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渤海春季营养盐限制的现场实验 总被引：22，自引：0，他引：22
1999年4－5月，在现场条件下对天然水体中浮游植物以外加营养盐受控培养的方式，研究和探讨春季渤海中部、莱州湾和渤海海峡3个海区的浮游植物生长的营养盐限制问题。结果表明，在莱州湾附近浮游植物生长受到显著的磷限制；尽管水体中硅酸盐浓度较历史水平大大降低，并且实验进行时硅藻为优势种，但是硅酸盐尚不成为限制因子；渤海中部不存在营养盐的限制问题，营养盐浓度和结构相对适宜；渤海海峡也不存在营养盐的限制问题，但是溶解无机氮的相对含量略低。 相似文献
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哑铃湾网箱养殖水体中氮磷结构特征 总被引：2，自引：0，他引：2
根据2002年4月-2003年1月对哑铃湾网箱养殖的调查数据,分析了养殖水体中不同形态N／P值的分布趋势、季节变化及哑铃湾网箱养殖水体中的限制性营养盐。结果表明：各形态N／P具有显著的季节变化,其分布趋势基本表现为网箱养殖区低于非养殖区,并且随着养殖年限的增加,这种现象更明显。总体上说,哑铃湾浮游植物生长主要受P的限制,但从无机态N／P来看,春、夏季以P为该海域浮游植物生长的控制因子：秋、冬季以N为该海湾浮游植物生长的控制因子。 相似文献
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文章通过2015年8月航次对厦门湾周边海域浮游植物群落结构特征以及相关环境因子进行调查。结果表明:调查共鉴定浮游植物2门25属41种,其中硅藻24属39种,甲藻1属2种,浮游植物细胞密度介于4.32×105~7.79×106个/m3。浮游植物的主要趋势是从九龙江口-厦门鼓浪屿海域向同安湾以及湾外递减,鼓浪屿海域属于高密度区域,这和营养盐的变化趋势基本相同。富营养化指数(E)平均为7.12,N/P值平均为17.36,说明水体呈富营养化,且营养盐结构表现为磷限制。根据研究结果显示,厦门湾近岸水体营养盐含量较高,浮游植物含量也较高,极容易引起赤潮,因此控制含氮磷污水的流入是改善水质状况的关键。 相似文献
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湛江港外海水富营养化水平与浮游植物多样性 总被引：3，自引：0，他引：3
利用2001年12月在湛江港外海现场调查的资料,分析研究了湛江港外海水营养化水平及其与浮游植物多样性的关系。结果表明:湛江港外海水营养状态指数由北向南、由湾口向湾外递减;浮游植物多样性指数和均匀度则是由北向南增加,东南部水质较好,东北部水质较差;将营养盐含量及营养状态水平与浮游植物多样性指数和均匀度利用最小二乘法进行相关性,相关性不显著,另外,调查期间氮磷比例均失去平衡,这可能是影响该海域浮游植物量与营养盐水平之间关系的原因。 相似文献
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《中国海洋大学学报(自然科学版)》2021,(7)
基于2016年5月至2017年2月山东省乳山湾和丁字湾临近海域浮游植物和水质参数的采样数据,开展了浮游植物季节变化及其与环境因子关系的研究。研究表明:4个季节共鉴定出浮游植物6门119种,其中,硅藻83种,占总种数的69.7%,为该海域浮游植物主要类群;甲藻32种,占26.9%;金藻、蓝藻、裸藻和隐藻各1种,各约占0.8%。水采和网采浮游植物的细胞丰度存在季节差异,夏季和冬季明显高于秋季和春季,季节变化呈典型的双峰模式。春、秋季浮游植物丰度受营养盐浓度和结构控制,其高值区与营养盐浓度的低值区分布基本一致;秋季多样性指数和均匀度指数均较高,而优势度均最低,表明该海域在秋季具有更高的生态系统稳定性和可调节性。本研究对浮游植物季节性差异进行了比较并对其与环境因子关系进行了分析,为探究乳山湾及其邻近海域的浮游植物的分布特征及演变趋势提供了依据。 相似文献
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《中国海洋大学学报(自然科学版)》2015,(5)
以胶州湾为研究区域,建立箱式生态动力学模型,模拟得到胶州湾浮游植物生长受营养盐限制情况的季节变化;通过数值实验分析了胶州湾营养盐限制的区域差异,并进一步比较了1960、1980年代及本世纪初营养盐限制情况的区别。结果表明,胶州湾内的营养盐限制作用有显著的季节变化。春季由于浮游植物旺发消耗大量营养盐,使得湾内营养盐限制春末最强;夏季是河流丰水季,营养盐补充充足,湾内营养盐限制最弱。从不同区域来看,养殖区全年表现为硅限制;河口区和湾口区夏季为磷限制,其他季节为硅限制。营养盐限制作用湾口区最强,养殖区次之,河口区最弱。受此影响,浮游植物生物量河口区最高,湾口区最低。从长期变化来看,1960年代,胶州湾内的营养盐限制作用以氮限制为主,1980年代呈硅和磷交替限制,逐渐演变到本世纪初的以硅限制为主,而且由于营养盐限制作用的逐渐增强,浮游植物生物量也呈现不断下降的趋势。 相似文献
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文章根据2011年5月和8月两个航次的调查资料,分析东山湾营养盐含量、分布、结构特征及其关键影响因子,并探讨了营养盐对浮游植物的限制情况。结果表明,除活性硅酸盐,夏季活性磷酸盐、总磷、无机氮和总氮含量均高于春季;春、夏活性硅酸盐、活性磷酸盐、总磷、无机氮和总氮分布整体呈现为漳江入海口和八尺门海域含量较高,其含量、分布主要受漳江陆源径流的影响,其次为浮游植物的消长;春季东山湾海域水体中N/P、Si/N、Si/P和TN/TP平均比值分别为64.3、9.1、583.1和13.4,夏季平均比值有所降低,分别为28.3、4.9、155.3和13.3;春季N/P、Si/N、Si/P、TN/TP高值区均位于湾口位置,而夏季N/P、Si/N、Si/P、TN/TP整体呈现以八尺门邻近海域为中心、自西向东扩散;2011年春、夏季均存在磷限制现象,春季尤为严重,磷限制的站位比例为83.3%。 相似文献
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莱州湾渔业资源与环境变化趋势分析 总被引：1，自引：0，他引：1
依据近30年来关于莱州湾环境典型污染物、浮游植物和渔业资源的调查资料,报道了莱州湾水环境质量、浮游植物和渔业资源的变迁规律,并简单分析了三者之间的关系;结果表明:(1)从上世纪80年代初起至本世纪初,莱州湾环境中无机氮平均含量经历了由低到高的变化,到2009年无机氮含量已超过劣四类海水水质标准;元机磷平均含量呈总体降低趋势,氮磷摩尔比在所考察的大部分时段内高于Redfield阈值(16);(2)1980年代末以来,磷是限制莱州湾浮游植物生长的限制性营养盐,莱州湾浮游植物的种类在减少,群落结构趋于简单化;(3)莱州湾渔获物种数年均减少1.5种;鱼卵、仔稚鱼种类年均减少0.7种;单位捕捞努力量渔获量年均降低10 kg/h;近海捕捞量逐年减少,仅潍坊市,近海捕捞量从1989年的18.7万t减少到2007年的1.7万t;(4)限制浮游植物生长的营养盐从氮转变为磷,莱州湾浮游植物群落已由硅藻占绝对优势演变为硅藻和甲藻共同占优势;(5)与其他因素相比,氮磷比与莱州湾近海捕捞量存在更显著的相关性;氮磷比及COD含量与渔获物种数存在显著相关性;说明海水氮磷比是决定莱州湾渔业资源量的关键因素,而资源种数受有机物污染影响较大。 相似文献
