黄河口近岸海域有色溶解有机质的时空分布及光降解特性

根据2018年10月（秋季）、2019年5月（春季）、 2019年8月（夏季）和2021年3月（冬季）在黄河口开展的溶解有机质（DOM）及其光学性质特征参数的陆海同步观测数据,结合同步开展的不同来源DOM的光降解船基现场培养试验,分析黄河口DOM及有色溶解有机质（CDOM）的时空分布特征,探讨该海域不同来源DOM光降解作用及控制机制.结果表明,黄河入海径流的溶解有机碳（DOC）和CDOM浓度呈现夏季高、冬季次之、春季和秋季低的变化特征;DOC和CDOM入海通量呈现夏季最高、秋季和春季次之、冬季最低的季节特征,主要受黄河流域汛期及调水调沙作用影响;黄河口DOC呈现不规则斑块状分布,CDOM呈现近岸高、离岸低的分布特征,为黄河输入、海源自生及光降解等多种因素影响所致.在黄河径流较大的夏季,DOC受陆源输入影响较其他季节更为明显,CDOM浓度明显高于其他季节;夏季DOC与CDOM之间的线性关系也显著高于其他季节.春季、夏季和秋季陆源DOM光化学降解速率均高于海源;受DOM来源组成和温度、光照等环境因子共同作用,研究海域夏季CDOM光降解率高于春、秋两季.     

环境中砷与溶解有机质的络合作用

砷(As)与溶解有机质(DOM)的络合从而形成As-DOM络合物是控制砷的形态、移动性和生物可利用性的关键过程.本文综述了目前为数不多的As-DOM络合物形成的研究,力争对这方面的研究有一系统认识.本综述包括:(1)砷与溶解有机质的络合形式;(2)As-DOM络合物的分离分析方法;(3)As-DOM络合物形成的观测证据...     

夏、秋季长江口外海域沉积物-水界面溶解无机碳的交换通量

沉积物-海水界面是海洋中溶解无机碳(DIC)转移和储存的重要场所,长江口外海域拥有特定的沉积物-水界面交换的空间格局,研究其沉积物-水界面DIC的交换过程对于碳的循环和转化具有重要意义.本研究于2021年8月和2021年10月在长江口外海域采集沉积物样品及原位底层海水,通过实验室模拟培养法计算了该海域沉积物-水界面DIC的交换通量,并研究了沉积物间隙水-上覆水的DIC浓度差、温度、盐度和pH对DIC交换通量的影响.结果表明,夏季和秋季研究海域沉积物-水界面DIC交换通量平均值分别为(432.45±190.78)μmol·m^-2·h^-1和(223.05±110.39)μmol·m^-2·h^-1.夏季交换通量高于秋季,DIC扩散方向均由沉积物向上覆水释放,表明沉积物表现为DIC的“源”.此外,交换通量会随着DIC浓度差或温度升高而升高,随着盐度或pH升高而降低.     

土壤溶解有机碳的研究进展

系统地综述了DOC的来源、组成、性质、影响因素、环境效应及测定方法等。尽管关于土壤DOC的研究目前还不完善,至今对DOC的组成、性质等问题都不是很清楚,但现有的研究已经表明,DOC是土壤圈中一种非常活跃的化学物质,它对土壤中化学物质的溶解、吸附、解吸、迁移和毒性等行为均有显著的影响。     

流域特征对南苕溪溶解有机质浓度的影响

溶解有机质(DOM)是水域生态系统中碳、氮、磷循环的重要组成部分,开展流域尺度上流域特征对河流DOM输出的调控机制研究,有助于加深对DOM经由河流向下游水体迁移的生物地球化学行为的认识,为改善河流及其下游水体富营养化状况和进行生态修复提供依据.选取南苕溪流域为研究对象,在其16个子流域开展近一年的采样调研,提取各子流域...     

土地利用方式对土壤碳库影响的敏感性评价指标

综述了目前国内外在监测土地利用方式对土壤有机碳动态的影响时所采用的一些敏感性指标：微生物量碳和微生物商、CO2通量和qCO2、轻组有机质和颗粒态有机质、溶解态有机碳(DOC)。大量的研究表明，与土壤有机碳相比，微生物量碳库的周转率更大，周转时间更短，在土壤总有机碳变化可检测之前，土壤微生物部分的变化可能被检测到，是土壤碳动态的敏感性指标。轻组和颗粒态有机质是自然土壤肥力的决定因素，也是土地管理方式影响最明显的部分，对于准确评价土地利用变化对土壤碳过程的影响具有重要意义。CO2，通量和qCO2，可以综合反映土壤微生物的活性、利用土壤有机碳的效率及土壤中碳的代谢作用等，也是土壤碳动态的敏感性指标。DOC通量比全球植物和大气间碳交换量小1-2个数量级，所以生物圈碳平衡的很小变化会导致DOC的巨大变化，DOC浓度和通量是土壤温度和湿度变化的敏感指标。     

