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1.
Light is an important parameter in algal culturing.In this work,the effects of different light qualities on growth of the marine diatom Chaetoceros gracilis are evaluated.The cells were cultured under light quantum flux density of 60μmol photons/(m2·s)with nine light qualities:LED red light(LR),LED blue light(LB),LED red plus LED blue light(LR+LB),LED white light(LW),fluorescent white light(FW),and combinations of LW and FW lights with increased proportions of red or blue light(FW+LR,FW+LB,LW+LR,and LW+LB).Blue light promoted the growth of C.gracilis largely.Three light qualities,FW+LR,LW+LR,and LR,resulted in the lowest growth rate.Both chlorophyll and carotenoids reached the highest level under LB and the lowest level under LR among monochromatic light sources;however,increasing of the proportion of blue or red light in the white light induced an increase of the chlorophyll and carotenoid concentrations.Light absorption ability of microalgae was critical for the growth of these organisms,as we observed a positive correlation between the extinction coefficient at different wavelengths and the specific growth rate.These findings are of importance to improve the culturing of this alga in bioreactors. 相似文献
2.
The effects of three photoperiods (24 hr illumination, 12 hr illumination + 12 hr darkness and 24 hr darkness) and three salinities (20‰, 30‰ and 35‰) on the uptake of 60Co and 137Cs for Chlorella sp. and on the growth of its algae are studied. The uptake of 60Co for the algae is two orders of magnitude higher than that of 137Cs. Of factorial effects, the effect of photoperiod is most significant either on the uptake of the radionuclides or on the growth of the algae; the effect of salinity comes next in order and that of their interaction remains with the last. The uptake of the two radionuclides increases with extended photoperiod while the uptake of 137Cs declines with increasing of salinity. The growth of the algae appears to be the best under the conditions of 24 hr illumination and 30‰ salinity. 相似文献
3.
《中国海洋工程》2021,(3)
Owing to different influence factors of foundation soil, the initial stress state of the soil under various working conditions is complex. To simulate this situation, in this paper, a series of tests on undisturbed soft clay under pure principal stress axis rotation were carried out by using the hollow cylinder apparatus(HCA). The influence of initial consolidation angle ζ(the angle between the vertical direction and direction of the applied load in consolidation) and intermediate principal stress coefficient b on pore water pressure accumulation of undisturbed soft clay were mainly studied. The test results show that, during pure principal stress axis rotation, the pore water pressure accumulation of the undisturbed soft clay fluctuates and increases with the rotation of the major principal stress; the values of major principal stress angles α, corresponding to the peak value of the pore water pressure in a certain cycle, are different with different initial consolidation angles; the pore water pressure accumulation of soft clay is greatly affected by the intermediate principal stress coefficient b. With the fixed initial consolidation angle ζ, the variation trend of the maximum pore water pressure for each cycle is appropriately the same with different b values. With the increase of cycles, the difference value of pore water pressure between b = 0 and b = 1 in each cycle increases gradually with different initial consolidation angles ζ. While with different initial consolidation angles ζ, the increase of the pore water pressure when b increases from 0 to 0.5 is different with that when b increases from 0.5 to 1; the variation of maximum pore water pressure with ζ is significantly affected by the value of b; the value of maximum pore water pressure increases with the cycle number increases under all test conditions, but the growth rate decreases gradually.And the variation of maximum pore water pressure with the cycle number N is obviously influenced by both ζ and b. 相似文献
4.
Growth and biochemical responses of the coenobial green alga Scenedesmus obliquus to salinity stress were monitored across different phases of growth.The alga was cultured on BG11 growth medium and subjected to 0,30,100,and 200 mmol/L NaCl for a period of 20 d,during which algal cultures were harvested at 4-d intervals.The salinity-induced inhibition of algal growth was accompanied with prolongation of timing of the different growth phases.The sharp and progressive salinity-induced inhibition of algal growth rate during the early phase of growth points to salt shock but moderation of inhibition at the subsequent stages of growth means algal acclimation to salinity.The concentrations of chlorophylls a and b,soluble sugars,proteins as well as those of K+and Na+in the alga exhibited peaks at the initiation of the exponential phase of growth,with increasing magnitude in proportion to the increase in the level of salinity.Nevertheless,whereas soluble sugars of the alga peaked at initiation of the exponential phase,starch concentration progressively increased with culture age,reaching saturation towards the stationary phase.Whereas the salinity-induced increase in soluble sugars was most evident at the early stages of growth the reverse was true for starch.The present results point to fast acclimation of S.obliquus to salt stress post a brief salt shock,utilizing soluble sugars,K+and Na+for osmotic adjustment.Increasing salinity from 0 to 200 mmol/L NaCl led to progressive increase in soluble sugars,proteins,K+and Na+concentrations of the algal cells,particularly at the early stages of growth.However,the salinity-induced increase in chlorophyll concentration approached a limit at 100 mmol/L NaCl whereas that in starch concentration was more evident at the later stages of growth. 相似文献
5.
