水力侵蚀过程中土壤有机碳循环研究进展

水力侵蚀(水蚀)是土壤侵蚀研究的焦点和热点领域,研究水蚀作用下侵蚀与沉积过程中土壤有机碳的动态变化对于评估土壤碳的“源/汇”效应具有重要意义。笔者总结了水蚀过程中土壤碳循环的研究现状,从侵蚀过程中土壤有机碳流失的定量研究、有机碳迁移与再分配以及有机碳矿化的影响等3个方面明确了土壤水蚀过程中土壤有机碳动态,并对国内外土壤水蚀过程中的有机碳主要研究成果进行了对比分析。建议未来研究中先对水蚀过程中有机碳的破坏、搬运和沉积等全过程进行精准解析和量化,在此基础上揭示其物理、化学及生物等共同作用下碳矿化特征的响应机制,全面探究水蚀过程中土壤碳收支的动态,量化土壤侵蚀对全球土壤碳循环的贡献率。     

改性滤料和活性炭去除有机物的特性研究

研究了改性滤料和活性炭去除有机物的分子量分布特性,以及二者结合使用时去除有机物的特性.研究结果表明:涂铁铝砂对水中的有机物有很强的吸附作用,0.45μm膜过滤后总有机物紫外消光值AUV254从0.1 cm-1降到0.055 cm-1,去除率达到45%.其中对分子量大于1×103u的有机物去除效果非常明显,去除率都超过了70%.而活性炭对小分子有机物有很好的去除能力,将涂铁铝砂和活性炭联合使用,可使有机物的去除率增加50%.在实际工程中,要根据原水水质来选择合适的处理工艺.     

Evidence for non-selective preservation of organic matter in sinking marine particles

The sinking of particulate organic matter from ocean surface waters transports carbon to the ocean interior, where almost all is then recycled. The unrecycled fraction of this organic matter can become buried in ocean sediments, thus sequestering carbon and so influencing atmospheric carbon dioxide concentrations. The processes controlling the extensive biodegradation of sinking particles remain unclear, partly because of the difficulty in resolving the composition of the residual organic matter at depth with existing chromatographic techniques. Here, using solid-state 13C NMR spectroscopy, we characterize the chemical structure of organic carbon in both surface plankton and sinking particulate matter from the Pacific Ocean and the Arabian Sea. We found that minimal changes occur in bulk organic composition, despite extensive (>98%) biodegradation, and that amino-acid-like material predominates throughout the water column in both regions. The compositional similarity between phytoplankton biomass and the small remnant of organic matter reaching the ocean interior indicates that the formation of unusual biochemicals, either by chemical recombination or microbial biosynthesis, is not the main process controlling the preservation of particulate organic carbon within the water column at these two sites. We suggest instead that organic matter might be protected from degradation by the inorganic matrix of sinking particles.     

水盐变化对滨海湿地土壤有机碳累积与碳排放的影响综述

滨海湿地作为海岸带蓝碳生态系统的重要组分,具有巨大的碳捕获和碳封存潜力,在减缓气候变暖方面具有重要意义．水盐变化通过影响滨海湿地土壤有机碳的累积和排放过程实现对滨海湿地生态系统碳收支的调控．本文综述了水盐变化对滨海湿地土壤有机碳累积和碳排放过程的影响,以及滨海湿地土壤碳排放研究方法等方面的研究进展,分析了水盐驱动下滨海湿地土壤有机碳分解的微生物作用机制．针对当前研究存在的不足,提出今后应重点关注滨海湿地土壤有机碳分解的温度、湿度和盐度敏感性及其水盐-温度的协同作用机制,氮磷输入和多重污染胁迫对滨海湿地土壤有机碳排放的作用机制,以及滨海湿地土壤微生物碳代谢过程与氮磷硫代谢过程的耦合作用及其水盐驱动机制等方面的研究,以期揭示水盐变化对滨海湿地土壤碳循环的作用机制,为气候变化背景下滨海湿地的碳汇功能提升与管理提供科学依据．      

Young organic matter as a source of carbon dioxide outgassing from Amazonian rivers

Rivers are generally supersaturated with respect to carbon dioxide, resulting in large gas evasion fluxes that can be a significant component of regional net carbon budgets. Amazonian rivers were recently shown to outgas more than ten times the amount of carbon exported to the ocean in the form of total organic carbon or dissolved inorganic carbon. High carbon dioxide concentrations in rivers originate largely from in situ respiration of organic carbon, but little agreement exists about the sources or turnover times of this carbon. Here we present results of an extensive survey of the carbon isotope composition (13C and 14C) of dissolved inorganic carbon and three size-fractions of organic carbon across the Amazonian river system. We find that respiration of contemporary organic matter (less than five years old) originating on land and near rivers is the dominant source of excess carbon dioxide that drives outgassing in medium to large rivers, although we find that bulk organic carbon fractions transported by these rivers range from tens to thousands of years in age. We therefore suggest that a small, rapidly cycling pool of organic carbon is responsible for the large carbon fluxes from land to water to atmosphere in the humid tropics.     

