网箱养鱼沉积物中有机污染物的检测分析

通过对网箱养鱼水域底部沉积物中有机污染物进行分析检测,结果显示,网箱养鱼水域底部沉积层中含有大量的有机污染物,其中酚类化合物和低价的含硫化合物含量特别高。经检测分析结果揭示的网箱养鱼水域底部沉积物中有机污染物的种类和含量,可为综合治理网箱养鱼沉积物中有机污染物提供参考。     

芳烃类有机物在黄河沉积物中的多组分吸附及其影响因素研究

以黄河包头段上游清洁河段的沉积物为吸附剂,以苯酚、苯胺和氯苯3组分体系为吸附质溶液,开展了多组分体系中芳烃类有机物的吸附特征及相关影响因素的研究.结果表明,苯酚、苯胺和氯苯在该段沉积物上的吸附过程均属非线性的,吸附等温线受吸附剂浓度影响,相互间存在吸附竞争.表层沉积物对苯酚、苯胺和氯苯的吸附量受pH值、溶液离子强度、沉积物中有机质含量等因素的影响.     

不同碳源物质对土壤无机氮生物固定的影响

采用培养试验方法 ,研究了不同碳氮比值的碳源物质对土壤无机氮生物固定的影响及其在土壤氮素调控中的作用。结果表明 :①单独施用碳氮比较高的麦秸、玉米秸和豆秸时 ,土壤微生物的固氮能力明显降低 ,高碳氮比的麦秸并没有表现出对土壤无机氮强烈固定的优势 ,而碳氮比较低的鸡粪对土壤无机氮没有固定作用 ;②当碳氮比较高的麦秸、玉米秸及豆秸与化肥配合施用时 ,土壤微生物的固氮能力明显增强 ,与单施化肥相比 ,麦秸、玉米秸和豆秸配施化肥 ,对肥料氮的最大固定率分别提高 2 5 31 %、 1 2 46%和 1 0 64%;③土壤微生物对土壤无机氮的生物固定有重要的“保肥”和“稳肥”机能。     

Sulfur diagenesis in everglades peat and origin of pyrite in coal

The pattern of sulfur transformation in peat across the Everglades basin indicates that pyrite formation in organic-rich swamps depends on the use of organic oxysulfur compounds in dissimilatory respiration by sulfur-reducing bacteria. This paragenesis explains the primary distribution of sulfur compounds in low-sulfur coals and possibly in most coals and many organic-rich soils and sediments. It also accounts for the occurrence of framboidal pyrite bound in fossil tissue in coal and sediments.     

Analytical Methods of the Organic Sulfur Compounds in Garlic

Garlic is a kind of widely planted agricultural product in China, which has plenty of nutritional and healthy functions, such as antibacterial, anti-inflammatory, and anti-oxidation. These functions are mainly attributed to the organic sulfur compounds, including the flavor precursors, thiosulfinates and thioether volatile compounds. The organic sulfur compounds either have its own biological activities, or multiple compounds work together to produce the same physiological effect. However, considering the poor stability and property diversity of the organic sulfur compounds, the analysis of organic sulfur compounds remains a big challenge. Existing reports are mainly on the determination of several compounds or one group of compounds, and there has been no comprehensive analysis of the organic sulfur compounds in garlic yet. Therefore, in the present review, the analysis methods of the main flavor precursors, thiosulfinates and thioether volatile compounds in garlic were separately discussed and summarized, including the sample pretreatment and detection methods.     

湿地磷的生物地球化学循环及影响因素

湿地作为一个独特的生态系统有其特殊的生物地球化学循环。本文从磷的生物地球化学循环要素出发,简要介绍了湿地磷的生物地球化学循环基本过程,在此基础上阐述了影响湿地磷的生物地球化学循环的要素及以后湿地磷生物地球化学研究的几个主要方向。     

大蒜中有机硫化合物及其分析方法

大蒜是在我国广泛种植和食用的农产品,具有抗菌、抗炎、抗氧化等多种营养健康功能。这些主要得益于大蒜中的有机硫化合物,包括蒜氨酸等风味前体化合物、大蒜素等硫代亚磺酸酯和大蒜烯等硫醚类挥发性化合物等。这些有机硫化合物或各自具有其生物活性,或多种化合物相互协同,共同产生同一种生理功效。但有机硫化合物普遍具有易酶解或稳定性差等特点,且不同类别有机硫化合物的化学性质差异也较大,目前对大蒜中有机硫化合物的分析方法仍然存在局限性,现有报道多是对某类化合物进行总量测定,或是针对个别化合物进行测定,尚未有研究对大蒜中的有机硫化合物进行全面系统的分析。因此,本研究分别对大蒜中主要风味前体化合物、硫代亚磺酸酯和硫醚类挥发性化合物的分析方法进行了分类讨论和综述,包括其样品前处理方法和检测方法。     

