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1.
对细胞干重的测定和应用气相色谱仪测定了不同碳、氮源浓度和不同培养时间下裂殖壶菌(Schizochytrium limac-inum)OUC88的生长和脂肪酸的组成。结果表明,在含有9%的葡萄糖和6%的豆粕水解物的培养基中,细胞生物量达到最高,为25.92 g/L;在含有6%的葡萄糖和2%的豆粕水解物的培养基中,细胞总脂含量以及总脂中的DHA含量均达到最高,分别为50.56%和35.83%。另外,不同生长时期内裂殖壶菌的总脂含量和脂肪酸组成不同。在培养到第4~5天,细胞的生物量、总脂以及DHA产量均最高。 相似文献
2.
考察了盐藻在氮浓度3mmol/L和0.59mmol/L两种条件下的生长、氮磷的利用以及色素积累的情况。结果表明氮浓度3mmol/L培养基有利于藻细胞的增值，最终藻体浓度大，稳定期可维持数日；0．59mmol/L培养基有利于细胞胡萝卜素积累，单位细胞胡萝卜素与叶绿素的比值达到12．3，是氮浓度3mmol/L培养基的两倍左右。盐藻细胞在生长初期快速利用氮源，之后即使培养基中仍有较高浓度的氮源，藻细胞也不再利用。两种条件下藻细胞对磷的利用情况相同。两种培养基中盐藻单位细胞叶绿素含量均先增加后减少，胡萝卜素含量均先降低后增加。 相似文献
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海洋酸化是当前一个严重的环境问题,而海水pH的变化与微藻生长时对溶解无机碳的吸收有关。在室内条件下采用生理生态学方法,研究中肋骨条藻Skeletonema costatum和三角褐指藻Phaeodactylum tricornutum在不同无机氮水平下生长到最大生物量时培养液pH的变化。结果表明,培养液无机氮浓度从10μmol.L-1上升到200μmol.L-1过程中,2种微藻的叶绿素浓度和最终pH均呈上升趋势。培养液pH的增加量与无机氮的消耗量呈正相关关系,培养液pH的增加量与溶解无机碳的消耗量也呈正相关关系。 相似文献
5.
以黄海绿潮暴发的主要漂浮种类浒苔 (Ulva prolifera)为材料,在实验室条件下研究了浒苔光合参数、固碳速率及提升海水pH的作用,结果表明:浒苔光合作用半饱和常数Km为0.25 mmol/dm3,光合作用饱和时海水溶解无机碳(DIC)浓度也只需1.2 mmol/dm3,为正常海水DIC浓度(2.4 mmol/dm3)一半,故黄海绿潮暴发时藻体可以一直保持光合作用饱和与旺盛生长状态。水生条件下浒苔藻体主要吸收海水中的DIC,0.5 g/dm3培养密度下,1个光周期内净光合固碳速率为10.92 mg /(g·d)(鲜重)。连续培养5 d,0.5,1.0和2.5 g/dm3培养密度组的DIC浓度从22 mg/dm3分别降为4.85,2.62和0.66 mg/dm3,表明DIC去除率随藻体培养密度提高而增强,分别可达77.78%,88.00%,96.98%;藻体吸收海水中无机碳的同时可使海水pH升高,0.5 g/dm3培养密度下,1个光周期内净提升pH速率高达0.96/(dm3·g·d)。连续培养5 d,0.5,1.0和2.5 g/dm3培养密度组第1天其pH分别可达到9.1,9.2和9.7,表明藻体密度越高pH提升越快,而且第5天pH均可稳定在9.9左右。浒苔暴露在空气中可直接吸收空气中CO2,1个光周期内其光合固碳速率约为46.14 mg/(g·d),而在海水中的光合固碳速率为10.92 mg/(g·d),可见浒苔在空气中的光合固碳速率是水中的4.23倍。水生和气生时单位质量藻体的固碳效率因藻体间相互遮蔽而下降。结果可为今后黄海绿潮暴发机制及CO2减排和防止海洋酸化作用的评估提供技术支撑。 相似文献
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通过气相色谱方法对南极冰藻的脂肪酸进行了分析，发现环境因素对2种绿藻总脂含量有一定的影响：(1)温度对Pymmixtomonas sp，总脂含量影响不大，一般为8．3％～8．9％，Chlorophyceae L-4在2℃时的总脂含量最高为10.33％；(2)光强显著地影响这2种绿藻脂肪在细胞内的积累。随着光强由限制生长的39 lx增加到3900 lx，2种绿藻的脂肪酸含量降低：(3)盐度的提高有利于2种绿藻脂肪的积累；(4)营养盐的限制也利于2种绿藻脂肪的积累。在氮源缺乏条件下，Pyramidomonas sp，和Chlorophyceae L-4细胞内脂肪大量积累，含量分别是以NH4Cl为氮源的2．2和3.2倍。环境因素对2种绿藻脂肪酸组成和含量的影响不同，其脂肪含量的改变反映了南极冰藻生长的改变。环境因子能够影响这2种绿藻的脂肪含量，同样也影响到它们的生长。在适合南极冰藻生长的条件下，脂肪酸积累降低；反之，在南极冰藻生长受到限制的条件下，脂肪合成增加。这表明2种绿藻的脂肪含量随生存环境的变化而变化。环境因子同样影响到2种绿藻的脂肪酸组成，尤其是不饱和脂肪酸的组成和含量，但组成和其生长不存在相关性。环境因子(温度、光强、盐度和营养盐)对2种绿藻脂肪酸的测定结果表明，在2种绿藻中，多不饱和脂肪酸的含量高于单不饱和脂肪酸和饱和脂肪酸。因此。这2种绿藻可望为多不饱和脂肪酸的开发利用提供藻种资源。 相似文献
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7种(13株)杜氏藻的总脂含量和脂肪酸组成 总被引：2，自引：0，他引：2
在实验室条件下培养7种(13株)杜氏藻(Dunaliella),在生长的平衡期收获.分别采用索氏提取法和气相色谱法进行了总脂含量和脂肪酸组成的测定.它们的总脂含量在6.64%~16.18%(m/m,干重,下同)之间,其中7株的总脂含量超过10%.杜氏藻的16碳和18碳脂肪酸含量丰富,有着较高的C16∶0、C18∶1(n-12)、C18∶2(n-6)和C18∶3(n-3)脂肪酸,其中8株的不饱和脂肪酸含量超过总脂肪酸的50%.杜氏藻的EPA和DHA的含量较低,但是有5株超过总脂肪酸的10%. 相似文献
8.
