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1.
根据1997年10月和1998年5月2次围隔生态系实验中获得的叶绿素a资料，分析了在富磷围隔实验中不同粒径叶绿素a的变化及各自所占的百分比以及油污染对叶绿素a变化的影响。实验结果表明：在P－meso中，10月份Chl-a的含量每天以10－16μg/L的速度呈指数生长，最高达到74．89μg/L，大于20μm的大型浮游植物是浮游植物总生物量的主要贡献者。5月份Chl-a含量在加磷后增长的速度每天为3－8μg/L，较10月份慢，2－20μm和GF／F－2μm的小型和微型浮游植物是浮游植物总生物量的主要贡献者。 相似文献
2.
依据改革开放40 a来胶州湾营养盐状况历史资料以及2018—2019年的现场调查,对胶州湾营养盐历史变化过程及其生态效应进行了系统分析。结果表明:营养盐的浓度变化大致以2008年为分界节点,在2008年前胶州湾溶解无机氮(DIN)浓度呈现持续上升趋势,而溶解无机磷(DIP)、活性硅酸盐(DSi)浓度则先略有减少后快速增加;2008年后胶州湾3种营养盐浓度均快速减少。营养盐限制状况由20世纪80年代初期的氮限制、20世纪90年代的硅限制转变为目前的磷限制。胶州湾Chl a年均质量浓度一直在3μg·L^-1上下波动但近年来则呈下降趋势,浮游动物生物量1994年后大幅度增加。分析发现,入湾营养盐通量的增加和海域面积缩小是2008年前胶州湾营养盐浓度增加的主要原因,而近十几年来胶州湾环境综合整治措施的大力实施则是氮、磷营养盐浓度减少的主要原因。2010年以前贝类养殖是控制胶州湾浮游植物生物量的主要因素,但近年来溶解无机磷浓度的减少和浮游动物生物量的增加是Chl a质量浓度呈下降趋势的主要原因。 相似文献
3.
海水中的磷以三种形式存在:颗粒磷(POP)(生命有机体内的磷和有机碎屑的磷)、溶解有机磷(DOP)和溶解无机磷(DIP)。浮游植物不仅可以吸收溶解无机磷,一些种类还可以吸收溶解有机磷[1];不同粒径的浮游植物对磷酸盐的吸收能力也有所不同,单位叶绿素a的浮游植物对磷酸盐的吸收速率:0.2~3μm浮游植物的吸收速率最大,3~20μm浮游植物的居中,20~200μm浮游植物的最小[2]。磷进入浮游植物以后,又因浮游动物的摄食沿着两条不同的途径向更高的营养级传递。 相似文献
4.
钦州湾磷营养状态与浮游植物的碱性磷酸酶活性分析 总被引：1，自引：0，他引：1
碱性磷酸酶(Alkaline phosphatase,AP)是浮游植物在磷胁迫的情况下诱导表达的一种酶,其作用是能够将溶解有机磷(Dissolved organic phosphate,DOP)水解成浮游植物可以直接利用的正磷酸盐形式,因此碱性磷酸酶活性(Alkaline phosphatase activity,APA)可用来指示海区浮游植物的磷胁迫状态。本研究以2015-2016年钦州湾4个航次(春季、夏季、秋季、冬季)的调查资料为依据,研究了钦州湾海域表层无机及有机磷的空间分布特征、APA的分布及其与磷营养之间的调控关系。调查期间,钦州湾海域春季、夏、秋、冬的单位叶绿素APA的平均值分别为20.42±5.32 nmol/μg Chl a/h,138.17±94.32 nmol/μg Chl a/h,142.60±72.60 nmol/μg Chl a/h和29.48±18.52 nmol/μg Chl a/h。经分析,APA与无机磷之间存在显著的负相关(P0.05),与N/P呈极显著负相关(P0.01),该海区APA可以反映钦州湾浮游植物的磷胁迫水平。海区氮磷比平均值在除春季外的三个季节均高于35,存在潜在的磷限制,浮游植物在夏季和秋季遭受较严重的磷胁迫。夏季和秋季浮游植物大量表达AP,由此推测DOP可能在钦州湾浮游植物生物量的维持甚至赤潮发生期间的磷补给上起着重要作用。 相似文献
5.
碱性磷酸酶活性(alkaline phosphatase activity, APA)是海洋研究中用于反映浮游植物磷限制状态的重要指标。在长江口等“氮过剩”海域,磷是控制海域初级生产力水平的主要因子,然而,磷限制的范围常常难以界定,当前对不同粒级浮游植物的磷限制效应所知甚少。该文根据2020年夏季长江口航次资料,给出了海洋表层各粒级浮游植物(Net:≥20 μm;Nano:2~20 μm;Pico:0.8~2 μm)APA、浮游细菌APA(0.2~0.8 μm)和溶解态APA(<0.2 μm)的空间分布特征,并分析了APA与环境要素间的相关性。结果显示,各粒级浮游植物APA均与无机磷酸盐浓度(dissolved inorganic phosphate, DIP)呈显著负相关,这表明DIP浓度是影响浮游植物APA分布的主要因素。在平面分布上,各粒级浮游植物APA在近口门的光限制区均较低,且呈现自口门向外逐渐升高的趋势,与DIP的分布特征相反。Net和Nano级APA[平均值分别为 (40.28±32.35) nmol/(L·h)和(52.38±34.78) nmol/(L·h)]显著高于Pico级APA[平均值为(28.43±20.23) nmol/(L·h)],这表明大粒级浮游植物可能更易受DIP下降的影响。该研究中,诱导浮游植物APA快速升高的DIP浓度为0.159 μmol/L,与近岸区磷限制经验阈值相接近。该研究揭示了夏季不同粒级浮游植物对长江口磷分布的响应特征,有助于理解长江口初级生产过程的环境调控机制。 相似文献
6.
