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31.
32.
Kazuo Abe 《Journal of Oceanography》2002,58(4):577-588
The relationship between dissolved cadmium (Cd) and phosphate (PO4) was examined at three stations in the subtropical area near the Ryukyu Islands in May 1999. Preformed PO4 was obtained using the Redfield ratio in order to separate the surface water and the other layers in this study area. Almost
0 μM (−0.043 μM to 0.094 μM) was estimated in the layers above 300 m and 250 m at Sts. 1 and 3 and at St. 2, respectively.
Up to these depths, water was considered to be uniform, and these layers were defined as the surface water in this study area.
In the surface water, the slopes of the regression lines of the Cd-PO4 plot were 0.162, 0.156, and 0.226 (nM/μM) at Sts. 1, 2, and 3, respectively, and these values were much closer to the estimated
regenerated ratio of Cd to PO4 from the Apparent Oxygen Utilization (AOU)-Cd/PO4 plots, which was 0.197 (nM/μM) in this study area. Below surface layers, the slopes of the Cd-PO4 plot changed to 0.371, 0.352, and 0.362 (nM//μM) at Sts. 1, 2, and 3, respectively. In the relationships between Cd and PO4, clear deviations or kinks were observed at three stations at a PO4 concentration of approximately 0.2 μM in the plot, which was attributable to the discontinuity of surface water and the other
layers across the North Pacific subtropical mode water. In studies of the interaction between surface water and biogenic particles
concerning the Cd/PO4 ratio, separate analyses of seawater (surface water and the other layers) should be carried out to obtain the individual
surface water ratio because the Cd/PO4 ratio in the surface water is expected to differ from that of the underlying water. Furthermore, the biological fractionation
of these constituents is based on the surface water ratio.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
33.
根据2001年7月对南黄海的大面积调查,研究了南黄海夏季pCO2的分布机制,着重讨论下层海水涌升和长江冲淡水对海-气界面CO2通量的贡献,并给出了南黄海海-气界面CO2通量。研究结果表明:夏季南黄海总体上是CO2的1个弱源,大约向大气中释放45.05×104t C。夏季南黄海表层海水pCO2分布表现出了极大的不均性,其汇区主要由长江冲淡水造成,影响区域占汇区吸收CO2的99.9%;而在源区,下层海水涌升虽然面积较小却占源区释放CO2的35.2%。可见陆架边缘海区源/汇格局的地域差异非常之特别。 相似文献
34.
Graham P. Wilson Angela L. Lamb Melanie J. Leng Silvia Gonzalez David Huddart 《Estuarine, Coastal and Shelf Science》2005,64(4):685-698
Microfossil analysis (e.g. diatoms, foraminifera and pollen) represents the cornerstone of Holocene relative sea-level (RSL) reconstruction because their distribution in the contemporary inter-tidal zone is principally controlled by ground elevation within the tidal frame. A combination of poor microfossil preservation and a limited range in the sediment record may severely restrict the accuracy of resulting RSL reconstructions. Organic δ13C and C/N analysis of inter-tidal sediments have shown some potential as coastal palaeoenvironmental proxies. Here we assess their viability for reconstructing RSL change by examining patterns of organic δ13C and C/N values in a modern estuarine environment. δ13C and C/N analysis of bulk organic inter-tidal sediments and vegetation, as well as suspended and bedload organic sediments of the Mersey Estuary, U.K., demonstrate that the two main sources of organic carbon to surface saltmarsh sediments (terrestrial vegetation and tidal-derived particulate organic matter) have distinctive δ13C and C/N signatures. The resulting relationship between ground elevation within the tidal frame and surface sediment δ13C and C/N is unaffected by decompositional changes. The potential of this technique for RSL reconstruction is demonstrated by the analysis of part of an early Holocene sediment core from the Mersey Estuary. Organic δ13C and C/N analysis is less time consuming than microfossil analysis and is likely to provide continuous records of RSL change. 相似文献
35.
氨基酸在粘土高岭石上吸附等温线的研究 总被引:2,自引:0,他引:2
研究了4种氨基酸(甘氨酸,赖氨酸,天冬氨酸,谷氨酸)在粘土高岭石上的吸附等温线以及金属铜离子对其等温线的影响。研究表明,氨基酸在高岭石上的吸附等温线以及金属铜离子存在时的吸附等温线均属Langmuir型等温线;铜离子浓度增加时,其等温线斜率也增加,并认为体系可形成Ⅰ型三元表面络合物,铜离子对氨基酸在高岭石上等温线影响的规律和在相同体系中它对氨基酸在高岭石上交换吸附百分率E(%)-pH曲线的影响规律相一致。 相似文献
36.