不同氮源对微小亚历山大藻生长和毒素产生的影响 总被引：12，自引：0，他引：12
通过尿素、氯化铵、酵母浸出粉和硝酸钠等氮源对微小亚历山大藻(Alexandrium minutum)生长及毒素产生的影响研究,分析了微小亚历山大藻对不同氮源利用状况的差异.结果表明,在氮饥饿条件下,加入硝酸钠和酵母浸出粉能显著促进微小亚历山大藻的生长;高浓度的氯化铵在加入后对微小亚历山大藻有一定的毒性效应,表现为生长停滞,但毒性效应在5 d后消失,并得到与添加硝酸钠及酵母浸出粉相似的增长速率0.21 d-1;添加尿素对微小亚历山大藻的生长没有显著促进作用.在四种氮源中,尿素对微小亚历山大藻毒素产生的刺激作用也最弱,在稳定期每个细胞藻细胞毒素含量维持在6.00~8.00 fmol;添加硝酸钠、氯化铵和酵母浸出粉的藻细胞在稳定期毒素含量分别达到11.85,12.86和14.64 fmol.硝酸钠和氯化铵刺激藻毒素产生的效果比酵母浸出粉更为直接.四种含氮营养盐对微小亚历山大藻毒素组成的影响都很小. 相似文献
9.
《中国海洋大学学报(自然科学版)》2017,(5)
为深入研究RNA干扰尿苷二磷酸葡萄糖焦磷酸化酶(UGPase)基因的表达对三角褐指藻(Phaeodactylum tricornutum Bohlin)碳流分配的影响,本研究以RNA干扰UGP表达的三角褐指藻为对象,测定了野生和转基因藻株的叶绿素荧光参数和生物量,分析了它们的脂肪酸组成和金藻昆布多糖、总脂及蛋白质的含量。研究显示,转基因藻株的最大光能转化效率(Fv/Fm)从指数生长后期开始显著低于野生型,但野生和转基因藻株的终生物量无明显差别。转基因藻株(AS、IR)的C16与C18之和分别占总脂肪酸含量的66.90%和68.89%,比野生藻株分别提高了19.40%和22.97%,说明抑制UGP表达改变了三角褐指藻的脂肪酸组成。转基因藻株的金藻昆布多糖、总脂及蛋白质含量与野生型藻株差别明显:藻株AS的金藻昆布多糖含量降低25.70%,蛋白质含量上升3.80%,总脂含量提高了13.2%;藻株IR的金藻昆布多糖含量降低40.70%,蛋白质含量上升8.30%,总脂含量增加了25.20%。研究结果表明,RNA干扰UGP的表达改变了三角褐指藻的脂肪酸组成,使得在最终生物量无明显减少的情况下,光合作用固定的碳更多转向油脂合成。本研究进一步明确了RNA干扰UGP的表达对三角褐指藻碳流分配的影响机制,为通过基因工程改造藻种提高微藻的生物柴油生产潜力提供了新思路。 相似文献
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《中国海洋大学学报(自然科学版)》2010,(Z1)
对5种海洋微藻的脂肪酸组成进行了研究。微藻在确定的条件下生长,分别于指数生长前期和稳定期后期,测定其脂肪酸组成。根据细胞膜上和细胞内脂肪酸极性差别,采用硅胶柱层析法分离脂肪酸,应用GC与GC-MS进行定量与定性分析。实验结果表明:在微藻生长的不同时期,细胞内脂与细胞膜脂含量及各自的脂肪酸组成明显不同;无论是指数生长前期还是稳定期后期,胞内物质的脂肪酸含量明显要低于细胞膜组分,细胞内与细胞膜中主要组成是C16系与C18系脂肪酸。 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
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
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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
19.
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
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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