Show simple item record

dc.contributor.authorCai, Pinghezh_CN
dc.contributor.authorShi, Xiangmingzh_CN
dc.contributor.authorMoore, Williard S.zh_CN
dc.contributor.authorPeng, Shiyunzh_CN
dc.contributor.authorWang, Guizhizh_CN
dc.contributor.authorDai, Minhanzh_CN
dc.contributor.author蔡平河zh_CN
dc.contributor.author王桂芝zh_CN
dc.contributor.author戴民汉zh_CN
dc.date.accessioned2015-07-22T03:12:39Z
dc.date.available2015-07-22T03:12:39Z
dc.date.issued2014-01-15zh_CN
dc.identifier.citationGEOCHIMICA ET COSMOCHIMICA ACTA, 2014,125:68-84zh_CN
dc.identifier.otherWOS:000329066500005zh_CN
dc.identifier.urihttps://dspace.xmu.edu.cn/handle/2288/88178
dc.descriptionNational Basic Research Program ("973" Program) of China [2009CB421203]; Natural Science Foundation of China (NSFC) [41076041, 41276062]; funds for creative research groups of the National Natural Science Foundation of China [41121091]zh_CN
dc.description.abstractWe utilized Ra-224/Th-228 disequilibrium in the sediment to investigate processes that regulate solute transfer across the sediment-water interface. Depth profiles of dissolved and surface-bound Ra-224 and Th-228 in the upper 0-20 cm sediment column were measured using a delayed coincidence counter during a cruise to the Yangtze estuary from 15 to 24 August 2011. Along with Ra-224 and Th-228, depth profiles of Th-234 were collected to determine the bioturbation rate in the sediment. At most study sites, a significant deficit of Ra-224 relative to Th-228 was observed in the upper 0-10 cm. In contrast, Ra-224 was in excess with respect to Th-228 in the upper 0-5 cm at the river mouth, possibly due to redistribution of Ra-224 from the mid-salinity region. By modeling the Ra-224 depth profiles in the sediment using the general diagenetic equation, we demonstrated that in most cases molecular diffusion and bioturbation together can account for only similar to 20-30% of the measured flux of Ra-224. We concluded that other mechanisms, especially irrigation, must be invoked to explain the remnant 70% of the observed deviation of Ra-224 relative to Th-228. On the basis of the Ra-224/Th-228 disequilibrium in the sediment and a concept of increased surface area for exchange by irrigation as developed by early investigators, we proposed a new approach - the Ra-224/Th-228 disequilibrium approach to quantify the transfer rate of other dissolved species across the sediment-water interface. We have utilized this new approach to determine the benthic consumption rate of dissolved O-2. The result reveals that benthic consumption is an important loss term of dissolved O-2 in the Yangtze estuary and must be considered as one of the mechanisms that lead to hypoxia in this area. (C) 2013 Elsevier Ltd. All rights reserved.zh_CN
dc.language.isoen_USzh_CN
dc.publisherPERGAMON-ELSEVIER SCIENCE LTDzh_CN
dc.source.urihttp://dx.doi.org/10.1016/j.gca.2013.09.029zh_CN
dc.subjectEAST CHINA SEAzh_CN
dc.subjectSUBMARINE GROUNDWATER DISCHARGEzh_CN
dc.subjectWASHINGTON CONTINENTAL-SHELFzh_CN
dc.subjectPARTICLE REWORKINGzh_CN
dc.subjectRADIUM ISOTOPESzh_CN
dc.subjectBENTHIC FLUXESzh_CN
dc.subjectYANGTZE-RIVERzh_CN
dc.subjectTH-234-U-238 DISEQUILIBRIUMzh_CN
dc.subjectATCHAFALAYA RIVERSzh_CN
dc.subjectCHANGJIANG ESTUARYzh_CN
dc.titleRa-224:Th-228 disequilibrium in coastal sediments: Implications for solute transfer across the sediment-water interfacezh_CN
dc.typeArticlezh_CN


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record