Sediment processes and mercury transport in a frozen freshwater fluvial lake (Lake St. Louis, QC, Canada)

An open-bottom and a closed-bottom mesocosm were developed to investigate the release of mercury from sediments to the water column in a frozen freshwater lake. The mesoscosms were deployed in a hole in the ice and particulate mercury (Hg_P) and total dissolved mercury (TDHg) were measured in sediments and in water column vertical profiles. In addition, dissolved gaseous mercury (DGM) in water and mercury water/airflux were quantified. Concentrations of TDHg, DGM, and mercury flux were all higher in the open-bottom mesocosm than in the closed-bottom mesocosm. In this paper we focus on the molecular diffusion of mercury from the sediment in comparison with the TDHg accumulation in the water column. We conclude that the molecular diffusion and sediment resuspension play a minor role in mercury release from sediments suggesting that solute release during ebullition is an important transport process for mercury in the lake.     

The sea–air exchange of mercury (Hg) in the marine boundary layer of the Augusta basin (southern Italy): Concentrations and evasion flux

The first attempt to systematically investigate the atmospheric mercury (Hg) in the MBL of the Augusta basin (SE Sicily, Italy) has been undertaken. In the past the basin was the receptor for Hg from an intense industrial activity which contaminated the bottom sediments of the Bay, making this area a potential source of pollution for the surrounding Mediterranean. Three oceanographic cruises have been thus performed in the basin during the winter and summer 2011/2012, where we estimated averaged Hg_atm concentrations of about 1.5 ± 0.4 (range 0.9–3.1) and 2.1 ± 0.98 (range 1.1–3.1) ng m⁻³ for the two seasons, respectively. These data are somewhat higher than the background Hg_atm value measured over the land (range 1.1 ± 0.3 ng m⁻³) at downtown Augusta, while are similar to those detected in other polluted regions elsewhere. Hg evasion fluxes estimated at the sea/air interface over the Bay range from 3.6 ± 0.3 (unpolluted site) to 72 ± 0.1 (polluted site of the basin) ng m⁻² h⁻¹. By extending these measurements to the entire area of the Augusta basin (∼23.5 km²), we calculated a total sea–air Hg evasion flux of about 9.7 ± 0.1 g d⁻¹ (∼0.004 t yr⁻¹), accounting for ∼0.0002% of the global Hg oceanic evasion (2000 t yr⁻¹). The new proposed data set offers a unique and original study on the potential outflow of Hg from the sea–air interface at the basin, and it represents an important step for a better comprehension of the processes occurring in the marine biogeochemical cycle of this element.     

鄱阳湖生态经济区生态产业发展研究

建设鄱阳湖生态经济区是对长江流域开发建设和综合治理新模式的探索，是落实科学发展观的必然要求。鄱阳湖生态经济区的建设和发展，离不开生态产业的建设和发展。通过对鄱阳湖生态经济区生态产业发展现状分析，研究了鄱阳湖生态经济区的产业发展的理论和现实基础，探讨了生态产业运行的经济发展原则、生态友好原则和产业优化原则，建立了鄱阳湖生态经济区各城镇2007年城镇辐射力模型，并根据区域经济开发“点-轴”理论，分析认为鄱阳湖生态经济区产业发展要实现从“点（南昌） 圈”式发展模式向“双核（南昌 九江）双轴（沿路和沿江）多动力”发展模式转变。在此基础上，提出了促进鄱阳湖生态经济区生态产业发展政策建议，即要做到区域内严格的空间开发管制和和谐的财政转移支付；要加大对高新技术产业的投入，大力发展新型工业；要加快新农村建设，促传统农业向现代农业转型；要依托自身优势，大力发展现代服务业.     

An Integrated Approach Towards Assessing the Value of Water: A Case Study on the Zambezi Basin

The aim of this paper is to develop a methodology for assessing the value of water in the different stages in the water cycle. It is hypothesised that if a cubic metre of water provides some benefit in some spot at a certain moment, this cubic metre of water has a certain value not only at that point in space and time, but in its previous stages within the water cycle as well. This means that, while water particles flow from upstream to downstream, water values ‘flow’ in exactly the opposite direction. The value of water in a certain place is equal to its value in situ plus an accumulated value derived from downstream. This value-flow concept is elaborated for the Zambezi basin. It is found that water produces the smallest direct economic benefits in the upper part of the Zambezi basin. However, water flows in this part of the basin − due to their upstream location − have the highest indirect values. Return flows from the water-using sectors are particularly valuable in the upstream sub-basins. The analysis shows that the value per unit of river water increases if we go from downstream to upstream. Another finding of the study is that percolation of rainwater is generally more valuable than surface runoff. Finally, a plan to export water from the river Zambezi to South Africa is evaluated in terms of its opportunity costs. The results of this study show that the value-flow concept offers the possibility of accounting for the cyclic nature of water when estimating its value. It is stressed, however, that for the current study many crude assumptions had to be made, so that the exact numbers presented should be regarded with extreme caution. Further research is necessary to provide more precise and validated estimates. This revised version was published online in July 2006 with corrections to the Cover Date.     