栗钙土不同土地利用方式下有机碳和无机碳剖面分布特征

栗钙土是半干旱地区典型的地带性土壤,主要分布在内蒙古自治区。文章以内蒙古自治区乌兰察布盟(简称乌盟)和锡林河流域为例,分析了栗钙土有机碳和无机碳含量及其密度的剖面分布特征,旨在了解不同土地利用方式下土壤碳库的储量和分布特点及其成因与机理。结果表明:土壤无机碳在剖面上的分布有两种类型:高—低—(高)—(低)型和低—高—(低)—(高)型,后者可能是由于土壤侵蚀引起的碳酸盐再分布所形成的。100cm深的土壤有机碳密度的平均值为8.48kg·m-2,退耕地>耕地>干旱半干旱草原>典型草原,主要分布在表层,0～30cm土壤有机碳密度为0～100cm的43%左右;而土壤无机碳密度的平均值为7.10kg·m-2,退耕地>典型草原>耕地>干旱半干旱草原,主要分布在下层土壤,50～100cm无机碳密度为0～100cm的58%左右。     

岩溶地区土壤溶解有机碳的季节动态及环境效应

对桂林岩溶试验场土壤溶解有机碳(DOC)进行了逐月的观测，结果显示DOC是岩溶生态系统中活跃的有机碳组分，在岩溶地区碳循环中发挥着重要的作用。一年中土壤DOC的变化特征表现为3个阶段：(1)3-7月，随气温升高、降雨量增加，土壤生物活性和新陈代谢能力极大提高，土壤溶解有机碳呈升高趋势；(2)8-11月，气温保持较高的水平，但降雨量偏低，土壤干燥，土壤微生物活性极大地减弱，土壤DOC质量分数全年最低；(3)12月至次年2月，随温度的降低，土壤生物活性逐渐降低，土壤DOC呈缓慢升高趋势，且与土壤微生物量碳之间存在互为消长的关系。土壤碳酸盐岩的溶蚀速率季节变化与土壤DOC之间存在负相关。文章还提出了岩溶地区土壤碳循环模式及DOC在其中的作用。     

森林生态系统土壤可溶性有机质(碳)影响因素研究进展

土壤活性有机质在土壤碳、氮、磷等养分元素的牛物地球化学循环方面起着十分重要的作用.森林土壤活性有机碳(SAOC)库是极易变动的,其组分动态与周转速率主要受森林植被类型、演替过程以及由此造成的凋落物输人类型、数量、质量和季节与温湿度、pH等变化的控制.尽管在过去几十年中,关于土壤可溶性有机碳(DOC)已开展了大量的研究,但关于其形成、转移与转化速率,以及对环境变化的反应等结论仍然零散,甚至相互矛盾,因此,研究土壤DOC动态及持续管理,必需从探讨其影响因子出发,找出其关键限制凶子进行调控.在将来的研究中,主要应集中在:(i)各种可溶性有机质(DOM)源和汇的大小与DOC定量变化关系,如何进行调控?(ii)在高度人为化管理的森林生态系统中,土壤DOC如何改变?(iii)DOC动态及周转速率的现代研究方法探索等.参110     

溶解性有机物对土壤中重金属环境行为的影响

为揭示在溶解性有机物（DOM）作用下土壤中重金属的吸附和迁移规律并确定迁移数学模型,通过不同条件下的等温吸附实验和土柱淋滤实验,研究了溶解性有机物对重金属Cu,Cd,Pb,Zn在褐土中吸附和迁移行为的影响。结果表明DOM对Cu和Cd在土壤中的吸附促进作用较明显,对Pb有微弱的促进作用,对Zn的吸附影响不明显;随着pH的改变,25℃下Cu在土壤中的吸附高于15℃和35℃条件下。DOM质量浓度越高,Cd、Zn溶出的促进效果越明显,Cu、Pb则恰好相反。DOM对土壤中Cd、Zn的垂直迁移起着促进作用,而对Cu、Pb迁移起着一定的抑制作用;DOM对土壤重金属的平均迁移量随时间的延长而减少。此迁移模型能够定量计算并预测重金属质量浓度的时空分布。     

土壤溶解性有机质的生态环境效应

土壤生态环境是一个复杂的多介质多界面体系。现有的研究表明，DOM作为环境中重要的天然配位体和吸着载体，是一种非常活跃的化学物质，它将土壤中的矿物质、有机质与生物成分联系在一起，通过物理或化学作用改变金属与外源性化合物的环境行为，促进温室气体的排放，调节土壤养分流失，指示土壤质量，并对成土过程、微生物的生长代谢过程、土壤有机质分解和转化过程有着重要作用，已经成为土壤科学、生态科学和环境科学交叉领域的研究热点。文章系统地评述了DOM的组成特点及其环境效应，同时介绍了未来的研究方向及一些有待于进一步研究的问题。     

