Soil mercury distribution in adjacent coniferous and deciduous stands highly impacted by acid rain in the Ore Mountains,Czech Republic     

《Applied Geochemistry》2016

Forests play a primary role in the cycling and storage of mercury (Hg) in terrestrial ecosystems. This study aimed to assess differences in Hg cycling and storage resulting from different vegetation at two adjacent forest stands - beech and spruce. The study site Načetín in the Czech Republic's Black Triangle received high atmospheric loadings of Hg from coal combustion in the second half of the 20th century as documented by peat accumulation rates reaching 100 μg m⁻² y⁻¹. In 2004, the annual litterfall Hg flux was 22.5 μg m⁻² y⁻¹ in the beech stand and 14.5 μg m⁻² y⁻¹ in the spruce stand. Soil concentrations and pools of Hg had a strong positive relation to soil organic matter and concentrations of soil sulfur (S) and nitrogen (N). O-horizon Hg concentrations ranged from 245 to 495 μg kg⁻¹ and were greater in the spruce stand soil, probably as a result of greater dry Hg deposition. Mineral soil Hg concentrations ranged from 51 to 163 μg kg⁻¹ and were greater in the beech stand soil due to its greater capacity to store organic carbon (C). The Hg/C ratio increased with depth from 0.3 in the O-horizon to 3.8 μg g⁻¹ in the C horizon of spruce soil and from 0.7 to 2.7 μg g⁻¹ in beech soil. The Hg/C ratio was greater at all mineral soil depths in the spruce stand. The organic soil Hg pools in beech and spruce stands (6.4 and 5.7 mg m⁻², respectively) were considerably lower than corresponding mineral soil Hg pools (39.1 and 25.8 mg m⁻²). Despite the important role of S in Hg cycling, differences in soil Hg distribution at both stands could not be attributed to differences in soil sulfur speciation.  相似文献   

黑潮主流径海域海水中的无机碳及其对东海陆架区的影响   总被引：3，自引：2，他引：1  

卢汐  宋金明  袁华茂  李宁  李学刚  段丽琴  曲宝晓 《海洋与湖沼》2016,47(1):16-28

基于2014年5—6月对黑潮主流径及毗邻东海陆架海区的调查,研究了该区域水体中无机碳体系参数(p H、总碱度TAlk、溶解无机碳DIC及DIC/TAlk)的垂直与水平分布,在此基础上定量评估了黑潮输入对东海陆架海区无机碳收支的影响。结果表明,黑潮水体中DIC、TAlk与DIC/TAlk总体而言随水深增加而升高,p H降低,综合体现了浮游植物生产、海-气界面交换、有机物降解及Ca CO3溶解等过程的影响;上升流中心站位无机碳参数均受较深层水体上涌影响,与黑潮主流径其它站位略有不同。东海陆架海区外侧站位表层、30m层无机碳主要受台湾海峡暖流影响,高p H、低DIC/TAlk的黑潮表层水影响区域局限于东南部;而在底层,低p H、高DIC/TAlk的黑潮入侵流离开黑潮主流径向正北方延伸并抬升至钱塘江口附近;上升流对无机碳的影响持续至表层,其携带的黑潮中层水因此也可能进入陆架海区。水量模型估算黑潮水在5—10月间跨域陆架边缘向东海陆架区输入溶解无机碳总计58798.9×109mol,净输入达37382.9×109mol,而东海向外输出的无机碳绝大部分经由对马海峡进入日本海。  相似文献   

Pore fluid evolution,distribution and water-rock interactions of carbonate cements in red-bed sandstone reservoirs in the Dongying Depression,China     

《Marine and Petroleum Geology》2016

The compositions, distribution and its interaction with rocks of the evolving pore fluids controls the distribution of carbonate cements and reservoir storage spaces. The reservoir quality of the red-bed sandstone reservoirs in the Dongying Depression was investigated by an integrated and systematic analysis including carbonate cement petrology, mineralogy, carbon and oxygen isotope ratios and fluid inclusions. The investigation was also facilitated by probing the mineral origins, precipitation mechanisms, pore fluid evolution and distribution, and water-rock interaction of carbonate cements and their influences on reservoir quality. Diagenetic-evolving fluids in the interbedded mudstones are the main source for the precipitation of calcite cements that completely fill the intergranular volume (CFIV calcite) with heavier oxygen and carbon isotopes. The ferro-carbonate cements in the reservoir sandstone are enriched in lighter carbon and oxygen isotopes. In addition to the cations released by the conversion of clay minerals in reservoirs, products of organic acid decarboxylation and the associated feldspar dissolution process provide important sources for such carbonate cementation. The carbon isotopes of CO₂ and the oxygen isotopic composition of fluids equilibrated with the CFIV calcite, ferro-calcite, dolomite and ankerite cements indicate that the pore in the red-bed reservoirs experienced high salinity fluids, which evolved from the early-formed interbedded mudstones, through organic acid input and to organic acid decarboxylation. Pore fluids from nearby mudstones migrated from the edge to the centre of sandbodies, causing strong calcite cementation along the sandbody boundaries and forming tight cementation zones. Pore fluids associated with organic CO₂ and acids and organic acid decarboxylation are mainly distributed in the internal portion of sandbodies, causing feldspar dissolution and precipitation of ferro-carbonate cements. The distribution of pore fluids caused the zonal distribution of carbonate cements in sandbodies during different periods. This may be advantageous to preserve the porosity of reservoirs as exemplified by the distribution of high-quality reservoirs in the red-bed sandbodies.  相似文献   