Effect of salinity on the growth, biological activity and secondary metabolites of some marine fungi
HUANG Jingjing LU Chunhu QIAN Xiaoming HUANG Yaojian ZHENG Zhonghui SHEN Yuemao 《海洋学报(英文版)》2011,30(3):118-123
The study investigated the effects of salinity on growth,antimicrobial activities and secondary metabolites of 47 marine filamentous fungi isolated from the East China Sea near the western shore of the Taiwan Straits.The results indicate that NaCl promoted the growth up to 91.5% of test strains.However,only 14.9% of them showed a significant increase of antimicrobial activity against Candida albicans.When incubated in different concentrations of NaCl,the colony growth, antimicrobial activities and composition of secondary metabolites of the strain Ty01b-8 of Penicillium sp.varied.Treatment with KCl also showed a similar effect.An alkaloid isolated from the fermentation broth of Ty01b-8 was identified as chrysogine,inhibition activity of which against Hela cells was 15.05% at 20 μ g/ml,and yield was 4.4 and 4.9 times higher in 3 percent and 6 percent NaCl treatments,respectively, compared with the non-salt culture condition. These findings prove that salinity is an important factor influencing growth and secondary metabolites of some marine fungi,which can be used to screen for new metabolites from marine fungi,and to enhance their metabolites production in industrial fermentation. 相似文献
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Vast declines in Zostera marina seagrass beds demand effective methods of rehabilitation. In this study, we developed a practical method by reducing salinity to induce seed germination followed with recovering salinity to facilitate seedling production of Z. marina. The results showed that Z. marina seeds collected from natural seawater(salinity 30) were induced to germinate at reduced salinities. Percent germination(GR) was higher and mean-time-to-germinate(MTG) was shorter at lower salinities. The highest GR and shortest MTG occurred at salinity 0(deionized freshwater). After germination in freshwater, seeds could develop into seedlings at salinities5–30 and continue the growth. Viability or development of germinated seeds was not significantly different during the 40 d of post-germination incubation at salinities 5–15 after 1–20 d of germination in freshwater. However,during the process of translating germinated seeds from salinity 0 and 5 to salinity 30, reducing the gradients of post-germination acclimation facilitated more seeds forming seedlings in less time. On average, after 60 d of static incubation, including 20 d in freshwater for germination followed with immediate shift to salinity 5 and increasing to salinity 30 at increment of 5 every two days until cultivation at constant salinity 30, 33% of Z. marina seeds produced healthy seedlings. The results indicate that the salinity-manipulation based method of artificial germination and seedling production is practical and effective in supporting rehabilitation of Z. marina bed. 相似文献
7.
