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121.
The differences in quality of the conditional stability constants deduced from ligand titration and metal titration methods are theoretically examined. The ecological role of the metal-organic complexes in seawater was considered on the basis of the concept of the metal buffering capacity index which is calculated from the conditional stability constant and the organic ligand concentration. The results of theoretical examination of the effect of metal contamination on the uptake of metals by phytoplankton indicate that the ecological significance of metal-organic complexes is essentially in the metal-buffering action. This means that the activities of free metal ions are maintained at a native constant level against relatively small perturbations by the addition or uptake of metals in the marine environment. 相似文献
122.
To clarify the nature of organic metal complexes dissolved in seawater, a ligand exchange reaction between ligands of natural origin and an aminopolycarboxylic acid (EDTA) was used to determine the conditional stability constants of organic metal complexes. The results indicate that more than two organic molecules complexed with copper and zinc exist in surface seawater. It is found that the conditional stability constants of these naturally-occurring organic metal complexes are 1–3 orders of magnitude higher than those of EDTA-Cu and EDTA-Zn complexes. These estimates of the conditional stability constants for the dominant species of organic copper and zinc complexes are 1011.8 and 109.3, respectively, at pH 8.1. The results indicate that these naturally-occurring organic metal complexes are stable species and not easily dissociated or displaced with others in the marine environment. 相似文献
123.
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125.
The interaction between thorium and marine organisms (cultured heterotrophic bacteria) was experimentally examined by using chemical equilibrium techniques. Thorium (Th) quantitatively reacts with a binding site on bacteria (Alteromonas, Vibrio, Pseudomonas and Flavobacterium) in 0.1 M HCl solution. According to mass balance analysis of adsorption experiment data, Th forms a 1:1 complex with a binding site similar in reactivity among bacteria used in this study, whose conditional stability constants are in the range from 10(6.63) to 10(7.07) M-1 under the experimental conditions of a 0.1 M HCl solution. The mole ratio of the strong ligand to organic carbon in bacteria ranged from 2.3 to 4.3 mmol/mol C. The strong ligand/carbon ratios in bacteria were more than one order of magnitude greater than in phytoplankton, zooplankton or other organic ligands in surface waters. The results suggest that the strong organic ligand reacting with Th is one of the functional groups commonly existing in oceanic microorganisms. The conditional stability constants of the Th complexes with the binding site in marine microorganisms are in the same order of magnitude as that with the strong ligand found in particulate and dissolved organic matter. These findings strongly suggest that the strong ligand in particulate and dissolved organic matter, reacting with trace metals under the conditions of seawater, originates from marine organisms. 相似文献
126.
Naoki Hirose Hideyuki Kawamura Ho Jin Lee Jong-Hwan Yoon 《Journal of Oceanography》2007,63(3):467-481
This study estimates a realistic change of the Japan Sea by assimilating satellite measurements into an eddy-resolving circulation
model. Suboptimal but feasible assimilation schemes of approximate filtering and nudging play essential roles in the system.
The sequential update of error covariance significantly outperforms the asymptotic covariance in the sequential assimilation
due to the irregular sampling patterns from multiple altimeter satellites. The best estimates show an average rms difference
of only 1.2°C from the radiometer data, and also explain about half of the sea level variance measured by the altimeter observation.
The subsurface conditions associated with the mesoscale variabilities are also improved, especially in the Tsushima Warm Current
region. It is demonstrated that the forecast limit strongly depends on variable, depth, and location. 相似文献
127.
Koji Hidaka 《Journal of Oceanography》1970,26(5):257-266
The free oscillation of water in a rotating rectangular basin of variable depth is discussed. The depth is assumed to decrease
from the center to the edges according to a paraboloidal law. The solution is obtained in terms of double series of zonal
harmonics. Numerical solutions were worked out. Complete sets of modes will be evaluated by an electronic computer. 相似文献
128.
Hiroshi Kitazato Takeshi NakatsukaMotohiro Shimanaga Jota KandaWonn Soh Yoshihisa KatoYoshihiro Okada Akio YamaokaToshiyuki Masuzawa Koji SuzukiYoshihisa Shirayama 《Progress in Oceanography》2003,57(1):3-16
Deep-sea benthic ecosystems are mainly sustained by sinking organic materials that are produced in the euphotic zone. “Benthic-pelagic coupling” is the key to understanding both material cycles and benthic ecology in deep-sea environments, in particular in topographically flat open oceanic settings. However, it remains unclear whether “benthic-pelagic coupling” exists in eutrophic deep-sea environments at the ocean margins where areas of undulating and steep bottom topography are partly closely surrounded by land. Land-locked deep-sea settings may be characterized by different particle behaviors both in the water column and in relation to submarine topography. Mechanisms of particle accumulation may be different from those found in open ocean sedimentary systems. An interdisciplinary programme, “Project Sagami”, was carried out to understand seasonal carbon cycling in a eutrophic deep-sea environment (Sagami Bay) with steep bottom topography along the western margin of the Pacific, off central Japan. We collected data from ocean color photographs obtained using a sea observation satellite, surface water samples, hydrographic casts with turbidity sensor, sediment trap moorings and multiple core samplings at a permanent station in the central part of Sagami Bay between 1997 and 1998. Bottom nepheloid layers were also observed in video images recorded at a real-time, sea-floor observatory off Hatsushima in Sagami Bay. Distinct spring blooms were observed during mid-February through May in 1997. Mass flux deposited in sediment traps did not show a distinct spring bloom signal because of the influence of resuspended materials. However, dense clouds of suspended particles were observed only in the spring in the benthic nepheloid layer. This phenomenon corresponds well to the increased deposition of phytodetritus after the spring bloom. A phytodetrital layer started to form on the sediment surface about two weeks after the start of the spring bloom. Chlorophyll-a was detected in the top 2 cm of the sediment only when a phytodetritus layer was present. Protozoan and metazoan meiobenthos increased in density after phytodetritus deposition. Thus, “benthic-pelagic coupling” was certainly observed even in a marginal ocean environment with undulated bottom topography. Seasonal changes in features of the sediment-water interface were also documented. 相似文献
129.
Kazufusa Ishibashi Kei Hirose Nagayoshi Sata Yasuo Ohishi 《Physics and Chemistry of Minerals》2008,35(4):197-200
The high-pressure stability limit of calcium aluminosilicate (CAS) phase has been examined in its end-member CaAl4Si2O11 composition at 18–39 GPa and 1,670–2,300 K in a laser-heated diamond-anvil cell (LHDAC). The in-situ synchrotron X-ray diffraction
measurements revealed that the CAS phase decomposes into three-phase assemblage of cubic Al-bearing CaSiO3 perovskite, Al2O3 corundum, and SiO2 stishovite above 30 GPa and 2,000 K with a positive pressure–temperature slope. Present results have important implications
for the subsolidus mineral assemblage of subducted sediment and the melting phase relation of basalt in the lower mantle. 相似文献