Negotiating Indigenous benefits from payment for ecosystem service (PES) schemes     

《Global Environmental Change》2016

This paper draws on research conducted with Aboriginal land managers across Northern Australia to show how and why payments for ecosystem service (PES) schemes should be framed around Indigenous rights to and relationships with their traditional estates. PES schemes offer opportunities to recognize and support Aboriginal communities' land and sea management knowledge and practices, and there is strong evidence that Indigenous communities are seeking to engage with such schemes. We focus on Aboriginal savanna landscape management, particularly traditional burning practices, to extend the ecosystem services framework to recognize Indigenous values and interactions with their lands as a critical service for Indigenous well-being. Drawing on case-study analysis of PES projects negotiated to support Aboriginal fire management programs across Northern Australia, we show how cultural ecosystem services can be applied to represent the active, dynamic and often interdependent relationships inherent in Indigenous human-environment relationships.  相似文献   

Distribution of CO2 parameters in the Western Tropical Atlantic Ocean     

《Dynamics of Atmospheres and Oceans》2016

The variability of sea surface Total Alkalinity (TA) and sea surface Total Inorganic Carbon (C_T) is examined using all available data in the western tropical Atlantic (WTA: 20°S-20°N, 60°W-20°W). Lowest TA and C_T are observed for the region located between 0°N-15°N/60°W-50°W and are explained by the influence of the Amazon plume during boreal summer. In the southern part of the area, 20°S-10°S/40°W-60°W, the highest values of TA and C_T are linked to the CO₂–rich waters due to the equatorial upwelling, which are transported by the South Equatorial Current (SEC) flowing from the African coast to the Brazilian shore. An increase of C_T of 0.9 ± 0.3 μmol kg⁻¹yr⁻¹ has been observed in the SEC region and is consistent with previous published estimates. A revised C_T-Sea Surface Salinity (SSS) relationship is proposed for the WTA to take into account the variability of C_T at low salinities. This new C_T-SSS relationship together with a published TA-SSS relationship allow to calculate pCO₂ values that compare well with observed pCO₂ (R² = 0.90).  相似文献   

A novel analysis of consumption-based carbon footprints in China: Unpacking the effects of urban settlement and rural-to-urban migration     

《Global Environmental Change》2016

Urbanization in developing countries greatly contributes to growing carbon emissions. Although studies have documented the urbanization effect, the science of consumption-based footprint assessments has yet to unpack various effects during the process of urbanization. Based on household expenditure data, this study innovatively proposes a methodology to conceptually and statistically deconstruct the observed urbanization effects on carbon footprint into selection effects and migration effects, which consist of human settlement effects and purposeful changes of migration (such as income and residential location). Applying propensity score matching and regression on the 2010 China Family Panel Study, we find that the apparent carbon-footprint difference between rural residents and migrants is about 1.5 t CO₂e per capita. The migration effects account for about 2/3 of the apparent difference and the remaining 1/3 is due to selection effects. Urban settlement effects and the purposeful changes account for 73% and 27% of the migration effects, respectively. Transport sector is the key driver of carbon-footprint growth: it accounts for 60% of the migration effects. We conclude that travel behavior of rural migrants, currently in scarcity in the lite rature, merits further investigation, and policies should emphasize transit-oriented land use and transportation to achieve low-carbon urbanization.  相似文献   