Alga-like forms in onverwacht series, South Africa: oldest recognized lifelike forms on Earth

Spheroidal and cupshaped, carbonaceous alga-like bodies, as well as filamentous structures and amorphous carbonaceous matter occur in sedimentary rocks of the Onverwacht Series (Swaziland System) in South Africa. The Onverwacht sediments are older than 3.2 eons, and they are probably the oldest, littlealtered sedimentary rocks on Earth. The basal Onverwacht sediments lie approximately 10,000 meters stratigraphically below the Fig Tree sedimentary rocks, from which similar organic microstructures have been interpreted as alga-like microfossils. The Onverwacht spheroids and filaments are best preserved in black, carbonrich cherts and siliceous argillites interlayered with thick sequences of lavas. These lifelike forms and the associated carbonaceous substances are probably biological in origin. If so, the origins of unicellular life on Earth are buried in older rocks now obliterated by igneous and metamorphic events.     

沉积物中硅释放的影响因素研究

为揭示沉积物中硅的迁移转化机制及其生物地球化学循环规律,给湖泊富营养化发生机制及水环境治理与保护研究积累基础数据,以乌梁素海为研究对象,深入探讨了p H、微生物和低分子量有机酸等环境因子对沉积物中Si释放的影响机制。结果表明,随着p H的升高(7.0~9.5),乌梁素海上覆水中Si浓度降低,沉积物中生源硅(BSi)含量升高,显示乌梁素海的偏碱性环境使硅在水-沉积物界面的扩散矢量方向指向沉积物。方差分析表明,有微生物体系和无微生物体系之间上覆水Si浓度具有显著差异,可能与微生物的捕食作用和降解作用有关。菖蒲区上覆水中Si浓度整体高于对应季节芦苇区上覆水,而菖蒲区沉积物中BSi含量低于对应季节芦苇区沉积物,主要是由于芦苇和菖蒲根基分泌的低分子量有机酸不同,进而对硅酸盐矿物的溶解能力存在差异导致的。沉水植物区沉积物冬春季和夏秋季整体表现为上覆水的硅汇,上覆水共向沉积物中转移约15.62 t Si;挺水植物区沉积物冬春季和夏秋季整体表现为上覆水的硅源,沉积物共向上覆水中释放约33.15 t Si。     

Physical model for the decay and preservation of marine organic carbon

Degradation of marine organic carbon provides a major source of atmospheric carbon dioxide, whereas preservation in sediments results in accumulation of oxygen. These processes involve the slow decay of chemically recalcitrant compounds and physical protection. To assess the importance of physical protection, we constructed a reaction-diffusion model in which organic matter differs only in its accessibility to microbial degradation but not its intrinsic reactivity. The model predicts that organic matter decays logarithmically with time t and that decay rates decrease approximately as 0.2 x t(-1) until burial. Analyses of sediment-core data are consistent with these predictions.     

浅水湖泊沉积物磷释放的重要因子——铁和水动力

就当前湖泊内源磷释放机制研究中的几个主要方面进行了探讨，指出了研究中的不足，为进一步研究湖泊磷的内源释放机制和湖泊富营养化治理提供参考。     

黄河沉积物对芳烃类有机物的吸附特性研究

以黄河包头段上游相对清洁河段的沉积物为吸附剂,分别以苯酚、苯胺、氯苯等3种代表性芳烃类有机污染物为吸附质,开展了芳烃类有机物的吸附特性及相关影响因素的研究。结果表明,苯酚、苯胺、氯苯在黄河沉积物上的吸附等温线属非线性,其吸附特性受吸附剂浓度和种类的影响;苯酚和苯胺的吸附行为受pH值影响显著;溶液的离子强度、沉积物中有机质含量、环境温度等均对3种有机污染物的吸附量产生较大影响。     

