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1.
悬浮颗粒物和沉积物是湖泊有机污染物的主要承载物质,其稳定同位素研究对有效识别有机质污染导致的湖泊富营养化具有重要意义.本研究选取乌梁素海为研究区,于2019年4月（融冰期）、7月（夏灌期）和10月（秋灌期）对湖区及入湖渠道的表层沉积物和悬浮颗粒物中有机碳的δ13C、C/N比及总有机碳（TOC、POC）和总氮（TON、PON）含量进行测定分析,联合采用δ13C、C/N及同位素多元混合模型研究湖泊有机碳来源及其贡献率.结果表明,乌梁素海悬浮颗粒物有机碳δ13CPOC的变化范围为-23.29‰~-29.75‰,呈现10月>4月>7月、入湖渠道>湖区的趋势,悬浮颗粒物POC/PON比变化范围为4.10~21.35,呈现出4月<7月<10月的时间变化,悬浮颗粒有机质主要来源于浮游植物（51.59%）、入湖渠道泥沙（34.60%）和大型水生植物（13.76%）.沉积物有机碳δ13CTOC变化范围为-27.58‰~-22.68‰,呈现4月<10月<7月的变化,沉积物TOC/TON比变化范围为3.06~23.77,时空变化明显,沉积物有机质则主要源于入湖渠道挟带的泥沙,贡献达72.79%以上,而浮游植物与大型水生植物的贡献率相差较小,分别为11.85%和15.36%.本研究可以初步判定受入湖渠道影响的富营养化湖泊中悬浮颗粒物和沉积物有机碳来源,为改善湖泊有机污染和研究有机碳来源提供更多理解. 相似文献
2.
鄱阳湖候鸟栖息地湖泊悬浮有机质的碳氮分布及来源分析——以大湖池和沙湖为例 总被引：1，自引：0，他引：1
以江西鄱阳湖国家级自然保护区的2个湖泊——大湖池和沙湖为研究对象，分析不同季节和水位悬浮有机质的碳氮稳定同位素（δ13C和δ15N）及碳氮比值（C/N）的变化特征，甄别悬浮有机质的来源.结果表明：在不同水位条件下，悬浮有机质的δ13C和δ15N均存在差异显著性.沙湖5月水位上涨时，悬浮有机质δ13C最正，均值为-26.4‰±0.9‰，10月退水后，δ13C最负，均值为-31.2‰±1.1‰.悬浮有机质δ15N值在5月和8月较低（范围为3.5‰~5.5‰），10月也相对较低，均值为6.1‰±0.6‰，而12月相对较高（7.3‰~10.8‰）.悬浮有机质C/N值在10月最低，均值为6.5±0.6，小于7，与其他各月的C/N有显著差异，而其他各月C/N在7.8~8.7之间，不存在显著差异.大湖池悬浮有机质δ13C、δ15N各月的变化趋势与沙湖类似，并且两个湖泊在相同月份的δ13C、δ15N或C/N均不存在显著差异，但大湖池的δ13C和δ15N比沙湖的δ13C和δ15N均值略偏正0.1‰~0.5‰，C/N比沙湖的C/N略偏低0~0.4.有机δ13C、δ15N结合C/N示踪表明，大湖池和沙湖的悬浮有机质在5月水位上涨和8月丰水期主要来源于河流运输的土壤有机质，表层沉积物对5月悬浮有机质也有一定贡献（16%），水生浮叶植物对8月悬浮有机质有一定贡献（25%）；10月秋季退水后悬浮有机质主要来源于藻类（77%），表层沉积物有一定贡献（23%）；12、3和4月冬、春季枯水期悬浮有机质主要来源于表层沉积物，候鸟粪便对12月悬浮有机质有较大贡献（40%），湿地植物碎屑对3和4月有较大贡献（47%和51%）. 相似文献
3.
