Deposition Rates of Terrestrial and Marine Organic Carbon in the Osaka Bay, Seto Inland Sea, Japan, Determined Using Carbon and Nitrogen Stable Isotope Ratios in the Sediment   总被引：1，自引：0，他引：1  

Yasufumi Mishima  Akira Hoshika  Terumi Tanimoto 《Journal of Oceanography》1999,55(1):1-11

Carbon and nitrogen stable isotope ratios (¹³C and ¹⁵N) of surface sediments were measured within Osaka Bay, in the Seto Inland Sea in Japan, in order to better understand the sedimentation processes operating on both terrestrial and marine organic matter in the Bay. The ¹³C and ¹⁵N of surface sediments in the estuary of the Yodo River were less than –23 and 5 respectively, but increased in the area up to about 10 km from the river mouth. At greater distances they became constant (giving ¹³C of about –20 and ¹⁵N about 6). It can be concluded that large amounts of terrestrial organic matter exist near the mouth of the Yodo River. Stable isotope ratios in the estuary of the Yodo River within 10 km of the river mouth were useful indicators allowing study of the movement of terrestrial organic matter. Deposition rates for total organic carbon (TOC) and total nitrogen (TN) over the whole of the Bay were estimated to be 63,100 ton C/year and 7,590 ton N/year, respectively. The deposition rate of terrestrial organic carbon was estimated to be 13,200 (range 2,000–21,500) ton C/year for the whole of Osaka Bay, and terrestrial organic carbon was estimated to be about 21% (range 3–34) of the TOC deposition rate. The ratio of the deposition rate of terrestrial organic carbon to the rate inflow of riverine TOC and particulate organic carbon (POC) were estimated to be 19% (range 3–31) and 76% (range 12–100), respectively.  相似文献   

青藏高原高寒草地小流域水体碳氮输出特征及其影响因素          下载免费PDF全文

杜陈军  张梦瑶  高永恒 《水文》2018,38(2):46-52

以青藏高原长江源区典型高寒草地小流域为研究对象,基于2012年小流域气象监测数据和小流域径流水样分析,探讨了小流域水体碳氮输出特征,分析了气象因子和土壤水热对小流域水体碳氮输出的影响。结果表明,径流水体碳氮质量浓度均较低,其中可溶性有机碳(DOC)、可溶性有机氮(DON)、铵态氮(NH4+-N)和硝态氮(NO3--N)含量分别在2.95~6.96mg.L-1、0.45~1.15mg.L-1、0.02~0.88mg.L-1和0.16~0.36mg.L-1之间;DOC、DON、NO3--N在8~10月份之间随时间逐渐升高,9月中旬达到峰值后波动下降,NH4+-N无显著的季节变化特征,溶解氮中DONNO3--NNH4+-N;DOC和DON的输出量与降水、不同土层(20、40、60、90、120cm)地温和不同深度(10、20、40、60cm)土壤水分、水温呈极显著正相关(P0.001),与90、120cm土壤水分呈极显著负相关(P0.001);NH4+-N的输出量与降水、气温、水温呈显著正相关(P0.05);NO3--N与降水呈极显著正相关(P0.001)。  相似文献   

元素分析仪-同位素比值质谱测量碳氮同位素比值最佳反应温度和进样量的确定   总被引：2，自引：2，他引：0  

徐丽  邢蓝田  王鑫  李中平  毛俊丽 《岩矿测试》2018,37(1):15-20

沉积有机质的碳氮稳定同位素值是进行古气候、古环境及生态系统研究不可或缺的主要研究手段,目前碳氮同位素主要利用元素分析仪-同位素比值质谱(EA-IRMS)系统来测定。EA-IRMS测定过程中的反应温度及样品进样量直接影响反应物在测试中的燃烧程度,从而影响测试数据的精度。本文利用EA-IRMS技术,以标准样品为参考,在不同转化温度下测试碳氮同位素值,研究保证测试精度的最佳反应温度条件;同时,通过分析不同含氮量样品的检测限,明确了样品含氮量与最低检测限之间的关系,确定了精确测定氮同位素值的最低进样量。结果表明:反应温度对测试精度有显著影响,在碳同位素测定时,将反应温度设定为900℃或以上时测试精度均能达到±0.2‰;氮同位素测定时,反应温度须设定为950℃时测试精度才能达到±0.3‰。实验得出样品含氮量与检测限之间的线性相关性为R2=0.873,开展氮同位素测定时可根据此关系来判断和控制进样量。  相似文献   

