滩表层向上发育长约10 cm的呼吸根以降低湍流垂向紊动;红树林边缘的枝、叶通过影响水平方向上的水流动力,致使潮流挟沙能耗降低。3）与正常天气比较,台风“森拉克”期间东湾自光滩到白骨壤红树林林内近底层水体流速无明显变化,但流向偏转幅度明显变大。同时湍流动能的耗散率和用以搬运泥沙为主的潮流挟沙能耗亦均增大。     

黄壁庄水库降水效应的分析

南极洲万达盐湖为饱和方解石湖水。计算出的方解石饱和指数随水深增加而变化。在Ca~(2+)及HCO_3~-活度值均一的上部氧化环境湖水中,pH及溶解氧(DO)是控制该变化的主要因素,在下部还原环境湖水中,Ca~(2+)及HCO_3~-的活度对方解石的饱和指数SI的变化起主要作用。这充分揭示了湖底部近代沉积物中分布较多方解石矿物的原因。     

香港一富营养河港内的底泥耗氧和营养盐释放

Tolo Harbour has received massive discharges of municipal sewage, agricultural wastes and cottage industrial effluents, via three river systems, in the past two decades before the mid Eighties. The Harbour is almost land locked and poorly flushed. The soft sediment acted as a sink for nutrients and organic pollutants. After a decade of efforts in establishing and enforcing water pollution control legislations and upgrading wastewater treatment facilities, the sediments have turned into sources of nutrients and exert a measurable oxygen demand upon the overlying waters. In vitro measurements showed that the sediments oxygen demand (SOD) was between 17.6 and 54.3 mgo₂ · m^-2 · h^-1. The maximum rates of release of ortho-phosphate phosphorus and ammonia nitrogen were 15.0 and 206.0 mg · m^-2 · h^-1, respectively.     

基于极化相干矩阵的河流水质污染监测初探

利用遥感手段监测水质污染具有监测范围广、实时性强的优点。本研究选择中国南方地区水质变化明显的河流区域作为研究对象,利用C波段星载极化合成孔径雷达(极化SAR)卫星RADARSAT-2提供的数据,对基于极化SAR的河流水质污染监测技术进行了初步研究。首先介绍了电磁波的极化现象以及极化SAR的基本原理;其次结合一次同步测量实验,提取河流区域,并对极化SAR数据与水质常见监测指标的监测数据进行对比分析,通过对10个采样点18组数据的分析发现,极化相干矩阵中的T 22元素与部分水质指标(如五日生化需氧量BOD₅等)具有较强的相关性,从而反映水质的污染状况;并通过实测数据和最小二乘法,拟合得到了利用[T]矩阵元素反演BOD₅的经验公式,拟合系数达到0.82。最后通过对地表散射模型和菲涅尔系数的分析,从理论上探讨了极化相干矩阵中部分元素与水体物理性质存在相关性的原因。初步理论分析和实验数据表明,T 22元素能够反映水体的污染状况。     

基于植物昼夜释氧变化规律的复合垂直流人工湿地氮形态

为了研究植物根系释氧规律对人工湿地中硝化与反硝化作用的影响,采用传统连续运行方式及根据释氧规律调节的新型运行方式(白天连续进水、夜间停水),在复合垂直流人工湿地小试系统中进行实验,采用代表性的挺水植物香蒲作为湿地植物,水力负荷为0.71 m3/(m2.d).结果表明:系统内白天以好氧的硝化作用为主,夜间以厌氧、缺氧的反硝化作用为主,且在新型运行方式下,系统内白天亚硝酸盐氮累积量为传统运行方式的5倍,硝酸盐氮累积量为其2倍,夜间亚硝酸盐氮和硝酸盐氮减少量又分别比传统运行方式高64%和26%.这说明在新型运行方式下,人工湿地脱氮效果优于传统运行方式.     

天山天池水体季节性分层特征

于2014年6-10月,对高山深水湖泊天山天池水温、电导率、溶解氧、p H值、叶绿素a浓度和蓝绿藻细胞密度进行垂直剖面的连续监测,通过对其季节动态和垂直分层结构的分析,探讨天池水体季节性分层特征.天池出现明显水温分层的时间短(6-9月),夏季温跃层变化范围为2~18 m,而秋季温跃层不断下移,10月在18 m水深以下;受水温分层影响,天池水体溶解氧浓度、电导率、p H值、叶绿素a浓度和蓝绿藻细胞密度在垂直剖面表现出明显的季节性分层,尤其是夏季水温分层影响溶解氧浓度、叶绿素a浓度和蓝绿藻细胞密度在水体中的分布,对天池水质变化产生重要影响.天池浅水层(水深小于10 m)溶解氧浓度较高(大于8 mg/L),而深水层(水深超过18 m)溶解氧浓度9月接近4 mg/L,季节性缺氧导致底泥营养盐向上扩散,对水体水质产生不利影响.所以,应在夏、秋季节加强水质监测,以防止天池水华发生;天池叶绿素a浓度与蓝绿藻细胞密度的垂直剖面变化趋势相似,均随水深增加呈先增加后减小的趋势,但叶绿素a浓度在2~12 m水深处较高,蓝绿藻细胞密度在5~15 m水深处较高,表明5~15 m深度适合藻类生长,同时,电导率、p H值的垂直变化也说明藻类的生长情况,这为监测天池水体富营养化取样和分析提供依据.