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371.
Distributions and seasonal variations of dissolved carbohydrates in the Jiaozhou Bay,China 总被引:1,自引:0,他引:1
Surface seawater samples were collected in the Jiaozhou Bay, a typical semi-closed basin located at the western part of the Shandong Peninsula, China, during four cruises. Concentrations of monosaccharides (MCHO), polysaccharides (PCHO) and total dissolved carbohydrates (TCHO) were measured with the 2,4,6-tripyridyl-s-triazine spectroscopic method. Concentrations of TCHO varied from 10.8 to 276.1 μM C for all samples and the ratios of TCHO to dissolved organic carbon (DOC) ranged from 1.1 to 67.9% with an average of 10.1%. This result indicated that dissolved carbohydrates were an important constituent of DOC in the surface seawater of the Jiaozhou Bay. In all samples, the concentrations of MCHO ranged from 2.9 to 65.9 μM C, comprising 46.1 ± 16.6% of TCHO on average, while PCHO ranged from 0.3 to 210.2 μM C, comprising 53.9 ± 16.6% of TCHO on average. As a major part of dissolved carbohydrates, the concentrations of PCHO were higher than those of MCHO. MCHO and PCHO accumulated in January and July, with minimum average concentration in April. The seasonal variation in the ratios of TCHO to DOC was related to water temperature, with high values in January and low values in July and October. The concentrations of dissolved carbohydrates displayed a decreasing trend from the coastal to the central areas. Negative correlations between concentrations of TCHO and salinity in July suggested that riverine input around the Jiaozhou Bay had an important effect on the concentrations of dissolved carbohydrates in surface seawater. The pattern of distributions of MCHO and PCHO reported in this study added to the global picture of dissolved carbohydrates distribution. 相似文献
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373.
S.C. Tripathy J. Ishizaka T. Fujiki T. Shibata K. Okamura T. Hosaka T. Saino 《Estuarine, Coastal and Shelf Science》2010
A comparative account of primary productivity (PP), in the characteristically turbid and highly dynamic waters of Ariake Bay, measured by 13C uptake and fast repetition rate fluorometer (FRRF) was conducted to ensure compatibility between the two methods. Estimates from both methods depicted strong linearity for both short-term (r2 > 0.90) and daily (r2 = 0.42–0.93) measurements, except in the near-surface (∼0 m) layer. 13C-based short-term (1 h; in situ) PP estimates showed similar magnitudes and trend with the instantaneous PP measured by FRRF concurrently. Whereas, unlike short-term measurements, the daily PP estimates from both methods showed large difference, with FRRF-based time integrated daily PP resulting in 1.09–1.82 times higher than the carbon-based daily (24 h; simulated in situ) PP. This difference between daily PP estimates was mainly due to: (1) the temporal variation of water column chlorophyll a (Chl a) because of frequent moving of water mass, and (2) the dissimilarity in ambient light field conditions between the two methods. Results revealed that considering the above two environmental factors invariable over a daylength, fairly close approximation of daily PP, compared to 13C-based daily PP, could be obtained from FRRF. Hence, FRRF-based daily PP can be considered as more realistic in this highly dynamic water body like Ariake Bay where water column parameters are subjected to strong temporal variation. The relationship between Chl a-specific photosynthetic rate (PB) and the corresponding photosynthetically active radiation (PAR) in the water column (PAR–PB relationship) was found to be linear for FRRF and curvilinear for 13C-based measurements in the near-surface layer, for the same intensities of incident PAR, and this is thought to be the primary basis for the higher difference in PP estimates at the near-surface layer. Considering the minor variations in FRRF-based time series of PAR–PB relationships, a combined and/or instantaneous PAR–PB relationship in combination with incubation Chl a and light field condition was used to obtain fairly close estimates of daily water column integrated PP from FRRF. 相似文献
374.
