有机组分对长石溶解和次生孔隙发育的影响

在储层温度下，长石溶解于有机组分水溶液的模拟实验提示了许多重要事实，这些事实对于含长石砂岩中次生孔隙的形成具有重要的意义。实验采用油田水中两种最常见的羧酸，一种多元羧酸和一种酚（儿茶酚）。草酸盐溶液能显著提高长石的溶解速率。但这种疚在溶液中存在钙和镁时明显受到抑制。醋酸盐的存在能有效地缓冲地下流体的ｐＨ值，进控制长石的溶解速率。在醋酸盐缓冲溶液里，当ｐＨ值由中性降为酸性时，钾长石的溶解速率增大。然     

洞穴溶解有机质组分和循环过程的季节变化特征

溶解有机质（DOM）是岩溶碳汇的关键部分和重要的碳源,但是对于DOM在岩溶含水层中的性质和代谢过程的研究仍然有限。本研究以重庆雪玉洞地下河为例,对洞穴有机碳的来源、组成以及微生物作用对季节补给源变化的响应进行探讨,为进一步了解微生物介导的有机碳转化过程提供研究基础。运用三维荧光EEM研究水体有色溶解有机质（CDOM）的性质和组分并反演地下河水中有机质的来源和组成,结合地下河水水化学特征和16S rDNA细菌群落及功能多样性的季节变化特征,以了解季节性补给源的变化对洞穴地下水DOM输入和性质的影响。结果发现,雪玉洞地下河水以微生物内源有机质为主（61%~77%）,降雨是引起岩溶给地下河水中CDOM光谱特征变化的最重要因素,雨季外源有机质输入增加,地下河水中外源有机碳组分含量和芳香性、腐殖酸类物质增加,细菌群落多样性和代谢功能基因随之变化,洞穴中向外输出的外源有机碳增加;旱季地下河水滞留时间和蒸发作用增强,因而微生物对有机质的代谢降解过程更加充分,向洞外输出的有机碳以内源为主。本研究有助于增加对岩溶洞穴地下水系统中微生物对有机碳转化过程的理解。     

外加剂与水泥掺量对有机质水泥红黏土强度的影响

在有不同外加剂的水泥加固条件下,通过三轴试验、压缩试验、无侧限抗压强度试验,探讨水泥掺量与水泥土黏聚力、内摩擦角、压缩系数及无侧限抗压强度之间的相关关系,并对试验结果进行回归分析。试验结果表明,无论在有无外加剂的条件下,水泥土黏聚力、内摩擦角、无侧限抗压强度都随水泥掺量的增加而逐渐增加,增加的幅度却逐渐变小,它们的变化趋势总体上是一致的,并且外加剂类型对它们的作用效果都表现为:高效减水剂复合早强剂早强减水剂无外加剂。但其压缩系数却随着水泥掺量的增加而近似于直线不断减小,在相同水泥掺量时,无外加剂的水泥土的压缩系数最高,早强减水剂的水泥土的压缩系数又分别大于复合早强剂、高效减水剂水泥土的压缩系数。高效减水剂对提高水泥土力学强度的效果最明显。     

溶液离子强度对自然水体生物膜吸附Pb2+和Cd2+的影响

通过改变支持电解质(NaNO3)浓度的方法来探讨自然水体生物膜对Pb2 、Cd2 的吸附机制,研究了离子强度对生物膜吸附Pb2 、Cd2 的影响以及不同离子强度下生物膜吸附Pb2 、Cd2 的热力学特征.结果表明:当NaNO3浓度在0～0.4 mol·L-1之间,随着离子强度的增加,生物膜对Pb2 和Cd2 的吸附量和最大吸附量迅速降低;当NaNO3的浓度大于0.4 mol·L-1,生物膜对Pb2 和Cd2 的吸附量和最大吸附量变化趋于平缓,说明自然水体生物膜对Pb2 和Cd2 的吸附可能同时包括电性吸附和专性吸附.此外,研究还发现当Cd2 与Pb2 共存时,Pb2 对生物膜吸附Cd2 的能力有较大影响,而Cd2 对生物膜吸附Pb2 的能力的影响并不显著.     

