Hydrological control of dissolved organic carbon dynamics in a forested headwater catchment,Kiryu Experimental Watershed,Japan     

Masatoshi Kawasaki  Nobuhito Ohte  Naoki Kabeya  Masanori Katsuyama 《水文研究》2008,22(3):429-442

To evaluate the influence of hydrological processes on dissolved organic carbon (DOC) dynamics in a forested headwater catchment, DOC concentration was observed along the flow path from rainfall to stream water via throughfall, soil water, groundwater, and spring water for 4 years, and DOC flux through the catchment was calculated. The spatial and temporal variations in DOC concentration and flux were compared with physical hydrological observations and the mean residence time of water. In the upslope soil layer, DOC concentrations were not significantly correlated with water fluxes, suggesting that DOC concentrations were not strictly controlled by water fluxes. In the upslope perennial groundwater, DOC concentration was affected by the change in the amount of microbial degradation of DOC produced by changes in the mean residence time of water. In stream water, the temporal variation in DOC concentration was usually affected by changes in DOC concentration of the inflow component via vertical infiltration from above the perennial groundwater. During dry periods, however, the component from inflow via vertical infiltration was negligible and DOC in the upslope perennial groundwater became the major component of stream water DOC. The temporal variation in stream water DOC concentration during baseflow was affected by rainfall patterns over several preceding months. Therefore, records of rainfall over several preceding months are one of the most important factors for predicting changes in DOC concentration on a catchment scale. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Distribution of Dissolved Inorganic Arsenic and Its Seasonal Variations in the Coastal Area of the East China Sea     

CHENG Yan REN Jingling LI Dandan LIU Sumei ZHANG Jing 《中国海洋大学学报(英文版)》2006,5(3):243-250

Water samples were collected in the coastal area of the Changjiang Estuary on four cruises from August 2002 to May 2003. The seasonal variations of dissolved inorganic arsenic （DIAs） distributions were analyzed. The results showed that the distributions of DIAs were mainly influenced by Water （KSSW）. The concentration of the total dissolved the terrestrial input and the intrusion of the Kuroshio Subsurface inorganic arsenic （TDIAs） decreased consecutively from winter to summer, while it increased in autumn. The distributions of TDIAs showed some relationships with salinity and suspended particulate matter （SPM）. The relationships between DIAs speciation （including arsenite [ As（ Ⅲ ） ] and arsenate [ As（ Ⅴ ） ]）, biological activity and the availabilities of the phosphate were investigated in the study area for the cruise August 2002. The ratio of As （Ⅲ）/TDIAs increased with the decrease of phosphate concentrations. In the bottom water, the As（ Ⅲ ）/TDIAs ratio decreased with the increasing of N/P. The concentration of TDIAs decreased 28.7% approximately after the occurrence of harmful algal blooms （HAB） because of the uptake of arsenate by algae. Further study is needed about the arsenic source/sink relationships in their vertical or horizontal profiles and the uptake mechanism during the occurrence of harmful algal blooms.  相似文献   

Accurate Determination of Sr Isotopic Compositions in Clinopyroxene and Silicate Glasses by LA‐MC‐ICP‐MS          下载免费PDF全文

Xirun Tong  Yongsheng Liu  Zhaochu Hu  Haihong Chen  Lian Zhou  Qinghai Hu  Rong Xu  Lixu Deng  Chunfei Chen  Lu Yang  Shan Gao 《Geostandards and Geoanalytical Research》2016,40(1):85-99

The low‐Sr content (generally < 100 μg g^?1) in clinopyroxene from peridotite makes accurate Sr isotopic determination by LA‐MC‐ICP‐MS a challenge. The effects of adding N₂ to the sample gas and using a guard electrode (GE) on instrumental sensitivity for Sr isotopic determination by LA‐MC‐ICP‐MS were investigated. Results revealed no significant sensitivity enhancement of Sr by adding N₂ to the ICP. Although using a GE led to a two‐fold sensitivity enhancement, it significantly increased the yield of polyatomic ion interferences of Ca‐related ions and TiAr⁺ on Sr isotopes. Applying the method established in this work, ⁸⁷Sr/⁸⁶Sr ratios (Rb/Sr < 0.14) of natural clinopyroxene from mantle and silicate glasses were accurately measured with similar measurement repeatability (0.0009–0.00006, 2SE) to previous studies but using a smaller spot size of 120 μm and low‐to‐moderate Sr content (30–518 μg g^?1). The measurement reproducibility was 0.0004 (2s, n = 33) for a sample with 100 μg g^?1 Sr. Destruction of the crystal structure by sample fusion showed no effect on Sr isotopic determination. Synthesised glasses with major element compositions similar to natural clinopyroxene have the potential to be adopted as reference materials for Sr isotopic determination by LA‐MC‐ICP‐MS.  相似文献   