Modeling the seasonal autochthonous sources of dissolved organic carbon and nitrogen in the upper Chesapeake Bay

In this paper we investigate the seasonal autochthonous sources of dissolved organic carbon (DOC) and nitrogen (DON) in the euphotic zone at a station in the upper Chesapeake Bay using a new mass-based ecosystem model. Important features of the model are: (1) carbon and nitrogen are incorporated by means of a set of fixed and varying C:N ratios; (2) dissolved organic matter (DOM) is separated into labile, semi-labile, and refractory pools for both C and N; (3) the production and consumption of DOM is treated in detail; and (4) seasonal observations of light, temperature, nutrients, and surface layer circulation are used to physically force the model. The model reasonably reproduces the mean observed seasonal concentrations of nutrients, DOM, plankton biomass, and chlorophyll a. The results suggest that estuarine DOM production is intricately tied to the biomass concentration, ratio, and productivity of phytoplankton, zooplankton, viruses, and bacteria. During peak spring productivity phytoplankton exudation and zooplankton sloppy feeding are the most important autochthonous sources of DOM. In the summer when productivity peaks again, autochthonous sources of DOM are more diverse and, in addition to phytoplankton exudation, important ones include viral lysis and the decay of detritus. The potential importance of viral decay as a source of bioavailable DOM from within the bulk DOM pool is also discussed. The results also highlight the importance of some poorly constrained processes and parameters. Some potential improvements and remedies are suggested. Sensitivity studies on selected parameters are also reported and discussed.     

Identification of sources,characteristics and photochemical transformations of dissolved organic matter with EEM-PARAFAC in the Wei River of China

• The source of DOM in surface water and sediment is inconsistent. • The DOC content changes differently in surface water and sediment. • The content of DOC in the surface water is lower than that in the sediment. • The DOM in the surface water had higher photodegradation potentials than sediment. Dissolved organic matter (DOM) in rivers is a critical regulator of the cycling and toxicity of pollutants and the behavior of DOM is a key indicator for the health of the environment. We investigated the sources and characteristics of DOM in surface water and sediment samples of the Wei River, China. Dissolved organic carbon (DOC) concentration and ultraviolet absorbance at 254 nm (UV₂₅₄) increased in the surface water and were decreased in the sediment downstream, indicating that the source of DOM in the water differed from the sediment. Parallel factor (PARAFAC) analysis of the excitation-emission matrices (EEM) revealed the presence of terrestrial humus-like, microbial humus-like and tryptophan-like proteins in the surface water, whereas the sediment contained UVA humic-like, UVC humic-like and fulvic-like in the sediment. The DOM in the surface water and sediment were mainly derived from microbial metabolic activity and the surrounding soil. Surface water DOM displayed greater photodegradation potential than sediment DOM. PARAFAC analysis indicated that the terrestrial humic-like substance in the water and the fulvic-like component in the sediment decomposed more rapidly. These data describe the characteristics of DOM in the Wei River and are crucial to understanding the fluctuations in environmental patterns.     

SOMPROF: A vertically explicit soil organic matter model

Most current soil organic matter (SOM) models represent the soil as a bulk without specification of the vertical distribution of SOM in the soil profile. However, the vertical SOM profile may be of great importance for soil carbon cycling, both on short (hours to years) time scale, due to interactions with the soil temperature and moisture profile, as well as on long (years to centuries) time scale because of depth-specific stabilization mechanisms of organic matter. It is likely that a representation of the SOM profile and surface organic layers in SOM models can improve predictions of the response of land surface fluxes to climate and environmental variability. Although models capable of simulating the vertical SOM profile exist, these were generally not developed for large scale predictive simulations and do not adequately represent surface organic horizons. We present SOMPROF, a vertically explicit SOM model, designed for implementation into large scale ecosystem and land surface models. The model dynamically simulates the vertical SOM profile and organic layer stocks based on mechanistic representations of bioturbation, liquid phase transport of organic matter, and vertical distribution of root litter input. We tested the model based on data from an old growth deciduous forest (Hainich) in Germany, and performed a sensitivity analysis of the transport parameters, and the effects of the vertical SOM distribution on temporal variation of heterotrophic respiration. Model results compare well with measured organic carbon profiles and stocks. SOMPROF is able to simulate a wide range of SOM profiles, using parameter values that are realistic compared to those found in previous studies. Results of the sensitivity analysis show that the vertical SOM distribution strongly affects temporal variation of heterotrophic respiration due to interactions with the soil temperature and moisture profile.     