Biogeochemical Controls and Feedbacks on Ocean Primary Production

Changes in oceanic primary production, linked to changes in the network of global biogeochemical cycles, have profoundly influenced the geochemistry of Earth for over 3 billion years. In the contemporary ocean, photosynthetic carbon fixation by marine phytoplankton leads to formation of approximately 45 gigatons of organic carbon per annum, of which 16 gigatons are exported to the ocean interior. Changes in the magnitude of total and export production can strongly influence atmospheric CO2 levels (and hence climate) on geological time scales, as well as set upper bounds for sustainable fisheries harvest. The two fluxes are critically dependent on geophysical processes that determine mixed-layer depth, nutrient fluxes to and within the ocean, and food-web structure. Because the average turnover time of phytoplankton carbon in the ocean is on the order of a week or less, total and export production are extremely sensitive to external forcing and consequently are seldom in steady state. Elucidating the biogeochemical controls and feedbacks on primary production is essential to understanding how oceanic biota responded to and affected natural climatic variability in the geological past, and will respond to anthropogenically influenced changes in coming decades. One of the most crucial feedbacks results from changes in radiative forcing on the hydrological cycle, which influences the aeolian iron flux and, in turn, affects nitrogen fixation and primary production in the oceans.     

呼伦湖沉积物生物硅的分布特征

以Si的生物地球化学特征为基础,结合本小组前期研究成果,探讨了我国纬度最高湖泊呼伦湖沉积物中生物硅(BSi)的分布特征以及有机质与BSi的相关性。研究表明,呼伦湖表层沉积物中BSi的含量介于4.04~18.30 mg.g-1之间,平均11.81 mg.g-1;受陆源输入和沉积物粒度分异的影响,呼伦湖表层沉积物中BSi的空间分布由北西向南东呈现明显递减趋势,BSi的高值区出现在北西部湖区。3个柱芯沉积物中BSi的含量均在10 cm处达到峰值,这可能与20世纪60年代出现的大规模厄尔尼诺现象对湖泊水体中营养盐及藻类繁殖带来的影响有关。沉积物中有机碳与生物硅呈显著正相关关系,OC/BSi值介于0.89~7.22之间,平均2.74,远远小于Redfield比值(106/16),揭示相同条件下,有机质的分解速率远远大于生物硅的溶解速率,颗粒物表层有机质对BSi起到了很好的保护作用,使沉积物中BSi的大部分不参与再循环。     

哈尔滨市城市河道沉积物中酸挥发性硫化物的分布研究

为了深入了解哈尔滨市城市河道沉积物硫污染情况,以哈尔滨三大内河之一——信义沟为例,对其沉积物中酸挥发性硫化物(AVS)的水平和垂直分布进行研究。结果表明,河道所在地的气温、酸雨沉降量以及河道水体-沉积物的氧化还原状态对表层沉积物中AVS的累积具有十分重要的影响;在垂直分布中,沉积物中AVS随深度增加呈现出不同的变化趋势,表明了信义沟河道各区域沉积物稳定性不同。在这一研究结果的基础上,将信义沟沉积物中AVS含量随深度的变化与有机质含量进行线性回归分析发现,信义沟沉积物中AVS与有机质呈正相关,说明了对于北方城市河道沉积物,有机质含量对AVS同样具有重要影响。     

Reactivity of organic compounds in hot water: geochemical and technological implications

Understanding of the reactivity of organic molecules in hot water is developing from studies aimed at explaining how organic matter (kerogen) forms in natural environments and then breaks down into energy source materials. In natural systems where kerogens are depolymerized, hot water is ubiquitous and usually contains salt and minerals. Reactions such as ionic condensation, cleavage, and hydrolysis are facilitated by changes in the chemical and physical properties of water as temperature increases. These changes make the solvent properties of water at high temperature similar to those of polar organic solvents at room temperature, thus facilitating reactions with organic compounds. An understanding of aqueous organic chemistry may lead to potential applications in areas as diverse as the recycling of plastics, the synthesis of chemicals, and coal liquefaction.     

长江口沉积物有机碳及溶解有机质结构对外源磷输入的响应

长江口沉积物总有机碳（TOC, Total Organic Carbon）含量会随着外源磷的输入而发生变化。采用泥（沉积物）水质量比约为1：1，周期为56d的室内模拟试验系统。设置包括对照组在内的6个输入过磷酸钠的浓度梯度试验组，研究不同水平的外源磷输入所引起的沉积物中TOC含量的变化特征。同时，运用紫外—可见光吸收光谱方法，研究含磷物质的加入对沉积物中溶解有机质结构变化的影响。实验结果显示：各试验组沉积物TOC含量在第56天比对照组分别减少了3.60%、7.08%、8.09%、9.33%、11.80%，表明随着外源磷输入量增加，长江口沉积物中TOC加速分解。在试验周期内,沉积物溶解有机质的腐殖化程度、芳香化程度最大值与磷的输入量呈正相关。溶解有机质分子量和芳香环结构变化幅度与外源磷的输入量呈正相关，说明外源磷输入量的增大能够加快沉积物溶解有机质的变化。随着试验时间的增加，不同磷水平的溶解有机质的腐殖化程度和芳香化程度呈现先上升，随后开始下降的趋势；而溶解有机质的分子量随着时间的增加逐渐减小，其芳香环取代基上的取代基逐渐替换为更具有活性的官能团。表明沉积物有机碳含量减少过程中，先生成腐殖质，随着腐殖质继续分解，其腐殖化程度降低，且腐殖化程度和芳香化程度具有同一性。     