模拟厌氧水稻土中氮、砷变化及迁移研究          下载免费PDF全文

蒙薪赟  赵嘉  刘璟 《岩石矿物学杂志》2023,42(2):275-284

矿渣和酸性矿山废水的排放会使矿区周围的农田受到污染。为研究厌氧条件下矿区农田中氮和砷之间的联系,本文通过摇瓶实验探究了含砷水铁矿在厌氧含氮农田中释放的砷形态的变化,通过柱实验探究了水稻生长对氮、砷形态和浓度的影响。研究结果发现,在厌氧条件下,外源氮的加入促进了砷污染水稻土中As(Ⅴ)的还原,使生成的As(Ⅲ)浓度最高达396μg/L;在柱实验模拟的厌氧农田不同层位中,水稻的生长过程促进了氮和砷的还原以及砷向下层位的迁移,使装置中的As(Ⅲ)浓度最高达517μg/L;摇瓶实验和柱实验在相近的厌氧条件下,NO^-₃的存在能够直接参与As(Ⅴ)还原。研究结果为农田砷污染的治理提供了一定的参考价值。  相似文献   

Microscale Simultaneous Measurement of Carbon and Nitrogen Isotopes on Natural Diamond     

Akizumi Ishida  Kouki Kitajima  Ko Hashizume  Michael J. Spicuzza  Alexander Zaitsev  Daniel J. Schulze  John W. Valley 《Geostandards and Geoanalytical Research》2023,47(3):569-578

Simultaneous analysis of carbon and nitrogen isotope ratios by SIMS was applied for the first-time to a natural diamond from the Kelsey Lake kimberlite, State Line Distinct, Colorado (UWD-1). This in situ procedure is faster, reduces sample size for analysis, and measures both isotope ratios from a single ~ 10 μm diameter pit, a critical advantage for zoned diamonds. The carbon isotope ratio (expressed as δ¹³C_VPDB) of the bulk UWD-1 crystal, determined by the conventional combustion method in the present study, is -5.9‰ ± 0.2‰ (VPDB, 2s). Nitrogen mass fraction ([N]) and isotope ratio (expressed as δ¹⁵N_Air) were determined by stepwise combustion and gas-source mass-spectrometry, resulting in 553 ± 64 μg g^-1 and -6.7‰ ± 1.1‰ (Air, 2s), respectively. Secondary ions of ¹²C₂^-, ¹²C¹³C^-, ¹²C¹⁴N^-, and ¹²C¹⁵N^- were simultaneously measured by SIMS using three Faraday cups and one electron multiplier. The spot-to-spot reproducibility of δ¹³C and δ¹⁵N values for the UWD-1 (178 spots on sixteen chips, 10 μm spots), were 0.3‰ and 1.6‰, respectively (2s). While ¹²C¹⁴N^-/¹²C₂^- ratios, which are an indicator for [N], varied up to 12% among these sixteen chips, such variation did not correlate with either δ¹³C or δ¹⁵N values. We propose that UWD-1 is a suitable reference sample for microscale in situ analysis of δ¹³C and δ¹⁵N values in diamond samples.  相似文献   

