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湖泊生态系统作为自然界重要的碳库，光照强度的变化对于湖泊的碳循环过程可能产生重要的影响.以云南老君山高山湖泊天才湖周边土壤中的腐殖酸作为外源溶解性有机物（DOM）的代表物，通过腐殖酸模拟光降解实验，考察光照强度对外源DOM光降解过程的影响.研究结果表明：腐殖酸光吸收系数a440、465 nm和665 nm波长处吸光度比值E4/E6的下降幅度均为：对照组 < 20 W光照组 < 40 W光照组，a440、E4/E6和光谱斜率SR显著相关，表明紫外辐射使得腐殖酸溶液浓度降低、相对分子量下降，且光照强度越强，腐殖酸的光降解程度越大.通过EEM-PARAFAC模型识别出光降解过程中腐殖酸溶液中含有5种荧光组分：UV类腐殖质（C1）、UVA类腐殖质（C2）、类色氨酸（C3）、UVC类腐殖质（C4）和类络氨酸（C5）.40 W光照组中4种荧光组分的降解程度与降解速率均大于20 W光照组，降解程度均为：C4 > C3 > C2 > C1，降解速率为C2 > C4 > C3 > C1，说明不同的荧光组分对光照强度的响应不同.该研究有助于阐明外源DOM的光降解途径与归趋. 相似文献
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为了揭示湖库内源性污染物的分布、来源、组成及垂向分布特征,以新建人工深水湖泊龙景湖为研究对象,采用紫外-可见光谱和三维荧光光谱技术,研究了该湖泊以成湖前用途划分的3个特征区域(原河道底部、新淹没区底部和新淹没区边坡)的沉积物上覆水和孔隙水中的溶解性有机质(DOM)的光谱特征.结果表明,孔隙水中的DOM芳香性和腐殖化程度高于上覆水;孔隙水中疏水组分含量大于上覆水,且水体中可能存在内源孔隙水释放的低分子量DOM.龙景湖上覆水和孔隙水中的DOM主要源于水体自身的微生物,自生源特征明显,且可能存在新近释放到水体的有机质.龙景湖沉积物上覆水和孔隙水中的DOM以类腐殖酸和类蛋白质为主,且随着深度增加,类腐殖酸峰强度增强,与龙景湖的建湖背景有明显联系. 相似文献
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鄱阳湖水体溶解有机质分子量分布、荧光特征及对重金属分布的影响 总被引：2，自引：0，他引：2
溶解有机质(DOM)在环境水体中广泛存在,具有连续的分子量分布特征,并可显著影响水体中污染物的迁移转化和归趋行为.于2019年春季采集鄱阳湖全湖水样,采用超过滤技术将DOM样品分为低分子量(LMW,1 kDa)和高分子量(HMW,1 kDa～0.45μm)组分,通过三维荧光光谱结合平行因子分析(EEM-PARAFAC)和ICP-MS分析不同分子量区间有机组分和重金属含量.结果表明,鄱阳湖水体DOM中LMW-DOM占比为43%～55%,HMW-DOM占比为45%～57%.平行因子模型提取出3个相互独立的荧光组分,分别为类富里酸组分C1、C2和类腐殖酸组分C3. 60%～73%的C1分布在LMW中,77%～93%的C2分布在HMW中,而C3几乎平均分布在LMW-和HMW-DOM中,可能与C1、C2、C3组分分别含有的传统荧光峰有关.通过对荧光参数FIX(1.4)、BIX(0.8)的计算发现鄱阳湖DOM陆源特征显著,且HMW组分具有比LMW组分更高的陆源特征和芳香度.重金属检测结果表明Cr、Mn、Fe、Pb则主要分布在HMW中(63%～94%),As、Cd、Ba、Se、Sb主要分布在LMW中(63%～84%),Cu、Zn、Ni、Co几乎均匀分布在LMW-和HMW-DOM中.重金属与DOM的相关性结果表明大多数金属与C2占比呈负相关,与C3占比呈正相关,说明重金属离子与水体中DOM的络合可能主要通过腐殖类组分C3进行.且重金属含量的分布受HMW-DOM的影响较大,说明人类活动也对鄱阳湖水体的重金属分布有着重要影响. 相似文献
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为探究典型精神类药物及其代谢产物在高宝邵伯湖——宝应湖、高邮湖和邵伯湖表层水体的污染水平、分布特征及生态风险,利用超高效液相色谱-串联质谱法,对研究区域18个采样点位表层水体中3类（抗抑郁药物、抗癫痫药物和抗精神病药物）21种精神类药物及其代谢产物的浓度水平进行检测分析.结果表明,除奥卡西平外,其余20种典型精神类药物及代谢产物均有不同程度地检出,检出率范围为22.2%～100%,总检出浓度范围为1.4～224.5 ng/L.其中抗精神病药物利培酮检出浓度最高,浓度范围为0.1～64.1 ng/L.不同采样点精神类药物及其代谢产物的浓度存在空间差异,呈现邵伯湖和高邮湖南部浓度较高,高邮湖北部和宝应湖浓度较低的趋势.由聚类分析可知,点位S1、S7单独形成聚类,浓度分别为175.7和102.9 ng/L.对精神类药物及其代谢产物的来源分析发现,污水处理厂、生活污水和农业废水排放可能是高宝邵伯湖地表水中精神类药物及其代谢产物的主要来源.采用风险商值法（risk quotient,RQ）进行生态风险评估,结果表明高宝邵伯湖表层水体中卡马西平和环氧卡马西平对水生生物具有高风险（RQ>1）.精神类药物及其代谢产物在环境中持续性赋存的风险需引起重视. 相似文献
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以艾比湖主要入湖河流——精河与博尔塔拉河为研究对象,分别分析了精河与博尔塔拉河的水体溶解性有机质(DOM)的组成结构及水质参数与荧光指数的关系.利用平行因子分析法对三维荧光光谱(EEM)分析发现,精河与博尔塔拉河均含有C1(260/420 nm)腐殖酸等有机质、C2(240,240/490 nm)UVC类腐殖质、C3(220/280,300/450 nm)蛋白质类有机质和C4(260,270/530 nm)类腐殖质,且不同荧光组分结构具有一定差异性.为了进一步了解DOM组分特征,采用三维荧光区域积分法分析各区域标准体积百分比,结果表明精河与博尔塔拉河EEM的区域Ⅰ与区域Ⅱ蛋白质有机质含量最高,区域Ⅲ富里酸含量最低.相关性分析表明,主要入湖河流的水质参数与荧光指数中,自生源指数(BIX)与总氮(TN)浓度以及腐殖化指数(HIX)与铵态氮(NH_4~+-N)浓度的相关性较强,相关系数分别为0.831和0.684,且具有显著性;HIX与TN浓度的相关系数为0.604,达到显著性水平.进而对相关性较强的水质参数与荧光指数进行3次拟合,其中HIX与NH_4~+-N浓度的拟合效果最好,相关性系数为0.908,其次是BIX与TN浓度,相关性系数为0.844.总之,通过分析精河与博尔塔拉河三维荧光特征,以及探讨荧光指数与水质参数的关系,可为治理干旱区水环境问题提供理论依据和参考. 相似文献
