Mercury partition in the interface between a contaminated lagoon and the ocean: The role of particulate load and composition

After having estimated the patterns of flow to the ocean and found some seasonal and tidal differences, mainly with regard to the relative importance of dissolved and particulate fractions, mercury partitioning at the interface between a contaminated lagoon and the Atlantic Ocean was investigated during four tidal cycles in contrasting season and tidal regimes. Mercury was found to be located predominantely in the particulate fraction throughout the year, contributing to its retention within the system. Seasonal conditions, variations in marine and fluvial signals and processes affecting bed sediment resuspension influenced the character and concentration of suspended particulate matter in the water column. Variation in the nature, levels and partitioning of organic carbon in the particulate fraction affected levels of particulate mercury as well as mercury partitioning. These results highlight the dominant role of suspended particulate matter in the distribution of anthropogenic mercury and reinforce the importance of competitive behavior related to organic carbon in mercury scavenging.     

中国二氧化碳地区间排放差异分析及减排政策建议

利用统计数据,参照政府间气候变化专门委员会（IPCC）的方法,对2008年我国各省区CO₂的排放情况进行了计算分析,并对东西部地区进行对比得出：东部发达地区在人均排放量和排放密度等方面均高于西部欠发达地区,但东部地区的排放强度却明显低于西部地区。国家经济战略,东、西部地区技术、经济社会发展水平差异是造成这一趋势的主要原因。提出了我国实现温室气体减排目标、分解减排任务的建议。     

Statistical study on great geomagnetic storms during solar cycle 23

Characteristics of great geomagnetic storms during solar cycle 23 were statistically investigated. Firstly, we focused on the uniqueness of solar cycle 23 by analyzing both the great storm number and sunspot number from 1957 to 2008. It was found that the relationship between the sunspot number and great storm number weakened as the activity of the storms strengthened. There was no obvious relationship between the annual sunspot number and great storm number with Dstxi≤-300 nT. Secondly, we studied the relationship between the peak Dst and peak Bz in detail. It was found that the condition Bz≤-10 nT is not necessary for storms with Dst≤-100 nT, but seems necessary for storms with Dst≤-150 nT. The duration for Bz≤-10 nT has no direct relationship with the giant storm. The correlation coefficient between the Dst peak and Bz peak for the 89 storms studied is 0.81. After removing the effect of solar wind dynamic pressure on the Dst peak, we obtained a better correlation coefficient of 0.86. We also found the difference between the Dst peak and the corrected Dst peak was proportional to the Dst peak.     

人类活动对土壤有机碳库的影响研究进展

土壤有机碳库动态变化直接影响全球的碳平衡, 土壤有机碳库研究是全球碳循环研究中的关键。研究人类活动影响下的土壤有机碳库的动态特征及其过程机制,不仅可降低对未来气候预测的不确定性,也可为土壤固碳技术的选择和政策制定提供理论依据。从土地利用方式变化、耕作方式与管理两方面详尽阐述了国内外关于人类活动影响下土壤有机碳库动态的研究进展,提出应加强土地管理、采取适当的农业耕作措施来减少土壤有机碳的流失,以提高土壤对碳的固定。     

凡纳滨对虾不同生长阶段食物组成结构的研究

利用稳定同位素碳比率δ13C作为天然示踪物,对高位养殖池生态系统中人工饲料和天然饵料提供的能源物质对养殖凡纳滨对虾生长的贡献比率进行研究。结果表明:虾体的δ13C值受食物δ13C值的影响,由于其摄食饵料的δ13C值逐渐减小,虾体的δ13C值也逐渐降低,逐渐接近于最后人工饲料的δ13C值,试验虾体的δ13C值由养殖开始时的-19.52‰±0.09‰变为实验结束时的-21.74‰±0.17‰;对虾的食性在10d左右时发生转变,34d左右时人工饲料和浮游动物对虾体的能量贡献基本相同,养殖结束时对虾生长能量的97.29%±0.98%来源于人工饲料。     

Geology and geochemistry of Huanggangliang stratabound skarn deposit in Inner Mongolia, China

Over the recent three decades,exploration of a large-size Sn-Fe polymetallic ore deposit at the Huanggangliang, the Da Hinggan Mountains, Inner Mongolia, China, has been largely focused on the premise that the mineralization represents epigenetic magmatic hydrothermal ore deposit in genetic connection with the Mesozoic magmatism. The Huanggangliang Sn-Fe polymetallic ore deposits occurred in Permian strata, with siltstone/marble of the Zhesi Formation and spilite/andesite/tuff of the Dashizhai Formation. The characteristics of geological and geochemical data demonstrated that sedimentary hydrothermal mineralization occurred during the basin evolution at the Permian, rather than representing epigenetic magmatic hydrothermal genesis with the following evidences. The ore-bearing skarns are stratiform with underlying metasedimentary rocks and overlying volcanic sedimentary rocks. Sedimentary hydrothermal textures and structures are observed in the stratabound ore-bearing skarn such as bedded-laminated skarn and magnetite ores with small-size folding or soft deformation, synsedimentary breccia of skarn and magnetite ores and concentric shell structure of magnetite ores. So the stratabound ore-bearing skarns associated with magnetite ore and micro-disseminated tin, are peculiar examples of exhalite. The REE contents of the stratabound ore-bearing skarns display ΣLREE-rich (36.91×10-6) but ΣHREE-depletion (6.42×10-6), with positive Eu anomaly (Eu/ Eu 1.28) and negative Ce anomaly (Ce/Ce 0.88), which is totally different from REE pattern of the Huanggang magmatic rocks(with ΣREE 277.73×10-6, ΣLREE 220.24×10-6, ΣHREE 57.49×10-6, Eu/Eu 0.06, Ce/ Ce 1.52), which is comparable with modern sea-floor hydrothermal fluid,sedimentary hydrothermal ore deposit and associated hydrothermal sedimentary rocks. Calcite samples with δ13CPDB from -5.400 ‰ to -4.397 ‰ and δ18OSMOW from 9.095 ‰ to 9.364 ‰ in the stratabound ore-bearing skarns show sedimentary hydrothermal genesis of the Huanggangliang deposit. This proposition is useful not only for interpretation of the genesis of the Huanggangliang large Sn-Fe polymetallic ore deposit but also significant for mineral exploration in the area especially for finding large deposits caused by sedimentary exhalative mineralization processes.     