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初步构建了一个以浮游植物（P）、浮游动物（Z）和营养盐（N,包括无机氮和活性磷酸盐）为生态变量的NPZ简单生态模型,并通过与POM三维水动力模型的耦合,建立了三维浮游生态动力学模型,开展了厦门湾全海域三维浮游生态系统时空变化的模拟研究.结果显示,厦门海域浮游动植物有明显的季节变化,春、夏季生物量最高,秋、冬季较低,但不同的海区达到峰值的季节并不相同;活性磷酸盐含量冬季最高,春季最低,与浮游植物量值有较明显的反位相关系,表明厦门湾海域浮游植物的生长主要受活性磷酸盐含量限制.模拟结果符合历史观测特征,且模拟值与实测值量级比较吻合,因此所建立的三维浮游生态动力学模型可用于描述厦门湾海域浮游生态的时空变化特征. 相似文献
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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
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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
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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
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《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
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The relationship between the flux of exotic benthic foraminiferal tests (i.e. tests which are supplied from open-sea sources alone) in a tidal inlet and that of bulk sediment was analysed, which can be expressed as two first-order linear equations. According to this relationship, in order to determine net sediment transport directions in the entrance, the test concentration in surficial sediments of the tidal basin can be compared against a ‘ critical level ’. The critical level is determined for the conditions that no net transport of bulk sediment is present within the entrance. If the observed concentration (averaged over the tidal basin) is higher than the simulated critical level, then the net sediment transport is directed to landward. This method is applied to the analysis of net sand transport at Christchurch Harbour, a tidal inlet system located in southern England. In this investigation, concentrations of exotic foraminiferal tests in the surficial sediments of the tidal basin and ebb tidal delta area were obtained from the analysis of sea-bed sediment samples. A series of probable critical levels were calculated based upon the data sets with regard to: (1) sediment discharge from the rivers; (2) magnitude of sediment discharge within the entrance during the ebb; (3) the test concentration outside the harbour; (4) the thickness of the moving layer; and (5) two parameters associated with dispersive processes. The results show that the concentration in the tidal basin sediment is higher than a number of simulated critical concentrations for representative cases. Consequently, the high level of the concentration of exotic benthic foraminiferal tests within the harbour should be explained as a result of landward net transport of sands within the entrance. 相似文献
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The behaviour of an axially pre-loaded cylindrical member of an offshore structure, hit by a supply ship, has been investigated. The effects of axial pre-loading on the dynamic properties of members, the extent of damage and propagation of dynamic instability in the tubular members have also been investigated. Numerical models have been validated using available experimental data from the literature although these are mostly static with no pre-loading. Axial pre-loading was found to change the dynamic characteristics of some cylindrical members quite dramatically while