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蓝藻水华暴发和衰亡对太湖有色可溶性有机物的影响 总被引：1，自引：1，他引：0
利用平行因子分析(PARAFAC)技术对藻华暴发季节太湖梅梁湾和开敞区水样中有色可溶性有机物(CDOM)的三维荧光光谱进行分析,获得代表类酪氨酸、类色氨酸和类腐殖酸等3种荧光组分,这3个组分的荧光得分值均与叶绿素a浓度呈极显著正相关,其中类腐殖酸物质荧光得分值占总分值的比例也与叶绿素a浓度极显著正相关,由此可以推测,蓝藻水华可能是太湖CDOM的一个重要来源,并极大地影响了湖泊CDOM的组成结构.为进一步探索蓝藻水华对湖泊CDOM的影响,于太湖梅梁湾湖岸进行藻华暴发和衰亡模拟试验.PARAFAC结果显示,模拟试验水样CDOM的三维荧光图谱同样含有3个组分,其中类酪氨酸和类色氨酸荧光峰位置与湖泊水样基本相同,而类腐殖酸物质荧光峰则有一定程度的蓝移,表明培养试验中有新的内源类腐殖酸物质产生.利用PARAFAC模型中的得分值计算后发现,初始叶绿素a浓度越高,类腐殖酸物质所占比例越大,而实验结束时添加了高浓度和中等浓度藻的2个处理中类腐殖酸物质对荧光的贡献率也有显著提高.因此,藻华的长期暴发可以显著改变湖泊CDOM的组成,导致类腐殖酸物质比例提高. 相似文献
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峡谷分层型水源水库表层沉积物溶解性有机物光谱特征 总被引：7，自引：1，他引：6
结合三维荧光光谱技术（EEMs）与紫外吸收光谱（UV-vis），并利用平行因子分析（PARAFAC）的方法，对金盆水库表层沉积物中溶解性有机质（DOM）光谱的空间分布特征及来源进行分析，并探讨沉积物DOM的荧光组分与可溶性有机氮（SON）、可溶性无机氮（SIN）之间的相关性.结果表明，金盆水库表层沉积物DOM由3类荧光组分组成，分别是类富里酸C1（235 nm，315 nm/430 nm）、类色氨酸C2（220 nm，275 nm/330 nm）和类胡敏酸C3（265 nm/520 nm），各组分荧光强度占总荧光强度百分比的平均值分别为43.15%、31.54%和25.31%.表层沉积物DOM浓度在空间上呈现从上游到主库区先减少后增加的趋势.光谱斜率S275-295、S350-400和光谱斜率比SR反映出各采样点陆源与内源占比的差异性.荧光指数、自生源指标和腐殖化指标都表明金盆水库沉积物DOM的来源具有内源与陆源双重特征.相关性分析表明，表层沉积物DOM各组分与SON和SIN均呈显著正相关，说明DOM与氮元素的迁移转化密切相关. 相似文献
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作为海陆交互作用的重要区域,河口在海洋碳循环中扮演着重要角色.近年来,溶解性有机质(dissolved organic matter,DOM)在河口区的来源、降解和保存一直是关注的热点.本研究结合三维荧光光谱和紫外可见吸收光谱,对珠江口3个沉积柱(S1、S2、S3站位,盐度依次增加)孔隙水溶解性有机质的空间分布和来源进行了表征分析.利用平行因子分析(parallel factor analysis,PARAFAC)方法对三维荧光光谱数据进行解析共得到5种荧光组分:类腐殖质组分C1、C3、C4,以及类蛋白荧光组分C2和C5.三个站位的C2组分同沉积物微生物DNA浓度表现出显著的正相关关系(R2=0.69,P<0.01),说明类蛋白组分C2可能主要来源于原位微生物的分解代谢.C5同DNA浓度相关性较弱(R2=0.40,P<0.05),推测是混入了荧光峰同类蛋白组分十分接近的酚类化合物所致.类腐殖质荧光组分来源复杂,S1站位类腐殖质荧光组分含量最高(1.45~8.83R.U.),推测是受到了显著的陆源输入影响.S2和S3站位3种类腐殖质荧光组分含量很低(<1R.U.),且分布规律十分相似,可能主要来源于水体和沉积物藻类微生物的代谢释放.三个站位的腐质化指标HIX随深度增加,类蛋白组分荧光相对含量随深度降低,并且同指示DOM分子量的光谱斜率比值SR分别呈显著的负相关和正相关关系.这说明从沉积物表层到深层,DOM由低分子量的类蛋白组分向高分子量的类腐殖质组分过渡.本研究结果对理解河口区沉积物中的孔隙水DOM分子量/活性模型(pore water size/reactivity,PWSR)以及DOM的生物有机地球化学过程提供了补充参考. 相似文献
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采用荧光滴定法研究四环素(tetracycline,TC)与太湖溶解性有机质(dissolved organic matter,DOM)和玄武湖DOM的相互作用.三维荧光光谱结合平行因子分析显示,2个湖泊的DOM含有3个荧光组分:类富里酸组分C1、类色氨酸组分C2和类络氨酸组分C3.其中C2的荧光强度远高于C1和C3,是DOM的主要荧光组成.3个荧光组分与TC发生了不同程度的静态猝灭,特别当TC浓度为45.5μmol/L时,类蛋白组分的荧光强度完全被猝灭(100%),并且猝灭作用改变了DOM分子的微环境极性.同步荧光光谱联合二维相关图谱进一步表明类色氨酸组分优先和TC发生猝灭作用,其次为类络氨酸组分和类富里酸组分.Ryan-Weber方程适于拟合DOM与TC的猝灭过程,2个湖泊的DOM中3个荧光组分的络合常数lg K值范围为5.05~5.85,大小顺序为C2C3C1.因此,类蛋白组分为主的DOM对TC的络合作用大于类腐殖组分为主的DOM,影响抗生素在湖泊水体中的生物有效性和生态毒性. 相似文献
