东北印度洋深海记录基本特征及其对青藏高原隆升的响应   总被引：14，自引：2，他引：14       下载免费PDF全文

方念乔  陈学方  胡超涌  丁旋  张振芳  刘勇勤 《第四纪研究》2001,21(6):490-499

本文在综合东北印度洋域5支深海钻芯和7支活塞柱状芯资料的基础上,对该区沉积作用及其形成的记录与北部山脉和高原隆升的关系进行讨论.过去有关深海记录对造山带构造活动响应的研究多集中于孟加拉浊积扇,而90°E海岭的远洋沉积记录通过海气相互作用系统作为中介,可能包含响应隆升的重大环境信号.初步研究表明,远洋记录中的碳酸盐含量、有孔虫的形态结构和若干微量元素特征的剧变期与已知的高原构造阶段存在密切的对应关系,其中,距今8Ma、3.7Ma、0.8Ma和0.16Ma所反映的变化尤为突出.  相似文献   

日光温室蔬菜栽培中人工增施CO2 技术   总被引：19，自引：0，他引：19       下载免费PDF全文

汪永钦  刘荣花 《应用气象学报》1997,8(4):460-468

根据国内外试验资料及近几年在河南省日光温室蔬菜栽培中进行人工CO2施肥的试验示范和应用推广的技术成果，对CO2温室人工施肥的增产机理、适宜气源、适宜浓度和每天适宜施放时间、适宜施放量的定量估算方法、适宜施放方式等重要技术问题和配套栽培措施进行了分析，以期有助于提高农用CO2的开发利用效率和温室生产力。  相似文献   

掺和氯化钠治理硫酸盐渍土膨胀的应用范围     

丁永勤  陈肖柏 《冰川冻土》1992,14(2):107-114

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The distribution and demography of Euphausia superba in Prydz Bay during the austral summer 2002     

LIU Yongqin  SUN Song  ZHANG Yongshan  LIU Huilian 《极地研究(英文版)》2012,23(1):12-18

This study documents the horizontal distribution and demography of Antarctic krill （Euphausia superba Dana）, col- lected using trawls, from the Prydz Bay region during January 2002. Euphausia superba （E. superba） was distributed primarily south of 64S. The average density and biomass were estimated as 68.85 ind.（1 000 m3） and 24.16 g wet weight-（1 000 m3）, re- spectively. Highest values were located in the open sea （depth 〉 3 000 m）. Body length ofE. superba ranged from 30 to 55 mm （N=1 758）, with a mean length of 38.45~3.68 mm （SD）. The overall sex ratio was approximately 1 ： 1, 47.6% females （41.9% sub-adults and 5.7% adults）, 46.6% males （42.7% sub-adults and 3.9% adults）, while 5.8% were juveniles. The population struc- ture of E. superba exhibited geographical variation. At stations in the western part of the survey area populations had a high pro- portion of juveniles, a lower sexual maturity stage for males and small body size, while the opposite was found at stations in the eastern part. A latitudinal difference was found at stations along 70.5°E and 73°E transects： body length was small and the sex ratio was high in regions of high latitude, while the opposite occurred in areas of low latitude.  相似文献   

Seasonal variation in abundance, diel vertical migration and body size of pelagic tunicate Salpa fusiformis in the Southern Yellow Sea   总被引：1，自引：0，他引：1  

刘永芹  孙松  张光涛 《中国海洋湖沼学报》2012,30(1):92-104

Mass occurrence of Salpa fusiformis was observed in the Southern Yellow Sea in May and June 2007. In order to investigate its population recruitment and environmental adaptation, temporal variation of abundance, diel vertical migration (DVM) and length frequency distribution of both aggregate and solitary forms were studied with samples collected from eight months during September 2006 to August 2007. S. fusiformis presented in six months other than September and October 2006, and average abundance of aggregate and solitary forms peaked in June and May, respectively. In December, aggregate forms were absent in the bottom layer and performed irregular DVM from surface to 50 m depth, while solitary forms was too scarce to perform diel vertical distribution analysis. Both aggregate and solitary forms presented reverse DVM in May and June. They migrated upwards during daytime and concentrated in surface layer at sunset. The bimodal distribution of aggregate forms was found in April and the average size was largest in this month. In other months, the smaller aggregate forms (1-5 mm) dominated in populations except for May, when the modal size ranged from 2 to 8 mm. The average size of solitary forms was largest in December, followed by April. The skewed nomal distribution of solitary forms was found in May and June, with the modal size of 2-7 mm and 5-13 mm, respectively.  相似文献   