Effects of salinity fluctuation in different ranges on the intermolt period and growth of juvenile Fenneropenaeus chinensis 总被引：1，自引：0，他引：1
1 Introduction Salinity is an important environmental parameter affecting the growth of the crustaceans, and the toler- ance to salinity varies with species and growth periods. Marsupenaeus japonicus is sensitive to salinity fluctua- tion, and abrupt decrease in salinity can result in high mortality (Chen and Bian, 1994). As reported by Dall (1981), tolerance of the juvenile Metapenaeus bennet- tae, Penaeus esculentus and Fenneropenaeus mer- guiensis to salinity fluctuation is not as strong … 相似文献
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Intertidal marine macroalgae experience periodical exposures during low tide due to their zonational distribution. The duration of such emersion leads to different exposures of the plants to light and aerial CO2, which then affect the physiology of them to different extents.The ecophysiological responses to light and CO2 were investigated during emersion in two red algae Gloiopeltis furcata and Gigartina interrnedia, and two brown algae Petaloniafascia and Sargassum hemiphyllum, growing along the Shantou coast of China. The light-saturated net photosynthesis in G. furcata and P. fascia showed an increase followed by slightly desiccation, whereas that in G.interrnedia and S. hemiphyllum exhibited a continuous decrease with water loss. In addition, the upper-zonated G. furcata and P. fascia,exhibited higher photosynthetic tolerance to desiccation and required higher light level to saturate their photosynthesis than the lower-zonated G. interrnedia and S. hemiphyllum. Desiccation had less effect on dark respiration in these four algae compared with photosynthesis. The light-saturated net photosynthesis increased with increased CO2 concentrations, being saturated at CO2 concentrations higher than the present atmospheric level in G. furcata, G. intermedia and S. hemiphyllum during emersion. It was evident that the relative enhancement of photosynthesis by elevated CO2 in those three algae increased, though the absolute values of photosynthetic enhancement owing to CO2 increase were reduced when the desiccation statuses became more severe. However, in the case of desiccated P. fascia (water loss being greater than 20 %), light saturated net photosynthesis was saturated with current ambient atmospheric CO2 level. It is proposed that increasing atmospheric CO2 will enhance the daily photosynthetic production in intertidal macroalgae by varied extents that were related to the species and zonation. 相似文献
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利用Argo剖面浮标分析上层海洋对台风“布拉万”的响应 总被引：9，自引：2，他引：7
In situ observations from Argo profiling floats combined with satellite retrieved SST and rain rate are used to investigate an upper ocean response to Typhoon Bolaven from 20 through 29 August 2012. After the passage of Typhoon Bolaven, the deepening of mixed layer depth(MLD), and the cooling of mixed layer temperature(MLT) were observed. The changes in mixed layer salinity(MLS) showed an equivalent number of increasing and decreasing because the typhoon-induced salinity changes in the mixed layer were influenced by precipitation, evaporation, turbulent mixing and upwelling of thermocline water. The deepening of the MLD and the cooling of the MLT indicated a significant rightward bias, whereas the MLS was freshened to the left side of the typhoon track and increased on the other side. Intensive temperature and salinity profiles observed by Iridium floats make it possible to view response processes in the upper ocean after the passage of a typhoon. The cooling in the near-surface and the warming in the subsurface were observed by two Iridium floats located to the left side of the cyclonic track during the development stage of the storm, beyond the radius of maximum winds relative to the typhoon center. Water salinity increases at the base of the mixed layer and the top of the thermocline were the most obvious change observed by those two floats. On the right side of the track and near the typhoon center when the typhoon was intensified, the significant cooling from sea surface to a depth of 200×104 Pa, with the exception of the water at the top of the thermocline, was observed by the other Iridium float. Owing to the enhanced upwelling near the typhoon center, the water salinity in the near-surface increased noticeably. The heat pumping from the mixed layer into the thermocline induced by downwelling and the upwelling induced by the positive wind stress curl are the main causes for the different temperature and salinity variations on the different sides of the track. It seems that more time is required for the anomalies in the subsurface to be restored to pretyphoon conditions than for the anomalies in the mixed layer. 相似文献
10.
CHAN Zhuhua CHEN Xinglin HOU Yanping GAO Boliang ZHAO Chungui YANG Suping ZENG Runying 《海洋学报(英文版)》2018,(2)
Agarases are hydrolytic enzymes that act on the hydrolysis of agar and have a broad range of applications in food,cosmetics and pharmaceutical industries. In this study, a glycerol feeding strategy based on induction mode optimization for high cell density and β-agarase production was established, which could effectively control acetate yield. First, exponential feeding strategy of glycerol with different overall specific growth rates(μ) was applied in the pre-induction phase. The results showed that the low μ(μ=0.2) was suggested to be the optimal for cell growth and β-agarase production. Second, the effects of induction temperature and the inducer concentration on cell growth and β-agarase production were investigated in the post-induction phase. When induced by isopropyl-β-d-thiogalactoside(IPTG), the strategy of 0.8 mmol/L IPTG induction at 20℃ was found to be optimal for β-agarase production. When cultivation was induced by continuous lactose feeding strategy of 1.0 g/(L·h), the β-agarase activity reached 112.5 U/mL, which represented the highest β-agarase production to date.Furthermore, the β-agarase was capable of degrading G. lemaneiformis powder directly to produce neoagarooligosaccharide, and the hydrolysates were neoagarotetraose(NA4) and neoagarohexaose(NA6). The overall research may be useful for the industrial production and application of β-agarase. 相似文献
11.
