检索结果-南通市图书馆

Bacterial community in deep subseafloor sediments from the western Pacific "warm pool"

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2008年第4期51卷 618-624页

作者： ZHAO Jing1 & ZENG RunYing2 1 College of oceanography and Environmental Science, xiamen university,{3., china 2 Key Laboratory of Marine Biogenetic Resources, Third Institute of oceanography, State Oceanic Administration,{3., china College of oceanography and Environmental Science Xiamen University Xiamen 361005 China Key Laboratory of Marine Biogenetic Resources Third Institute of Oceanography State Oceanic Administration Xiamen 361005 China

The bacterial community in deep subseafloor sediments at a depth of 23. 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 / Flexi-bacteria / 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 alca-ligenes 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 23. cm in the western Pacific "warm pool" . These bacteria in this deep biosphere may play an impor-tant role in the nitrogen cycle of deep sea sediments at "warm pool" .

关键词： western Pacific 'warm pool' deep subseafloor sediment bacterial community

Disequilibria between ^(210)Po and ^(210)Pb in surface waters of the southern South china Sea and their implications

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2006年第1期49卷 103-112页

作者： YANG Weifeng, HUANG Yipu1,2, CHEN Min1,2, ZHANG Lei, LI Hongbin, LIU Guangshan1,2 & QIU Yusheng1,2 1. department of oceanography, xiamen {3., xiamen 3.1005, china 2. State Key Laboratory of Marine Environmental Science, xiamen {3., xiamen 3.1005, china 1. department of oceanography Xiamen University Xiamen 361005 China 2. State Key Laboratory of Marine Environmental Science Xiamen University Xiamen 361005 China

Activities of the naturally occurring radionuclides, ^(210)Pb and ^(210)Po,were measured in both dissolved ( 0.45 μm) phases from surfacewaters of the southern South china Sea. The average activity of particulate ^(210)Pb, 0.23.Bq/m^3.(n= 23., accounted for about 12% of the total ^(210)Pb, which corresponds with values of open *** ^(210)Po, with an average activity of 0.43.Bq/m^3. accounted for about 40% of the total^(210)Po, which was much higher than those of open and eutrophic oceans. The residence times oftotal ^(210)Po and ^(210)Pb in surface waters estimated from an irreversible steady-state model were0.82 a and 1.16 a, respectively. The consistently high fractionation factor calculated either byscavenging rate constants (5.42) or K_d values (6.69) suggested that a significant fractionationoccurred between ^(210)Po and ^(210)Pb during their removal from solution to particles and that thetwo radionuclides had different biogeochemical cycling pathways in the oligotrophic South china ***, our results indicated that there exist different fractionation mechanisms between^(210)Po and ^(210)Pb in different marine environments: in eutrophic ocean, plankton detritus andfecal pellets are the main carrier of ^(210)Po and ^(210)Pb, by which ^(210)Po and ^(210)Pb havebeen scavenged and removed; while in oligotrophic ocean, microbes could become the main carrier of^(210)Po and fractionate ^(210)Po and ^(210)Pb significantly as a result of scarce plankton detritusand fecal pellets. These results suggest the use of ^(210)Po to trace marine biogeochemicalprocesses relating to microbial activities and the cycling of sulfur group elements (S, Se, Te andPo).

关键词： South china Sea, 210Po, 210Pb, disequilibria, scavenging.

Studies on ecological characteristics variation and population dynamics of four lizardfishes in the southern Taiwan Straits

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2011年第6期30卷 72-81页

作者： DU Jianguo LU Zhenbin YANG Shengyun CHEN Mingru department of oceanography Xiamen University Xiamen 361005 China Third Institute of oceanography State Oceanic Administration Xiamen 361005 China Fisheries Research Institute of Fujian Xiamen 361012 China

The ecological characteristics of four lizardfishes, Trachinocephalus myops, Saurida undosquamis, Saurida tumbil and Saurida elongata, were studied from specimens （910 T. myops, 454 S. un-dosquamis, 686 S. tumbil and 744 S. elongata） collected monthly in the southern Taiwan Straits from April 2005 to March 2006. The population dynamics of the four lizardfishes was also discussed by the comparison with the previous studies. All being composed of 7 a classes; the dominant group of T. myops and S. tumbil was 1–2 a, while S. undosquamis and S. elongate were 2–3.a. The total mortality coefficient Z and the fishing mortality F were at high as indicated by the exploitation ratio E（0.5）, and a large number of by-caught juvenile and young fishes showing that the stock of lizardfishes in this area was overexploited and the fishing gear was irrational. Compared with the previous studies, the maximum and mean fork length, body mass and age of the four lizard- fishes declined gradually, the lizardfishes populations were younger in age and smaller in size. The asymptotic fork length L ∞ decreased while increasing growth coefficient k, and age at the inflexion point of mass t r was younger compared with the previous studies. The declining of older ones has moderated the feeding competition and the younger ones grew faster. The larger mortality param-eters Z, M and F have revealed higher fishing pressure. The smaller change of the first mature fork length of female T . myops and the change from K selection pattern to r selection pattern of S. tumbil have indicated a more vulnerable fishery ecosystem in this area. The changes of ecological characteristics and population dynamics may be caused by over-exploitation of demersal fishes such as the lizardfishes, especially a large number of juvenile and young fishes by-catch by the current fishing gears and methods. Therefore, in addition to the traditional fishery management approach such as the minimum length-limit, ecosystem approach