南极南设得兰群岛附近海域表层沉积物中有色溶解有机物的分布特征及来源分析          下载免费PDF全文

霍城李盼盼  葛林科那广水 朱小梅 《极地研究》2016,28(4):484-490

在南极南设得兰群岛附近海域采集了6个表层沉积物样品,测定了提取液中溶解有机物(DOM)的有机碳含量、紫外-可见吸收光谱和三维荧光光谱,并对有色溶解有机物(CDOM)的分子量信息及各荧光组分的成分和来源进行了分析。结果表明,南设得兰群岛附近海域表层沉积物中DOM提取液的溶解有机碳(DOC)及沉积物有机碳(SOC)的含量呈现由近岸向开阔海域递减的趋势,紫外-可见吸收光谱中的吸收系数(a)也表现出了相似的性质,光谱斜率比(SR)表明近岸沉积物CDOM老化程度较强。通过对三维荧光光谱的分析可知,南设得兰群岛附近海域表层沉积物中的CDOM包含3种荧光组分,即类色氨酸、海洋类腐殖质和陆源类腐殖质,表现出较强的自生源特征,整个研究海域CDOM来源以内源为主,受陆生植物和土壤有机质的外源输入影响较小。通过CDOM各参数的相关性分析发现,沉积物DOM提取液的DOC含量与SOC含量以及吸收系数和腐殖化指数(HIX)等参数相互之间都呈显著正相关,相关系数(r)均在0.88以上,显著性水平P0.01。  相似文献   

赣南小流域水体中溶解态稀土含量及pH和Eh值变化特征     

何晗晗  于扬  刘新星  黄凡  赵芝  李超 《岩矿测试》2015,34(4):487-493

测试流经稀土矿区河水的p H和Eh值,可以反映矿区的酸碱性、氧化还原环境。本文以赣南地区濂水、桃江、东江流域为研究对象,利用ICP-MS和三通道多参数测试仪分别测试水样中溶解态稀土含量(DREEs)和p H、Eh值,分析p H、Eh值的变化特征以及DREEs含量与p H值的相关性。结果表明:1研究区水体中DREEs含量变化较大,介于几μg/L至几十mg/L之间;DREEs经球粒陨石标准化后表现为弱的轻稀土富集模式,Eu、Ce显示负异常;2溶解态稀土及La含量分别与p H值呈弱的负相关性,说明地表水体中DREEs浓度及分布模式在一定程度上受外部环境酸碱性的影响;3对于流经地层、地层内离子吸附型稀土矿区的水样,其p H均值分别为7.40、6.94,Eh均值分别为-0.023 V、6.55 mV;对于流经岩体、风化壳离子吸附型稀土矿区的水样,其p H均值分别为6.61、4.37,Eh均值分别为0.024 V、0.15 V,表明赣南地区离子吸附型稀土矿区处于中酸性的氧化环境。  相似文献   

白云鄂博碳酸岩中矿物的次生反应边结构     

王凯怡  毛骞  马玉光  周建雄 《岩石学报》2015,31(9):2674-2678

在白云鄂博粗粒方解石碳酸岩中,发现了三种围绕硅酸盐矿物的次生反应边结构:1)在方解石中的石英被磷硅钙铈矿反应边环绕与方解石分隔开;2)在方解石中的碱性闪石被磷硅钙铈矿反应边环绕与方解石分隔开;3)方解石中的榍石被硅钛铈矿反应边环绕与方解石分隔开。这种情况表明,在后期阶段该区有富稀土的流体活动,该流体沿石英或硅酸盐矿物与方解石矿物颗粒接触边缘进行交代,生成了次生稀土矿物的反应边环带。这进一步表明,白云鄂博矿床稀土的富集至少与一期富稀土流体的交代作用有关。流体除含REE外,还含有铁和钠,该种流体的成分与以往有关白云鄂博矿床流体研究所得的成分结论是完全一致的。  相似文献   

