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1.
上海滨岸潮滩水沉积物中无机氮的季节性变化 总被引:31,自引:0,他引:31
对长江口南翼上海滨岸带3个站点潮滩上覆水,沉积物和间隙水中的3态无机氮的含量分布的年度季节性监测研究表明:潮滩上覆水中溶解无机氮以NO3-N为主:表层沉积物中可交换态无机氮以NH4-N为主,约占70%-85%,沉积物间隙水中主要无机氮为NH4-N和NO3-N。潮滩水体中NH4-N的季节性变化幅度不大,而NO3-N和NO2-N的季节性变化明显,在冬季含量明显降低;但沉积物和间隙水中氮氨和硝态氮的浓度在冬季则有较大增加。初步探讨了潮滩水和沉积物中无机氮分布季节性变化的主要影响因素,估算了潮滩表层沉积物-水界面无机氮的扩散通量,指出NH4-N的扩散释放对滨岸水环境质量影响较大。 相似文献
2.
通过对有排污口的老港(LG)、白龙港(BLG)潮滩和附近没有排污口的朝阳农场潮滩(CY)的沉积物-水界面营养盐通量的研究发现:污水排放造成潮滩上覆水体中营养盐含量增加,进而影响到潮滩沉积物-水界面营养盐氮磷的交换通量;各点中低潮滩的差异(特别是生物活动的影响),造成了中低潮滩对上覆水中N、P作用的差异;老港和白龙港潮滩由于污水的排放使影响沉积物-水界面营养盐交换通量的盐度因素的作用变得不太明显。 相似文献
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基于多参数指标的长江口滨岸多环芳烃来源辨析 总被引:2,自引:0,他引:2
在长江口滨岸及临近排污口、滨岸河流、城市中心城区采集悬浮颗粒物、表层沉积物、街道灰尘等样品, 分别利用GC-MS 和GC-C-IRMS 定量分析了不同环境介质中的多环芳烃 (PAHs) 与有机单体化合物稳定碳同位素(δ13C), 开展了基于PAH 环数、分子量特征比值和有机单体化合物稳定碳同位素组成等参数指标的长江口滨岸悬浮颗粒物与表层沉积物中PAHs 源解析研究。研究结果显示, 长江口滨岸悬浮颗粒物与表层沉积物中的PAH 化合物主要以3~4 环为主, 与吴淞排污口、石洞口污水处理厂、黄浦江、滨岸小河流以及上海中心城区等潜在来源区域不同环境介质中的PAHs 组成特征相似, 主要来源于汽油、柴油、煤炭和木材的不完全燃烧以及石油残余物的混合。其中, 木材和煤炭不完全燃烧形成的PAHs 以及石油残余物, 枯季经过滨岸河流及排污口直接输入, 洪季则为城市街道灰尘被暴雨冲刷, 随地表 径流最终汇入河口; 汽车排放(汽油、柴油不完全燃烧) 产生的PAHs 主要富集在城市交通区和商业区的街道灰尘中, 枯季借助区域盛行风迁移至河口区, 洪季则主要通过暴雨径流冲刷进入河口。 相似文献
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长江口潮滩沉积物-水界面无机氮交换通量 总被引:11,自引:1,他引:10
对长江口滨岸潮滩7个典型断面三态氮的界面交换通量进行了三年多的季节性连续观测,结果表明无机氮的界面交换行为存在复杂的空间分异和季节变化。NO-3-N和NH+4-N的界面交换通量正负变化范围较大,分别介于-32.82~24.13 mmol.m-2.d-1和-18.45~10.65mmol.m-2.d-1之间;而NOsup>-2-N的界面交换通量很小,仅为-1.15~2.82 mmol.m-2.d-1。NO-3-N的界面交换具有明显的上下游季节性时空分异特征,而NH+4-N的界面交换则表现为南北岸季节性时空分异现象。盐度是控制长江口滨岸潮滩NH+4-N界面交换行为的主要因素,而沉积物粒度、水体 NO-3-N浓度、沉积物有机质含量、水温和溶解氧含量则以不同的组合方式,共同制约着 NO-3-N在潮滩界面交换的时空分异格局。 相似文献
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长江口滨岸湿地无机氮界面交换通量量算 总被引:1,自引:0,他引:1
基于3年长江口滨岸湿地沉积物-水界面无机氮季节性交换通量连续实测数据,建立无机氮界面交换通量空间插值模型与量算模型,对无机氮界面交换通量季节性空间分布特征、滨岸湿地不同岸段无机氮季节性界面交换总通量量算等研究。结果表明:修正GIDS插值模型在无机氮界面交换通量空间插值预测过程中精度明显优于IDS方法,而略优于普通Kriging方法;长江口滨岸湿地沉积物-水界面无机氮交换通量空间分布在不同季节表现出复杂的空间分异特征;利用修正GIDS插值模型对长江口滨岸湿地无机氮交换通量进行空间插值过程中,为提高通量量算模型精度,应采用1.2'×1.2'的空间尺度为最佳;长江口滨岸湿地无机氮界面交换总通量量算表明,长江口滨岸湿地在春季向水体释放无机氮,是水体无机氮的释放源,释放量为1.33×104 t,夏季、秋季和冬季表现为净化水体中无机氮,是水体无机氮的吸收汇,分别净化无机氮量为4.36×104 t、6.81×104 t和2.24×104 t,全年总体表现为净化水体中无机氮,净化量为12.1×104 t;长江口多年水体中无机氮通量多项式拟合分析得出,2002~2004年3年长江口水体中无机氮通量平均值为52.6×104 t,滨岸湿地对长江口水体中无机氮的年均净化率达23.0%。 相似文献
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《中国地理与资源文摘》2006,(4)
P342,S153.612006043070长江口滨岸湿地无机氮界面交换通量量算=CalculationofinorganicnitrogenfluxesintheYangtzeEstuarytidalwetland/王军,陈振楼…∥地理学报.—2006,61(7).—729~740基于3年长江口滨岸湿地沉积物-水界面无机氮季节性交换通量连续实测数据,建立无机氮界面交换通量空间插值模型与量算模型,对无机氮界面交换通量季节性空间分布特征、滨岸湿地不同岸段无机氮季节性界面交换总通量量算等研究.图5表5参43(广兵)BeTV148.1,TV1472006043071钱塘江河口段长周期泥沙冲淤和河床变形=Long-termsed-imenterosion/depositionand… 相似文献
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大河口潮滩地貌动力过程的研究-- 以长江口为例 总被引:1,自引:0,他引:1
