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1.
Understanding the hydrological processes of colloids within the karst vadose zone is vital to the security of karst groundwater and providing appropriate paleohydrological explanations of colloid-facilitated metals in speleothem. This study addresses the mobilization mechanisms driving colloidal organic matter (COM) transport in the karst vadose zone using a 15-year long monthly monitoring dataset from a cave drip point (HS4) in Heshang Cave, Qingjiang Valley, China. Variations in COM concentrations were reported as the fluorescence difference values of raw and filtered (<0.22 μm) samples at an excitation wavelength of 320 nm and emission wavelength of ~400 nm. A fluorescence humification index (HIX) lower than 0.8 and an autochthonous index (BIX) higher than 1.2 indicated that the origin of COM was mainly from the karst vadose zone, rather than the soil zone. The COM concentration varied from 0.001 to 0.038 Raman Unit (RU), with evident seasonal fluctuations. Rising limbs for COM values occurred prior to rising limbs within a dripwater hydrograph; moreover, the COM peak values corresponding to the beginning of the increasing hydrograph generally suggested that the mobilization of COM reflected the movement of the air–water interface (AWI) in the karst vadose zone rather than rainfall intensity or flow velocity. COM peak values were positively correlated with the antecedent drying duration and negatively correlated with HIX values. These phenomena may be explained by the increased amount of organic matter that was aggregated and absorbed on the surface of carbonate in the karst vadose zone during a longer drying duration. Moreover, the longer drying duration was also beneficial to autochthonous biological activity, which subsequently decreased the HIX value of the organic matter in the karst vadose zone. The movement of AWI and the drying duration are both controlled by the outside weather conditions. This study is therefore conducive to evaluating the security of karst groundwater in response to climate change, and challenges prevailing paleoclimate interpretations of colloid-facilitated metal abundance timeseries reported from speleothems. 相似文献
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Global research progress on coastal flooding was studied using a bibliometric evaluation of publications listed in the Web of Science extended scientific citation index. There was substantial growth in coastal flooding research output, with increasing publications, a higher collaboration index, and more references during the 1995–2016 period. The USA has taken a dominant position in coastal flooding research, with the US Geological Survey leading the publications ranking. Research collaborations at institutional scales have become more important than those at global scales. International collaborative publications consistently drew more citations than those from a single country. Furthermore, coastal flooding research included combinations of multi-disciplinary categories, including ‘Geology' and ‘Environmental Sciences Ecology'. The most important coastal flooding research sites were wetlands and estuaries. While numerical modeling and 3 S(Remote sensing, RS; Geography information systems, GIS; Global positioning systems, GPS) technology were the most commonly used methods for studying coastal flooding, Lidar gained in popularity. The vulnerability and adaptation of coastal environments, their resilience after flooding, and ecosystem services function showed increases in interest. 相似文献
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Zhou Liqing Wang Xuemei Wu Biao Sun Xiujun Zhao Qing Zhang Gaowei Liu Zhihong Yang Aiguo 《中国海洋湖沼学报》2019,37(1):169-175
Journal of Oceanology and Limnology - Blepharipoda liberate Shen is a commercially valuable seafood species that has important ecological significance in Shandong Province, China. Although B.... 相似文献
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Influence of core property on multi-electron process in the collisions of q=6-9 and 11 isocharged sequence ions with Ne is investigated in the keV/u region. The cross-section ratios of double-, triple-, quadruple- and total multi-electron processes to the single electron capture process as well as the partial ratios of different reaction channels to the relevant multi-electron process are measured by using position-sensitive and time-of-flight techniques. The experimental data are compared with the theoretical predictions including the extended classical over-barrier model, the molecular Columbic barrier model and the semi-empirical scaling law. Results show a core effect on multi-electron process of isocharge ions colliding with Neon, which is consistent with the results of Helium we obtained previously. 相似文献
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深空探测是对宇宙中地球以外的行星、卫星、小行星和彗星等星体或空间环境的探测活动.合理选择深空探测科学仪器,了解被测星体的物理及化学性质、地表地貌、动态特性以及有机物和水的存在,对人类了解地外水和生命信息、认识太阳系的起源和演化有着重要意义,是深空探测的重要任务.本文总结了深空探测的科学目标,介绍了近50年来典型深空探测任务中探测器所搭载的科学仪器及其特点,包括质谱仪、光谱仪、探地雷达和磁力计等,整理了其性能参数及面向的探测功能任务,最后讨论了深空探测科学仪器目前呈现出的小型化、低功耗、更强的环境适应能力和多仪器联合使用的发展趋势. 相似文献
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潮汐测量与验潮技术的发展 总被引:10,自引:0,他引:10
潮汐是由各天体作用于地球上的引潮力所产生,不仅海洋中有潮汐,大气圈和地球固体部分也同样存在着潮汐。海道测量中的潮汐测量仅指海洋潮汐测量仅指海洋潮汐测量,潮汐测量的手段很多,主要包括采用水尺;浮子式、引压钟式、声学式、压力式验潮仪验潮。而GPS验潮及潮汐遥感测量等技术研究国内外正在开展。所有这些验潮技术各有自己的特点。 相似文献
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ODP与冲绳海槽海底热水活动研究 总被引:2,自引:1,他引:2
本文简要介绍了ODP与海底热水活动研究,冲绳海槽中部现代海底热水活动区热水活动研究简况及其热水活动特征;就冲绳海槽中部热水活动研究中存在的问题与ODP在冲绳海槽热水区钻探的科学目标进行了讨论。 相似文献