不同形态磷源对具槽帕拉藻(Paralia sulcata)生长和磷酸酶活性的影响   总被引：1，自引：0，他引：1  

于倩  王清  袁泽轶  吴惠丰  赵建民 《海洋与湖沼》2015,46(5):1018-1023

分别采用磷酸二氢钾(KH2PO4)、β-甘油磷酸钠(Sodium-β-glycerophosphate,β-G-P)、葡萄糖-6-磷酸(Glucose-6-phosphate,G-6-P)、卵磷脂(Lecithin,LEC)和三磷酸腺苷二钠(Adenosine disodium triphosphate,ATP)作为f/2培养基的磷源,探讨了不同形态磷源对具槽帕拉藻(Paralia sulcata)生长及磷酸酶活性的影响。结果发现,具槽帕拉藻能够有效利用上述五种磷源,且溶解有机磷(Dissolved organic phosphorus,DOP)比KH2PO4更有利于具槽帕拉藻的生长;对碱性磷酸酶(Alkaline phosphatase,AP)活性分析发现,大分子DOP(LEC)可能需要通过磷酸酶的水解作用才能被吸收利用。在胞外磷充足的情况下,具槽帕拉藻能够在胞内储存磷源,而在磷限制时则可利用胞内储存的磷源来维持藻细胞的生长。  相似文献   

黄、东海海域溶解无解机砷分布特征与化学形态   总被引：2，自引：1，他引：1  

吴斌  宋金明  李学刚 《海洋学报(英文版)》2015,34(6):12-20

Distribution and chemical speciation of dissolved inorganic arsenic were examined in Yellow Sea and East China Sea. Results demonstrated that: (1) both As(III) and As(V) were detected, with As(V) domin...  相似文献   

钱塘江河口溶解硅的变化与影响研究   总被引：1，自引：1，他引：0  

张丽君  臧家业  马永星  李玲玲  刘炜  张波涛  冉祥滨 《海洋科学》2015,39(8):51-57

根据2013年~2014年四个季度的调查资料,结合历史数据并采用数理分析与经验模型计算相结合的方法,分析讨论了钱塘江河口溶解硅的分布、年代际变化和潜在影响。结果表明,研究区域受到河流冲淡水和东海海水混合的双重影响,溶解硅的分布与浓度呈现出明显的梯度变化与季节规律,其浓度在秋季最高,夏季次之,春季与冬季较低。近些年来溶解硅的浓度呈降低趋势,较历史水平降低了12%~25%,硅氮比也有大幅度的降低,比值自1.25降低到0.52。钱塘江河口溶解硅浓度降低主要是由于东海低溶解硅浓度海水的稀释造成的,而浮游植物量对溶解硅浓度影响有限。另外,河口叶绿素a含量与历史数据相比也存在明显降低,浮游植物细胞总量和种数都有显著下降;硅藻种类减少了近70%,并出现了绿藻、蓝藻和甲藻等非硅藻类生物,造成这几方面变化的原因很可大程度上与营养盐结构和浓度的变化有关。  相似文献   

A Review of the Biogeochemical Cycles of Dissolved Silicon in Rivers   总被引：1，自引：0，他引：1  

Zhang Qianzhu  Tao Zhen  Gao Quanzhou  Ma Zanwen 《地球科学进展》2015,30(1):50-59

The riverine dissolved silicon (DSi) brings environmental information on biogeochemical processes of terrestrial surface, of which the input, transferring, transformation and output are influenced by many factors. Among the weathering of global silicate rocks, 31.53%~64.87% of DSi are intercepted by terrestrial vegetation and only about 12.9% are transferred into rivers. During being transported into ocean, riverine DSi gets impacts from aquatic biological absorption, reverse weathering process and artificial lake effect. The quantity of output is further reduced, which weakens the effect of the oceanic biological pump. According to limited data, the DSi concentration of global rivers has a large variation, ranging from 138 μmol/L to 218μmol/L. It is necessary to quantify contribution rates of influencing factors and establish output models controlled by multiple factors. The δ³⁰Si of riverine DSi ranges from -0.2‰ to 3.4‰. Comparing with the δ³⁰Si of silicate rock, which is about -0.5‰, the fractionation factor is significantly partial to positive from 0.3‰ to 3.9‰. That is because of the occurrence of kinetic fractionation process in river basin including inorganic and organic fractionation. Thus, the key problems, sources and transformation mechanisms of riverine DSi during migration and being transported should be solved in future.  相似文献