该文阐述河口潮滩的发育依赖于河流泥沙来源、河口动力和海底地形诸方面的有利条件.长江口潮滩在世界大河三角洲潮滩发育中独具特色.大河口潮滩的平面形态有“长条状”、“裙状”、“沙咀状”和“江心洲”型,横剖面形态有“宽缓型”、“陡岸型”和“侵蚀崖型”.主河道两侧潮滩水流基本上是往复流,但岛屿面向外海一侧的潮滩是旋转流.潮滩近底流速随着高程的增大而减小.虽然潮汐始终是潮滩水动力的控制因子,但径流起着加强落潮流和改变流速不对称性的作用.潮滩上的波能随风力、水深、滩坡和植被状况而变化.长江口潮滩水体属高浑浊水体,悬沙浓度变化于每升几百毫克至每升几万毫克之间.在总体迅速淤涨的背景下,大河口潮滩存在不同时间尺度的冲淤循环. 相似文献
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长江河口潮滩表层沉积物对磷酸盐的吸附特征 总被引:53,自引:2,他引:53
实验研究了长江口滨岸潮滩表层沉积物对上覆水体中磷酸盐(PO4-P)的吸附特性,结果表明,沉积物吸磷过程主要发生在0-10小时(h)内,尔后基本上达到一种动态平衡过程,但在0-0.5h沉积的对PO4-P的吸附速率最大,达到10.40-56.40mg/kg h,且其吸附速率受细颗粒物含量影响明显。沉积物对PO4-P宾吸附容量达26.32-204.08mg/kg,且吸附容量与Fe^3 和总有机碳(TOC)含量有了的正相关关系;PO4-P的吸附效率达21.55-248.30L/kg,且吸附效率主要取决于TOC含量。此外,环境因子(温度,pH和盐度等)圣沉积的吸磷作用显著。 相似文献
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《中国地理与资源文摘》2005,(2)
TV14 8 2 0 0 5 0 2 0 971海河口水沙特征及运动规律分析 =ThecharacteristicsofwaterandsandintheHaiheRiverestuaryandmovementruleanalysis/温随群 ,邢焕政∥海河水利 .— 2 0 0 4 (2 ) .— 2 8~ 31介绍了海河口水沙基本特征 ,分析了海河口潮汐水沙运动规律 ,介绍了其发展趋势 .指出 ,如果今后河口下泄径流量还维持近年来的水平 ,且不采取任何治理措施 ,则河口仍然会维持现状的水沙运动状态 ,最终导致河口萎缩 ,淤成海岸岸滩 .图 1(白识英 )HBP6 4 ,P736 2 0 0 5 0 2 0 972长江口滨岸潮滩柱样沉积物与孔隙水中氮的垂直分布特征=Nitr… 相似文献
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长江口水域悬沙浓度时空变化与泥沙再悬浮 总被引:29,自引:0,他引:29
根据近年来长江河口及其邻近水域8个测站1年的表层悬沙浓度逐日观测资料,并结合水动力状况,对悬沙浓度的时空变化进行了分析。结果发现,长江口自徐六泾以下悬沙浓度不断增高,并呈现口内夏高冬低,而口外冬高夏低,且量值为口外大于口内,杭州湾大于长江口。表明长江入海泥沙在海洋动力作用下强烈再悬浮;悬沙浓度在时间上呈现明显的大小潮周期和季节性变化。进一步分析认为,海洋动力 (风浪和潮流) 是泥沙再悬浮的主导因素,制约悬沙浓度的年内变化,其中潮流控制悬沙浓度的大小潮周期变化,风浪引起悬沙浓度的季节性变化,河流径流和海洋动力的对比制约悬沙浓度的空间分布。 相似文献
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A detailed analysis of suspended sediment concentration (SSC) variations over a year period is presented using the data from 8 stations in the Yangtze River estuary and its adjacent waters, together with a discussion of the hydrodynamic regimes of the estuary. Spatially, the SSC from Xuliujing downwards to Hangzhou Bay increases almost constantly, and the suspended sediment in the inner estuary shows higher concentration in summer than in winter, while in the outer estuary it shows higher concentration in winter than in summer, and the magnitude is greater in the outer estuary than in the inner estuary, greater in the Hangzhou Bay than in the Yangtze River estuary. The sediments discharged by the Yangtze River into the sea are resuspended by marine dynamics included tidal currents and wind waves. Temporally, the SSC shows a pronounced neap-spring tidal cycle and seasonal variations. Furthermore, through the analysis of dynamic mechanism, it is concluded that wave and tidal current are two predominant factors of sediment resuspension and control the distribution and changes of SSC, in which tidal currents control neap-spring tidal cycles, and wind waves control seasonal variations. The ratio between river discharge and marine dynamics controls spatial distribution of SSC. 相似文献