外加剂对桂林含有机质水泥红黏土力学性质影响的试验研究

红黏土是碳酸盐岩在湿热环境下经过风化作用形成的一种特殊性土,孔隙大、含水量高,而其结构性强且存在上硬下软的成层分布特征,上部为坚硬、硬塑状态,下部为软塑、流塑状态。水泥搅拌法因其有加固效果好、造价低、工期短、污染小等特点被广泛应用在处理软弱红黏土。近年来环境和工程地质条件不断恶化,造成大面积红黏土被有机质污染,严重影响地基的强度,但是研究表明合理使用外加剂可以改善被有机质污染红黏土的物理力学性质。本文从外加剂掺量和类型对抗剪强度、压缩系数、无侧限抗压强度等方面进行室内试验研究,得出外掺剂种类和掺量与它们之间的关系。结果表明:其间的相关性较好。     

农林生态系统的转变对土壤有机质影响的C示踪研究

生态转变系统中土壤有机质的变化与土壤的初级生产力和温室气体的释放有着密切的关系。同时 ,它也是目前农业的可持续发展和全球环境变化的研究内容之一。对于毁林造田和退耕还林等农林生态系统发生转变的特殊地点 ,土壤有机质的源物质产生了Ｃ3植物 (森林 )与Ｃ4 植物 (农作物 )的转变 ,这就为我们利用δ13Ｃ来示踪土壤有机质的迁移和赋存提供了可能。茂兰保护区曾长期生长Ｃ3植物 (常绿混叶林 ) ,近几十年 ,部分毁林后种植Ｃ4 植物 (玉米 )。本实验分别采集 3个剖面相邻的森林点和农田点的土壤样品 ,分析了样品的有机碳含量和δ13Ｃ值。     

页岩孔隙空间的形成与演化及孔隙对含气性的影响

虽然页岩气的勘探已经在北美以及中国取得了突破,但是对页岩中孔隙空间的形成与发育仍然存在较大的争议,页岩中是否存在有效的孔隙,这些孔隙与气体的赋存有何联系都需要解答。本文对不同地区、不同岩石类型以及不同热成熟度的页岩进行微观分析,对比前人的研究,同时结合四川盆地龙马溪组页岩的实际分析数据,将页岩划分为富有机质页岩和含粉砂质泥页岩。富有机质页岩中有机质纳米孔是主要的孔隙类型,同时也是气体聚集与吸附的主要空间,有机质孔隙度与有机质含量、热成熟度密切相关;含粉砂质泥页岩中以粒间、粒内溶蚀孔为主,由于有机质含量较少,因而受热成熟影响很小。对页岩的孔隙形成机理分析发现,富有机质页岩孔隙度与有机质含量呈正相关,特别是与初始有机碳含量密切相关,因此恢复初始有机碳的含量是评价页岩含气量与含气性的关键。在热演化程度较低时（Ro < 0.6%）,页岩中有机质孔隙不发育,页岩几乎不含气;随着热演化程度升高（Ro = 0.8%）,页岩微孔隙发育,此时页岩以吸附气为主;随着热演化程度增大（Ro > 1.2%）,微孔逐渐向中孔和宏观孔转化,总的比表面积减小,页岩中游离气含量开始增加,吸附气含量减少。     

湿地溶解性有机质（DOM）源识别方法研究

湿地是位于水陆生态系统之间的重要生态交错带,而溶解性有机质(DOM)是陆地向水生生态系统输送营养物质的重要载体物质。湿地中DOM的来源分为内源和外源。对湿地中DOM的来源进行识别有助于认识湿地中营养物质的生物化学循环特征,从而进一步了解水陆生态系统之间的物质循环。目前,对湿地DOM进行源识别的方法较多。根据各种方法在研究中应用的广泛性和可用性,本文主要介绍了光学法、同位素法、C/N比值法和生物标志法在湿地DOM源识别中的应用。综合分析表明,光学法、同位素法和C/N比值法在湿地DOM源识别研究中的应用较多。近几年,由于生物标志物(特别是木质素)不仅能够对来源进行识别,而且对源的变化很敏感,因此生物标志法在湿地DOM源识别中的应用成为研究的热点。论文在分析各种湿地DOM源识别方法的基础上,指出了目前研究中存在的问题,并提出进一步研究的方向。     

Spatial Variation in the Optical Properties of Dissolved Organic Matter (DOM) in Lakes on the Canadian Precambrian Shield and Links to Watershed Characteristics

In the present study, we explored the use of various optical parameters to detect differences in the composition of the dissolved organic matter (DOM) in a set of lakes that are all located on the Canadian Precambrian Shield, but within which Cu and Ni speciation predictions were previously shown to diverge from measured values in some lakes but not in others. Water samples were collected with in situ diffusion samplers in 2007 (N = 18 lakes) and 2008 (N = 8 lakes). Significant differences in DOM quality were identified between the sampling regions (Rouyn-Noranda, Québec and Sudbury, Ontario) and among lakes, based on dissolved organic carbon concentrations ([DOC]), specific UV absorbance (SUVA₂₅₄), fluorescence indices (FI), and excitation–emission matrix (EEM) fluorescence measurements. Parallel factor analysis (PARAFAC) of the EEM spectra revealed four components, two of which (C3, oxidized quinone fluorophore of allochthonous origin, and C4, tryptophan-like protein fluorescence of autochthonous origin) showed the greatest inter-regional variation. The inter-lake differences in DOM quality were consistent with the regional watershed characteristics as determined from satellite imagery (e.g., watershed-to-lake surface area ratios and relative percentages of surface water, rock outcrops vegetative cover and urban development). Source apportionment plots, built upon PARAFAC components ratios calculated for our lakes, were used to discriminate among DOM sources and to compare them to sources identified in the literature. These results have implications for other areas of research, such as quantifying lake-to-lake variations in the influence of organic matter on the speciation of trace elements in natural aquatic environments.     

