共查询到20条相似文献，搜索用时 46 毫秒
1.
桑沟湾海水中营养盐分布及潜在性富营养化分析 总被引：3，自引：0，他引：3
根据2003年8月—2004年7月桑沟湾海区12个航次海水营养盐的调查资料,分析了该海区海水营养盐的分布特征及时空变化,评价了水质的潜在性富营养化状况。结果表明,溶解无机氮的年平均浓度为10.15μmol/dm3。4个季节中溶解无机氮以NO3-N为主要存在形式,占年平均含量的78.69%,其中以秋季的含量为最高。NH3-N占无机氮年平均含量的15.11%,NO2-N占无机氮年平均含量的6.20%。活性磷酸盐的年平均浓度为0.23μmol/dm3,浓度呈现春季较低和秋季较高的分布特征。活性硅酸盐的年平均浓度为2.86μmol/dm3,浓度呈现冬季较低和夏季较高的分布特征。DIN∶P,Si∶DIN和Si∶P的比值年平均分别为43.2,0.31和13.4,磷酸盐和硅酸盐为限制因素。与1983年在该海域所获数据比较发现,溶解无机氮的浓度是20年前的10.7倍,活性磷酸盐的浓度较20年前降低了43.9%,活性硅酸盐的浓度较20年前降低了34.1%。桑沟湾海区营养水平仍很低,总体上处于贫营养或中度营养化阶段,海水水质质量较好。 相似文献
2.
胶州湾海水营养盐的分布及潜在性富营养化研究 总被引：2，自引：0，他引：2
根据2009年5、8、10月胶州湾海区3个航次海水营养盐的调查资料,分析了该海区海水营养盐的分布特征和时空变化,利用潜在富营养化评价模式评价水质营养状况。结果表明,溶解无机氮、活性磷酸盐以及活性硅酸盐的年均含量分别为0.335、0.028和0.725 mg/L,NO3-N是DIN的主要组成部分,占溶解无机氮含量的71.6%;8月营养盐含量高于5月和10月,营养盐的空间分布从东部河口区和北部养殖区两个高含量区向湾中心和湾口呈逐步递减之势;DIN∶P,Si∶DIN和Si∶P的比值年平均分别为53.9,2.03和57.7,活性磷酸盐为限制因素,胶州湾海域处于磷中等限制-磷限制潜在性富营养化,楼山河口和李村河口为中度营养-富营养,一旦有外界磷大量输入可能发生赤潮。 相似文献
3.
通过3个航次的调查,分析了2008年枯水季、丰水季和平水季广西铁山港附近海域无机氮、活性磷酸盐和活性硅酸盐的分布特征及营养盐结构特征,探讨该海域营养盐季节变化及其影响因素。结果表明,铁山港附近海域无机氮的浓度范围为1.03~44.99μmol/L,活性磷酸盐浓度为0.03~1.57μmol/L,活性硅酸盐的浓度为7.86~102.14μmol/L。高浓度的营养盐主要分布在铁山港湾内及靠岸站点,营养盐的浓度均从铁山港湾口向北海南部海域呈递减的趋势。无机氮、活性磷酸盐和活性硅酸盐显现了相近的季节变化特征,即枯水期到丰水期浓度增加之后从丰水期到平水期浓度降低。该海区无机氮主要以硝酸盐氮和氨氮占最主要比重,枯水期和丰水期以硝酸盐氮为主而平水期以氨氮为主。海区N/P和Si/P较高,表明该海区N限制减弱而P限制加重。铁山港营养盐的季节变化主要受到径流等输入的影响,浮游植物的消耗也可能是其季节变化的原因之一。 相似文献
4.
