The Distribution of Dissolved Oxygen and Eutrophication Assessment in the Downstream, Estuary Water of Minjiang River

闽江流域在我国东南沿海具有重要地位，但由于种种原因，其研究程度和所受的关注度相对较低。近年来，随着闽江流域沿岸经济发展，其污染程度日益加重，不仅使流域水质恶化，更对沿岸生产生活带来不利影响，更进一步威胁近岸的生态环境。为了解闽江下游与河口水域溶解氧四季变化规律，综合评价其富营养化程度，探讨污染物源汇之间的输运通量情况，本文利用2014年8月~2015年5月期间，闽江下游水口水库，至河口表层水样，依据《海洋调查规范》等多项标准中的方法，对温度、盐度、溶解氧、高锰酸钾指数、化学需氧量（COD）、硝酸氮（NO3-N）、亚硝酸氮（NO2-N）、氨氮（NH3-N）、活性磷酸盐（PO4-P）等多项水质指标...Minjiang river has important position in southeasterncoast of China, but because of some reasons, there is low attention and researches paied on it. In recent years, with the economic development along the river, the problems of increasing pollutions become more and more serious. It not only makes the river water quality worsen, but also has negative influences on the production and living along t...学位：理学硕士院系专业：海洋与地球学院_海洋化学学号：2232013115138

Progress in research of hypoxia in estuaries and coastal areas in China

对长江、珠江等河口及其近海水域缺氧现象与影响因素进行研究,结果表明,主要分布于长江与珠江河口及其邻近海域的缺氧现象,夏季(6-8月)达到最盛,秋; 冬季消失;长江口的缺氧区域主要位于30.75°N~32°N,122.5°E~123.25°E附近海域,具有南北2个缺氧中心;珠江口缺氧程度相对较; 轻,缺氧区域主要在广州黄埔区河段至虎门水域和伶仃洋;辽河、钱塘江、海河等河口区域也时而出现零星的缺氧现象;水体缺氧受控于多项环境要素,物理层化作; 用是缺氧产生的最初诱因之一,陆源污染物的分解则是重要的耗氧负荷;各河口区特征各异,潮汐、洋流、营养盐、叶绿素a等要素对缺氧区的范围、程度和持续时; 间影响程度不一。In order to study hypoxia in the main estuaries and adjacent coastal; areas in China, we compared the hypoxia in the estuaries of the Yangtze; River, the Pearl River, and other rivers, and analyzed the factors. We; found that hypoxia mainly occurred in the estuaries of the Yangtze; River, the Pearl River, and the adjacent coastal areas; it had the most; significant increase in the summer (from June to August) and disappeared; in the autumn and winter. The hypoxia zone in the Yangtze River Estuary; was mainly located in the area with latitudes from 30.75°N to 32°N and; longitudes from 122.5°E to 123.25°E, and there were two hypoxia centers; in the south and north, respectively. The degree of hypoxia in the Pearl; River Estuary was relatively moderate, and hypoxia mainly occurred from; the Huangpu section to Humen waters in Guangzhou and in the Lingdingyang; Channel. In addition, hypoxia occasionally occurred in the estuaries of; the Liaohe River, Qiantang River, and Haihe River. We also found that; hypoxia was subjected to many environmental factors, of which the; stratification of water was one of the initial factors and the; decomposition of terrigenous pollutants was a major factor of oxygen; consumption. Tides, upwellings, nutrients, and chlorophyll-a had; different influences on the scale, degree, and duration of hypoxia, due; to the various characteristics of the estuaries

Characteristics of trace elements in sediments of lower reach and estuary of Minjiang River