可溶性有机物对土壤中主要有机污染物环境行为的影响

概括了环境中可溶性有机物的特点，并系统总结了当前国内外关于可溶性有机物对土壤中主要污染物环境行为的影响的研究进展。阐述了可溶性有机物对农药、多环芳烃在土壤中的吸附、解吸及分配等环境行为所起的作用。最后指出了该方面研究存在的问题及今后应加强的方向。     

哈尔滨市降雪中溶解性有机物光谱特性分析

研究雨雪中的溶解性有机物(DOM)将有利于把握其理化性质及其在生态系统中的行为和功能.本研究运用三维荧光光谱(EEMs)技术结合平行因子分析(PARAFAC)、紫外-可见光谱技术(UV-vis),对哈尔滨市2018年3月1日降雪样品中DOM的光谱特性及来源进行解析.结果表明,降雪样品中DOM的相对分子质量较大,芳香构造...     

Influence of dissolved organic matter from corn straw on Zn andCusorption to Chinese loess

The interaction of Zn and Cu with dissolved organic matter (DOM) is a significant physicochemical process affecting their sorption as well as mobility in soil. The objective of this study was to examine the influence of DOM from corn straw on the sorption of Zn and Cu by loess through batch adsorption technique. The sorption isotherms of Zn and Cu could be well described by the Freundlich equation, and the partition distribution coefficient (k) in the presence of DOM was reduced by 86% for Zn and 58% for Cu, as compared to the control receiving no DOM, suggesting that DOM had a stronger inhibitory effect on Zn sorption than that of Cu. In addition, the sorption of metal increased with an increase in pH for loess, with maximum inhibition on metal sorption observed at pH > 7.6 for Zn and pH > 5.5 for Cu in the absence ofDOM but Cu sorption of DOM was suddenly decreased with an increase of pH at pH > 7.9 in the presence of DOM. At a DOM concentration of <200 mg L^?1, sorption of Zn and Cu was reduced by 46% for Zn and 32% for Cu with an increase in DOM concentration.     

溶解性有机质在红壤水稻土碳氮转化中的作用

溶解性有机质(DOM)是土壤中活跃的C、N库,在土壤有机质分解转化等过程中有着重要的作用。但其在水田土壤C、N转化过程中究竟起多大作用仍不明确。本研究采用室内恒温培养法观测了DOM和红壤水稻土C、N矿化的关系。结果表明,去除DOM显著降低了培养期间土壤有机质的累计矿化量。其中土壤有机碳的累计矿化量下降了11.4%～20.8%(平均15.4%),且其影响主要体现在培养前期;土壤有机氮的累计矿化量下降了16.4～22.9%(平均19.2%)。研究结果初步表明,虽然DOM只占土壤有机质的很少一部分,但在红壤水稻土C、N矿化中起重要作用。     

红树植物凋落叶分解对土壤可溶性有机质的影响

研究红树林湿地土壤可溶性有机质（DOM）的来源、性质及其归宿对于揭示 DOM 在红树林湿地生物地球化学循环中的作用具有重要意义。采集了木榄（Bruguiera gymnoihiza）、秋茄（Kandelia candel）和桐花树（Aegiceras corniculatum）3种红树植物的新近落叶进行室内48 d分解实验,探讨了凋落叶分解过程对土壤可溶性有机碳（DOC）和可溶性总氮（TDN）含量、C/N比（DOC/TDN）及紫外-可见（UV-Vis）光谱特征（A280、A240/A420和A250/A365比值）的影响。在48 d分解期间,3种红树植物凋落叶的输入均明显增加了土壤DOC的含量,其变化在分解第6 d最为显著,各凋落叶添加组比对照组平均增加了149%（秋茄）~196%（桐花树）,随后各凋落叶添加组土壤DOC含量呈下降趋势。与土壤DOC的变化不同,凋落叶输入后土壤TDN的变化与对照组的差异不明显,但木榄和桐花树添加组的C/N比在分解初期（第6天）显著高于对照组（P<0.05）。凋落叶的输入亦在不同程度上增大了土壤DOM的A280值,降低了DOM的A240/A420和A250/A365比值。与土壤DOC的变化相似,凋落叶输入使DOM的UV-Vis光谱特征在分解初期（第6天）的变化最明显,其中桐花树凋落叶的影响最大,秋茄凋落叶的影响最小。结果表明：凋落叶输入使培养初期土壤DOM的含量和性质发生明显改变,DOM中大分子及芳香类组分增多、团聚化程度增加,DOM 的生物可降解性变小。然而,随着分解的进行,不同凋落叶处理组之间土壤DOM的变化差异性逐渐缩小,并在分解后期与对照组趋近。