大兴安岭多年冻土泥炭地无机氮动态对秋季冻融的响应北大核心CSCD     

焦亚青  宋立全  臧淑英  孙超峰  鲁博权 《冰川冻土》2022,44(2):387-401

大兴安岭多年冻土泥炭地是对全球变暖响应敏感的地区之一。在全球变暖、多年冻土退化背景下,为了探明秋季冻融对多年冻土泥炭地无机氮时空变化的影响,本研究于2019年9—11月以大兴安岭三种多年冻土泥炭地为研究对象进行野外原位实验,分析了秋季冻融前、中和后期多年冻土泥炭地浅层和深层土壤无机氮的时空变化特征以及浅层和深层土壤含水量和温度的变化规律,建立了土壤无机氮含量与土壤温度和含水量间的多元线性回归模型。研究表明:多年冻土小叶章泥炭地(XY)、兴安落叶松-泥炭藓泥炭地(XA)和白毛羊胡子苔草泥炭地(BM)的土壤铵态氮(NH_(4)^(+)-N)含量变化范围:(1.00±0.00)~(20.60±0.20)mg·kg^(-1),硝态氮(NO_(3)^(-)-N)含量的变化范围:(0.02±0.01)~(14.64±1.11)mg·kg^(-1),且无机氮以土壤NH_(4)^(+)-N为主;秋季冻融后期无机氮含量明显高于前期。尽管水热交互作用对该时期无机氮没有显著影响,但是在不同冻融阶段,无机氮对环境因子的响应程度存在差异:在秋季冻融前、中和后期浅层无机氮动态分别与浅层温度和含水量的变化相关,但在整个秋季冻融期间BM浅层无机氮含量仅对10~20 cm含水量存在响应(R^(2)=0.344,P<0.01)。研究表明,秋季冻融期内,多年冻土泥炭地无机氮发生初步累积,且浅层环境因子对无机氮响应程度最大。本研究可补充大兴安岭多年冻土泥炭地秋季冻融对土壤无机氮影响研究的相关数据,并为多年冻土泥炭地响应全球变暖的温室气体释放的研究提供基础数据支撑。  相似文献   

全球氦气勘探开发进展与利用现状          下载免费PDF全文

贾凌霄  马冰  王欢  于洋  徐佳佳  陈静  邢佳韵 《中国地质》2022,49(5):1427-1437

【研究目的】 由于氦气具有独特的物理特性,在科学研究、医学和高科技行业的用途越来越广泛。寻找更多的氦气资源,满足市场需求,是地质行业的责任。【研究方法】 按照统计分析原则,对全球氦气勘探成果与供需形势进行梳理、总结。【研究结果】 全球氦气资源分布极不均匀,主要氦气供应国为美国、卡塔尔、俄罗斯等。近期,许多公司开始在北美地区、俄罗斯、卡塔尔、坦桑尼亚等地开展氦气的勘探开发,其中北美部分地区的氦气资源位于富含氮气的储层中,具有广阔的开发前景,全球氦气勘探活动掀起新一轮热潮。【结论】 2021年全球氦市场出现供应缺口,当今全球氦气需求的增长开始转向亚洲和中东。建议高度重视氦气不可再生性和不可替代性,开展氦气资源潜力评价工程,勘查国内非烃类氦气矿床前景,加强国际合作,开展国内氦气储备地下空间评价与选址工作,增强中国的氦气储备能力。  相似文献   

液氮溶浸对不同煤阶含水煤样渗流特性的影响     

张磊  田苗苗  曾世攀  郭鲁成  卢硕  唐俊 《岩土力学》2022,43(11):3015-3026

中国包含多种煤阶煤层,由于煤质、地质条件等差异,不同煤层中的水分赋存情况也具有较大差异性。煤阶、饱水度作为影响液氮低温致裂效果的两个重要因素,有必要对其进行深入研究。为此,分别选择褐煤、烟煤与无烟煤3种煤阶煤样,并制备得出饱水度分别为0%、33%与99%的煤样进行液氮溶浸处理,使用摄像机定点拍摄、观察煤样表面宏观裂隙处理前后的演化规律,并对煤样进行氮气渗流试验。试验结果表明：液氮溶浸后褐煤因产生的一条与多条贯穿裂隙发生整体结构上的断裂,烟煤表面有新裂隙产生,原生宏观裂隙有一定的扩展与延伸,无烟煤表面宏观裂隙无明显发育;煤样饱水度越高,液氮的致裂增透效果越显著;液氮溶浸对3种煤阶煤样的致裂增透效果关系为：褐煤>烟煤>无烟煤,在完全干燥状态下,由于热应力不足以破坏颗粒间链接,烟煤与无烟煤的增透效果近似相等;对于褐煤,液氮溶浸处理对完全干燥状态下的煤体即产生有效致裂,渗透率平均增幅高达559.35%,对于烟煤,在饱水度为33%和99%的状态下,液氮溶浸对煤体具有明显致裂效果,渗透率平均增幅分别为330.60%和448.77%,对于无烟煤,在饱水度为99%的状态下液氮溶浸处理才能对煤体产生有效致裂,渗透率平均增幅为185.53%。  相似文献   