江苏近岸海域表层海水中营养盐组成、分布及季节变化特征 总被引：1，自引：0，他引：1
根据2014~2015年江苏近岸海域4个航次现场调查资料,分析探讨了该海区表层海水的溶解无机氮(DIN)、活性磷酸盐和硅酸盐含量及分布特征,并对江苏近岸海域表层水质进行富营养化评价。海区全年表层DIN平均浓度均符合国家4类海水水质标准,表层活性磷酸盐平均浓度均符合国家二类海水水质标准。DIN表现为冬季夏季秋季春季。NO_3-N在4个季节均为DIN的主要存在形态,NO_2-N的比例随水温的升高而呈上升趋势。灌河口和江苏海域南端启东嘴处为营养盐高值区,而海州湾是营养盐低值区。江苏近岸海域在夏季基本处于磷限制潜在性富营养。而秋季北部海域基本处于磷限制潜在性富营养,南部海域处于中度营养及富营养状态;冬季海州湾基本处于磷限制潜在性富营养,其余海域处于中度营养及富营养状态,春季海区整体呈现中度营养及富营养状态。 相似文献
5.
文章基于2020年5月（春季）和10月（秋季）莱州湾近岸海域环境监测数据，研究无机氮（DIN）和活性磷酸盐（DIP）的营养盐空间分布特征，分析海水质量状况和富营养化状况，并完成营养盐与环境因子的相关性分析。研究结果表明：莱州湾海域春季DIN的浓度范围为0.115~1.830 mg/L，呈现近岸高于远岸、西部高于东部的分布特征；秋季DIN的浓度范围为0.009~2.070 mg/L，高值区位于黄河河口附近；春、秋季DIP的浓度范围分别为未检出~0.009 mg/L、0.000 4~0.012 9 mg/L，受我国“控磷”“限磷”等磷负荷消减政策的影响，DIP的浓度一直处于较低水平。受DIN浓度的影响，春、秋季分别有35.7%和30.7%的调查站位超第二类海水水质标准。春季有1.4%的调查站位处于轻度富营养化状态，位于小清河河口附近；秋季有1.6%的调查站位处于轻度富营养化状态，位于黄河河口附近；其他站位均未达到富营养化水平。莱州湾海域营养盐的分布特征与多种环境因子呈现明显的相关性，其空间分布受多因素影响。 相似文献
6.
莱州湾营养盐空间分布特征及年际变化趋势 总被引：1，自引：0，他引：1
基于2004-2014年期间,在莱州湾5月及8月开展的22个航次调查结果,研究了莱州湾营养盐的时空分布特征及年际变化趋势。研究发现:莱州湾溶解态无机氮(DIN)、可溶性磷酸盐(PO_4-P)、可溶性硅酸盐(SiO_3-Si)高值区主要出现在莱州湾西南近岸尤其是小清河口海域,小清河及邻近区域陆源输入是影响莱州湾营养盐空间分布的主要因素。2004-2014年莱州湾DIN中位值变化范围8.14~53.98μmol/L,尽管2004年以来莱州湾DIN浓度呈现降低的年际变化趋势,但仍然高于历史数据。硝酸盐是DIN的主要形态,贡献了DIN组成的83%,亚硝酸盐和铵盐的含量占比分别为7%和10%。莱州湾PO_4-P年际变化呈下降趋势,中位值变化范围为0.03~0.49μmol/L。SiO_3-Si中位值变化范围8.5~52.9μmol/L,8月份年际变化呈下降趋势。小清河营养盐入海通量与莱州湾营养盐含量年际波动具有较好的吻合性,是影响莱州湾营养盐年际波动的重要因素。莱州湾DIN/PO_4、SiO_3/DIN、SiO_3/PO_4中位值变化范围分别为:78.9~1112.4、0.2~2.2、40.2~442.5,其中DIN/PO_4、SiO_3/PO_4年际变化呈升高趋势,SiO_3/DIN年际变化趋势不明显。2004-2014年调查期间,莱州湾存在严重的磷限制及季节性的硅限制,营养类型由20世纪80、90年代的贫营养转变为磷限制潜在性富营养,且磷限制的程度呈加剧趋势。 相似文献
7.
