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91.
92.
An Ecosystem Model Coupled with Nitrogen-Silicon-Carbon Cycles Applied to Station A7 in the Northwestern Pacific 总被引:1,自引:0,他引:1
Yasuhiro Yamanaka Naoki Yoshie Masahiko Fujii Maki N. Aita Michio J. Kishi 《Journal of Oceanography》2004,60(2):227-241
A model based on that of Kishi et al. (2001) has been extended to 15 compartments including silicon and carbon cycles. This model was applied to Station A7 off
Hokkaido, Japan, in the Northwestern Pacific. The model successfully simulated the observations of: 1. a spring bloom of diatoms;
2. large seasonal variations of nitrate and silicate concentrations in the surface water; and 3. large inter-annual variations
in chlorophyll-a. It also reproduced the observed features of the seasonal variations of carbon dioxide partial pressure (pCO2)—a peak in pCO2 in winter resulting from deep winter convection, a rapid decrease in pCO2 as a result of the spring bloom, and an almost constant pCO2 from summer through fall (when the effect of increasing temperature cancels the effect of biological production). A comparison
of cases with and without silicate limitation shows that including silicate limitation in the model results in: 1. decreased
production by diatoms during summer; and 2. a transition in the dominant phytoplankton species, from diatoms to other species
that do not take up silicate. Both of these phenomena are observed at Station A7, and our results support the hypothesis that
they are caused by silicate limitation of diatom growth.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
93.
韩宗珠 《中国海洋大学学报(自然科学版)》1994,(1)
以微量元素、稀土元素、Sr和Nd同位素变异特征为依据,确定鲁苏榴辉岩为多成因、多来源和多阶段,指出主要是在印支期扬子陆块与华北陆块碰撞造山作用过程中,挤入的上地幔碎片以及不同原岩类型的壳内高压变质岩碎块。燕山晚期的区域构造热事件使得某些榴辉岩的同位素体系再平衡。 相似文献
94.
东海温度锋的分布特征及其季节变异 总被引:8,自引:4,他引:8
根据1934-1988年东海水文观测资料,重点分析东海温度锋的分布特征及其季节变异,并结合近期中日黑潮合作调查研究成果,初步探讨温度锋季节变异和水团演变的关系,所得主要结论是:(1)东海不仅常年存在浙闽沿岸锋,东海北部陆架锋和黑潮锋,而且、春、夏两季,在东海南部还出现一条东海中部出架锋。(2)江海温度锋季节变化的特点是:冬季,锋的宽度和强度皆是表层最强,夏季,表层温度锋仅出现在浙江近岸小范围海域。 相似文献
95.
AnomalouschangeoftheAntarcticseaiceandglobalsealevelchange¥XieSimei;ZouBing;WangYiandBaoChenglan(1.NationalMarineEnvironmentF... 相似文献
96.
97.
IwrincrIONOn the evolution of palcoenvironment, salt-water encroachmnt and the distributionof subsurface brine in the LaizhOu Bay area, many researches had been carried out, and muchknowledge abeut the gcolOgical features in this area since Late QUaternary was aCquired' ) (H8nand Wu, l992; Han and Meng, l994; Wen et al. l989). However there was IittIe studyon the sediment geOChemical characteristics since Quaternary. In this Paper, the element strati-graphic characteristics and evolut… 相似文献
98.
The Princeton Ocean Model with realistic bottom topography has been used to investigate the summer temperature decrease in
the past 25 years in Fukuoka Bay. The vertical mixing of the model is expressed by a scheme that effectively includes the
influences of interannual variations of tidal currents and wind. The results show that the historical temperature decrease
in summer has been caused by tidal currents and wind weakening in the past 25 years in Fukuoka Bay. The weakening of tidal
currents and wind gives rise to weakening of the vertical mixing, and to enhancement of the estuarine circulation in the bay.
The enhancement of the estuarine circulation activates the inflow of open-ocean water toward Fukuoka Bay. Coastal water in
summer has therefore tended to be colder and more saline in the past 25 years. This interannual variation in coastal waters
is called “open-oceanization” in this study. On the basis of the numerical model, it is anticipated that the temperature will
decrease by 0.2°C in the next 25 years in Fukuoka Bay if the tide and wind weaken persistently as in the present bay. 相似文献
99.
S. C. Gonalves J. C. Marques M. A. Pardal M. F. Bouslama M. El Gtari F. Charfi-Cheikhrouha 《Estuarine, Coastal and Shelf Science》2003,58(4):901-916
The biology, population dynamics, and production of Talorchestia brito were studied at two sandy beaches located on the Atlantic (Portugal) and on the Mediterranean (Tunisia) coasts, respectively. The seasonal variation in abundance and the overall densities were similar in both populations. Reproduction occurred from February to September in the Atlantic, and from March to early November in the Mediterranean. The sex ratio was male biased in the Atlantic, and female biased in the Mediterranean. Based on data from the Atlantic population, both abundance and the proportion of reproductive females were positively correlated with temperature, while the proportion of juveniles in the population was positively correlated with temperature and sediment moisture. On average, individuals from the Atlantic were larger than the ones from the Mediterranean. Life span was estimated at six to nine months in the Atlantic, and five to eight months in the Mediterranean. Talorchestia brito was shown to be a semiannual species, with iteroparous females producing two broods per year, and exhibited a bivoltine life cycle. The minimum age required for males' and females' sexual differentiation and for female sexual maturation was shorter in the Mediterranean. Growth production (P) was estimated at 0.19 g m−2 y−1 ash free dry weight (AFDW; 4.3 kJ m−2 y−1) in the Atlantic population, and 0.217 g m−2 y−1 AFDW (4.9 kJ m−2 y−1) in the Mediterranean one. Elimination production (E) was estimated at 0.35 g m−2 y−1 AFDW (7.9 kJ m−2 y−1) in the Atlantic, and 0.28 g m−2 y−1 AFDW (6.3 kJ m−2 y−1) in the Mediterranean. The average annual biomass (
) (standing stock) was estimated at 0.032 g m−2 in the Atlantic beach, and 0.029 g m−2 in the Mediterranean one, resulting, respectively, in
ratios of 5.9 and 7.5 and
ratios of 10.8 and 9.6. Like other talitrids, T. brito exhibited geographic variation in morphometrical characteristics, sex ratio, growth rates, life span, and reproduction period, with the Atlantic population presenting a slower life history. 相似文献
100.
非常规管节点疲劳寿命分析与计算 总被引:6,自引:1,他引:6
对非常规管节点的疲劳寿命进行了分析研究,用SESAM计算疲劳载荷,应用精细有限元分析计算热点应力,用规范的S—N曲线计算管节点的疲劳寿命。通过实例计算表明,这些处理对非常规管节点疲劳寿命分析与计算是很有效的。 相似文献