阴离子树脂—活性炭吸附石墨炉测定铂钯

将样品用王水分解定容静置后,采用阴离子树脂—活性炭混合吸附体系进行静态吸附,将吸附体高温灰化后再以王水分解定容,用石墨炉原子吸收光谱仪测定溶液中的铂、钯.该方法检出限为铂0.084ng/g,钯0.025 ng/g,回收率铂为95％～ 103％,钯为95％～ 98％.     

碳同位素技术在湿地甲烷排放中的应用综述

碳同位素技术对碳元素在生态系统中的迁移动态具有示踪作用,有助于研究生态系统中碳元素的源与去问题,在生态系统碳循环研究中发挥着极其重要的作用。重点阐述了碳同位素技术在湿地甲烷的产生、传输过程中的应用,并对将来该方面的研究方向作出展望。     

Dynamics of coarse particulate matter in the turbidity maximum zone of the Gironde Estuary

There is a lack of studies devoted to coarse particulate matter (CPM) in estuaries, although this fraction can disturb activities that filter large volumes of water, such as industrial or fishery activities. In the macrotidal and highly-turbid Gironde Estuary, a monthly sampling of CPM was performed in 2011 and 2013 at two stations in the Turbidity Maximum Zone (TMZ) to understand its seasonal, tidal and hydrological dynamics. Regardless of the season and station, low quantities of CPM (few g m⁻³) were observed in comparison with suspended particulate matter (several 10³ g m⁻³). The highest concentrations were consistently recorded in bottom waters and at the upstream station. Whereas there is no clear link between the CPM present in the column water and spring or neap tides, an increase in the CPM size has been identified at the two stations after a flood event, fact potentially critical regarding filtering functioning of estuarine activities.     

Particle flux across the mid-European continental margin

Results are presented from particle flux studies using sediment trap and current meter moorings along a transect at the European continental margin at 49°N within the EU-funded Ocean Margin Exchange (OMEX) project. Two moorings were placed, at the mid- and outer slope in water depths of 1500 and 3660 m, with traps at 600 and 1050 m and at 580, 1440 and 3220 m, respectively. Residual currents at the mid-slope follow the slope contour, whereas seasonal off-slope flow was registered at the outer slope. At 600 m on the slope fluxes are similar to those in the abyssal North Atlantic. The flux of all components (bulk dry weight, particulate organic and inorganic carbon, lithogenic matter and opal) increased with water depth. Highest fluxes were recorded at 1440 m at the outer slope, where off-slope residual currents mediate particle export. The injection of biogenic and lithogenic particles below the depth of winter mixing results in the export of particles from shallower waters. Calculated lateral fluxes of particulate organic carbon exceed the primary flux by over a factor of 2 at 1440 m on the outer slope. Estimated lateral fluxes of suspended particulate matter in the water column and intermediate nepheloid layers at the outer slope are potentially large compared to sinking fluxes measured by sediment traps. A comparison is made of particle flux at three continental margin sites and two sites in the adjacent open North Atlantic, from which it is seen that bulk and organic matter flux increases exponentially with proximity to the shelf break. The percentage contribution of particulate organic carbon to biogenic fluxes increases from a mean of 5.7% in the abyssal N. Atlantic to 13.9% at the continental margins.     

The Application of Alkenone-Based pCO2 Reconstructions

The changing of atmospheric carbon dioxide concentration is closely related with the changing of global ice sheet,temperature and sea level. Knowledge of the past atmospheric carbon dioxide concentration and its relationship with climate is an important method of predicting the future climate change. Coccolith derived long-chain alkenone carbon isotope is one of the important proxies to reconstruct past carbon dioxide, which is wildly applied in the reconstruction of the Cenozoic atmospheric carbon dioxide. In this paper, we focused on the method of alkenone-based atmospheric carbon dioxide concentration, including the geochemical properties of long-chain alkenone, carbon diffusive model and the carbon isotope fraction. Then, we introduced the development of alkenone-based carbon dioxide proxy and its uncertainty. Coccolith cell geometry and growth rate have great influence on carbon dioxide fraction. Besides, there are some uncertainties about carbon concentration mechanisms in coccolithes, which may have some influence on alkenone-based carbon dioxide method to reconstruct ancient carbon dioxide more accurately. At the end, we summarized the Cenozoic carbon dioxide record with various proxies including alkenone carbon dioxide, boron isotope, palaeosol carbonate nodules and stomatal indices of fossil leaves.     