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《Limnologica》2021
The influence of dissolved organic matter (DOM) on mineral extraction from salt lake brines depend on DOM quality. This study contributes to our knowledge of DOM’s metal binding behavior in hypersaline environments by characterization of DOM from lakes in the Qaidam Basin, i.e., Qarhan Lake (LQDOM), Da Qaidam (DQDOM) and West Ginair Salt Lake (WGDOM). The DOM was fractionated based on solid phase extraction (SPE) and ultrafiltration (UF), and the spectral and metal binding behavior of these fractions were studied by absorption spectroscopy, Pb(II) titration techniques and fluorescence parallel factor (PARAFAC) analysis. The results showed that bulk DOM generally contained more dissolved organic carbon (DOC), lower specific UV absorbance (SUVA254), higher fluorescence and biological indices, comparable humification index, and lower condition stability constants compared to the other nature waters. Compared with UF, SPE-derived DOM exhibited higher DOC recovery and aromaticity and lower carbohydrate yield. It appeared that the SPE procedure used affects the spectral composition of bulk DOM to a larger extent than UF. Source and molecular weight (MW)-dependent differences in abundance and quality of brine DOM was indicated by higher SUVA254 in high MW DOM, for LQDOM and DQDOM, and humic-like fluorophores were mainly in high MW-DOM in each lake. Moreover, the high MW humic-like component exhibited higher metal binding potential than the bulk and low MW counterparts for LQDOM and DQDOM, while the inverse was observed for WGDOM. This study revealed the effects of isolation techniques on interpretation of DOM characteristics, and meanwhile highlighted the importance of origin- and MW-dependent DOM in manipulating the behavior, fate, and bioavailability of heavy metals in salt lake brine. 相似文献
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《Limnologica》2019
This study aimed to evaluate the importance of physical, chemical and biological factors (e.g., chlorophyll-a, and carbon) in the regulation of the summer epilimnion thickness (Zmix) of the tropical lakes focusing on trends of the current environmental variability. We sampled a set of tropical lakes from the middle Rio Doce lacustrine system (Minas Gerais, Brazil) for two consecutive summers. Besides Zmix, we analyzed the visible light attenuation (KdPAR), dissolved organic carbon (DOC), chlorophyll-a (Chl-a), total suspended solids (TSS), and fetch. We also analyze the quality of the dissolved organic matter (DOM) through colored dissolved organic matter (CDOM), spectral slope (S), DOC-specific absorbance (SUVA) and