高锰酸钾与颗粒活性炭联用去除水中微量有机污染物

研究了高锰酸钾与颗粒活性炭联用对水源水微量有机污染物的去除效果,以CODMn和剩余苯酚浓度为检测指标,考察高锰酸钾对苯酚的氧化去除效果.以GC-MS分析和Ames试验为检测手段,考察了水源水经高锰酸钾和颗粒活性炭联用处理后,水中有机物的去除效果.结果表明,高锰酸钾对苯酚有较好的去除效果,实际水源水在高锰酸钾与颗粒活性炭联用处理后,水中有机物大部分被去除,水源水的致突变活性有明显降低.     

文思湖底泥污染物覆土缓释可行性研究

通过实验室模拟研究了覆土法对三峡大学文思湖底泥中污染物缓释的可行性.通过监测上覆水体中总氮、总磷和有机质浓度水平监控底泥中污染物释放过程,发现底泥覆土之后上覆水体中总氮、总磷和有机质浓度水平均显著降低,与覆土材料自身向上覆水体释放的氮源、磷源和有机质浓度水平相当.结果表明,覆土可以明显抑制底泥中污染物向上覆水体的释放,因此通过覆土以抑制底泥污染物释放可行.     

生物粉末活性炭与超滤组合工艺膜污染物质研究

为了研究生物粉末活性炭与超滤组合工艺膜污染物质特性,在工艺稳定运行条件下,分别对受污染膜丝表面泥饼层、水洗后的受污染膜丝、生物粉末活性炭进行了红外光谱分析.结果显示,通过红外光谱分析,生物粉末活性炭可以有效的延缓膜表面泥饼层的形成,缓解膜污染;水洗后的受污染膜丝孔内有机污染物较少,而且是小分子有机污染物;还得出含有-OH伸缩振动基团和CO伸缩振动基团的污染物是造成膜污染的主要有机污染物质.     

试论Haberer水处理工艺的特点及其应用范围

Ｈａｂｅｒｅｒ工艺由上向流轻质滤料技术、再絮凝过滤技术及其载粉末活性炭过滤技术组成，集接触絮凝、过滤及粉末活性吸附为一体，以扩大过滤的原水范围，提高水处理效果，变革了水处理传统工艺．本文分析了其除浊、去除有机物的机理及特点，并提出了其应用范围．     

组合工艺对水源水中有机物的去除研究

由于黄河水受污染严重,而以黄河水为源水的自来水厂,多数目前仍然沿用以除浊为目的的常规处理工艺,其出水水质不甚理想。利用移动床生物膜反应器预处理、常规处理及臭氧活性炭深度处理组合工艺处理黄河水研究表明,组合工艺各单元都能有效去除TOC, 组合工艺对TOC的总去除率的平均值为42.2%。组合工艺对UV₂₅₄、藻类、AOC 、 BDOC的去除效果十分理想。虽然原水的致突变性已经较低,组合工艺仍能有效地降低致突变性,其中预处理工艺对降低致突变性的效果较显著。     

荒漠化逆转地区耕层土壤有机碳时空动态研究

以陕西省榆林市为例研究荒漠化逆转地区耕层土壤有机碳时空动态特征．研究表明近20年来耕层土壤有机碳质量分数、密度和储量分别增加了0．510g／kg，0.161kg／m^2，10．78Gg．这表明自然植被恢复、人工种草、退耕还草等土地利用／覆被变化措施能显著提高荒漠化地区土壤固碳能力．     

互花米草与盐地碱蓬群落交错带土壤因子的梯度变化特征

[目的]研究互花米草(Spartina alterniflora)入侵对土壤因子的改造作用,以及土壤因子改变对互花米草生态入侵过程的影响.[方法]以江苏沿海滩涂湿地互花米草群落与和盐地碱蓬(Suaeda salsa)群落的交错带为研究对象,从互花米草群落到盐地碱蓬群落分6个生境梯度带,对各梯度带植物生长状况及表层(0～...     

Massive dissociation of gas hydrate during a Jurassic oceanic anoxic event

In the Jurassic period, the Early Toarcian oceanic anoxic event (about 183 million years ago) is associated with exceptionally high rates of organic-carbon burial, high palaeotemperatures and significant mass extinction. Heavy carbon-isotope compositions in rocks and fossils of this age have been linked to the global burial of organic carbon, which is isotopically light. In contrast, examples of light carbon-isotope values from marine organic matter of Early Toarcian age have been explained principally in terms of localized upwelling of bottom water enriched in 12C versus 13C (refs 1,2,5,6). Here, however, we report carbon-isotope analyses of fossil wood which demonstrate that isotopically light carbon dominated all the upper oceanic, biospheric and atmospheric carbon reservoirs, and that this occurred despite the enhanced burial of organic carbon. We propose that--as has been suggested for the Late Palaeocene thermal maximum, some 55 million years ago--the observed patterns were produced by voluminous and extremely rapid release of methane from gas hydrate contained in marine continental-margin sediments.     

