上海市城区非渗透性地面径流的污染特性研究

通过2003～2005年连续3 a对上海市城区非渗透性地表径流的采样与检测,获得了19个采样点56组径流水样污染物（COD、BOD₅、SS、NH⁺₄-N、TP、TN）浓度随降雨历时的变化过程线.据此分析了径流污染物浓度的变化规律及其与降雨特性之间的关系,计算了地表径流水质的事件平均浓度,分析了事件平均浓度的分布规律及其与降雨特性参数之间的相关关系.研究表明,上海市区非渗透性地面径流事件平均浓度中值（mg/L）为：COD 205,BOD₅ 68,SS 185,NH⁺₄-N 3.14,TP 0.40,TN 7.23,大大高于法国巴黎同类研究的结果;BOD₅与COD的比值约为0.37,明显高于发达国家相关监测的结果.结果表明,上海市城区地表径流污染严重,即使实现了理想的分流制也难以控制面源污染对城市水环境的危害.     

论水污染物排放许可证制度的法律规制——《中华人民共和国行政许可法》在水污染防治中的作用

我国部分地方规定了水污染物排放许可证制度,由于此类法律文件法律效力的低层级性,制约着水污染防治的司法与执法实践。提高设定该制度法律文件效力位阶,不仅可以解决调整该制度法制不统一状况,而且为其进行法律规制提供了直接、具体的法律依据。对促使排污主体科学、合理排污将起到积极作用。     

生物炭施用对农田土壤团聚体及有机碳影响的整合分析

生物炭作为一种土壤改良剂,已广泛用于农田土壤的改善.为明确生物炭对我国农田土壤固碳效应的影响,基于已公开发表的文献数据,利用Meta分析法研究生物炭施用在不同试验条件下对土壤团聚体、团聚体碳和土壤有机碳的响应.结果表明,与不施生物炭相比,施用生物炭显著增加土壤大团聚体比例（10.8%）和平均重量直径（MWD,13.3%）,对土壤微团聚体和粉黏粒组分无显著作用;施用生物炭能够显著增加土壤各粒径团聚体碳和土壤总有机碳含量,土壤有机碳增幅为56.9%.通过亚组分析和Meta回归分析表明,华北地区施用生物炭土壤有机碳增幅最大（39.4%）;不同试验类型下施用生物炭均能显著提高土壤有机碳含量;相比不施肥,施肥条件下施用生物炭能显著改善土壤结构,提升土壤肥力;生物炭在施用>2 a条件下,能显著提高大团聚体比例（15.7%）、MWD （21.2%）、大团聚体碳（31.7%）和土壤有机碳含量（40.0%）;相比木材、木屑等原料制备的生物炭,农作物秸秆制备的生物炭对土壤的改良效果更佳;在高氮土壤中施用生物炭更有利于提高土壤团聚体稳定性.综上所述,生物炭施用可以改善土壤团聚结构,促进土壤有机碳积累,对农田肥力维持与提升具有重要意义.     

典型有色金属矿山城市小河流沉积物重金属形态分布及风险评估

采用改进的Tessier连续提取法分析了铜陵市惠溪河表层沉积物中7种重金属(Cd、Cr、Cu、Zn、Ni、Pb、As)的形态分布,并以风险评价编码法(RAC)和平均沉积物质量基准系数法(SQG-Q)对沉积物重金属污染程度和生态风险进行评价.结果表明:①Cr和As主要以残渣态存在,Zn、Ni和Pb主要以残渣态和Fe-Mn氧化物结合态存在,Cu主要以有机结合态存在,Cd有机结合态的质量分数较低,其它几种形态大体接近.②Cd、Cr、Cu、Zn、Ni、Pb和As有效态的质量分数分别为46.48%、4.62%、4.05%、4.12%、9.17%、0.97%和0.03%;按照RAC判定,Cd对环境构成高风险,Cr、Cu、Zn和Ni的环境危害处于低风险水平,Pb和As则无风险.③惠溪河沉积物SQG-Q均值为10.42,远大于1.0,表明该河流具有非常高的潜在生物毒性效应;Cd、Cr、Cu、Zn、Ni、Pb和As的PEL-Q系数分别为4.23、1.14、20.75、6.04、2.33、4.58和41.71,表明7种重金属的潜在生物毒性很大,不利生物效应将频繁发生.     

巢湖流域SRTM高程误差的空间分异研究

数字高程模型是进行地学研究的重要基础数据,SRTM、DEM是公众可以免费获取的精度达90m的DEM数据.以我国1:5万DEM为参考数据,以巢湖流域为研究区,利用高程中误差模型和单位面积土地填挖方对SRTM、DEM进行高程精度研究,并分析了高程误差的空间分异规律.结果表明,SRTM、DEM的高程中误差和单位面积土地填挖方随着地貌类型的变化呈现明显的空间分异性,这主要由于SRTM像元精度不高所致.在研究区内的33块样区中,绝大部分都是在二级精度评价标准之内,可见SRTM、DEM整体精度较高.     