the ratio between the absorbance at 250 nm and 365 nm (E250:365). Our results showed quite different results during the two years studied. In the summer of 2012, when there was higher rainfall, variations in Zmix were correlated to the optical factors associated with DOM quality, while in the drier summer of 2013 Chl-a, TSS and fetch were the variables that more explained Zmix. It suggests that DOM regulates the Zmix in the rainy periods in the studied tropical lakes and that control is determined by the balance between the DOM input (runoff) and output (such as photodegradation) of the aquatic systems. In reduced rain conditions (summer 2013), the factors responsible by chemistry photodegradation of DOM were predominant, and the organic matter was no longer controlling Zmix, which was driven by internal mixing, productivity, and the wind (Chl-a, TSS and fetch). In this study we showed how changes in precipitation might cause shifts in the factors that regulate the epilimnion thickness in tropical lakes. 相似文献
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以艾比湖流域主要入湖河流为研究对象，在5月（丰水期）和8月（枯水期）分别沿博尔塔拉河（博河）和精河进行采样，采用平行因子模型（PARAFAC）和三维荧光区域积分法对水体三维荧光特性进行研究并对其与水质的关系在枯、丰水期下的变化进行探讨.结果表明①河流DOM在枯水期与丰水期都含有C1（240、425 nm） UVC类腐殖质，C2（225、290 nm）紫外区内络氨酸类有机物，C3（230/280、330 nm）蛋白类有机物，C4（265、260 nm）腐殖质类共4种组分.通过对水体三维荧光进行区域积分可以看出DOM荧光成分的占比在不同时期的变化.博河在枯水期时EEM光谱中的区域Ⅲ富里酸含量低于丰水期，枯水期时区域Ⅱ芳香类蛋白质、区域Ⅳ可溶性微生物代谢物以及区域Ⅴ类腐殖质酸高于丰水期；对于精河来说，区域Ⅱ芳香类蛋白质和区域Ⅳ可溶性微生物代谢物在枯水期的含量高于丰水期，区域Ⅲ富里酸和区域Ⅴ类腐殖质酸的含量枯水期低于丰水期，这表明水体腐质化程度较高.②本研究选取了一些常规的荧光指数来描述枯、丰水期水体的荧光指数特性.经研究发现，精河的荧光指数、自生源指数和腐殖化指数在不同时期的变化幅度较小，而博河的变化幅度较大.③将荧光指数与水质参数进行相关性分析并建模，结果表明枯水期自生源指数（BIX）与化学需氧量呈显著正相关，相关系数R=0.688；丰水期时BIX与铵态氮浓度呈显著负相关，相关系数R=-0.493.通过对比分析艾比湖主要入湖河流的三维荧光光谱特性与水质在枯、丰水期时的关系进一步表明水体中DOM的特性以及在枯、丰水期下的差异，为艾比湖流域的治理改善提供一定的理论支持和参考依据. 相似文献
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Characterizing the properties of dissolved organic matter isolated by XAD and C-18 solid phase extraction and ultrafiltration 总被引：1，自引：0，他引：1
Sara B. Schwede-Thomas Yu-Ping Chin Karl J. Dria Patrick Hatcher Edith Kaiser Barbara Sulzberger 《Aquatic Sciences - Research Across Boundaries》2005,67(1):61-71
17.
Stefania Mazzuoli Steven Loiselle Vincent Hull Luca Bracchini Claudio Rossi 《洁净——土壤、空气、水》2003,31(6):461-468
The spatial and temporal distribution of humic substances in aquatic ecosystems can have important effects on ecosystem productivity, negatively impacting primary productivity while positively impacting secondary productivity. In the present investigation, a large shallow lake ecosystem was studied to determine the spatial and seasonal variation of the composition and concentration of humic substances. Concentrations of total