白洋淀沉积物氮磷赋存特征及其内源负荷 总被引：11，自引：2，他引：9
白洋淀环境整治对区域生态文明建设具有重要意义，然而，目前对加剧白洋淀富营养化的内源氮、磷污染负荷依然缺乏系统的研究.本研究以野外调研和室内培养实验相结合形式，在白洋淀主要水域内采集原位柱状沉积物样品，详细地研究了白洋淀沉积物中氮、磷赋存形态、间隙水中氮、磷剖面特征以及沉积物-水界面氮、磷交换特征.结果表明，白洋淀沉积物总氮、总磷含量分别为1230.8~9559.0 mg/kg（均值2379.5 mg/kg）和344.4~915.4 mg/kg（均值608.4 mg/kg），氮、磷累积污染量大.沉积物中铵态氮赋存量大（3.2~175.8 mg/kg），由此导致间隙水中铵态氮浓度较高，最高达到28.8 mg/L.沉积物磷形态以Ca-P和Fe-P为主，分别占总量的38.3%~76.1%和3.98%~18.0%，间隙水中磷酸盐浓度已接近甚至高于国内外典型富营养湖区.间隙水中高浓度的铵态氮和磷酸盐导致沉积物-水界面氮、磷交换通量较高，铵态氮平均释放和扩散通量分别为106.37和12.42 mg/（m2·d）；磷酸盐平均释放和扩散通量分别为15.06和2.33 mg/（m2·d），沉积物内源氮、磷污染负荷较高，已严重威胁到白洋淀水环境质量，迫切需要整治.其中，北部河口区域以及中部府河入湖区和人口密集活动区沉积物氮、磷内源负荷尤为突出，应成为白洋淀沉积物内源污染整治的关键区域. 相似文献
4.
溶解态有机质(DOM)是湖泊沉积物的重要组分,解析DOM的组成和来源对于深入理解湖泊有机质生物地球化学循环及控制水体富营养化具有重要意义。 本研究于2021年5月和8月采集了大庆市库里泡表层及柱状沉积物、泡内水生物(浮游藻类、挺水植物和沉水植物)、岸边土壤、陆生C3和C4植物、禽畜粪便以及城镇污水等样品,分析了样品DOM的稳定同位素(δ13C 和 δ15N)组成及三维荧光光谱特征,并利用IsoSource软件计算了不同来源样品对沉积物DOM的贡献率。结果显示:(1)库里泡内表层沉积物DOM的δ13C和δ15N组成存在季节性差异,5月δ13C和δ15N均值分别为-25.54‰和9.02‰,8月分别为-26.81‰和8.40‰。(2)库里泡内柱状沉积物DOM的δ13C和δ15N组成在垂直方向存在差异,表层(0~3 cm)δ13C和δ15N均值分别为-26.58‰和9.04‰,深层(3~30 cm)均值分别为-25.40‰和10.61‰。(3)表层沉积物DOM的三维荧光组分存在季节性差异。5月以类腐殖质荧光组分为主,占比为87.89%,HIX和BIX分别为6.27和0.67;8月蛋白类荧光组分占比为49.58%,HIX和BIX指数均值分别为1.72和0.87。(4)5月表层沉积物DOM外源输入占比为61%,以土壤(21.40%)和城镇污水(18.08%)为主;而8月内源贡献占比稍高(55.10%),且以挺水植物为主(48.68%)。(5)柱状沉积物(0~30 cm)不同深度DOM来源组成相近,主要为城镇污水、沉水植物/藻和挺水植物,贡献率均值分别为42.13%、25.07%和18.53%。整体上,库里泡沉积物DOM来源主要受到流域内人类活动及气候特征的影响,本文研究结果有利于加深对我国东北地区湖泊沉积物有机质迁移转化及累积规律的认识。 相似文献
5.
基于内蒙古寒旱区达里诺尔湖（简称"达里湖"）无河流外泄、冬季湖面冰封、水体流动缓慢等典型区域水文气象特征，对夏、冬季湖泊底层、表层水（冰）、入湖河水、浅层地下水（井水、泉水）等样品中稳定氢、氧同位素（δD、δ18O）值的变化进行对比分析，结果显示湖区不同水体δD和δ18O平均值均存在湖泊水体（水、冰体） > 大气降水 > 入湖河水 > 浅层地下水的变化特征.在达里湖，夏、冬季底层水δD、δ18O值均比表层水（含湖冰）中δD、δ18O值偏负且季节变化幅度较小.此外，冬季不同采样点底层水δD、δ18O平均值的区域差异性比夏季明显，这反映了湖泊底层水体相对封闭、稳定的储存环境，也说明地下水补给过程存在一定程度的区域差异.而基于不同区域底层水δD、δ18O值及氘盈余指数（d）值和水深变化间相互关系的分析，发现水深变化可能是影响达里湖底层水δD、δ18O值分布区域差异及补给过程的主要因素之一：东北部水体较浅（水深小于8 m）区域采样点水体δD、δ18O平均值多数比达里湖整体平均值偏负且d值偏正，指示浅层地下水输入及二次蒸发作用的影响；西南部水体较深（水深超过8 m）区域采样点水体δD、δ18O平均值多数比达里湖整体平均值偏正且d值偏负，说明水体相对稳定，受二次蒸发作用的影响较弱. 相似文献
6.