大亚湾海域营养盐与叶绿素含量的变化趋势及其对生态环境的影响 总被引：27，自引：0，他引：27
分析了近20a来大亚湾海域营养盐和叶绿素a含量的时空变化规律及其对生态环境的影响.结果表明:大亚湾海域水体中NH3N、NO3N、NO2N、PO4P、SiO3Si、DIN、叶绿素a的多年平均含量分别为1.73±0.89、1.55±0.86、0.30±0.25、3.57±1.55、0.33±0.35、22.03±9.40μmol/dm3和2.47±1.28μg/dm3.自1991年以来,水体中活性磷酸盐的含量有较大幅度的下降,溶解态的无机氮的含量则上升,活性硅酸盐的含量变化较小.大亚湾大部分水体属于贫营养水平,养殖海区水体属于中营养水平.大亚湾海域水体的N/P平均值为21.69±19.38.浮游植物的生长从过去的氮限制转变为现在的磷限制.大亚湾海域营养盐含量和结构的改变,已对该海湾生态系统产生了一定的影响,如浮游植物的小型化和渔获量的大幅下降等. 相似文献
8.
九龙江-河口表层水体营养盐含量的时空变化及潜在富营养化评价 总被引：1，自引：0，他引：1
分别于2012年9月、2013年1、6月,对九龙江两大支流北溪、西溪及河口区开展了3个航次的营养盐监测.研究结果表明,河口区表层水体溶解无机氮（DIN）、总磷（TP）和活性磷酸盐（PO4-P）质量浓度范围分别为0.13-17.35、0.14-1.00和0.00-0.38 mg/dm3,受上游输入和海水稀释作用,营养盐浓度由淡水端至海水端逐渐降低.北溪表层水体的DIN、TP和活性磷酸盐质量浓度范围分别为1.99-24.92、0.12-1.47和0.04-0.68 mg/dm3,受龙岩地区工农业生产及城市进程影响,由上游至下游逐渐降低.西溪表层水体的DIN、TP和活性磷酸盐质量浓度范围分别为2.74-20.61、0.14-0.92和0.02-0.37 mg/dm3,受上游农业生产和下游漳州地区人类活动影响,上下游的DIN质量浓度较高.此外,九龙江沿岸的人类活动可能影响了该地区水体中的溶解无机氮形态组成：北溪和西溪上游的NH4-N和NO3-N占比分别较高.水期分析表明,2013年1月的DIN浓度显著高于其他水期,而不同区域TP和活性磷酸盐的水期波动不尽相同.营养盐结构分析表明,九龙江总体处于磷限制状态,但在河口及北溪部分站位,CDIN/CPO4-P比值已达到适合浮游生物生长繁殖的水平.潜在富营养化程度评价表明,九龙江河口多数站位均处于N或P限制的富营养化级别,但由于N、P营养盐的绝对浓度较高,具有水华暴发的潜在风险. 相似文献
9.
依据2013 年夏季和秋季对黄海海域两个航次的调查结果,对该海域溶解无机氮的季节变化,垂直变化,平面分布状况及其影响因素进行了初步分析和探讨。结果表明,该海域溶解无机氮的分布及组成存在明显的季节性：秋季NO3-N的平均浓度为（7.09±4.15）μmol/dm3,远高于夏季（3.21±3.31） μmol/dm3;夏季NH4-N 含量（0.99±0.95）μmol/dm3 较秋季（0.79±0.82）μmol/dm3 高;夏、秋两个季节溶解无机氮的主要组成部分均为NO3-N,其比例约为70 %和90 %。受浮游植物生长、海水层化以及黄海冷水团存留的影响,调查海域夏季表层溶解无机氮的浓度较低,底层浓度较高;此外,研究海域表层溶解无机氮的分布明显受陆源输入控制,表层溶解无机氮的整体呈现出近岸高外海低的现象,NH4-N的高值区主要出现在靠近城市的近岸海区。该论文可以为该海域氮盐的海洋化学循环研究及赤潮等有害藻华的预防提供科学的理论依据。 相似文献
10.