冰川表面冰尘洞内病毒研究进展   总被引：3，自引：2，他引：1  

臧琳  刘勇勤  刘晓波 《冰川冻土》2019,41(6):1496-1504

病毒在驱动生态系统高生物多样性形成以及生态系统营养物和有机物的循环过程中均发挥着重要的作用。冰川洞作为冰冻圈微生物活动的热点, 为病毒提供了特殊的生存环境, 驱使病毒产生了生存与适应机制。通过综述国际上近些年来关于冰川表面冰尘洞内病毒的主要研究成果, 内容涉及冰尘洞在冰川生态系统中的重要性, 冰尘洞内病毒的丰度与生产力, 冰尘洞内病毒的遗传多样性, 病毒与宿主的相互作用关系, 以及病毒对于冰尘洞碳循环和食物网的重要性。此外, 还总结了当前冰尘洞内病毒研究存在的空白： 形态多样性、 降解率、 分离培养、 冰川表面散落冰尘内病毒, 指出了未来研究需要重点关注的几个方面, 为进一步研究病毒对于冰尘洞生态系统的重要影响提供科学参考, 并且对青藏高原冰川表面冰尘洞内病毒未来的研究提出了展望。  相似文献   

Multiscale variability of streamflow changes in the Pearl River basin,China   总被引：1，自引：1，他引：0  

Yongqin David Chen  Qiang Zhang  Xiaohong Chen  Ping Wang 《Stochastic Environmental Research and Risk Assessment (SERRA)》2012,26(2):235-246

The Pearl River basin bears the heavy responsibility for the water supply for the neighboring cities such as Macau, Hong Kong and others. Therefore, effective water resource management is crucial for sustainable use of water resource. However, good knowledge of changing properties of streamflow changes is the first step into the effective water resource management. With this in mind, stability and variability of streamflow changes in the Pearl River basin is thoroughly analyzed based on monthly streamflow data covering last half century using Mann–Kendall trend test and scanning t- and F-test techniques. The results indicate: (1) significant increasing monthly streamflow is observed mainly in January–April, June and October–December. Monthly streamflow during May–September is in not significant changes. Besides, stations characterized by significant monthly streamflow changes are located in the middle and the lower Pearl River basin; (2) changing points of monthly streamflow series are detected mainly during mid-1960s, early 1970s, mid-1970s, early 1980s and early 1990s and these periods are roughly in good agreement with those of annual, winter and summer precipitation across the Pearl River basin, implying tremendous influences of precipitation changes on streamflow variations; (3) abrupt behaviors tend to be ambiguous from the upper to the lower Pearl River basin, which should be due to enhancing combined effects of abrupt changes of precipitation. The streamflow comes to be lower stability in recent decades. However, high stability of streamflow changes are observed at hydrological stations in the lower Pearl River basin. The results of this study will be of great scientific and practical merits in terms of effective water resource management in the Pearl River basin under the influences of climate changes and human activities.  相似文献   

Wavelet-based characterization of water level behaviors in the Pearl River estuary, China   总被引：1，自引：0，他引：1  

Qiang Zhang  Chong-Yu Xu  Yongqin David Chen 《Stochastic Environmental Research and Risk Assessment (SERRA)》2010,24(1):81-92