We conducted studies of phytoplankton and hydrological variables in a semi-enclosed bay in northern China to understand the spatial–temporal variability and relationship between these variables. Samples were collected during seven cruises in Jiaozhou Bay from November 2003 to October 2004, and were analyzed for temperature, nutrients and phytoplankton pigments. Pigments from eight possible phytoplankton classes (Diatoms, Dinoflagellates, Chlorophyceae, Prasinophyceae, Chrysophyceae, Haptophyceae, Cryptophyceae and Caynophyceae) were detected in surface water by high performance liquid chromatography (HPLC). Phytoplankton pigment and nutrient concentrations in Jiaozhou Bay were spatially and temporally variable, and most of them were highest in the northern and eastern parts of the sampling regions in spring (May) and summer (August), close to areas of shellfish culturing, river estuaries, dense population and high industrialization, reflecting human activities. Chlorophyll a was recorded in all samples, with an annual mean concentration of 1.892 μg L−1, and fucoxanthin was the most abundant accessory pigment, with a mean concentration of 0.791 μg L−1. The highest concentrations of chlorophyll a (15.299 μg L−1) and fucoxanthin (9.417 μg L−1) were observed in May 2004 at the station close to the Qingdao Xiaogang Ferry, indicating a spring bloom of Diatoms in this area. Although chlorophyll a and other biomarker pigments showed significant correlations, none of them showed strong correlations with temperature and nutrients, suggesting an apparent de-coupling between the pigments and these hydrological variables. The nutrient composition and phytoplankton community composition of Jiaozhou Bay have changed significantly in the past several decades, reflecting the increasing nutrient concentrations and decline of phytoplankton cell abundance. The unchanged total chlorophyll a levels indicated that smaller species have filled the niche vacated by the larger species in Jiaozhou Bay, as revealed by our biomarker pigment analysis. 相似文献
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376.
广东流沙湾4个测站2个周日潮流观测的准调和分析 总被引:2,自引:0,他引:2
采用短期资料的潮流准调和分析方法,对水深为4.4~17.0 m的流沙湾4个测站2个周日潮流观测获得的表、中、底层的潮流资料进行了分析,分别计算了4个测站O1、K1、M2、S2、M4、MS4共6个主要分潮的潮流调和常数,并给出了各观测站位在各层的潮流椭圆要素.计算结果表明:流沙湾主要为日潮流海区,其中湾外为规则日潮流,湾内为不规则日潮流;湾外主要分潮流的北分量一般大于东分量,而湾内主要分潮流的北分量一般小于东分量.观测期间余流的流向主要呈西北向,最大余流流速出现在湾内地形突然收窄处,且在湾内中层余流流速要大于表、底层余流流速.整个海区潮流的可能最大流速表层在57~107 cm/s之间,中层在53~106 cm/s之间,底层在34~98 cm/s之间.流沙湾湾外潮流主要为顺时针的旋转流运动,湾内为带有旋转流的往复流运动. 相似文献
377.
以高精度再分析风场为驱动,利用SWAN模式模拟了台风“达维”Damrey(2005)经过北部湾海域时的波浪场。通过与实测的风和波浪实测对比发现,波浪后报结果与实测结果符合较好。文章给出了台风浪期间波高、周期、波长和波向等要素的分布特征,讨论了以台风眼为中心不同海域的波浪方向谱特征。本文最后分析了台风期间实测波浪能谱的变化特征。 相似文献
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380.
根据1979年的胶州湾水域调查资料,分析重金属Cd在胶州湾水域的水平分布、垂直分布和季节变化。研究结果表明:在整个胶州湾水域,水质没有受到任何Cd的污染。在胶州湾和湾口水域只有两个Cd的来源。一个是来源于地壳岩石风化,通过陆地径流把重金属Cd注入胶州湾水域;另一个是来源于海底,经过海洋水流的作用把重金属Cd注入湾口水域。作者提出了重金属在水域的环境本底值结构:基础本底值、陆地径流的输入量和海洋水流的输入量,并且应用于胶州湾水域。作者认为在来源的迁移过程中,有陆地来源迁移和海底来源迁移。根据杨东方的水域迁移过程研究,陆地径流决定了Cd的表、底层质量浓度变化。 相似文献