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长江口水域悬沙浓度时空变化与泥沙再悬浮 总被引:4,自引:0,他引:4
A detailed analysis of suspended sediment concentration (SSC) variations over a year period is presented using the data from 8 stations in the Yangtze River estuary and its adjacent waters, together with a discussion of the hydrodynamic regimes of the estuary. Spatially, the SSC from Xuliujing downwards to Hangzhou Bay increases almost constantly, and the suspended sediment in the inner estuary shows higher concentration in summer than in winter, while in the outer estuary it shows higher concentration in winter than in summer, and the magnitude is greater in the outer estuary than in the inner estuary, greater in the Hangzhou Bay than in the Yangtze River estuary. The sediments discharged by the Yangtze River into the sea are resuspended by marine dynamics included tidal currents and wind waves. Temporally, the SSC shows a pronounced neap-spring tidal cycle and seasonal variations. Furthermore, through the analysis of dynamic mechanism, it is concluded that wave and tidal current are two predominant factors of sediment resuspension and control the distribution and changes of SSC, in which tidal currents control neap-spring tidal cycles, and wind waves control seasonal variations. The ratio between river discharge and marine dynamics controls soatial distribution of SSC. 相似文献
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We present, to our knowledge, the first dissolved arsenic (As) data from the pore waters of a closed-basin, saline lake, Pyramid Lake, USA. The As concentrations first decrease across the sediment-water interface to values below lake water concentrations and then rapidly increase to values as high as 5.85mol L–1 at a depth of 15 cm. This maximum value is reached at the top of the sulfate reduction zone. The profile suggests that As is remobilized in the suboxic and anoxic zones of the sediments and is reprecipitated near the sediment-water interface under oxic conditions. 相似文献
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北部湾北部滨海湿地水体和表层沉积物中营养元素分布与污染评价 总被引:2,自引:0,他引:2
2009年4~5月,对北部湾北部滨海湿地水体和表层沉积物进行了取样调查,研究水体中营养盐和表层沉积物中碳、氮和磷元素含量、分布及其影响因素,并在此基础上评价了滨海湿地水体富营养化水平和表层沉积物的污染状况.研究区水体中的溶解无机氮(dissolved inorganic nitrogen,DIN)、活性磷酸盐PO43-—P和化学需氧量(CODMn)平均含量分别为(211.84±37.44) μg/L、(11.01±12.11) μg/L和(0.92±0.32) mg/L;表层沉积物中总氮(TN)、总磷(TP)和总有机碳(TOC)的平均含量分别为(373±355) μg/g、(232.28±157.34) μg/g和(0.45±0.46)%.北部湾北部滨海湿地水体中的DIN含量和PO43-—P含量在茅尾海和廉州湾东部西场海区都很高,且水体富营养化比较严重,大规模的海水养殖可能是造成该现象的主要原因.研究区水体中CODMn含量空间分布呈近岸高、远岸低的特征.研究区铁山港顶部、南流江口、大风江口、钦江和茅岭江口较细的表层沉积物中的TN、TP和TOC含量较高.研究区表层沉积物的TOC/TN值分布表明,钦江口、钦州港区、防城港、企沙港区和珍珠湾东北部的沉积物有机质含量受到了强烈的陆源影响.根据加拿大安大略省环境质量评价标准,除了钦州湾顶部的龙门港区、大风江口中部和铁山港顶部西北角一小部分区域的表层沉积物中的TOC、TN和TP含量分别略高于1%、550μg/g和600μg/g,已被明显污染,而处于最低级别或严重危害级别,会对部分底栖生物产生影响外,其他绝大部分区域都属安全级别,为清洁或部分已被轻微污染. 相似文献
16.