海水养殖对沿岸生态环境影响的研究进展 总被引：2，自引：1，他引：1
综述国际上海水养殖对沿岸环境影响的研究进展 ,并结合中国实际探讨减少养殖污染和海水养殖业可持续发展的途径。海水养殖主要通过有机物和营养物的排放、化学药物的使用、养殖动物的逃逸、红树林的破坏等途径对沿岸生态环境产生负面影响。为减小这一影响 ,认为应采取提高人工饲料的质量、单一养殖系统结构优化和复合养殖系统的结构优化、处理养殖排放水、海岸带综合治理等措施。 相似文献
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对标准实施情况的监督是标准化工作重要的内容,海洋标准化工作经过多年的发展已取得长足进步,但是对海洋标准实施情况的监督工作仍有待加强.运用经济博弈理论,探讨在开展海洋标准实施情况的监督过程中利益群体间的关系.研究影响监督效果的主要因素,并提出相应的监督管理对策. 相似文献
13.
Experimental Investigation on Breakup of Ice Floe on Waves 总被引：2，自引：0，他引：2
WANG Yongxue 《中国海洋工程》2000,14(4):511-516
Experimental investigation of for floe breakup on waves by use of non-refrigerated breakablematerials has been carried out.The incident wave heights for breakup of ice floe with different lengths,andthe influence of rigidity on reflection and transmission coeffcients are discussed.The experimental resultsshow that the ratio of the ice floe length,L_i,to the wavelength,L,is one of the significant factor affectingthe minimum wave height to cause fracture of ice floe,and another key factor is the ratio of the ice floethickness,h_i and L_i. 相似文献
14.
本文基于SLAMM模型分析了不同情景下海平面上升对广西沿海红树林分布面积的影响及其空间差异,通过对比实验定量分析了潮差和沉积速率的作用。结果显示,与基准年2007年相比,2100年广西红树林面积在当前海平面上升速率、典型浓度路径RCP2.6、RCP4.5和RCP8.5情景下分别减少0.57%、4.99%、7.99%和17.39%,珍珠港、茅尾海、丹兜海和英罗港受影响程度较大。当地潮差与红树林面积减少率呈负相关关系。需维持红树林生长区域的沉积速率以应对未来的海平面加速上升。 相似文献
15.
本研究以三疣梭子蟹Portunus trituberculatus为研究对象,通过急性和亚急性暴露试验,研究Cd2+对其肝胰腺和鳃的毒性效应。结果表明:Cd2+对三疣梭子蟹的48、72和96 h半致死质量浓度分别为6.55、4.33和3.12 mg/L,Cd2+对三疣梭子蟹的安全质量浓度为0.31 mg/L;在安全质量浓度和渔业水质标准质量浓度(<0.005 mg/L)下,随着暴露时间的延长,三疣梭子蟹的肝胰腺和鳃中HSP70的表达量都出现“先升后降”的趋势,与对照组相比,鳃中HSP70的表达量比肝胰腺的变化明显。在安全质量浓度以下,三疣梭子蟹的存活率并没有明显的变化,但是HSP70的诱导表达反映机体受到Cd2+的胁迫。因此HSP70基因可用作低质量浓度Cd2+污染检测的生物标志物。 相似文献
16.
下放式声多普勒海流剖面仪(LADCP)是20世纪90年代出现的一种海流剖面测量方式,能够快速获得大范围、全深度的海流剖面数据,在国内外有很广泛的应用。中科院声学所第一次将声通信部分加入LADCP中,完成了LADCP下放的实时监控。文中介绍了适用于LADCP通信特点的一种基于DS-CDMA的通信方法,完成了理论仿真,并通过进行相应的海试,验证了该方法的有效性。 相似文献
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基于统一身份管理平台的组模型的研究 总被引：1，自引：0，他引：1
提出在数字化校园建设中实现统一权限管理需要解决的关键问题。参考顶层设计方法论,建立学校用户组数据原型,并提出新型组管理必须具备的特征,在此基础上,提出1种基于统一身份管理平台的组模型,较好地解决统一权限控制的角色管理问题,并详细地描述了该模型的设计和实现。 相似文献
20.
Claffy在1994年对1 h的主干数据分析的基础上,提出了基于时间驱动技术比基于报文驱动技术得出的抽样结果要差一些,但是二者之间的差别很小。为验证这个结论是否依然适用,以CERNET某2.5 G省网边界链路3个不同阶段连续1 h报文数据构成的Trace为对象,采用Claffy相似的方法,对报文长度分布测度进行了分析,获得了1组有关的结论,可以用于与网络测量和网络行为学有关的研究。 相似文献