Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin     

Chandralata Raghukumar  G. Sheelu  P. A. Loka Bharathi  Shanta Nair  C. Mohandass 《Marine Georesources & Geotechnology》2001,19(1):1-16

In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.  相似文献   

VLBI单基线解算地球自转参数的秩亏性证明     

郑勇 《测绘学院学报》1993,(2)

本文由VLBI延迟观测的基本方程出发,证明了VLBI单基线观测解算地球自转参数时存在的秩亏性。  相似文献   

GPS相位测量轨道改进基线定位     

周建华 《测绘学院学报》1990,(1)

利用GPS载波相位观测值进行基线测定具有重要意义。本文讨论了基线测定中卫星星历误差对定位结果的影响,提出了基线上轨道改进的定位方法,编制了基线测定的定位软件,并使用高精度基线上的实际观测资料进行了计算。计算结果表明在基线上用轨道改进定位方法是可行的,可以提高定位精度。  相似文献   

区域站和基准站气溶胶的分析   总被引：8，自引：1，他引：8       下载免费PDF全文

杨东贞  于晓岚  房秀梅  吴凡  李兴生 《应用气象学报》1996,7(4):396-405

文章讨论了秋季（1994年10月）和冬季（1995年1月）在中国西部青海省共和县瓦里关山（36°17′N，100°54′E，海拔3816 m）基准站和中国东北黑龙江省五常县的龙凤山（44°44′N，127°36′E，海拔331 m）及中国东南沿海的浙江省临安县的横畈乡（30°18′N，119°44′E，海拔131 m）两个区域本底站（上述3站均属WMO）所采集的气溶胶样品的质量浓度、可溶性离子浓度的时空分布特征和变化规律。初步得出:气溶胶质量浓度和可溶性离子浓度以临安为最高。其次是龙凤山，而瓦里关山为最低  相似文献   

Organochlorine pesticide residues in sediments and biota from the coastal area of Dar es Salaam city,Tanzania   总被引：1，自引：0，他引：1  

Mwevura H  Othman OC  Mhehe GL 《Marine pollution bulletin》2002,45(1-12):262-267

Sediment and biota samples were collected from Msimbazi and Kizinga rivers and from the coastal marine environment of Dar es Salaam during both dry and wet seasons. The samples were analyzed for various organochlorine pesticide residues using GC-ECD and GC-MS. Dieldrin, p,p^′-DDT, p,p^′-DDE, p,p^′-DDD, o,p^′-DDT and γ-HCH were detected at significantly greater concentrations above the method detection limits. Recoveries of pesticide residues ranged 86.5–120% in sediments and 62–102% in biota. The average concentrations of total DDT in sediments for the two seasons were almost the same. Biota samples showed significant difference in levels of residues depending on mode of feeding and age of analyzed biota. p,p^′-DDT to total DDT ratios in all matrices indicated recent use of DDT. The levels of residues in sediments suggest possible adverse effects to humans consuming biota that are directly exposed to the sediments. This effect, which is associated with bio-concentration of residues in the tissues of edible aquatic biota, should not affect wildlife. In spite of concern on the adverse effect to humans posed by pesticide residues in sediments, edible biota from the examined water bodies were found to be safe for human consumption.  相似文献   

全球变化中的地球化学基线值研究及中国的研究现状   总被引：1，自引：0，他引：1  

陈静生  尹玉军 《地球科学进展》1991,6(2):36-39

介绍了“全球地球化学制图”(IGM)项目及其在中国的进展情况。展望了我国地球化学基线值研究工作方向及研究重点。  相似文献   

Could baseline establishment be counterproductive for emissions reduction? Insights from Vietnam’s building sector     