Transformation of ammonium nitrogen and response characteristics of nitrifying functional genes in tannery sludge contaminated soil          下载免费PDF全文

Kong Xiang-ke  Zhang Zi-xuan  Wang Ping  Wang Yan-yan  Zhang Zhao-ji  Han Zhan-tao  Ma Li-sha 《地下水科学与工程》2022,10(3):223-232

High concentrations of ammonium nitrogen released from tannery sludge during storage in open air may cause nitrogen pollution to soil and groundwater. To study the transformation mechanism of NH₄⁺-N by nitrifying functional bacteria in tannery sludge contaminated soils, a series of contaminated soil culture experiments were conducted in this study. The contents of ammonium nitrogen (as NH₄⁺-N), nitrite nitrogen (as NO₂^?-N) and nitrate nitrogen (as NO₃^?-N) were analyzed during the culture period under different conditions of pollution load, soil particle and redox environment. Sigmodial equation was used to interpret the change of NO₃^?-N with time in contaminated soils. The abundance variations of nitrifying functional genes (amoA and nxrA) were also detected using the real-time quantitative fluorescence PCR method. The results show that the nitrification of NH₄⁺-N was aggravated in the contaminated silt soil and fine sand under the condition of lower pollution load, finer particle size and more oxidizing environment. The sigmodial equation well fitted the dynamic accumulation curve of the NO₃^?-N content in the tannery sludge contaminated soils. The Cr(III) content increased with increasing pollution load, which inhibited the reproduction and activity of nitrifying bacteria in the soils, especially in coarse-grained soil. The accumulation of NO₂^?-N contents became more obvious with the increase of pollution load in the fine sand, and only 41.5% of the NH₄⁺-N was transformed to NO₃^?-N. The redox environment was the main factor affecting nitrification process in the soil. Compared to the aerobic soil environment, the transformation of NH₄⁺-N was significantly inhibited under anaerobic incubation condition, and the NO₃^?-N contents decreased by 37.2%, 61.9% and 91.9% under low, medium and high pollution loads, respectively. Nitrification was stronger in the silt soil since its copy number of amoA and nxrA genes was two times larger than that of fine sand. Moreover, the copy numbers of amoA and nxrA genes in the silt soil under the aerobic environment were 2.7 times and 2.2 times larger than those in the anaerobic environment. The abundance changes of the amoA and nxrA functional genes have a positive correlation with the nitrification intensity in the tannery sludge-contaminated soil.  相似文献   

再力花/菖蒲生物湿地床去除河水中氮磷的试验     

王骥  张兰英  卢少勇  甘树  金相灿 《吉林大学学报(地球科学版)》2012,(Z1):408-414

采用再力花和菖蒲构建湿地床,以考察其对污染河水的净化效果。6个月的连续试验表明:在水力负荷为0.24 m3/(m2.d)、植物种植密度大于158株/m2的条件下,2种植物存活率均大于93%,说明植物能适应低污染负荷、高种植密度的无土培养环境;再力花和菖蒲湿地床月均去除率分别为:总氮(TN),48.22%～78.53%和43.23%～72.42%;总磷(TP),77.62%～85.67%和58.07%～80.77%。再力花湿地床对TN、TP的净化效果好于菖蒲湿地床;2种植物吸收N、P含量分别占去除总量的比例:N为44.14%、37.75%,P为73.43%、62.05%。湿地床技术可有效去除来水中的TN、TP,通过植物吸收作用累积N、P含量较高,不同种类的植物构建湿地床对污染河水中N、P去除效果存在显著差异,且硝化反硝化和植物吸收是去除N的主要途径,而植物吸收是去除P的有效手段。  相似文献