The carbon cycle and biogeochemical dynamics in lake sediments 总被引:27,自引:3,他引:27
Walter E. Dean 《Journal of Paleolimnology》1999,21(4):375-393
The concentrations of organic carbon (OC) and CaCO3 in lake sediments are often inversely related. This relation occurs in surface sediments from different locations in the same lake, surface sediments from different lakes, and with depth in Holocene sediments. Where data on accumulation rates are available, the relation holds for organic carbon and CaCO3 accumulation rates as well. An increase of several percent OC is accompanied by a decrease of several tens of percent CaCO3 indicating that the inverse relation is not due to simple dilution of one component by another. It appears from core data that once the OC concentration in the sediments becomes greater than about 12%, the CO2 produced by decomposition of that OC and production of organic acids lowers the pH of anoxic pore waters enough to dissolve any CaCO3 that reaches the sediment-water interface. In a lake with a seasonally anoxic hypolimnion, processes in the water column also can produce an inverse relation between OC and CaCO3 over time. If productivity of the lake increases, the rain rate of OC from the epilimnion increases. Biogenic removal of CO2 and accompanying increase in pH also may increase the production of CaCO3. However, the decomposition of organic matter in the hypolimnion will decrease the pH of the hypolimnion causing greater dissolution of CaCO3 and therefore a decrease in the rain rate of CaCO3 to the sediment-water interface. 相似文献
17.
Concentrations of heavy metals (Cu, Pb, Zn, Cr and Cd), and phosphorous (P) were determined in surface tidal flat sediments of the Yangtze estuary and Shanghai coast. Results demonstrate that there were significant differences among the accumulation of the heavy metals in sediments, following the order: Zn > Cu > Cr > Pb > Cd. The spatial distribution and chemical forms of heavy metals in tidal flat sediments were closely related to the distribution of pollution resources (outlet of sewage) and the local sedimentary and hydrodynamic conditions. The dominated form of non-residual heavy metals is bound to Fe/Mn oxides, and the next form is bound to carbonates. Moreover, contents of total P in sediments range from 18.0 μmol.g-1 to 31.4 μmol.g-1 along the coastline, speciation of P in sediments was different, most of P in tidal flat sediments is associated with calcium phases (as Ca-P) similar to marine sediments. 相似文献
18.
区域地下水水质是水质评价的重要内容,也是合理制定地下水开发利用及保护治理方案的基本前提。以科尔沁沙地奈曼地区地下水水质为研究对象,选取2005-2014年地下水水质监测数据,分析地下水水质时空变化特征。结果表明:近10年来奈曼地区地下水水质各指标均值均低于地下水Ⅱ类标准,pH值、NO3-含量、化学需氧量(CODcr)在局部地区出现超标现象,但水质总体较好;该地区地下水矿化度(TDS)与Ca2+、Mg2+、Na+、HCO3-、SO42+浓度及CODcr具有明显的正相关关系,即随着Ca2+、Mg2+、Na+、HCO3-、SO42+、CODcr浓度的增加,TDS也会增加;各主要指标浓度随时间呈下降趋势,SO42+、Na+、HCO3-浓度及TDS较稳定,而Ca2+、Mg2+、Cl-、PO43-浓度及CODcr随时间变化较为明显;Ca2+、Mg2+ 、HCO3-、SO42+浓度及TDS农田非灌溉井> 农田灌溉井> 沙地水位井,Na+、CODcr浓度沙地水位井> 农田非灌溉井> 农田灌溉井,NO3-浓度沙地水位井> 农田灌溉井> 农田非灌溉井;该地区地下水水质变化主要与碳酸盐岩溶解、农药化肥的使用、工业及生活污水排放有关。 相似文献