长江中游沿岸地下水中有机质分子组成特征及其对碘富集的指示

长期摄入高碘地下水（碘浓度＞100 μg/L）会造成人体甲状腺机能损伤.天然有机质被认为是影响高碘地下水形成的关键组分,为研究地下水中溶解性有机质（DOM）分子组成对碘富集的影响,选取长江中游沿岸浅层地下水作为研究对象,运用傅立叶变换离子回旋共振质谱仪（FT-ICR-MS）表征不同碘浓度地下水中DOM分子组成差异.研究发现碘易富集在还原环境的浅层地下水中,地下水中碘的浓度与溶解性有机碳（DOC）浓度无显著关系,DOM分子总数越多碘浓度越高;高碘地下水较低碘水DOM分子均一性、多样性更强,氧化程度和不饱和程度更高,含更多芳香性结构.长江中游沿岸高碘地下水的形成受DOM分子组成控制,主要与不饱和程度高尤其是含芳香性结构的大分子DOM有关,含芳香性结构的DOM分子与碘络合在高碘地下水的形成过程中起重要作用.      

Dissolved organic matter (DOM) export to a temperate estuary: seasonal variations and implications of land use

Inputs of dissolved carbon, nitrogen, and phosphorus were assessed for an estuary and its catchment (Horsens, Denmark). Seasonal patterns in the concentrations of DOM in the freshwater supply to the estuary differed depending on the soil and drainage characteristics of the area. In streams draining more natural areas the, patterns observed were largely driven by seasonal temperature fluctuations. The material exported from agricultural areas was more variable and largely controlled by precipitation events. Positive exponential relationships were found between the nitrogen and phosphorus loading, and the percentage of catchment area used for agriculture. Colored DOM (CDOM) loading measurements were found to be a good predictor of dissolved organic carbon (DOC) loading across the different subcatchments, offering a rapid and inexpensive alternative of operationally monitoring DOC export. For all the dissolved nutrient inputs to the estuary, dissolved inorganic nitrogen (DIN) and dissolved organic phosphorus dominated the loadings. Although 81% of the nitrogen annually supplied to the estuary was DIN, 83% of the nitrogen exported from the estuary was dissolved organic nitrogen (DON). Results show that increasing the area of the catchment covered by forest and natural pastures would have a positive effect on the trophic status of the estuary, leading to a considerable decrease in the phosphorus loading and a shift in the nitrogen loading from DIN to DON. Such a change in land use would also increase the export of DOC and CDOM to the estuary having the potential to increase oxygen consumption and reduce the photic depth.     

土壤溶解性有机质对植物吸收-输送-贮存重金属的影响研究现状与进展

土壤溶解性有机质对重金属生物地球化学循环中的生物可利用性起着重要作用。近年来,在土壤溶解性有机质对植物吸收、输送和贮存重金属过程的影响研究领域,国际上主要聚焦于以下三个探索方向: ①土壤溶解性有机质与重金属形成配位体,改变重金属在土壤中的迁移性和植物根际环境的作用机理研究; ②土壤溶解性有机质可突破植物细胞内重金属吸附点位的限制,通过控制植物细胞壁-重金属复合体的形态及重金属在细胞壁内外的吸收平衡,来干预重金属穿过细胞壁进入植物体的动力学过程研究;③土壤溶解性有机质-重金属的络合形态影响重金属在植物体内的输送和贮存作用过程与机理研究。本文基于研究溶解性有机质和重金属的植物过程中,水体溶解性有机质研究多而土壤溶解性有机质研究少的现状,针对溶解性有机质异质性的研究难点和溶解性有机质与植物亚细胞结构的配位特征的复杂性与局限性,从极性、官能团、配位结构等角度,分析并评述了土壤溶解性有机质和重金属生物地球化学中,植物吸收、输送和贮存重金属过程的研究现状和未来发展趋势。     