从科学和政策视角看碳预算对全球气候治理的作用

IPCC第五次评估报告进一步阐述和明确了全球平均地表温升与累积CO₂排放之间的近似线性关系。尽管在科学上仍存在一定的不确定性,国际社会对2℃温升目标及所对应的全球累积碳排放空间(即全球碳预算目标)已达成一定的科学认知和政治共识。但如何将碳预算从目标要求转变为各国决策和实际行动,仍是政策制定者们所面临的一个重要问题。在此背景下,提出建立一个有效的碳预算综合管理框架,努力避免人为温室气体排放导致气候系统危害,并利用其科学和政策的双重内涵,来推动谈判进程和加大行动力度,在新型气候治理模式下推动全球减排目标的实现。     

天然沸石对二氧化碳的吸附和对混合气体的分离纯化

作为燃料的沼气含有30%以上的CO₂和少量的硫化物,影响其燃烧值、污染环境。本实验利用天然沸石的吸附性能吸除CO₂和少量的硫化物、富集甲烷,效果很好。处理结果既能提高沼气燃烧值又能减少环境污染。沸石对CO₂吸附量20-30 ml/g,吸附后可以用变压的方法反复活化,反复使用。     

Methane and Carbon Dioxide Seasonal Cycles at Urban Brazilian Inland Sites

Methane and carbon dioxide seasonal cycles during years 1998 and 1999 at two Brazilian urban and inland sites are presented. The mixing ratio averages over the studied period of time were 1.80 ppm CH₄ and 384.7 ppm CO₂. A comparison is made between continental averages and theaverages of the three nearest global network background sites of NOAA-CMDL comprising Ascension Island, Namibia and Easter Island. Inland sites had 0.08 ppm or 4.9% more CH₄ and 19.0 ppm or 4.9% moreCO₂ than background over the same time span. The CH₄ summer minimum observed in remote sites was also detected inland. During the month of October 98 and 99 inland mixing ratios were frequently similar to background.     

A New Carrier Gas Type for Accurate Measurement of N$_{2}$O by GC-ECD

The accurate measurement of concentration is the basis for determining emission sources and sinks of nitrous oxide (N2O). The detection of N2O showed that the presence of carbon dioxide (CO2 biased the N2O response when pure nitrogen (N2) was used as a carrier gas for gas chromatography (GC) equipped with an electron capture detector (GC-ECD). In this study, laboratory experiments were carried out to explore how the presence of CO2 interferes with the accurate determination of N2O. The aims were to address the extent of the influence to try and explain the underlying mechanism, and to uncover technical options for solving the problem. Three GC carrier gases are discussed: pure nitrogen (DN); a mixture of argon and methane (AM); and a high concentration CO2, which was introduced into the ECD cell with a low flow rate based on DN (DN-CO2). The results show that when DN was used, the existence of CO2 in the ECD cell greatly enhanced the response of N2O, which increased with CO2 content and remained constant when the content reached a limit. Comparisons between the three methods show that the DN method is defective for the accurate determination of N2O. The bias is caused by ifferent electron capture mechanisms of CO2 and N2O and depends heavily on the detector temperature. New GC carrier gas types with make-up gases that can remove the CO2-induced influence, such as the DN-CO2 and DN-CH4 methods reported in this paper, are recommended for the accurate measurement of N2O.     

试论二氧化硅观测中标样系列的选定对观测质量的影响

本文通过对同一批次的标样系列及水样先后进行两次对比观测实验,指出标样系列的取值范围在一定程度上影响观测质量,尤其对直线首尾两端点的测值影响较大,而测值居中的则影响较小;符合所测水样系列的标样系列则可以使水样取得稳定的测值。并据此指明标样系列取值范围应尽可能遵循的原则。