生态补水是维持和改善白洋淀生态环境的重要途径.为研究生态补水对白洋淀水环境的影响，分别在补水前与补水后采集淀水、河水及地下水样品，分析区域地表水和地下水水化学特征.结果表明：（1）白洋淀补水前、后地表水与地下水的水化学组成中Na+为主要阳离子，补水后阴离子以HCO3-为主，淀区南部地表水电导率高；补水后地表水与地下水Ca2+、Mg2+和HCO3-浓度显著增加，水体电导率降低.（2）补水前地下水为Na-HCO3型水，地表水主要为Na-Cl·SO4及Na-Cl·HCO3类型；补水后地表水与浅层地下水向Ca·Mg-HCO3型演化，深层地下水水化学类型基本保持不变.（3）生态补水使白洋淀水位升高，淀区水面积增大，缓解了水资源短缺的问题；同时也使浅层地下水水化学组成发生改变，而深层地下水暂未受到影响.生态补水后，受稀释和混合作用的影响，水体Na+、Cl-和SO42-浓度显著下降，Ca2+、Mg2+及HCO3-浓度增加.在白洋淀生态补水中应"先治污，后补水"，以减少补水过程中污染物向淀区的运移，还应注意区域地下水位上升过程中的阳离子交换及水岩相互作用，为合理调配生态补水及改善白洋淀生态环境提供科学依据. 相似文献
7.
内蒙古高原达里诺尔湖夏季水体稳定同位素变化特征 总被引：4，自引：2，他引：2
基于内蒙古高原寒-旱区达里诺尔湖（简称"达里湖"）相对集中的夏季大气降水、强烈的蒸发作用等典型区域气候环境特征，结合湖泊水体温度、盐度等理化指标变化，对夏季达里湖湖水、入湖河水、区域大气降水等样品中稳定氢、氧同位素（δD、δ18O）值变化进行了对比分析.结果显示：虽然整体上达里湖夏季水体并没有形成明显的物理性质"跃层"（如温跃层、盐跃层等），水体理化指标的空间分布相对稳定，但是夏季湖水中δD、δ18O值却随着水深增加逐渐偏负：δD值由表层水体（0~1 m）到底层水体（7~9 m）偏负约1.40‰，δ18O值由表层水体到底层水体偏负约0.27‰.达里湖夏季"大气水线"为δD=8.22δ18O+6.82，显示大气降水中δD、δ18O值受季风降水效应影响的同时受到区域蒸发作用影响.特别是7、8月大气降水同位素变化受降水效应的影响比6、9月更明显，而6、9月大气降水同位素变化受蒸发作用的影响比7、8月更明显.这也导致达里湖夏季上层水体受大气降水的稀释作用影响显著；伴随水深的增加，降水效应及蒸发作用的混合影响逐渐减弱，底层水体受区域地下水补给过程等因素的影响则可能更加明显，即达里湖夏季上层水体和底层水体中稳定同位素组成变化的影响因素存在差异. 相似文献
8.
phoD基因编码的碱性磷酸酶驱动沉积物有机磷矿化并释放生物可利用磷,促进了富营养化湖泊蓝藻的生长与暴发,但对富营养化湖泊蓝藻生消周期phoD基因细菌群落动态变化的认识依然有限.本文研究了中国典型富营养化湖泊巢湖蓝藻生消过程沉积物碱性磷酸酶活性（APA）、phoD基因细菌多样性和群落结构的动态变化及其与环境的关系.结果显示：巢湖沉积物APA活性在蓝藻生长与暴发阶段显著升高,且与水温、pH、溶解氧（DO）等环境因子显著相关.蓝藻生消各阶段沉积物phoD基因细菌群落的优势菌属均由Pseudonocardia和Friedmanniella构成;与蓝藻潜伏期和衰亡期相比,生长初期与暴发期大多数样点沉积物Pseudonocardia的丰度显著降低而Friedmanniella显著升高.携带phoD基因的菌属丰度呈显著的时空变化,其中菌属丰度的空间异质性较高.蓝藻生长初期与暴发期的phoD基因细菌群落的Ace指数与Shannon多样性指数显著大于潜伏期与衰亡期.研究表明,携带phoD基因细菌群落结构的变化主要受APA、DO、叶绿素a、水温、总磷以及无机磷的驱动;春季蓝藻的生长消耗大量上覆水溶解性无机磷,激发了沉积物APA活性并诱发Friedmanniella生长从而缓解水体磷限制. 相似文献
9.