Changes in soil and vegetation on moving sand dunes after exclosure in Horqin Sandy Land, Northern China

In the semiarid Horqin Sandy Land of northern China, land desertification is the main causation in vegetation degradation and formation of moving dunes. A study was conducted from 1996 to 2005 to monitor the changes of vegetation characteristics and soil properties after moving dunes were fenced. The changes were compared between moving sand dunes with exclosure and without exclosure to evaluate the effectiveness of vegetation and soil restoration after exclosure establishment. The results show that exlosure establishment facilitated the colonization and development of plant species by ameliorating stressful environmental conditions. Species diversity, average coverage, and plant density significantly increased after exclosure of moving sand dunes along sequence compared with sand dunes without exclosure. Vegetation recovery on moving sand dunes accelerated by exclosure resulted in significant changes in soil properties including increased silt and clay contents, organic C and total N and decreased sand content, especially at the 0-5 cm depth. The results implied that moving sand dunes can be rapidly fixed by construction of exclosure.     

中美商品贸易的碳排放转移研究(英文)

中美两国均为温室气体排放大国,且双边贸易额巨大。由于两国在基础设施、技术、装备水平、能源综合效率和资源禀赋上存在差异,使得通过中美商品贸易,美国将大量的碳排放转移到了中国。本文采用投入产出分析方法,结合经济、能源与贸易3个系统,建立了基于国际商品贸易的碳排放转移模型,并分别测算了1997与2002年中美商品贸易中各相应部门的碳排放转移量。研究表明:(1)1997与2002年,基于中美商品贸易的中国产业部门通过出口转移到美国的载碳量分别达到4010.13×104 与5056.21×104 t C,分别占中国相应产业部门载碳总量的6.61%与8.33%;而美国产业部门出口到中国商品的载碳量仅为290.65×104与335.61×104 t C,相应的仅占美国产业部门载碳总量的 0.53%与 0.66%;(2)1997 与 2002 年,中美商品贸易的碳转移总量分别达 3719.75×104与4719.60×104 t C,其中化学工业、金属冶炼及其压延加工业是主要的碳转移部门。(3)1997与2002年,通过国际商品贸易,美国分别有相当于其相应部门碳排放总量的6.77%与9.32%的碳被泄露到了中国,中国为美国的碳减排做出了很大的潜在贡献,因此,美国等发达国家应该为中国等发展中国家提供切实有效的气候与环境友好型技术援助。     

A comparison of annual and seasonal carbon dioxide effluxes between sub-Arctic Sweden and High-Arctic Svalbard

Recent climate change predictions suggest altered patterns of winter precipitation across the Arctic. It has been suggested that the presence, timing and quantity of snow all affect microbial activity, thus influencing CO₂ production in soil. In this study annual and seasonal emissions of CO₂ were estimated in High-Arctic Adventdalen, Svalbard, and sub-Arctic Latnjajaure, Sweden, using a new trace gas-based method to track real-time diffusion rates through the snow. Summer measurements from snow-free soils were made using a chamber-based method. Measurements were obtained from different snow regimes in order to evaluate the effect of snow depth on winter CO₂ effluxes. Total annual emissions of CO₂ from the sub-Arctic site (0.662–1.487 kg CO₂ m^–2 yr^–1) were found to be more than double the emissions from the High-Arctic site (0.369–0.591 kg CO₂ m^–2 yr^–1). There were no significant differences in winter effluxes between snow regimes or vegetation types, indicating that spatial variability in winter soil CO₂ effluxes are not directly linked to snow cover thickness or soil temperatures. Total winter emissions (0.004–0.248 kg CO₂ m^–2) were found to be in the lower range of those previously described in the literature. Winter emissions varied in their contribution to total annual production between 1 and 18%. Artificial snow drifts shortened the snow-free period by 2 weeks and decreased the annual CO₂ emission by up to 20%. This study suggests that future shifts in vegetation zones may increase soil respiration from Arctic tundra regions.     

碳足迹研究进展及其对低碳旅游研究的启示

旅游业不仅是气候变化的受害者,也是造成气候变化的重要原因。基于生命周期评价理论的碳足迹研究,可以对产品或服务从“摇篮”到“坟墓”的整个生命过程所排放的直接和间接的CO2量进行估算。通过整理国内外对碳足迹研究起源,碳足迹内涵,碳足迹分类,碳足迹研究理论与方法,区域碳足迹,碳足迹与贸易、碳足迹与家庭生活,碳足迹计算器,碳足迹标签等方面的研究,总结国内外在碳足迹研究上的差异,并从旅游碳足迹研究,低碳旅游政策,碳汇旅游,低碳旅游衡量标准等方面提出低碳旅游研究的启示。