U–Th decay series isotopes, δ18O and Si measurements in the river estuarine waters and sediments of the polluted Hooghly estuary as well as the surface waters of the Bay of Bengal, its high salinity end member, are reported. Dissolved Si indicates that there are probably two mixing regimes, dissolved U behaviour is nonconservative and δ18O behaves conservatively in the overall estuarine region. Isotopes of reactive elements, viz. 234Th and 210Po, are removed from the estuarine waters in <2 days and <1 month, respectively, which is due to high suspended matter (30–301 mg l−1). 228Ra and 226Ra are profusely released into the estuarine waters in the low to mid-salinity regions.As expected, the opposite trend is observed in the case of estuarine sediments and suspended matter. Reactive isotopes of Th, 210Pb and 210Po are enriched, whereas Ra isotopes are depleted with respect to their parent nuclides in the estuarine sediments and suspended matter. 232Th/Al ratio appears well suited to study the distribution and mixing of the bed load sediments of the Ganga–Brahmaputra (G–B) and the Hooghly rivers with those from other rivers on the Bay of Bengal floor. 相似文献
37.
38.
以苯酚和4—溴苯甲酸为原料,合成一种尚未见文献记载的新化合物——4—溴苯甲酸—2,3,4,5,6—五溴苯酯,用无水三氯化铝催化苯酚的全溴化。此产物可望在阻燃剂方面得到应用。 相似文献
39.
Shane M. Ohline Malcolm R. Reid Shamus L.G. Husheer Kim I. Currie Keith A. Hunter 《Marine Chemistry》2007
Accurate measurement of seawater pH has long been sought by marine chemists (for example: [Dickson, A.G. 1993a. The measurement of sea water pH. Marine Chemistry, 44, 131–142, Dickson, A.G. 1993b. pH buffers for sea water media based on the total hydrogen ion concentration scale. Deep-Sea Research, 40, 107–118; Zhang, 1996; Tapp, M., Hunter, K.A., Currie, K. and Macaskill, B. 2000. Apparatus of continuous-flow underway spectrophotometric measurement of surface water pH. Marine Chemistry 72(2–4), 193–202; Friis, K., Koetzinger, A., Wallace, D.W.R. 2004. Spectrophotometric pH measurement in the ocean: Requirements, design and testing of an autonomous charge-coupled device detector system. Limnology and Oceanography: Methods 2, 126–136]. Recently, such attempts have taken on greater significance as anthropogenic carbon dioxide emissions may create rapidly changing oceanic pH. Spectrophotometric techniques have been accepted generally as the best for determination of seawater pH. Here we report a new technique using thymol blue as the indicator dye and fitting the entire spectrum from 400 to 900 nm rather than measuring the absorbance values at only two or three points in the spectrum. This full-spectrum modelling enables a reduction in signal to noise over other techniques. In the laboratory, we find with seawater samples a pH precision increase of five-fold “within” a sample and seven-fold “between” samples when comparing the full spectrum to the three-point method of analysis [Zhang, H., Byrne, R.H. 1996. Spectrophotometric pH measurements of surface seawater at in-situ conditions: absorbance and protonation behaviour of thymol blue. Marine Chemistry 52, 17–25]. 相似文献
40.
In order to investigate the relationships between the change of TCO2, △PCO2 and SST, current, upwelling and biological activities during El Nin(~)o event in the subtropical Pacific, the responses of TCO2 and △PCO2 in surface water in the subtropical Pacific during El Nin(~)o and La Nina have been simulated using a three-dimension carbon cycle model with biota pump. The results of numerical simulations show that TCO2 in sea water increases with reducing of SST during mature phase of El Nin(~)o in the subtropical West Pacific . At the same period , the Kuroshio in this region was weakened , the zonal currents were divergence , the upwelling carried the water with high concentrations of CO2 to the sea surface , so both of TCO2 and △PCO2 in surface water were increased . But TCO2 and △pCO2 were decreased during La Nina period. These simulated results confirmed the observations in 1982/1983 , 1986/1987 ,1991/1995 and 1997/1998 El Nin(~)o events . 相似文献