盐分是参与湖泊物质循环的重要成分之一，湖泊盐度增加对湖泊生态系统健康造成了严重的威胁.乌梁素海总溶解性固体（TDS）和盐度均处于较高的水平，为揭示盐分在冰-水-沉积物中的分布及迁移规律，冰封期在乌梁素海7个采样点采集冰、冰下水和不同深度沉积物样品，分析样品的TDS、Na+和Cl-浓度，得到各自在冰-水间浓度的比值，即分配系数K，并对水-沉积物界面Na+和Cl-的扩散通量进行估算.结果显示，TDS、Na+和Cl-在冰-水中分配系数K的均值分别为0.02、0.03和0.01，表明在湖水结冰形成冰盖的过程中，随着冰晶的析出，TDS、Na+和Cl-逐渐在水体中浓缩，水体中Na+和Cl-在浓度梯度驱动力作用下，向沉积物间隙水中扩散，估算其扩散通量均值分别为-229和-676 mg/（m2·d）.总之，湖水在冻结过程中，由于冰晶的析出，盐分向冰下水体中迁移，使得盐分浓度在冰下水体中浓缩增加，继而向沉积物中迁移，对湖泊水生态环境构成胁迫. 相似文献
10.
蓝藻水华暴发形成的大量有机碎屑，沉降到沉积物表面，影响沉积物有机质矿化，进而影响碳氮磷循环.本实验选择于桥水库湖心区作为沉积物采样点，通过设置不同密度藻屑添加组（×1倍组和×20倍组）及空白对照组，研究藻屑堆积对沉积物矿化特征的影响及其环境效应，为蓝藻水华影响下的饮用水环境修复和科学管理提供一定的理论依据.结果表明：（1）藻屑添加降低了上覆水pH值，改变了沉积物生物酶活性.藻屑添加密度越大，上覆水pH值越低、波动越大，反映了培养过程异养微生物活性的变化.×1倍组的转化酶活性较高；×20倍组蛋白酶活性和碱性磷酸酶活性较高.（2）藻屑添加对沉积物的矿化途径和沉积物产物的释放速率产生了显著影响.藻屑添加密度越大，有机质矿化速率越大.其中，×1倍组主要增强好氧矿化，释放CO2；×20倍组主要增强厌氧产甲烷矿化，释放CH4.（3）不同密度的藻屑添加组，其氮磷扩散、释放通量存在明显差别.×1倍组以沉积物吸附为主，其上覆水NH4+和PO43-平均释放速率与对照组差异较小；×20倍组的NH4+在第0~10天以沉积物吸附为主，之后和PO43-均以向上覆水中释放为主，其NH4+和PO43-平均释放速率（分别为0.223）和0.075 mg/（L·d））明显大于其他实验组.因此，大量蓝藻堆积明显促进沉积物的碳氮磷矿化，释放大量CO2、CH4和氮磷营养盐至上覆水中，对湖泊水环境造成污染，为蓝藻的生长繁殖作贡献. 相似文献
11.
《中国科学:地球科学(英文版)》2014,(12)
正SCIENCE CHINA Earth Sciences,an academic journal cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press and Springer,is committed to publishing high-quality,original results in both basic and applied research. 相似文献
12.
《中国科学:地球科学(英文版)》2014,(9)
正SCIENCE CHINA Earth Sciences,an academic journal cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press and Springer,is committed to publishing high-quality,original results in 相似文献
13.
In natural waters arsenic concentrations up to a few milligrams per litre were measured. The natural content of arsenic found in soils varies between 0.01 mg/kg and a few hundred milligrams per kilogram. Anthropogenic sources of arsenic in the environment are the smelting of ores, the burning of coal, and the use of arsenic compounds in many products and production processes in the past. A lot of arsenic compounds are toxic and cause acute and chronic poisoning. In aqueous environment the inorganic arsenic species arsenite (As(III)) and arsenate (As(V)) are the most abundant species. The mobility of these species is influenced by the pH value, the redox potential, and the presence of adsorbents such as oxides and hydroxides of Fe(III), Al(III), Mn(III/IV), humic substances, and clay minerals. 相似文献
14.