氮、磷对金藻的增殖效应 总被引：14，自引：0，他引：14
本文通过室内培养试验，研究了水体中氮、磷含量变化及氮、磷交互作用对金藻增殖的影响，并比较了不同形态的氮盐对该藻增殖的反应。试验得出该藻生长的氮氨（氯化铵）最适浓度水平为150μmol－N／L，相应的无机磷的最适浓度水平为10μmol-P/L；有机氮（尿素）的最适浓度水平为250μmol－N／L，相应的无机磷最适度水平为5μmol－P／L。氨氮和尿素的试验中，金藻的生长趋势相似，但是相对应浓度下，氨氮的增殖效应大于尿素。氮的形态不同时，藻类对同一种磷的利用也可能产生差异。 相似文献
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《海洋通报》2021,(5)
长江口外潮汐混合和低盐度羽流形成的泥沙锋和羽状锋对浮游植物与环境因子的空间分布具有重要控制作用。本研究依据2019年夏季长江口及邻近海域典型断面叶绿素a (Chl-a)浓度和环境因子的调查结果,以锋面为边界,探讨了不同区域Chl-a浓度与环境因子的分布特征及相互关系,以期深入了解锋面的生态效应。结果表明,在泥沙锋以内的近岸区域,水体垂直混合均匀;受长江径流输入和泥沙锋"屏障"作用影响,总悬浮物(TSM)和营养盐浓度最高,其中TSM为220.0±275.3 mg/L,溶解无机氮(DIN)、溶解无机磷(DIP)和溶解硅酸盐(DSi)分别可以达到94.7±21.2μmol/L、0.85±0.33μmol/L和95.3±22.6μmol/L;高浓度TSM引起显著的光限制效应,导致Chl-a浓度较低(1.7±0.5μg/L)。在羽状锋以外的区域,出现垂直层化现象;表层海水的TSM和营养盐显著降低,其中TSM为5.1 mg/L,DIN、DIP和DSi分别为1.0μmol/L、0.03μmol/L和2.4μmol/L;Chl-a浓度受到营养盐供应不足的影响,浓度仅为0.2μg/L。高浓度的Chl-a (7.5±4.1μg/L)主要出现在泥沙锋和羽状锋之间的过渡区域,该区域营养盐得到长江径流与上升流的补充;同时,由于大量TSM在泥沙锋快速沉降,缓解了水体的光限制效应,有利于浮游植物的生长和积累。研究结果验证了泥沙锋和羽状锋对TSM与营养盐的重要控制作用,这对于理解长江口及邻近海域藻类灾害高发区的成因具有科学参考价值。 相似文献
9.
风暴潮过后秦皇岛海域两次赤潮过程浮标数据变化 总被引：1，自引：0，他引：1
使用2016年7月22日-8月12日水质自动监测浮标数据,对秦皇岛近岸海域两次赤潮的诱因进行分析。第一次赤潮由夜光藻(Noctiluca scintillans)引发,赤潮期间Chl a浓度最高达到38.84μg/L,平均水温为26℃,盐度在15.9~29.1之间大幅度波动;第二次赤潮由诺氏海链藻(Thalassiosira nordenskioldi)和丹麦细柱藻(Leptocylindrus danicus)引起,赤潮期间Chl a浓度最高达到35.12μg/L,水温较赤潮发生前升高2℃。研究结果表明,风暴潮为夜光藻赤潮的重要诱因,温盐变化也影响着赤潮生物种类的演替。 相似文献
10.
人类活动引起的营养物质输入导致大亚湾出现海水富营养化、赤潮频发和生物多样性下降等生态问题。为探究陆源输入影响下大亚湾湾顶淡澳河输入对湾内浮游植物粒级结构和种类组成的影响, 2016年10月在大亚湾进行了原位观测和培养试验。原位观测结果显示, 淡澳河口的总溶解态氮、磷浓度分别达到85.3μmol·L-1和1.5μmol·L-1。加富培养试验结果表明, 淡澳河河口水加富对总叶绿素a (Chl a)和总浮游植物丰度有显著促进作用, 并导致浮游植物粒级结构由小粒级Chl a (0.7~20μm)占主导; 浮游植物丰度中甲藻比例升高, 主要种类为锥状斯氏藻(Scrippsiella trochoidea)和原甲藻(Prorocentrum spp.)。同样, 尿素加富也促进了浮游植物群落中小粒级Chl a和甲藻的比例增加, 且主要甲藻种类与河口水加富结果一致。无机氮、磷同时加富促进了总Chl a和浮游植物总丰度增加, 而对浮游植物粒级结构和甲藻丰度则没有明显影响。对照河口水和氮、磷营养盐加富试验结果, 说明河口水携带的溶解性有机氮源可能是导致大亚湾浮游植物群落小型化, 促进甲藻生长的关键营养盐形态, 其携带的无机氮、磷同时促进总浮游植物丰度增加。本研究结果表明有机形态营养组分对大亚湾富营养化和有害藻华可能产生重要影响。 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
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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
16.
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
17.
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
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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
20.
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