饮用水中微量有机污染物质的GC/MS分析

采用XAD树脂富集技术和GC／MS方法,对长沙市某管网末梢水中的微量、痕量有机污染物进行分析,共检出有机污染物38种,其中以氯代化合物、邻苯二甲酸酯类、醇类、杂环类、芳烃为主,并且有5种物质在中国环境优先污染物“黑名单”之列,分别是三氯乙烯、萘、邻苯二甲酸二丁酯、乙苯、1,4-二甲基苯．由于常规水处理工艺无法去除这些对人体有害的物质,因此建议水厂在考虑自身条件的基础上,积极采用活性炭吸附、臭氧氧化以及膜分离等饮用水深度处理技术,生产出更加优质的饮用水．     

粉末活性炭-超滤膜工艺净化松花江水

为了研究超滤(UF)技术对地表水的处理效果,建造了一座120吨/天的中试规模的膜处理水厂.以松花江水为水源,用粉末活性炭(PAC)吸附作为超滤的预处理工艺,组成了PAC-UF系统.结果表明:PAC-UF工艺的出水浊度在0.15NTU左右,而且不受进水浊度的影响;原水不经过PAC吸附直接超滤时,膜出水有机物浓度和膜进水有机物浓度存在线性关系;UF对UV254的平均去除率在10%左右,对溶解性有机碳(DOC)的平均去除率在8%左右;加入PAC吸附后对有机物的去除有明显提高.     

固定化生物活性炭除微量有机物的应用研究

采用筛选、驯化的工程菌,对刚投入使用的新炭进行固定化,研究结果果证明,在相同条件下,固定化生物活性炭对微量有机物的去除效果显著,保证在低温低浊期炭滤出水的ＣＯＤＭｎ小于２．５ｍｇ／Ｌ。同时,还对固定化生物活性炭的微观结构和作用机理进行了探讨,并对其综合效益进行了分析。     

AK糖石膏中有机碳测定与去除

针对石膏中含有的有机物,研究石膏中有机碳的测定方法,同时对石膏进行预处理,以降低或减少石膏中有机物含量.通过实验确定,硫酸亚铁滴定测定有机碳方法可靠且简单易行;研究了水洗预处理的用水量、酸碱度、洗涤时间对处理效果的影响.     

湘江微污染饮用水源生物过滤试验研究

通过试验探讨了生物过滤对湘江微污染饮用水源的处理效果。试验结果表明，生物过滤可有效去除湘江微污染饮用水源中的可同化有机炎(AOC)、可生物降解有机炎(BDOC)、氨氮、铁、锰和浊度，提高饮用水生物稳定性。不同滤料介质组成的生物滤池具有不同的去除效果。由活性碳、石英砂组成的生物滤池对AOC、BDOC、氨氮、铁、锰等的去除效果比由无烟煤、陶粒和石英砂等滤料组成的生物滤池好，加氯水反冲洗对生物过滤具有明显的负面影响。     

褐煤氧化制备水溶酸

实验研究发现,黄县褐煤的碱空气深度氧化法制备水溶酸的最佳氧化条件：温度为２２０℃,压力为２．８ＭＰａ,碱煤质量比为１．６∶１,反应时间为６ｈ。在此条件下,有机碳的有效转化率为６７．５％,其中水溶酸中的碳占７２．３％。采用蒸汽压渗透法测定水不溶酸和水溶酸的相对分子质量,并采用色质谱对用石灰乳处理后的氧化液的组成进行了定性分析。由分析结果知,水溶酸主要由苯多羧酸组成,酯化后可作为聚氯乙烯增塑剂和润滑剂添加剂     

Efficient export of carbon to the deep ocean through dissolved organic matter

Oceanic dissolved organic carbon (DOC) constitutes one of the largest pools of reduced carbon in the biosphere. Estimated DOC export from the surface ocean represents 20% of total organic carbon flux to the deep ocean, which constitutes a primary control on atmospheric carbon dioxide levels. DOC is the carbon component of dissolved organic matter (DOM) and an accurate quantification of DOM pools, fluxes and their controls is therefore critical to understanding oceanic carbon cycling. DOC export is directly coupled with dissolved organic nitrogen and phosphorus export. However, the C:N:P stoichiometry (by atoms) of DOM dynamics is poorly understood. Here we study the stoichiometry of the DOM pool and of DOM decomposition in continental shelf, continental slope and central ocean gyre environments. We find that DOM is remineralized and produced with a C:N:P stoichiometry of 199:20:1 that is substantially lower than for bulk pools (typically >775:54:1), but greater than for particulate organic matter (106:16:1--the Redfield ratio). Thus for a given mass of new N and P introduced into surface water, more DOC can be exported than would occur at the Redfield ratio. This may contribute to the excess respiration estimated to occur in the interior ocean. Our results place an explicit constraint on global carbon export and elemental balance via advective pathways.