Due to deleterious effects on non-target organisms, the use of organotin compounds on boat hulls of small vessels (<25 m) has been widely prohibited. The International Maritime Organisation (IMO) resolved that the complete prohibition on organotin compounds acting as biocides in antifouling systems should commence in 2008. As a result of restrictions on the use of organotin based paints, other antifouling formulations containing organic biocides have been utilised. This survey was conducted to assess the contamination of replacement biocides in the marine environment following the ban of TBT-based paints. Surface sediments samples were collected in the major ports and marinas along the France Mediterranean coastline (Cote d’Azur) and analysed for organotin compounds, Irgarol 1051, Sea-nine 211TM, Chlorothalonil, Dichlofluanid and Folpet. Every port and marina exhibited high levels of organotin compounds, with concentrations in sediments ranging from 37 ng Sn g−1dry wt in Menton Garavan to over 4000 ng Sn g−1dry wt close to the ship chandler within the port of Villefranche-sur-Mer. TBT degradation indexes suggested that fresh inputs are still made. Among the other antifoulants monitored, only Irgarol 1051 exhibited measurable concentrations in almost every port, with concentrations ranging from 40 ng g−1dry wt (Cannes) to almost 700 ng g−1dry wt (Villefranche-sur-Mer, ship chandler). 相似文献
15.
Ian R. Falconer 《洁净——土壤、空气、水》2005,33(1):64-71
Microcystins are cyclic heptapeptide toxins produced by a range of cyanobacterial genera. These cyanobacteria occur naturally in drinking water reservoirs subject to eutrophication, and in rivers and natural lakes. Because of the diversity of organisms, the toxins occur, from oligo‐mesotrophic lakes in North Temperate latitudes, to hypertrophic tropical ponds. The toxins are responsible for numerous cases of injury and death of domestic animals, and human poisoning from drinking water. The initial poisoning includes hepatic cell death. This leads to secondary effects from liver deficiency, including jaundice and photosensitisation. The toxic effects are largely due to inhibition of phosphatase enzymes, acting to regulate protein phosphorylation. The consequences include structural damage, apoptosis and, at lower concentrations, cell cycle effects and tumour promotion. As there is no clear evidence for direct carcinogenesis by microcystins, they are classed as non‐carcinogenic toxins in drinking water. Guideline Values for safe drinking water are derived from data for subchronic rodent toxicity, using the No Observed Adverse Effect Level (the highest dose giving no toxicity). To this dose are applied uncertainty factors, to calculate a Tolerable Daily Intake. On the basis of a standard bodyweight and water consumption the Guideline Value is determined for drinking water. For microcystin‐LR the WHO have set a provisional Guideline Value of 1 μg/L for drinking water. 相似文献
16.
The geomagnetic field and secular variation exhibit asymmetrical spatial features which are possibly originating from an heterogeneous thermal control of the Earth's lower mantle on the core. The identification of this control in magnetic data is subject to several difficulties, some of which can be alleviated by the use of core surface flow models. Using numerical dynamos driven by heterogeneous boundary heat flux, we confirm that within the parameter space accessible to simulations, time average surface flows obey a simple thermal wind equilibrium between the Coriolis and buoyancy forces, the Lorentz, inertial and viscous forces playing only a secondary role, even for Elsasser numbers significantly larger than 1. Furthermore, we average the models over the duration of three vortex turnovers, and correlate them with a longer time average which fully reveals the signature of boundary heterogeneity. This allows us to quantify the possibility of observing mantle control in core surface flows averaged over a short time period. A scaling analysis is performed in order to apply the results to the Earth's core. We find that three vortex turnovers could represent between 100 and 360 years of Earth time, and that the heat flux heterogeneity at the core-mantle boundary could be large enough to yield an observable signature of thermal mantle control in a time average core surface flow within reach of the available geomagnetic data. 相似文献
17.
George W. Housner 《地震工程与工程振动(英文版)》2008,7(2):I0001-I0001
Destructive earthquakes have caused great damage in China and the United States and collapsing buildings havecaused many deaths and injuries. The field of earthquake engineering studies earthquake hazards, the occurrence ofearthquakes of various magnitudes, the nature of the ground shaking during an earthquake, the vibration of structuresduring earthquakes, the strengthening of existing structures and the design of new structures to be earthquake resistant,and finally, how to cope with earthquake damage and restore a city to normal functioning. Such efforts are in progressin both countries, but unfortunately, the language barrier interferes with the free flow of information between China andthe Untied States. It would be mutually beneficial if some means could be developed to promote the exchangeof information across the Pacific Ocean. This new journal has been established for this purpose and its success willbe an important step in promoting earthquake engineering in China and the United States. 相似文献
20.
JianCheng Shi 《中国科学:地球科学(英文版)》2014,57(10):2281-2282
正Global Change includes climate change and other environmental changes caused by the joint interaction among various layers of Earth. From the positive side, global change provides new opportunities to human and other living forms on Earth. In the meantime, it creates tremendous challenges and negative impact. At present, the negative impacts have reached all primary processes of the global ecosystem and every aspect of human society, especially causing degradation of the ecosystem. For instance, intensive deforestation causes decline of biodiversity; global warming causes sea level rise and increases 相似文献