Maryna Karavai  Søren E. Lütken  Daniel Puig 《Climate Policy》2018,18(4):459-470

This article provides insights into the role of institutions involved in climate governance working towards a future low-carbon society at the national level, within the global climate change governance architecture. Specifically, it contributes to understanding the fragmented governance of energy efficiency policy in developing countries by focussing on Vietnam’s building sector, identifying key institutions related to underlying discourses, national and international power relations, resource distribution and coalitions. It uses the case of baseline setting in developing Nationally Appropriate Mitigation Actions (NAMAs) to illustrate institutional dynamics, nationally and transnationally, as well as to question whether demands for baseline setting achieve the ideal trade-off between actual GHG emissions reduction and institutionalized demands for accountability. The analysis reveals that, in addition to domestic efforts and challenges, the international agenda greatly influences the energy efficiency policy arena. The article presents lessons to be learnt about policy processes from the specific Vietnamese case, reflecting on the role of international actors and discourses in it. Finally, it argues for the abolition of baselines in favour of adequate monitoring and evaluation, from the perspective that requirement for deviation from fictitious baselines is unproductive and only serves an international techno-managerial discourse.

POLICY RELEVANCE

Baseline establishment is commonly considered an initial step in developing NAMAs, in order to facilitate the demonstration of a deviation from such baselines. The requirement to produce baselines is traditionally not questioned by policy practitioners. Thus, significant development resources are allocated to the establishment of baselines and the bridging of data gaps, often without consideration as to whether baselines are a necessary instrument for NAMA implementation. We suggest omitting the lengthy and resource-consuming practice of establishing baselines and recommend proceeding forthwith to the planning and implementation of mitigation and energy efficiency policies. As conditions vary significantly in different contexts, it would be more appropriate to measure the initial situation, establishing the ‘base point’, and monitor development from that point. The present article might serve as motivation for policymakers to question traditional approaches to policy development and consider alternatives to maximize the cost efficacy of NAMA programmes and facilitate their implementation.  相似文献   

Preliminary Study on Horizontal Deformation and Tectonic Activity in the Northern Part of North China Using GPS Remeasurement Results     

Guo Liangqian  Ying ShaofenFirst Crustal Deformation Monitoring Center  CSB  Tianjin  China 《中国地震研究》1999,(3)

In this paper, the baseline variation and displacement vector was analyzed using the calculated results of GPS measurements carried out from 1995 to 1996 in North China. Based on these analytical results, we studied the recent tectonic activity. In general, the regional extension is dominant in the direction of proximately EW, but there is a difference in the SN direction. Extension is significant in the Shanxi fault-depression zone and Bohai region, while compression with strike-slip is characterized along the Yishui-Tancheng segment of the Tanlu fault zone. The baseline shortening zone is distributed along the Baotou-Zhangjiakou-Ninghe areas. It is a boundary zone of regional variation where many differences of crustal horizontal deformation are discovered between the southern part and the northern part of this zone. The baseline shortening zone in NE direction is distributed along the Jianchang-Tangshan-Gucheng area. It is consistent with the Tangshan-Xingtai seismic zone which indicates that tectoni  相似文献   

磁偏角（D）的数据处理   总被引：2，自引：0，他引：2  

史勇军  孙燕萍 《内陆地震》1999,13(1):84-87

磁偏角观测数据既有东西方向的区别,又有数值大小的变化,由于喀仁台所处的地理纬度,其磁偏角方向偏东,观测工作就是要搞清磁照图上Ｄ与ＤＢ相对位置及Ｄ↑及Ｄ↓的物理意义;箭头表示磁场变化的向东偏的方向。在处理Ｄ观测数据时很容易发生混乱的错误,针对存在的问题,对数据处理展示了讨论。  相似文献   

近场强震动记录基线校正方法的振动台实验研究     

卢滔  胡国瑞  何福  郭迅  霍敬妍 《震灾防御技术》2017,12(3):625-634

为了获取近场永久位移,通常采用基线校正方法,对近场加速度记录进行基线校正并积分得到永久位移值,但这一结果主观性较强,其可靠性也往往缺乏验证。为了解决这一问题,本文提出了一种能产生包含永久位移振动过程的振动台实验方案,采用振动台加滑动机构的方法,模拟记录到永久位移台站测点的真实振动情况;在实验中分别采用加速度计、摄影测量方法分别直接得到加速度和位移时程,对加速度时程进行基线校正并积分得到位移时程,将其与直接获得的位移时程进行对比,以验证采用基线校正方法的有效性。实验结果表明,在实验室条件下采用现有的基线校正方法校正后,通过积分能得到可以接受的位移时程。  相似文献