为探讨闽江下游及河口区表层沉积物中元素组成、分布规律,用X射线荧光法分析了研究区域表层沉积物中11种微量元素的含量,并简要讨论了其分布特征和影响因素.分析结果表明,研究区沉积物中元素bA含量最高,平均为515 Mg/kg,元素gA最低,平均为7.54 Mg/kg,11种元素按含量由高到低排列是bA、rb、zr、Sr、Cr、V、zn、nb、y、Cu、gA;元素变异系数介于0.17~1.05之间,最大为zr,最小为bA.被测元素含量均呈现出沿河道向河口递增的趋势,部分元素表现出南、北港下游含量高于上游的分布特征,显示人类活动的影响.元素含量高值与SI/Al比值所反映出的沉积物细颗粒区域相对应.沉积物微量元素含量与花岗岩成分相近,与石英砂岩存在较大差别.研究区域沉积物与长江、黄河和珠江沉积物相比,bA、rb两种元素含量差异相对较小,4条河流bA约500Mg/kg、rb约100 Mg/kg,其余元素在闽江沉积物中的含量相对较低,元素zn、Cu差异最大.Cu、zn和Cr 3种重金属元素相对以往分析结果较低.被测元素中V、y、zr、nb 4种元素彼此相关性较强,相关系数均在0.8以上.被测元素均与SI/Al比值呈负相关关系,其中rb、bA、Sr关系相对密切,相关系数分别为:-0.887 2,-0.886 5和-0.885 8.通过沉积物微量元素分布及其影响因素探讨的分析表明,元素分布反应出在该区域物源和气候等特征条件影响下物理、化学风化的结果,同时受到沉积物粒度、人为活动和潮汐等因素的共同作用.In ord er to study the element components and distributions of the surface sediments in the lower reach and estuary of Minjiang River,we measured the concentrations of trace elements( V,Cr,Cu,Zn,Ga,Rb,Sr,Y,Zr,Nb,Ba) in the surface sediments of the areas studied with X-ray fluorescence( XRF) and discussed the distribution characteristics of the elements.Analysis results show the maximum concentration among the studied elements is Ba,with an average 515 mg / kg,while the minimum is Ga,with an average 7.54 mg / kg.The coefficients of variation( CV) of elements are calculated between 0.17 ~ 1.05,of which Zr is the lowest and Ba is the highest.The concentration of all elements shows increase from the lower reach to the estuary,and some elements have higher concentrations in the lower reach than the up reaches in North and South branches,reflecting the anthropogenic activities.Higher concentrations and the ratio of Si / Al of the stations are accorded with the areas where sediments grain is fine.The concentration of elements in sediments is similar to that of granite,and differs with quartz sandstone.The results are compared with that of Changjiang River,Yellow River and the Pearl River.It shows little differences between Ba and Rb,with Ba around 500 mg / kg and Rb around 100 mg / kg,in these 4 rivers.The concentrations of other elements are lower,and Cu and Zn are quite difference between Minjiang river and the others.The concentrations of Cu,Zn and Cr are lower than the historical data.V,Y,Zr and Nb have much stronger relations each other.All the correlation coefficients are higher than 0.8.All the elements studied have negative correlation with Si / Al,where Rb,Ba and Sr are much closer with Si / Al and the correlation coefficients are- 0.887 2,- 0.886 5 and- 0.885 8,respectively.The patterns of element distribution responding the characteristics of sediments in Minjiang river suggest that they are the physical and chemical weathering results under the combined influences of provenance and climates,as well as the particle sizes,anthropogenic factors and the tides.国家自然科学基金资助项目(41076122;41376050

Distribution characteristic of clay minerals contents in Minjiang River and its environmental significance