关键词： lizardfish ecological parameters population dynamics ecosystem approach to fish- eries management southern Taiwan Straits

Studies on the tropomyosin of marine zooplankton

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 1989年第3期8卷 431-440页

作者： Su Yongquan and Xiao Jinglin’ department of oceanography, xiamen {3., xiamen, china department of Biology, xiamen {3., xiamen, china

-Investigations on the preparation, structure and biochemical characteristics of tropomyosin (Tm) of Acetes japonicus, A. chinensis and Pseudeuphausia sinica, collected from xiamen coastal water, show that: (1) Tm could be isolated by salting fractionation in the range of 20-3.% ammonium sulphate saturation, and the contents of them are 0.86%, 0.87% and 0.70% of dry weight respectively. (2) Molecular weight of Acetes detected by SDS-PAGE method is 3.3.3.6×104, while that of P. sinica, 3.2-3.5×104. (3. Isoelectric points of all the three Tm determined by isoelectric focusing method are at about pH 5.0. (4) Crystalline spindles of above three Tm can be formed in phosphate buffer containing Mg+f at pH 4.8 or pH 7.2, showing cross striations with a repeat period of 3.-40 nm under the electron microscope by negative staining, and there are fine lines at irregular intervals in each striation. (5) The characteristics of the chemical composition of three Tm reveal that the strong polar amino acids account for more than 54% of the total amount, and the acidic amino acids, 3.-41%. This is in correspondence with the proteins pi 5.0. Littel or no Pro and Trp can be found in these three proteins. (6) Results obtained by the circular dichroism method show that two typical negative peaks of α-helix appeared from 250-190 nm, while the tops of the peaks are at 222 and 208 nm. The percentages of α-helix of the whole chain at 208 nm are 76.6% for A. japonicus, 74.2% for A. chinensis and 61.6% for Psinica.

关键词： Tm

Radiochemical studies of deep - sea manganese nodules

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 1989年第2期8卷 253-261页

作者： Huang Yipu, Luo Shangde, Shi Wenyuan Chen Zhen department of oceanography, xiamen {3., xiamen , china Dept. of oceanography Xiamen Univ. Xiamen China China

Five manganese nodules collected from the Northern Mid - Pacific have been analysed for their U and Th *** is found that the enrichment of thorium compared to uranium is universal in deep- sea manganese, nodules and in the top sides of the nodules there are large excesses of Th and Pa decreasing exponentially with depth. For each of the nodules, the concordant growth rates are obtained from three different methods: 23.Thex 23.Thex/23.Th and *** growth rates of manganese nodules are closely related to the chemical compositions of the nodules and the types of the underlying sediments. The growth rates of five nodules are determined to be in the range of 0.79-7.4 mm/106a, in agreement with those predicted from the chemical compositions of the nodules. By the comparison of the extrapolated 23.Thex,23.Thex/23. Th and 23.PaeX data from the top and bottom surfaces of the nodule from Site M21 yields, the nodule turnover time is (9.83.13.7)×104a.

关键词： Th rate sea manganese nodules Radiochemical studies of deep

Maximal possible accretion rates for slim disks

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2009年第12期52卷 2054-2058页

作者： LIN YiQing1 & JIAO ChengLiang2 1 department of Mathematics and Physics,xiamen university of Technology,xiamen 3.1024,china 2.department of Physics and Institute of Theoretical Physics and Astrophysics,xiamen university,xiamen 3.1005,china 1. department of Mathematics and Physics Xiamen University of Technology Xiamen 361024 China 2. department of Physics and Institute of Theoretical Physics and Astrophysics Xiamen University Xiamen 361005 China

It was proved in the previous work that there must be a maximal possible accretion rate $ \dot M_{max} $ for a slim disk. Here we discuss how the value of $ \dot M_{max} $ depends on the two fundamental parameters of the disk, namely the mass of the central black hole M and the viscosity parameter α. It is shown that $ \dot M_{max} $ increases with decreasing α, but is almost independent of M if $ \dot M_{max} $ is measured by the Eddington accretion rate $ \dot M_{Edd} $ , which is in turn proportional to M.

