共查询到20条相似文献，搜索用时 15 毫秒
1.
利用深海潜水艇进行海底重力测量 总被引：1，自引：0，他引：1
用肉眼可以观察海底的细微变化和表层地质构造 ,要想了解海底表层未显示出的构造 ,海底重力测量是非常有效的方法。将陆用重力仪置于潜水艇中进行测量的方法目前应用得最多 ,如根据在东太平洋海底隆起的海岭顶部进行的近距离测量 ,推测了岩浆堆积体的形状和规模 ( Macdonald和 L uyendyk,1 981 )。日本从前代潜水艇“SHINKAI”时起 ,就尝试着用这种方法进行测量 (科学技术厅 ,1 971 ) ,从 1 970年起 ,利用“SHINKAI”开展重力测量试验。当时建设省国土地理院和海上保安厅水路部分别承担地面重力测量和海域重力测量。每年进行 3次下潜… 相似文献
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Biocorrosion by Bivalves 总被引：2，自引：0，他引：2
Abstract. A survey of the historical background of chemically boring bivalves and the proposed methods of boring, indications for biocorrosion, observations, and experimental results are provided. The regional impact to the ecosystem is discussed with examples from the N. Adriatic, Caribbean, and E. Pacific. The fossil record of the geologically oldest biocorroders extends back into the Mesozoic, i.e ., U. Triassic for Lithophaga and Jurassic for gastrochaenids. 相似文献
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采用高效毛细管电泳法（HPCE）对酶解褐藻胶寡糖进行了分离分析,考察了缓冲液浓度、pH、电压及温度等参数对寡糖分离的影响.实验结果表明在pH=2.5,100mmol/L 磷酸盐缓冲液中,运行电压20kV,电泳由负极到正极,温度30℃,235nm紫外检测条件下,酶解褐藻胶寡糖获得了高效分离. 相似文献
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Abstract. Upon enrichment with lithium 385.6 μM Li, culture of Pseudo-nitzschia multiseries H asle produces substantially higher level of the neurotoxin domoic acid DA 230 fg · cell-1 than the control 135 fg · cell-1 . We hypothesize that in Cardigan Bay, where the first domoic acid episode was reported, high levels of Li could have originated via a massive freshwater run-off involving an adjacent dump. Lithium enrichment may have played a part in enhancing DA production leading to the intoxication episodes of 1987. Thus, anthropogenic activities may play a role as a sustainer of algal blooms and should be included in habitat management considerations involving coastal and inshore algal blooms, both toxigenic and non-toxigenic. 相似文献
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Bacterial degradation of the hydrocarbons of lubricating oils was investigated by mass spectrometric analysis which gives
both total amount and the composition of hydrocarbon types of residual oil. An unused lubricating oil, which mainly consisted
of hydrocarbon types with only a small percentage ofn-alkanes, was degraded by marineBacillus sp. andPseudomonas sp. with 55 % and 25 % decreases in 10 days, respectively. Susceptibility of respective hydrocarbon types to biodegradation
was in the following order: alkanes > non-condensed cycloalkanes, mono-aromatics > condensed cycloalkanes. A used lubricating
oil of different brand showed a larger decrease than the unused oil. Both species of bacteria degraded large portions of alkane
fraction of Arabian light crude oil. 相似文献
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Long-term changes in the production by estuarine macrobenthos affected by multiple stressors 总被引：1，自引：0，他引：1
M. Dolbeth P.G. Cardoso T.F. Grilo M.D. Bordalo D. Raffaelli M.A. Pardal 《Estuarine, Coastal and Shelf Science》2011
The macrobenthic production of an estuarine system was evaluated over a 14-year study period in a seagrass bed and in a sandflat. Over this period, the estuary suffered severe eutrophication and extreme weather events with important impacts on the community, impairing system functioning and ultimately the goods and services provided by the estuary (decline in the seagrass bed, decreased community production and/or a boost in the production by opportunist species, such as Hydrobia ulvae). Following the anthropogenic impacts, management measures were introduced which allowed a gradual recovery of the seagrass bed and a new macrobenthic community structure manifested by production increases of slow-growing species, such as Scrobicularia plana and Hediste diversicolor. There was a gradual re-orientation of energy into population biomass instead of population density but this was not translated into higher community production, mainly due to the decreased production of opportunist species (H. ulvae and several polychaetes). Several weather extreme events occurred during this post-mitigation phase - floods, heatwaves and droughts, all of which had negative impacts on macrobenthic dynamics and production. The heatwaves led to the greatest decreases in macrobenthic production, mainly due to S. plana perhaps associated with its physiological intolerance of higher temperatures. The prolonged drought that followed the heatwaves maintained low levels of production by S. plana and H. ulvae. With climate change, the frequency and intensity of extreme weather events are likely to increase worldwide so that the recovery of impacted/disturbed systems from impacts such as eutrophication may be seriously affected by these additional stressors, compromising attempts to improve the ecological quality of estuarine ecosystems. 相似文献
