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971.
The bacterial community in deep subseafloor sediments at a depth of 230 cm from the western Pacific “warm pool” is studied
by construction of 16S rDNA clone library and PCR-RFLP (Restriction Fragment Length Polymorphism) analysis. The results indicate
that the bacterial community in these sediments is mainly composed of five groups: α-Proteobacteria, β-Proteobacteria, CFB group (Cytophaga / Flexibacteria / Bacteroides), Acidobacteria and gram positive bacteria, with a few genera detected in each group. The most abundant bacteria group is α-Proteobacteria, and the next is β-Proteobacteria. The dominant species in α-and β-Proteobacteria are Sphingomonas paucimobilis and Pseudomonas alcaligenes respectively. The CFB group is simply composed of members belonging to Flavobacterium. The gram positive bacteria are rich, and mainly consists of the genus Geobacillus. The analysis of bacterial community indicates that organic matter is still abundant in the subseafloor sediments at the
depth of 230 cm in the western Pacific “warm pool”. These bacteria in this deep biosphere may play an important role in the
nitrogen cycle of deep sea sediments at “warm pool”.
Supported by the National Key Basic Research Support Foundation of China (Grant No. G2000078500) and China Ocean Mineral Resources
R&D Association Project (Grant No. DY105-4-2-4) 相似文献
972.
The abundance curves derived from area proportions of brachiopods and Girvanella in the thin sections from the Yangdi section, South China, exhibits complex relationships during the Late Devonian Frasnian-Famennian
transition. The living activity of brachiopods such as grazing and borrowing did great damage to the growth of Girvanella. However, there was more to just a mere a survival competing relationship between them, Girvanella actually improved marine environments by oxygenating the dysoxic ambient sea-water through photosynthesis in the lower Kellwasser
Horizon. Profited from this improvement brachiopods’ abundance increased subsequently and suppressed Girvanella again. Nonetheless, without Girvanella’s photosynthesis, brachiopods were wiped out by the farther anoxic environments in the upper Kellwasser Horizon. The complex
relationships between Girvanella and brachiopods may be a key to unlocking the relationships between geomicrobes and metazoans in the geological overturn
periods.
Supported by NSFC Innovation Research Group Program (Grant No. 40621002), MOE Innovative Research Team Program (Grant No.
IRT0546), the National Natural Science Foundation of China (Grant Nos. 40472020, 40730209, 40802005 and 40872001) and SINOPEC
Project (Grant No. G0800-06-ZS-319) 相似文献
973.
Gang Zeng Wei-Chyung Wang Caiming Shen Zhixin Hao 《Asia-Pacific Journal of Atmospheric Sciences》2014,50(3):355-364
We present a study of summer precipitation changes over the Yangtze River Valley (YRV) and North China (NC) simulated from 20 models of the CMIP3 (phase 3 of the Coupled Model Intercomparison Project). It is found that the LASG-FGOALS-g1.0 (fgoals) model has the highest ability in simulating both the interannual variability of individual regions and the seesaw pattern of the two regions observed during the past few decades. Analyses of atmospheric circulations indicate that the variability in precipitation is closely associated with the 850 hPa meridional winds over the two regions. Wetness in the YRV and dryness in NC are corresponding to strong meridional wind gradient and weak meridional wind over these two regions, respectively. The ability of a coupled general circulation model (CGCM) to simulate precipitation changes in the YRV and NC depends on how well the model reproduces both observed associations of precipitation with overlying meridional winds and observed meridional wind features in summer. Analysis of future precipitation changes over the two regions projected by the fgoals model under the IPCC scenarios B1 and A1B suggests a significant increase of 7–15% for NC after 2040s due to the strengthened meridional winds, and a slight increase over the YRV due to less significant intensification of the Mei-yu front. 相似文献
974.
Simulations of the effects of soil temperature and humidity disturbances on regional climate of China 总被引:1,自引:0,他引:1
Zheng Yiqun Qian Yongfu Yu Ge Gui Qijun Zeng Xinmin Liu Huaqiang 《Meteorology and Atmospheric Physics》2002,81(1-2):85-102
Summary ?This simulation study was applied by a regional climate model (RegCM2) and forced by reasonable soil temperature and humidity
disturbances, in order to examine the disastrous weather and climate-produced such disturbances that were performed in a series
of experiments of different climatic zones, seasons and space/time scales, to recognize the persistence and to understand
the mechanisms of their respective climatic responses under the current climatic background of China.
The simulation results showed that, in regions of East Asian monsoon climate, the soil humidity disturbance (SHD) has greater
impact on posterior climate responses than the temperature disturbance has. The SHD forcing exerts noticeable influence on
rainfall generally. Although the centers of changed precipitation generally do not coincide with those of the disturbances,
the centers are located mostly in downwind areas of the SHD core and in areas of prevailing updraft, even some places far
away; with neighboring dry/moist SHD zones, a bigger rainfall increase tends to show up in the dry region instead of in the
wet one.
The simulation suggested that the SHD lasts for a rather long time, whose length is controlled by the presence of a positive
feedback between the precipitation, the synchronous circulation patterns, the latitude and season, and the intensity of the
SHD forcing.
This study has found that the humidity disturbance (especially from rainfall) is in good correspondence to posterior temperature
that the previous SHD enhancement leads to the subsequent temperature drop in the surface and near-surface layer, while the
centers of lowered temperature can remain more than three months.
Received April 3, 2001; Revised December 19, 2001 相似文献
975.
976.
利用1988~2000年7~9月南昌、建阳、长沙三站探空资料及同期地面和500 hPa天气图与降雨量资料等,对照1988~2000年7~9月南昌(建阳、长沙713雷达站部分资料)"713"雷达站回波素描图进行统计分析,得出南方夏季对流云回波的顶高、强度、性质等参数变化规律与主要特征,从宏观上了解影响南方夏季对流云回波参数等特征量的变化规律,为南方各省人工影响天气作业提供科学依据. 相似文献
977.
978.
979.
广东省寒潮、强冷空气的气候特征及与ENSO的关系 总被引:3,自引:13,他引:3
本文对影响广东的寒潮、强冷空气与ENSO的关系进行了分析,结果表明:寒潮和强冷空气活动多的年份一般出现在中等或强的El Nina期间。寒潮和强冷空气活动少的年份容易出现在La Nina期间,而较难出现在El Nina期间。 相似文献
980.