Evaluating weather effects on interannual variation in net ecosystem productivity of a coastal temperate forest landscape: A model intercomparison

Forest productivity is strongly affected by seasonal weather patterns and by natural or anthropogenic disturbances. However weather effects on forest productivity are not currently represented in inventory-based models such as CBM-CFS3 used in national forest C accounting programs. To evaluate different approaches to modelling these effects, a model intercomparison was conducted among CBM-CFS3 and four process models (ecosys, CN-CLASS, Can-IBIS and 3PG) over a 2500 ha landscape in the Oyster River (OR) area of British Columbia, Canada. The process models used local weather data to simulate net primary productivity (NPP), net ecosystem productivity (NEP) and net biome productivity (NBP) from 1920 to 2005. Other inputs used by the process and inventory models were generated from soil, land cover and disturbance records. During a period of intense disturbance from 1928 to 1943, simulated NBP diverged considerably among the models. This divergence was attributed to differences among models in the sizes of detrital and humus C stocks in different soil layers to which a uniform set of soil C transformation coefficients was applied during disturbances. After the disturbance period, divergence in modelled NBP among models was much smaller, and attributed mainly to differences in simulated NPP caused by different approaches to modelling weather effects on productivity. In spite of these differences, age-detrended variation in annual NPP and NEP of closed canopy forest stands was negatively correlated with mean daily maximum air temperature during July-September (T_amax) in all process models (R² = 0.4-0.6), indicating that these correlations were robust. The negative correlation between T_amax and NEP was attributed to different processes in different models, which were tested by comparing CO₂ fluxes from these models with those measured by eddy covariance (EC) under contrasting air temperatures (T_a). The general agreement in sensitivity of annual NPP to T_amax among the process models led to the development of a generalized algorithm for weather effects on NPP of coastal temperate coniferous forests for use in inventory-based models such as CBM-CFS3: NPP′ = NPP − 57.1 (T_amax − 18.6), where NPP and NPP′ are the current and temperature-adjusted annual NPP estimates from the inventory-based model, 18.6 is the long-term mean daily maximum air temperature during July-September, and T_amax is the mean value for the current year. Our analysis indicated that the sensitivity of NPP to T_amax was nonlinear, so that this algorithm should not be extrapolated beyond the conditions of this study. However the process-based methodology to estimate weather effects on NPP and NEP developed in this study is widely applicable to other forest types and may be adopted for other inventory based forest carbon cycle models.     

付老文泡湿地贴地气层中CO_2日平均浓度沿环境梯度的空间分异特征

以付老文泡湿地为研究区,在典型样带内设置具有不同环境梯度的六个观测区,研究了样带内贴地气层CO2日平均浓度的空间分异特征。结果表明,付老文泡湿地在7月份的贴地气层CO2日平均浓度较低,总平均值为264.14μmol/mol;付老文泡湿地最大CO2日平均浓度出现在近地面层,CO2日平均浓度由近地面层向上呈现下降趋势。在四个高度水平上,CO2日平均浓度的水平分异特征明显,高值区和低值区分别出现在洼地和高地。在水分梯度作用下,洼地区内CO2日平均浓度在四个高度水平上均表现为样地A<样地B<样地C,且在垂直方向上均呈现出由近地层向上呈先减后增再骤然减少的变化趋势;样地D和样地E的CO2日平均浓度在垂直方向上变化趋势一致,由近地层向上呈现逐渐减少的变化趋势;而样地F的CO2日平均浓度的垂直变化不明显。     

A forest pathogen drives change in plant functional trait composition in the Southwest Australian Floristic Region

Plant functional traits weighted by cover-abundance have been used to measure change across a wide range of temperature, moisture and grazing gradients. We use this approach along a chronosequence of disease infestation (Phytophthora cinnamomi) in the species-diverse Banksia woodlands of the Southwest Australian Floristic Region (SWAFR). We compare the use of absolute (community-weighted totals-CWT) and relative cover data (community-weighted means-CWM) to demonstrate the importance of total cover change in reference to the Mass Ratio Hypothesis.Plant species cover-abundance was recorded along a space-for-time disease chronosequence, and functional trait data collected for the 48 dominant species from healthy vegetation. Six traits with deduced links to key ecosystem functions were measured for each species and values for two indices (CWT and CWM) compared along the disease chronosequence. Trait data was collected on plant height, growth form, specific leaf area, leaf dry matter content, root pattern and carbohydrate storage.Despite substantial shifts in individual species cover and a reduction in total species cover, the majority of CWM values did not change significantly following disease infestation. The use of relative cover-abundance data disregards important changes in total species cover, apparent from our comparative analysis. In contrast to CWMs, all CWT values were reduced following disease infestation, suggesting a potential reduction in productivity, reduced capacity as a carbon sink and altered site water balance. Verification of these potential changes in ecosystem functions is required using fine-scale quantitative techniques. The CWT index is complementary to traditional CWMs and useful when analysing changes in plant trait data where total species cover changes have been detected. In relation to P. cinnamomi infestation, shifts in CWT trait values indicate the ability of an introduced plant pathogen to have substantial indirect impacts beyond substantial floristic change.     

温州城市不同下垫面径流中无机氮的含量及初期冲刷效应

在温州两个采样区分别监测了4场降雨事件,选取交通干道、停车场、小区屋面、小区路面、城市排水系统汇流口、草地等6种下垫面,测定地表降雨径流中溶解铵态氮（NH＋4-N）、溶解硝态氮（NO-3-N）、溶解亚硝态氮（NO-2-N）的含量及基本理化指标.结果表明,温州城市降雨径流中NH＋4-N、NO-3-N和NO-2-N的降雨事件平均浓度（EMC）值分别介于0.40～5.55、0.01～4.70、0～0.87mg·L-1（以N计）之间,九山外河区域氮污染比山下河区域严重,交通干道、居民生活区是氮污染严重的地方,应加以重视.多数下垫面径流中溶解态无机氮以NH＋4-N为主,比例可达50%以上,九山外河区域各下垫面径流中NH＋4-N普遍超过了地表水环境V类水标准.除小区路面以外,各下垫面径流多次出现NH＋4-N的初期冲刷效应,仅小区屋面和汇流口径流中出现过NO--N初期冲刷效应.