一价阳离子和水溶性有机质对生物沥浸中次生铁矿物形成的影响

在嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)作用下,污泥生物沥浸体系中常会有次生铁矿物形成,这些矿物对污泥脱水和重金属溶出有重要影响。本研究模拟生物沥浸体系,考察了一价阳离子(K+、NH4+、Na+)和污泥DOM(dissolved organic matter)对次生铁矿物形成的影响。结果表明,一价阳离子生成次生黄铁矾类矿物的能力迥异,其中K+的成矾能力最强,120 mmol/L NH4+和80 mmol/L Na+会抑制体系中黄钾铁矾形成。在1.6 mmol/L K+-120 mmol/L NH4+-40 mmol/L Na+和1.6 mmol/L K+-80 mmol/L NH4+-80 mmol/L Na+两个处理所得矿物的结晶度均低于1.6 mmol/L K+-80 mmol/L NH4+-40 mmol/L Na+处理所得矿物的结晶度。另外,在50 mg/L DOM(以DOC计)存在的生物氧化体系,Fe2+最大氧化速率为4.96 h-1,比没有DOM存在时降低48.1%,矿物结晶度也明显低于后者。可见,过高的一价阳离子和DOM含量会影响A.ferrooxidans菌生理生化活性,降低Fe2+氧化速率,继而影响Fe3+供应,使微环境中的黄铁矾形成动力发生改变,最终在一定程度上影响了次生铁矿物的形成。     

Airborne Laser-Induced Fluorescence (LIF) Light Detection and Ranging (LiDAR) for the Quantification of Dissolved Organic Matter Concentration in Natural Waters

Analysis of dissolved organic matter (DOM) concentration and composition is essential to quantifying biological and chemical oxygen demand and atmosphere?Cocean heat flux exchange in natural waters. However, manual water sampling is costly and time consuming over large areas. The purpose of this research was to analyze the applicability of airborne laser-induced fluorescence light detection and ranging (LiDAR) for the detection of DOM in estuarine ecosystems impacted by agriculture. A fluorescence LiDAR system (Airborne Marine) (FLS-AM) was used to assess the DOM concentration of the Annapolis River and Basin, Nova Scotia, Canada, as well as three rivers and their estuaries in Prince Edward Island, Canada. Two FLS-AM flight missions were conducted in the summers of 2008 and 2009 and the resulting datasets were compared with spectral fluorescence signature (SFS DOM) and dissolved organic carbon (DOC) analysis of in situ water samples. Significant positive correlations were found at five of seven sites between the FLS-AM DOM and SFS DOM relationship which indicates that the FLS-AM sensor is a good surrogate for traditional sample collection of DOM data in estuaries in this region. Positive correlations were also found at all sites between FLS-AM DOM values and DOC. FLS-AM DOM patterns show that DOM values are significantly higher in rivers and estuaries that drain watersheds which are heavily impacted by agricultural practices. The results of this study show that the FLS-AM can be used efficiently as a general indicator for how estuaries are affected by runoff from agricultural watersheds in real time and thus reduce the requirement for traditional water sample collection and laboratory analysis methods.     

The Kinetics of the Interaction Between Iron(III)-Ethylenediaminetetraacetate and Peroxynitrite

The kinetics of the formation of the purple-colored species between Fe^III-EDTA and peroxynitrite were studied as a function of pH (10.4–12.3) at 22°C in aqueous solutions using a stopped-flow technique. A purple-colored species was immediately formed upon mixing, which had an absorbance maximum at 520 nm. The increase in absorbance with time could be fit empirically by a power function with two parameters a and b. The power equation determined was absorbance = a*t ^b , where a increased linearly with pH and the concentration of peroxynitrite, while b almost remained constant with a value of ~0.25. The molar extinction coefficient ε_520 nm for the colored species was determined as 13 M⁻¹cm⁻¹, which is much lower than ε_520 nm = 520 M⁻¹ cm⁻¹ for the [Fe^III(EDTA)O₂]³⁻, a purple species observed in the Fe^III–EDTA–H₂O₂ system. The results of kinetics and spectral measurements of the present study are briefly discussed and compared with those of the reaction between Fe(III)-EDTA and hydrogen peroxide.     

渝东南下志留统龙马溪组页岩有机质孔隙发育特征:基于聚焦离子束氦离子显微镜(FIB-HIM)技术

页岩中的有机质孔隙对烃类气体的赋存至关重要。为了明确渝东南下志留统龙马溪组页岩的有机质孔隙发育特征,使用聚焦离子束氦离子显微镜(FIB-HIM)技术进行观察。FIB-HIM具有极高的分辨率,分辨精度可达到亚纳米级,能够有效识别直径为0~20 nm的孔隙。结果表明:龙马溪组页岩的焦沥青内部发育大量的有机质孔隙,孔隙直径大,连通性好,大量较小直径的孔隙嵌套在直径较大的有机质孔隙中,增加了页岩有机质孔隙系统的比表面积和孔隙连通性,有利于烃类气体在页岩有机质孔隙内的赋存及有效渗流。龙马溪组页岩的固体干酪根内部有机质孔隙的发育特征与焦沥青相比存在较大差别,固体干酪根内部发育的有机质孔隙数量少,孔隙直径小,连通性差,孔隙多呈孤立状存在于固体干酪根内部。