Hype among low-carbon technologies: Carbon capture and storage in comparison     

《Global Environmental Change》2016

Carbon dioxide capture and storage (CCS) technology has become a crucial part of climate change mitigation strategies around the world; yet its progress has been slow. Some have criticised CCS as a distracting hype, even as mainstream support continues. This article adapts the literature on technological hypes to develop a framework suitable for technologies with limited media/public exposure, such as CCS. It provides a qualitative context and analyses seven quantitative indicators of hype that are largely internal to the CCS technology regime. Throughout, the article contrasts results for CCS with those of comparable technologies. The main findings, which support the view that CCS has been hyped, are as follows. “Expectations” mounted rapidly in the form of project announcements for electricity applications of CCS and deployment forecasts in influential reports. However, announcements soon plummeted. “Commitments” remained high, nonetheless, judging by allocations in public budgets and number of peer-reviewed publications. Meanwhile, “outcomes”—in terms of patents, prototypes and estimated costs—reveal few if any improvements for CCS. Considering these findings and the characteristics of CCS, its development is likely to be more difficult than initially expected. Accordingly, this article calls for decisively prioritising CCS for industrial and, potentially, bioenergy uses. Coal- and gas-fired power plants may be replaced by non-CCS technologies, so power CCS development is far less pressing.  相似文献   

Greenhouse gas emissions from soils—A review     

《Chemie der Erde / Geochemistry》2016,76(3):327-352

Soils act as sources and sinks for greenhouse gases (GHG) such as carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). Since both storage and emission capacities may be large, precise quantifications are needed to obtain reliable global budgets that are necessary for land-use management (agriculture, forestry), global change and for climate research. This paper discusses exclusively the soil emission-related processes and their influencing parameters. It reviews soil emission studies involving the most important land-cover types and climate zones and introduces important measuring systems for soil emissions. It addresses current shortcomings and the obvious bias towards northern hemispheric data.When using a conservative average of 300 mg CO₂e m⁻² h⁻¹ (based on our literature review), this leads to global annual net soil emissions of ≥350 Pg CO₂e (CO₂e = CO₂ equivalents = total effect of all GHG normalized to CO₂). This corresponds to roughly 21% of the global soil C and N pools. For comparison, 33.4 Pg CO₂ are being emitted annually by fossil fuel combustion and the cement industry.  相似文献   

Forest offsets and the California compliance market: Bringing an abstract ecosystem good to market     

《Geoforum》2016

Improved Forest Management (IFM) projects under the California cap-and-trade market allow production of new, non-traditional commodities: forest carbon offsets. Earlier analyses have considered forest offsets generated through tree planting in the Global South, as vehicles for sustainable development. However, the California IFM program is testing offset production in new geographic and forest management contexts: with offsets produced and consumed within the US on working (timber producing) forests. With data drawn from California IFM project design documents and in-depth interviews with carbon project developers, this study traces the development, sale, and maintenance of forest offsets, in order to map access to benefits along the commodity chain. Results reveal that the cost and complexity of rendering biological services ‘real’ for market legitimacy are reducing benefits to marginal landowners, who lack needed capital, knowledge, and technology to bring offsets to market. An important insight of this study is that the state has maintained power over program participation and offset supply through control of the forest offset methodology, creating a production process largely mediated by the state, adding risk and uncertainty to market participation. Findings provide an empirical example of neoliberal nature and offer broader lessons on governance and benefit distribution for ecosystem service commodity chains.  相似文献   

朝鲜平南盆地埃迪卡拉系-下寒武统地层碳同位素特征   总被引：2，自引：1，他引：1  

金明哲  杨正赫  彭澎  翟明国  朴贤旭  冯连君  李忠日  朱成赫 《岩石学报》2016,32(10):3180-3186

中朝古陆(华北古陆)平南盆地位于朝鲜半岛中部,广泛发育新元古界-古生界地层。根据化石记录,一般认为燕滩群(自下而上包括飞狼洞组和棱里组)主体属于埃迪卡拉系,黄州(超)群坪山组和中和组主体属于下寒武统。然而,该套地层记录的新元古界-古生界界线处在什么位置,燕滩群是否记录冰期事件(如,Gaskiers冰期),尚有争议。本文对这些地层开展了碳、氧同位素分析。结果表明,飞浪洞组δ13C值从底部+2‰开始,在+2‰和+6‰之间变化,最上部为+2‰;棱里组从下到上从0降至-7‰;坪山组在-3.1‰~0‰之间变化;中和组基本上在-1.2‰~+1.9‰范围变化。这些数据表明,原先认为有冰碛岩的飞浪洞组可能没有记录Gaskiers冰期;棱里组δ13C值与Gaskiers或Marinoan等冰期不可对比,而可能对应于埃迪卡拉系最末期的负漂移。通过将平南盆地燕滩群-黄州群地层碳同位素值变化趋势与国际地层对比,明确地层时代属于埃迪卡拉系末期-下寒武统;由于不存在明确的的不整合,燕滩群-黄州群地层可以作为这一时期连续剖面。我们认为黄州群坪山组底部含磷、含金属硫化物黑色板岩可以作为界线标志层。  相似文献