西藏达则错盐湖沉积背景与有机沉积结构

以西藏拟溞(Daphniopsis tibetana Sars)为优势浮游动物物种的低盐度盐湖是西藏湖泊的一个重要类型,以达则错为代表,分析了其沉积背景及沉积物组成。结果如下:(1)湖泊敞水区无机沉积以内生化学沉积为主,可代表深水盐湖无机沉积物的自然沉积过程。(2)达则错盐湖浮游植物以蓝藻、硅藻、裸藻、绿藻为主,总生物量11.35 mg/L;浮游动物生物量为4.92 mg/L,其中西藏拟溞占 82.30%;浮游植物残体受盐梯度影响在盐梯度层之上聚集,而浮游动物残体及粪粒(Fecal pellets)因外表有碳酸盐附着可穿过盐梯度层沉积湖底,生物残体与浮游动物代谢产物构成了沉积有机物的物质基础。(3)表层沉积物平均含水量为66.70%,粒径0.004-0.02 mm范围内的颗粒物含量最大,占20.42%,其次为<0.004 mm的粘土,占4.53%。(4)表层沉积物总有机碳(TOC)平均含量为27.99 mg/g(干重),其中颗粒有机碳(POC)约为18.11 mg/g,占TOC的64.70%;在POC中,西藏拟溞粪粒贡献最大,约占POC的60.48%,占TOC的39.06%,占沉积物总量的1.12%,其次为西藏拟溞残体,占POC的38.85%。分析结果表明盐湖因其独特的水化学和生物学特征具有较强的沉积能力,以化学沉积为主的无机沉积及以西藏拟溞粪粒和残肢碎屑为主的有机沉积构成了该类型盐湖颗粒物沉降及沉积的主要过程。     

促生细菌挥发性物质通过lncRNA调控拟南芥的 关键功能基因表达

促生细菌的挥发性有机物可以促进拟南芥生长,提高拟南芥对多种生物和非生物胁迫的抗性。近年来的研究表明,植物lncRNA参与生长、发育和胁迫反应等生理过程。通过去rRNA全转录组测序,筛选出受到根际促生细菌ACCC 01380挥发性有机物处理影响的拟南芥lncRNA,并通过顺式分析获得可能受到这些lncRNA调控的蛋白编码基因;通过ceRNA分析获得lncRNA影响蛋白编码基因表达的调控网络。结果发现,拟南芥重要的生长发育调控和胁迫响应基因,如细胞分裂素降解基因At CKX7、SOS2-like protein kinase PKS5,都受到促生细菌的挥发性有机物通过lncRNA的调控。研究结果初步证实了根际促生细菌挥发性有机物在促生过程中lncRNA的作用,并为进一步研究lncRNA功能以及根际促生细菌挥发性有机物的作用机理奠定了基础。     

几种酚类化合物在黄河水体沉积物上吸附行为的实验研究

采用现场采集河底表层沉积物及室内分析的方法,研究了邻硝基苯酚、对硝基苯酚、2,4-二硝基苯酚、2,4-二氯苯酚、五氯酚等酚类化合物在黄河水体沉积物上的吸附行为。结果表明,邻硝基苯酚等酚类化合物在黄河水体沉积物上的吸附量随pH值的增大而减小;随着离子强度的增加,对硝基苯酚和邻硝基苯酚在黄河水体沉积物上的吸附量增加;沉积物的有机质含量是影响酚类化合物吸附量大小的一个重要因素,即溶解分配过程在黄河水体沉积物吸附酚类化合物中起重要作用;当表面活性剂SDBS存在时,酚类化合物在黄河水体沉积物上的吸附以分配作用为主,SDBS在所测定的浓度范围内(小于CMC),酚类化合物的沉积物-水分配系数均增大,分配系数的增大倍数与它们的辛醇-水分配系数KOW成正相关。