青海省的主要灾害类型与防灾减灾对策

论述了青海地区常见的主要灾害类型及危害，并提出了防灾减灾的对策。     

基于府际博弈的跨行政区流域水污染治理困境分析

水资源短缺和水污染是我国面临的重要环境问题.受流域自然整体性和流动性的影响,某一行政区的污染通常可以通过水体向另一个或多个行政区转移.传统理论上,人们认为造成跨行政区流域水污染治理困境的主要原因是经济增长方式、产业结构、环境执法效率和管理体制的障碍.实际上,以上因素难以从根本上解释跨行政区流域水污染的治理困境.文章运用博弈理论对流域污染治理中中央政府和地方政府之间的信号传递博弈,以及流域上下游地方政府之间的污染治理博弈进行了分析,结果表明:在区域利益、信息不对称和缺乏激励机制的影响下,地方政府很难真正履行中央政府的治理政策,而污染外部性和利益冲突则使各行政区之间难以达成合作治理,府际博弈的非理性均衡成为跨行政区流域水污染治理困境的深层次原因.鉴于此,跨行政区流域水污染治理必须理解政府的角色和行为,才能找到有效的治理对策.中央政府有必要增强政策威胁的置信度,提高监督和惩治水平,克服地方政府和污染企业达成利益同盟,并通过重复博弈建立行政区之间的流域合作治理机制.     

洞庭湖区畜禽排泄物的环境效应

洞庭湖湿地是长江中游重要的生态功能区，其生态功能的退化制约了湖区经济的可持续发展。近些年来，随着湖区集约化畜牧业的迅速发展，畜禽粪尿等排泄物对湖区生态环境构成了严重威胁。从畜禽养殖量、粪尿等污染物的年排泄量、粪便猪粪当量及负荷量、土地畜禽粪便负荷承受程度4个方面估算并分析了洞庭湖各县（市区）畜禽养殖业的环境威胁性。结果表明:2007年洞庭湖区各类畜禽粪尿排泄总量为3 17279万t，相当于猪粪当量2 92113万t。全年畜禽粪尿流失总量达1 11048万t。畜禽排泄物中年流失化学需氧量50.80万t，氨氮7. 81万t。从畜禽粪便负荷量警报值及分级结果看，畜禽排泄物对岳阳楼区、汩罗市的环境威胁比较严重，对云溪区、临澧县、武陵区、岳阳县、津市市和湘阴县生态环境亦有一定的影响。〖     

Assessment of Biological and Environmental Phenology at a Landscape Level from 30 Years of Fixed-Date Repeat Photography in Northern Sweden

A 30-year series (1978–2007) of photographic records were analysed to determine changes in lake ice cover, local (low elevation) and montane (high elevation) snow cover and phenological stages of mountain birch (Betula pubescens ssp. czerepanovii) at the Abisko Scientific Research Station, Sweden. In most cases, the photographic-derived data showed no significant difference in phenophase score from manually observed field records from the same period, demonstrating the accuracy and potential of using weekly repeat photography as a quicker, cheaper and more adaptable tool to remotely study phenology in both biological and physical systems. Overall, increases in ambient temperatures coupled with decreases in winter ice and snow cover, and earlier occurrence of birch foliage, signal a reduction in the length of winter, a shift towards earlier springs and an increase in the length of available growing season in the Swedish sub-arctic.     

洞庭湖湿地生态系统管理面临的威胁及应对策略初探

生态系统管理可以实现自然资源的多目标管理。洞庭湖湿地生态系统优越，区域内社会经济发达，但面临保护与发展的双重压力。其中，开展洞庭湖区湿地生态系统管理面临众多威胁，包括自然灾害频发、资源利用不当、工农业污染突出、自然保护能力不足以及季节性缺水等新老问题交织在一起，共同导致了洞庭湖湿地生态系统功能降低，包括生物多样性降低、调蓄能力减弱、洪渍涝灾害加剧、地下水位升高、垸老田低等现象日益突出，而且这种人类不合理活动的后效放大驱动将长期存在，危及到了湖区水产养殖的自然增殖以及自然资源基础的安全性，成为湖区社会经济发展的严重制约因素。为此，建议在遵循生态系统方法的前提下，洞庭湖地区应该加强管理体制机制创新实践，加快湿地保护的立法与执法进程，通过编制洞庭湖区中长期发展总体规划，促进各种利益相关方参与和共管洞庭湖湿地退田还湖等生态恢复工程的巩固、湿地资源合理利用、湿地产业的开发以及湖区湿地生态与环境建设，最终实现湖区生态美好、民生改善的“人地和谐     

玛纳斯河流域生态系统服务功能价值研究

土地利用/覆被变化是生态环境演变最重要的因素之一,其研究对于促进区域生态经济协调发展有重要意义。根据1976年和2006年玛纳斯河流域两期遥感影像资料,基于生态经济学的最新方法采用卫星遥感技术以及Costanza等的生态系统服务价值评价手段,对期间玛纳斯河流域生态服务系统服务功能价值变化进行分析研究。结果表明:①玛纳斯流域土地利用结构变化在30年间表现为草地、林地、不断减少,而耕地、水域、沙地和建设用地不断增加,反映出人类因素及生态环境恶化的趋势;②该流域生态系统服务功能价值总额由1976年123.831 08元减少至2006年101.521 08元。减幅:18.02%,年均减少0.741 08元,通过对玛纳斯河流域生态系统服务功能价值进行评价,为玛纳斯河流域生态开发和治理,以及环境整治提供决策依据。