本研究根据2016—2020 年厦门近岸海域15个航次的监测数据，对该区域营养盐的时空分布特征、影响因素及营养盐限制状况进行综合分析，并评估各海区的富营养化状态。结果表明，空间上，营养盐的分布特征表现为从近岸向远岸逐渐下降的趋势，溶解无机氮(Dissolved Inorganic Nitrogen, DIN)平均浓度排序为：九龙江口＞西海域＞同安湾＞南部海域＞东部海域＞大嶝海域，溶解无机磷(Dissolved Inorganic Phosphorus, DIP)平均浓度排序为：同安湾＞西海域＞九龙江口＞东部海域＞南部海域＞大嶝海域；时间上，营养盐浓度总体呈逐年下降趋势；枯水期最高，平水期次之，丰水期最低。研究海域平均DIN/DIP摩尔比值为40，总体表现为磷限制。2016—2020年厦门近岸海域富营养化指数(E)基本呈逐年下降的趋势；从空间分布上看，九龙江口和西海域富营养化较为严重。富营养化指数与盐度呈显著负相关关系，说明陆源输入对研究海域富营养化存在重要影响。 相似文献
11.
Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
12.
Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
13.
The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
14.
Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding. 相似文献
15.
16.
《海洋学报(英文版)》2014,(9):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
17.
Hoi-Soo Jung Kap-Sik Jeong Yong-Shik Chu Sung-Hyun Park Ki-Hyune Kim 《Marine Georesources & Geotechnology》2001,19(3):181-195
Grain size and water content in box-core sediments from the Clarion-Clipperton fracture zone (C-C zone) in the northeast equatorial Pacific were analyzed in detail to understand the downcore variations across a hiatus between Quaternary and Tertiary layers. Grain-size distributions in the topmost core sediments show two modes: a coarse mode (peaked at 50 μm) and a fine mode (at 2-25 μm). The coarse mode disappears gradually with depth accompanied by the dissolution of siliceous fossil tests, whereas the fine mode coarsens due to the formation of authigenic minerals. Water content increases abruptly across a color boundary between an upper pale brown layer and a lower dark brown layer that is the hiatus between Quaternary and Tertiary layers. Abundant smectites and microvoid molds, which are created by the prolonged fossil dissolution in the underlying sediment, are attributed for the abrupt downcore variation of water content. Overall variations in grain size and water content in the topmost core sediments in the western C-C zone are possibly constrained by the dissolution of biogenic siliceous fossils. Variations in geotechnical properties related to these changes must be considered in the design of nodule collectors. 相似文献
18.
Shigehisa Nakamura 《Marine Geodesy》2001,24(1):27-33
This article concerns an interrelation between the sea levels and the western boundary flow near a tectonic boundary in a local zone in the Northwestern Pacific. In this zone, sea level variations at stations located on the coast facing the Pacific are studied to find the interrelation between variations of the Kurosio flow as an index of the distance of the flow axis off a specific coast. The result is discussed after data processing of the monthly means of the sea levels, and a notice is taken of variations caused by active crustal upheavals during a seismic event, a local earthquake. 相似文献
19.
This study tests the hypothesis that the in situ void ratio of surficial marine sediments may be predicted from shear wave velocity-depth data with a reliability equal to that of other methods currently available. Shear wave velocity is fundamentally controlled by the number of grain-to-grain contacts per unit volume of material and by the effective stress across those contacts. In this study, three previously established empirical formulae are used to predict void ratio from velocity-depth data. Field data were acquired along a transect off the northern Californian coast across which water depth increased from 35 to 70 m and seafloor sediment type varied from sand to silty-sand, respectively. A towed seafloor sled device was used to collect shear wave refraction data, and a marked, systematic decrease in velocity was observed along the line, ranging from 35-70 m/s for the coarse, near-shore material to 25-40 m/s for the finer, offshore deposits. Void ratios predicted from these velocities were compared with data measured directly from box-core samples. Of the formulae used for prediction, two agree remarkably well with the control data. Both predicted and control values increase from 0.6-0.8 for the sandy material to 1.1-1.5 for the silty-sand. Thus, this study does not disprove the hypothesis set and demonstrates the potential of field shear wave velocity-depth data as a means of delineating spatial variation in void ratio for surficial marine sediments in a remote, nondestructive manner. 相似文献
20.
Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease (0.84% ～ 1.88%) of organic carbon content from the upper reaches to the estuary.δ13C values of particulate organic carbon was in the range of -24.9×10-3 to -26.6×10-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ13C and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs (soil organic matter) among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream. 相似文献