In this paper, we analyzed the high/low water levels of eight stations along the Pearl River estuary and the high/low tidal levels of Sanzao station, and streamflow series of Sanshui and Makou stations using wavelet transform technique and correlation analysis method. The behaviors of high/low water levels of the Pearl River estuary, possible impacts of hydrological processes of the upper Pearl River Delta and astronomical tidal fluctuations were investigated. The results indicate that: (1) the streamflow variability of Sanshui and Makou stations is characterized by 1-year period; 1-, 0.5- and 0.25-year periods can be detected in the high tidal level series of Sanzao station, which reflect the fluctuations of astronomical tidal levels. The low tidal level series of Sanzao station has two periodicity elements, i.e. 0.5- and 0.25-year periods; (2) different periodicity properties have been revealed: the periods of high water levels of the Pearl River estuary are characterized by 1-, 0.5- and 0.25-year periods; and 1-year period is the major period in the low water levels of the Pearl River estuary; (3) periodicity properties indicate that behaviors of low water levels are mainly influenced by hydrological processes of the upper Pearl River Delta. High water levels of the Pearl River estuary seem to be affected by both hydrological processes and fluctuations of astronomical tidal levels represented by tidal level changes of Sanzao station. Correlation analysis results further corroborate this conclusion; (4) slight differences can be observed in wavelet transform patterns and properties of relationships between high/low water levels and streamflow changes. This can be formulated by altered hydrodynamic and morphodynamic processes due to intensifying human activities such as construction of engineering infrastructures and land reclamation.  相似文献   

鄱阳湖流域水沙时空演变特征及其机理   总被引：12，自引：1，他引：11  

孙鹏  张强  陈晓宏  陈永勤 《地理学报》2010,65(7)

运用改进的Mann-Kendall(M-K)趋势与突变检验以及线性回归分析等方法,系统分析了鄱阳湖流域的赣江、抚河、信江、饶河和修河等五大支流的5个主要水文控制站(外洲、李家渡、梅港、虎山、万家埠)1956-2005年的水沙序列,在系统搜集流域内水库信息的基础上,深入探讨了流域内水沙变化的原因.研究结果表明:(1)鄱阳湖流域各支流的水沙变化特征相异;除李家渡站径流无明显变化外,其余4站都有增加趋势(但未达到95%的置信度水平1.五大支流的输沙量变化比较复杂,外洲站、李家渡、梅港站和虎山站的输沙量在1985年以后减少的趋势显著,而万家埠站的输沙量直到1999年才开始减少;(2)森林覆盖率对输沙量变化的影响远远大于其对径流变化的影响,森林对减少湿季径流量的作用不明显,但对枯季径流量增加的影响显著.(3)水利设施(尤其是水库)对五大支流的水沙变化影响很大,尤其对输沙量的影响最为明显,这也是鄱阳湖流域大部分水文观测站输沙量减少的主要原因.  相似文献   

Study on the Tripolyphosphatase （TPPase） Property of Bighead Carp （Aristichthys nobilis） Myosin Subfragment-1     

GAO Ruichang XUE Changhu YUAN Li ZHANG Yongqin XUE Yong SUN Yan FENG Hui 《中国海洋大学学报(英文版)》2007,6(4):398-402

Myosin subfragment-1 was prepared from the myofibrils of bighead carp (Aristichthys nobilis). The myosin subfrag- ment-1 was proved to have the activity of tripolyphosphatase (TPPase) responding to the hydrolysis of sodium tripolyphosphate (STPP). The optimum temperature and pH for the TPPase of myosin subfragment-1 were 30℃ and pH 5.0, and at pH 8.0 the TPPase also showed a high activity. Mg2 was necessary to TPPase. The TPPase activity of myosin subfragment-1 was activated by Mg2 under low concentrations, but was inhibited when the concentration was over 17 mmolL-1. The TPPase activity was also affected by KCl. The optimum concentration of KCl for TPPase was 0.3 molL-1 under the condition of 17 mmolL-1 Mg2 . The TPPase activity was significantly inhibited by EDTA-Na2. Reagents such as KBr, KI and KIO3 could inhibit the TPPase effectively. K2Cr2O7 as well as KMnO7 and KNO3 exhibited weak inhibiting effects. The TPPase converted STPP to pyrophosphate (PP) and orthophosphate (Pi) stoichiometrically with a KM of 3.2 mmolL-1.  相似文献