NUTRIENT LOADS TO WISCONSIN LAKES: PART I. NITROGEN AND PHOSPHORUS EXPORT COEFFICIENTS1

ABSTRACT: Export coefficients (kg/km²/yr) for dissolved ortho-phosphate (OP), total phosphorus (TP), total inorganic nitrogen (TIN), and total nitrogen (TN) were derived for watersheds in Wisconsin using data bases available for 17 basins from the U.S. Environmental Protection Agency — National Eutrophication Survey, U.S. Geological Survey, and the Wisconsin Department of Natural Resources. Three general land use categories, representative of most regions in Wisconsin, were established: forest, mixed, and agricultural. Data for the 17 basins indicated greater exports of OP. TP, TIN, and TN as the percentage of forest decreased and agriculture increased. These region-specific coefficients are compared to the values reported in the literature representing much broader areas of the U.S.     

Testing hypotheses about management to enhance habitat for feeding birds in a freshwater wetland

The level of water was manipulated in a freshwater wetland, with the aim of enhancing abundances of benthic animals and, ultimately, improving habitat for feeding birds (Japanese Snipe, Gallinago hardwickii). We tested whether these actions had the predicted and desired effects on benthic animals, by contrasting changes in two managed locations to one control location which was left unmanipulated. The number of taxa and abundances of chironomids decreased strongly and significantly in the manipulated locations, while the abundance of oligochaetes appeared to vary in a seasonal manner. Temporal variability of the structure and composition of assemblages was also increased in manipulated locations. Such effects have previously been suggested to indicate stress in benthic assemblages. Therefore, in contrast to what was predicted, managerial actions made benthic fauna less abundant and thus, less suitable as habitat for feeding birds. Several general lessons can be learned from these results. (1) Effects of managerial actions like these are difficult to predict a priori and can only be reliably evaluated with an experimental framework. (2) Because abundances of animals vary naturally, evaluations of managerial actions must include appropriate spatial replication. (3) Sampling at hierarchical temporal scales is important, because abundances of animals may vary in an unpredictable manner at short temporal scales and because changes in temporal variability may be a symptom of stress. (4) Combined use of uni- and multivariate techniques provides a comprehensive set of tools to assess the effects of restoration and creation of new habitats. Finally, these results emphasise the need for clear predictions about desired outcomes and specific experimental plans about how to test whether the desired results were achieved, before managerial actions are taken. Although this is often very difficult to achieve in real situations, it is necessary for practices of management to evolve on the basis of sound empirical experience.     

AN EXAMINATION OF LAND USE - NUTRIENT EXPORT RELATIONSHIPS1

ABSTRACT: Lake and watershed management strategies and recent environmental legislation dictate that nonpoht nutrient sources associated with storm water runoff must be assessed. Accordingly, a nutrient flu assessment for phosphorus and nitrogen is conducted through an extensive literature review of nutrient export studies. These studies are reevaluated. The nutrient export coefficients are screened according to sampling design criteria and compiled according to land use. The ecological mechanisms within each land use influencing the magnitude of nutrient flux are also discussed     

TIDE GATE INFLUENCES ON A TIDAL MARSH1

ABSTRACT: Construction of a tide gate at the mouth of the north channel of the Savannah River in Georgia has resulted in significant changes in salinities influencing marsh community changes. The tide gate is directly responsible for a 2 to 6 mile upstream displacement of salt water in the river. In the marsh, soil salinities ranged from 0.0 ppt at upstream sites to 12 ppt at downstream sites when the tide gate was in operation. Within two months of taking the tide gate out of operation, interstitial salinities at the downstream sites dropped to 4 ppt. Influences of the tide gate on marsh vegetation were modeled in a geographic information system. With the tide gate out of operation, the model predicts that freshwater marsh would increase in area by 340 percent.     

Comparing Environmental Conditions Using Indicators of Pollution Hazard

/ Land use/land cover classifications for 1973 and 1991, derived from the interpretation of satellite imagery, are quantified on the basis of biophysical land units in a study area in southeastern Australia. Nutrient export potentials are estimated for each land unit based on their composition of land use/land cover classes. Spatial and temporal comparisons are made of the land units based on the calculated pollution hazard indicators to provide an insight into changes in the state of the environment and the regional significance of land use changes. For example, one ecosystem, unique to the study, showed a large increase in pollution hazard over the study period as a manifestation of an 11-fold rise in cleared area and an expansion of cropping activities. The benefits to environmental management in general are discussed.KEY WORDS: Land cover change; Nutrient export; Environmental condition; Pollution hazard; Agricultural pollution; Nonpoint source pollution; Diffuse pollution; Environmental degradation     