为探究闽江下游及河口区粘土矿物的含量分布特征,于2009年在该区域采集表层沉积物样品25个,利用X射线衍射进行了粘土矿物的含量测定.结果表明粘土矿物的相对百分含量范围分别为:高岭石(33%~47%,平均值为42%),伊利石(27%~43%,平均值为34%),绿泥石(20%~29%,平均值为24%),蒙脱石(0%~3%,平均值为1%).在显著水平为0.01时,伊利石与高岭石、绿泥石的含量呈显著负相关关系,伊利石与高岭石的相关系数为-0.825,伊利石与绿泥石的相关系数为-0.611.通过对闽江下游及河口区粘土矿物含量分布的分析及与中国近海的粘土矿物含量分布对比,闽江下游及河口区粘土矿物的含量分布受物质来源、地形条件、介质环境、粘土矿物自身颗粒大小形态和人类活动的影响.相对于黄河和长江,闽江表层沉积物中具有较高的高岭石含量,较低的伊利石含量,与珠江的粘土矿物组合特征类似,这反映出气候效应的影响.In order to explore the distribution of clay minerals contents in Minjiang River,25 surface sediment samples were collected in 2009.In this paper,clay mineral content of the Minjiang River was measured with X-ray diffraction.The result showed that clay minerals were composed of kaolinite( 42%),illite( 34%),chlorite( 24%)and montmorillonite( 1%).There are good negative correlations of illite with kaolinite and with chlorite.At the significant level of 0.01,the correlation coefficient between illite and kaolinite is- 0.825,and the correlation coefficient between illite and chlorite is- 0.611.The terrigenous kaolinite and illite at sites near the estuary are determined and distributions of clay minerals contents between the Minjiang River and offshores in China compared.In addition to the matter source influence,the distribution of clay minerals contents in Minjiang River are affected by matter source,terrain conditions,depositional environment,particle size and shape of clay minerals and the anthropogenic impacts.In contrast to the Yellow River and the Yangtze River,Minjiang River,similar to that of the Pearl River,has higher content of kaolinite and lower content of illite which suggested the evident of climatic impacts.国家自然科学基金资助项目(41076122;40976037;41376050

Characters of magnetic susceptibility of surface sediments and their significance in the lower reach and estuary of Minjiang River

闽江是中国东南沿海最大的河流,具有落差大、水动力强等典型的山溪型河流特征.本研究对采自闽江流域的43个表层沉积物样品进行了磁学参数分析,结果显示,低频磁化率(χ_(lf))、高频磁化率(χ_(hf))分别为0.79×10~(-8)~24.97×10~(-8)、0.74×10~(-8)~24.80×10~(-8)m~3/kg,与长江、黄河相比低一个数量级;频率磁化率(χ_(fd))为0.06%~7.20%,大多小于5.00%,沉积物中超顺磁颗粒含量较低.χ_(lf)和χ_(fd)总体呈现从下游到河口增长的趋势,并在北港、南港、闽侯、大樟溪等人口密集区域受到不同程度的人为影响,分析表明研究区磁化率受控于源岩特征、水动力条件、沉积作用和人为活动等因素.在p<0.01时,χ_(lf)与Al2O3、Fe2O3、Na2O、Mg O、Ti O_2、Ca O等氧化物显著正相关,与Si O_2显著负相关,说明其受控于源岩成分.此外,χ_(lf)与Si/Al值显著负相关,与化学风化指数(CIA)正相关,表明磁化率可以作为现代沉积物风化程度的替代指标.χ_(lf)与溶解态As含量、χ_(fd)与溶解态Cd含量均在p<0.05时相关,表明磁学参数可作为指示研究区水体的As和Cd污染的参考指标.Minjiang River is the largest river in South-east coastal area of China and it is,as a mountain river,characteristic of large elevation gradient and strong hydrodynamics. Low frequency magnetic susceptibility( χ_(lf)),high frequency magnetic susceptibility( χ_(hf)) and frequency magnetic susceptibility( χ_(fd)) of 51 surface sediment samples collected from the Minjiang River were measured with Bartington MS2. The results shows that χ_(lf)ranges from 0. 79× 10~(-8)to 24. 97 × 10~(-8)m~3·kg~(-1),which is an order less than those of the Changjiang River and Huanghe River sediment. Most of the value of χ_(fd)are lower than 5. 0%,indicating that the content of superparamagetism particles in surface sediment samples are low. In general,the values of χ_(lf)and χ_(fd)progressively increase from low reach to estuary,with significant influence of anthropogenic impact in densely populated areas of the North and the South port,Minhou Country and Dazhangxi Brook. It suggests that magnetic susceptibility is controlled by the source rock differences,hydrodynamics,sedimentation and anthropogenic impact. Magnetic susceptibility can be taken as indicators of source rock differences and weathering intensity,considering its remarkable correlation with major element abundance and ratios of Si / Al( p < 0. 01). χ_(lf)and χ_(fd)are also positively correlated with As and Cd abundance in water,which it means that χ_(lf)and χ_(fd)could be used as a simple proxy of As and Cd contamination in water.国家自然科学基金资助项目(41076122,40976037,41376050