关键词： accretion disks black hole physics hydrodynamics

Study of colloidal phosphorus variation in estuary with salinity

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2010年第1期29卷 17-25页

作者： CHEN Ding ZHENG Airong CHEN Min department of oceanography and Institute of Subtropical oceanography Xiamen University Xiamen 361005 China State Key Laboratory of Marine Environmental Science. xiamen university Xiamen 361005. China

The variation of colloidal phosphorus with salinity in estuary was studied in this paper, which was compared with those of particle and truly dissolved phosphorus with the purpose of finding out the similarities and differences between their behaviors in the estuary. Distribution patterns of phosphorus in particle, colloidal and truly dissolved phase at different salinities and their relationships with suspended particulate matter were also studied to understand the transformation and transporta- tion of colloidal phosphorus in estuarine area. The result showed that the concentrations of total colloidal phosphorus, organic colloidal phosphorus and inorganic colloidall phosphate all descended from river-end to sea-end, illustrating their terrigenous source. *** of organic to total colloidal phosphorus decreased with salinity＇s increment, indicating that organic phosphorus was influenced by scavenging process of colloid more significantly as compared with inorganic phosphate. Both of the phosphorus variation tendencies and the proportion between organic and inorganic phosphorus in colloidal phase was similar with that in truly dissolved phase while different from that in particle phase.

关键词： truly dissolved phase colloidal phosphorus salinity

The experimental studies on the carbon and nitrogen budgets of Pseudeuphausia sinica

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2003年第2期22卷 265-272页

作者： Guo Donghui, Li Shaqjing, Chen Feng, Wang Guizhong, Chen Gang department of oceanography,Institute of Subtropic Ocean,xiamen {3.,xiamen 3.1005,china xiamen Univ Dept Oceanog Inst Subtrop Ocean Xiamen 361005 Peoples R China

The carbon and nitrogen budgets were estimated on the adult females, juveniles and post-furcilia larvae of Pseudeuphausia sinica fed on newly hatching nauplii of Artemia salina in the laboratory. It was found that the ingestion rate was linearly related to the food concentration, suggesting high feeding potential. The linear correlation could be established between the respirating rate (carbon consumption rate) and carbon ingestion rate, as well as carbon assimilation rate. The regression coefficients (*** dynamic action coefficients) were in the range from 9% to 16% (ingested C) or 10% to 17% (assimilated C) respectively, with lower in the post-furcilia larvae. There also existed a linear correlation equation between estimated total nitrogen excretion rate and the rates of nitrogen ingestion and assimilation separately, except for the juveniles. The defecation rates increased with the increase of the ingestion rate; as a result, assimilation efficiency was not related to the ingestion rate, ranging from 0.84 to 0.95. The results inducated that the nitrogen content in food particles was a key factor limiting the growth of P. sinica. The critical ingestion rate was 10 μgN·mg-1 body dry weight per day. Assimilated N was lost mostly by excretion, following allocated to somatic growth. The nitrogen loss by moult only accounted for a minor part. As for carbon budget, respiration and somatic growth also accounted for most of assimilation, but varied with ingestion rates. Moult loss was minor. Estimated reproductive growth (C&N) in the adult females accounted for somewhat higher percent of assimilation than the moult growth. The net growth efficiency (K2) increased with the increase of the ingestion rates, but decreased slightly for juvenile and post-furcilia larvae after the rates up to a certain value.

关键词： Pseudeuphausia. sinica carbon and nitrogen budgets xiamen harbour

Qeochemical behaviour of iodine in Jiulong River Estuary

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 1989年第1期8卷 91-99页

作者： Guo Jinbao and Peng Zhen department of oceanography, xiamen {3., xiamen, china

Dissolved iodine species and the relationship between its distribution and salinity in Jiulong River estuarine water have been determined. It has been found that the total iodine, iodate and iodide are positive linear with salinity. This indicates that dissolved iodine species (IO-3.and I- ) in estuarine water .how conservative behaviour. The river water contains 2. 40μg/1 as iodide and less than 1. 0μg/1 as iodate, and iodide is the predominant species. Whereas the sea water contains 3.. 4μg/1 as iodate and 4. 00μg/1 as iodide, and iodate is the dominant form. The distribution of dissolved iodine in pore water, as a function of depth, has been studied. Iodine in pore water occurs as iodide. The apparent fluxes of soluble iodine from the sediment to the overlying water in the estuary have been determined. The values are 2. 4 (15℃) and 27μmol/(m2·d) (3.℃) respectively.

关键词： Qeochemical behaviour of iodine in Jiulong River Estuary