dissolved organic matter, humic acid, and fulvic acid were found to display significant spatial distributions (1.3…13.5 mg/L, DOM; 0.1…5.4 mg/L, HA). The distribution is described by using mapping techniques and the analysis of the spatial distribution of the lake. An analysis of the seasonal variations also indicated the dependence of the occurrence of these compounds on meteorological and hydrological conditions. To identify the potential sources of these organic materials, an analysis was made of the ratio of humic and fulvic acid fractions and total DOM. It was found that areas of high DOM concentration coincided with the areas of highest HA percentage of total DOM. Furthermore using the ratio of the normalised concentrations of HA, FA, and residual DOM (< 5000 g/mol) it was found that areas dominated by each are spatially distinct. This confirms the hypothesis that in these shallow lakes, photodegradation and bacterioplankton activity will create a residence time dependent zonation of each component of the total DOM. 相似文献
18.
The fluorescence and molecular weight characteristics of dissolved organic matter (DOM) in groundwater of Bangladesh were investigated to evaluate its multiple roles on arsenic (As) mobilization and poisoning. Fluorescence properties of DOM were measured in groundwater samples collected from two As contaminated areas of Bangladesh (Faridpur at the Ganges floodplain and Sonargaon at the Meghna floodplain) from different locations and depths. The three dimensional excitation–emission matrix (3DEEM) fluorescence spectra of groundwater samples showed two characteristic peaks around Ex/Em = 335–365 nm/435–480 nm for fulvic-like peaks and peak at around Ex/Em = 275–290 nm/310–335 nm for the protein-like materials. The similarity of fluorescence spectra of groundwater and surface water of both the study areas with high intensity of fluorescence and its strong correlation with DOC reflect the in situ generation of fluorescent DOM from sedimentary organic matter (SOM) and recent recharge of terrestrial labile organic carbon into shallow aquifer. High performance size-exclusion chromatography (HPSEC) analysis of DOM shows positive correlations between fluorescence intensities (FI) of small molecular fractions (0.65 kDa) and As concentrations, with the signatures of protein-like peaks of DOM in groundwater. This result provides new evidence that small molecular weight fraction of DOM in groundwater of Bangladesh can play an important role on As mobilization and toxicity. In addition, high concentration of fluorescence materials in DOM of As contaminated groundwater of Bangladesh may pose a threat to public health. 相似文献