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Ｎｕｍｅｒｉｃａｌｓｉｍｕｌａｔｉｏｎｏｆｓｅｄｉｍｅｎｔｌｉｆｔｅｄｂｙｗａｖｅｓａｎｄｔｒａｎｓｐｏｒｔｅｄｂｙｔｉｄａｌｃｕｒｒｅｎｔｓ￥ＣａｏＺｕｄｅａｎｄＷａｎｇＧｕｉｆｅｎ（ＴｉａｎｊｉｎＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆＷａｔｅｒＴ... 相似文献
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浮游生物来源溶解有机物的三维荧光特征研究 总被引：2，自引：0，他引：2
应用三维激发-发射荧光光谱技术,研究了中肋骨条藻和采集水样中浮游植物在光照和避光条件下培养实验过程中产生的溶解有机物,分析了三维荧光光谱中荧光峰数目、位置和荧光强度的变化,探讨了浮游植物和细菌在有机物产生中的作用.结果表明,光照条件下浮游植物生长产生类蛋白和类腐殖质荧光有机物,在衰亡期2类有机物的荧光强度迅速增加;而在避光条件下,类蛋白有机物荧光强度明显降低,类腐殖质有机物的荧光强度保持不变.2类有机物的荧光峰位置和荧光强度变化与初始有机物的性质及光照环境有关. 相似文献
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An analytical theory is developed to study the effects of a coaxial tube-sector-shaped supporting structure on the conversion efficiency of a suspended, circular OWC converter. An eigen-function expansion method is employed in a cylindrical coordinate system to study wave interaction with an OWC converter in finite depth of water. Effects of the supporting structure, OWC dimensions, wave direction on energy conversion efficiency, and optimization of power-takeoff devices are discussed. Our results show that the coaxial tube-sector-shaped support with an opening in the range of π/2–5π/4 can significantly increase the conversion efficiency and widen the frequency range over which the conversion efficiency is high. 相似文献
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Sediment segregation by biodiffusing bivalves 总被引：1，自引：0，他引：1
F. Montserrat C. Van Colen P. Provoost M. Milla M. Ponti K. Van den Meersche T. Ysebaert P.M.J. Herman 《Estuarine, Coastal and Shelf Science》2009,83(4):379-391
The selective processing of sediment fractions (sand and mud; >63 μm and ≤63 μm median grain size) by macrofauna was assessed using two size classes of inert, UV-fluorescent sediment fraction tracers (luminophores). The luminophores were applied to the sediment surface in 16 m2 replicated plots, defaunated and control, and left to be reworked by infauna for 32 days. As the macrofaunal assemblage in the ambient sediment and the control plots was dominated by the common cockle Cerastoderma edule, this species was used in an additional mesocosm experiment. The diversity, abundance and biomass of the defaunated macrobenthic assemblage did not return to control values within the experimental period. Both erosion threshold and bed elevation increased in the defaunated plots as a response to the absence of macrofauna and an increase in microphytobenthos growth. In the absence of macrobenthos, we observed an accretion of 7 mm sediment, containing ca. 60% mud. Image analysis of the vertical distribution of the different luminophore size classes showed that the cockles preferentially mobilised fine material from the sediment, thereby rendering it less muddy and effectively increasing the sand:mud ratio. Luminophore profiles and budgets of the mesocosm experiment under “no waves–no current” conditions support the field data very well. 相似文献
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N. Christian Smoot 《Geo-Marine Letters》1990,10(3):137-144
The Mariana Trough on the eastern part of the Philippine plate is a product of backare extension. Fine-grained bathymetry shows the trough to have a diffuse spreading center and to be spreading obliquely, thus refuting several previous theories. Unzipping of the trough from south to north has occurred for the past 6 m.y. This is reflected in spreading lineations perpendicular to the tectonic spreading fabric. The growth history of the trough is shown since 48 m.y. BP including speculation as to its continued eastward extension. 相似文献