中国出口隐含碳排放影响因素研究——基于反事实法的分析

中间消耗的"消耗规模与部门构成"是影响中国出口碳排放的重要因素。基于世界投入产出数据库(WIOD)1995—2015年数据,在部门归类与形式变换基础上,本文选取"单位产出碳排放量"、"完全消耗系数"与"出口值"为中国出口隐含碳排放的影响因子,构建"因子变动—反事实构造—效果评价"分析框架,借助规模指数与结构指数对影响因子的变化动态进行描述,并通过反事实构造对"因子变动"的影响效果进行评价。研究发现:"单位产出碳排放量"规模指数单调递减,Spearman偏度系数为右偏态,说明相比于意愿产出而言,非意愿产出"碳排放量"具有内在的规模不经济;"中间消耗"规模指数与碳偏向性指数在截面上始终处于高位水平,时序上出现了显著的递增趋势,说明中国单位出口值的中间消耗量偏大,消耗投入在结构上偏向于高碳部门,与"技术前沿国"美国存在显著"技术差距";"出口值"规模指数呈现"平缓扩张——快速攀升——V型震荡"的阶段性特征,结构指数经历了以基期2002年为顶点、"先下降、后上升、再平稳"的变化轨迹,说明"出口值"作为最具弹性的影响因子,受"亚洲金融危机"、"加入世界贸易组织"与"美国次债危机"等外部冲击的影响明显,对出口碳排放的推动作用存在伸缩性与阶段性差异。从"因子变动"影响效果来看,中国产出、中间消耗与出口的部门构成具有内生关联,均显著偏向于高碳部门,对出口隐含碳排放增长产生了叠加性的"正向"扩张效应。基于此,本文认为,总量控制与结构优化的视角需从产品环节向中间消耗环节扩展,现阶段应深化要素市场改革,加速要素禀赋升级,借力要素价格机制与差别化产业规制政策,从上游环节抑制出口碳排放的输入来源。     

Variation in the Parameters of the Life Cycle in Prawns of the Genus MacrobrachiumBate (Crustacea, Palaemonidae)

Variations in the parameters of the life cycle in freshwater prawns of the genus MacrobrachiumBate and some populations of the species Macrobrachium nipponense(De Haan) were analyzed comparatively. Using factor analysis, these parameters were systematized and expressed through two factors. The first factor is related to the parameters of larval development and the dimensions of an egg, and the second, to the length of adults and their fecundity. The greatest differences in the values of intrageneric and intraspecific variation of parameters are noted for the dimensions of larval stages. It is assumed that the formation of a species proceeds primarily through the appearance of adaptations at larval stages.     

苯并(a)芘在四种食用淡水鱼中的含量和分布

利用GC-MS测定了购自北京市场的4种食用淡水鱼(鲫鱼、胖头鱼、鲤鱼、草鱼)的5种组织器官(脑、肝、泡、卵和肌肉)中BaP的含量,分析了BaP在4种食用淡水鱼中的分布特征及其对人体的健康风险.结果表明,鱼体BaP湿重含量范围为0～0.057ng·g-1,BaP脂标化含量范围为0.02～21·22 ng˙g-1·BaP在不同组织器官和不同鱼种中的湿重含量差别不显著;而不同鱼种和组织器官中BaP脂标化含量则有一定的差异性.4种鱼中,胖头鱼BaP脂标化含量水平最高,鲫鱼次之,草鱼和鲤鱼较低;各组织器官中,肝脏的BaP脂标化含量相对最高,肉、泡、籽次之,脑中BaP脂标化含量相对最低.鱼体中BaP湿重含量均低于USEPA规定的可食用生物组织器官中BaP含量的上限值(0.67 ng·g-1,wetweight),对人体的致癌风险远小于10-5.     

明矾石在水体微藻去除中的应用研究

以温州市某大学校区内富营养化水体为研究对象,采用本地明矾石对含藻水体进行混凝除藻、除浊实验研究,分别进行投加量、搅拌强度、搅拌时间、静置时间及pH值对微藻去除效率的影响研究,以获得处理工艺的最佳条件,为恢复河流水体生态自净功能提供理论基础.试验中对投加明矾石前后,水体中浊度、总磷、氨氮和总氮进行了测定,结果表明：明矾石最佳投加量为0.35 g/L,最佳搅拌方式为200 rpm搅拌4 min;最佳静置时间为25 min;在碱性或中性水体的处理效果尤佳.     

长江流域污染物输出对河口水质的影响

基于EFDC模型建立长江口及邻近海域三维水质模型,模拟2004—2007年不同水期的ρ(COD_Mn)、ρ(DIN)、ρ(PO₄3--P)状况,分析水质分布的变化特征,研究流域污染物输出对河口水质分布的影响. 根据GB 3097—1997《海水水质标准》,长江口门以上ρ(COD_Mn)为Ⅱ类水质,ρ(DIN)、ρ(PO₄3--P)为劣Ⅳ类,并且有明显的分层现象. 枯水期各指标等值线均向东北方向延伸,丰水期和平水期向东南延伸,丰水期流域污染物输出对河口水质的影响最大,不同类别水体的分布形态和水体面积年际变化不明显. 按不同时期ρ(COD_Mn)、ρ(DIN)、ρ(PO₄3--P)分布面积进行统计,长江口ρ(COD_Mn)、ρ(DIN)、ρ(PO₄3--P)分布与流域污染物输出之间有显著关系,河口水质分布面积与流域污染物输出之间存在定量的压力-响应关系.ρ(COD_Mn)、ρ(DIN)、ρ(PO₄3--P)达Ⅳ类以上水体面积(y)与流域污染物输出通量(x)的关系分别为:y_CODMn=2 061.4 ln x_CODMn-15 357.0,y_DIN=1 386.8 ln x_DIN-6 546.1,y_PO43--P=2 219.3 ln x_PO43--P-6 166.1.