it had no significant effect on others. The study examined whether there was any change in the behaviour between local and global modes when the loading was dynamic rather than static. The effect of damping on the dynamic instability of axially pre-loaded tubes under lateral dynamic loads was also studied. It was observed that for some geometries the quasi-static response can be used to define the boundary between bounded and unbounded dynamic responses. The main contribution of this study, compared with previous investigations reported in the literature, is that both pre-loading and dynamic effects have been included. 相似文献
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Rahul Sharma 《Marine Georesources & Geotechnology》2000,18(3):237-250
Observations on seafloor features from subbottom profiling and seabed photography data show that the undisturbed and natural conditions before the benthic disturbance undergo a substantial change after operation of the disturber. The effects can be seen in the form of deep trenches and grooves, formed by the action of the sleds and the pumping of the sediment along its path, as well as sediment piles on either side of the track. Biological traces such as fecal coils, casts, tubes, burrows, and trails get obliterated in the areas of disturbance and resedimentation. The smooth, uniform nature of the seafloor observed in predisturbance phase shows microtopographic changes in and around the disturbed area as a result of sediment excavation and resettlement. Vertical mixing as well as lateral transport of sediment alter the geological, biological, physical, and chemical conditions on the seafloor, which need to be monitored over time to assess the process and the time taken for restoration of environmental conditions. 相似文献
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Vance P. Vicente 《Marine Ecology》1989,10(2):179-191
Abstract. Long-term changes in the distributional patterns of commercial sponges ( Spongia spp. and Hippospongia spp.) within the West Indian Region indicates that: 1) commercial sponges had a widespread distribution throughout the whole West Indian Region and were ubiquitous in very shallow water until about the first half of the present century; 2) they were fished commercially not only in the traditional northern Caribbean sites (Florida, Gulf of Mexico, Bahamas) but also in the Greater ( e. g. , Hispaniola, Jamaica) and Lesser Antilles; and 3) they became extinct throughout most of the Lesser Antilles ( e. g. , Puerto Rico, Vieques, St. Thomas) sometime during the first half of this century. Mortalities of spongiids within the Antilles were found to differ from other marine mortalities in that: 1) species disappeared from a large region; 2) species vanished from different habitats and depths; and 3) natural populations never recovered. Species richness patterns suggest that commercial sponge genera ( Spongia and Hippospongia ) evolved under slightly cooler elimatic conditions than those found at present, and that these extinctions occurred as a direct or indirect effect of positive thermal anomalies in sea surface and atmospheric temperatures between 1900–1950. The concept that species diversity is stable on a regional scale is questioned. 相似文献