Advances in the Study of Geochemistry and Paleo-oceanography of the Co-rich Crust

The current advances in the study of geochemistry and paleo-oceanography of the Co-rich crust are reviewed in this paper. We summarize the study of geochemistry of the Co-rich crust, discuss the diffusion of elements in the Co-rich crust and the exchange with ambient seawater. Besides, we discuss the effect of phosphatization and substrate rocks on the composition of the Co-rich crust. We also introduce the application of stable isotopes(including the stable isotopes of Pb, Nd, and Hf), radioactive isotopes..

大亚湾与南海东北部海域沉积物中的 ~(137)Cs

用ＨＰＧｅγ谱仪测量了大亚湾和南海东北部海域沉积物中的人工放射性核素１３７Ｃｓ。大亚湾海域沉积物中１３７Ｃｓ含量在０．９２～３．７２Ｂｑ／ｋｇ，南海东北部为１．０４～１．５２Ｂｑ／ｋｇ；大亚湾海域沉积物中１３７Ｃｓ含量平均值高于南海东北部。在南海东北部海域，随离岸距离的增加沉积物中１３７Ｃｓ含量呈减小趋势

白令海盆氮吸收速率的同位素示踪

于白令海中心海盆与陆坡区采集了四个站位真光层以浅的垂直水样,利用15N示踪法确定了研究海域NO3-和NH4+的吸收速率.结果表明,真光层中NO3-和NH4+绝对吸收速率的积分平均值分别为1.3和4.5mmol.m-2.d-1,中心海盆区的数值低于陆坡区.氨盐的绝对吸收速率、比吸收速率均较硝酸盐的相应值来得高,表明氨盐是研究海域浮游植物优先利用的氮营养盐,研究海域低的f比值(≤0.3)、NO3-和NH4+的相对优先指数数值(RPINO31)进一步证实了上述论断.将研究海域表层水营养盐、Chl.a,PON含量、氮的比吸收速率、绝对吸收速率与沿岸上升流、HNLC海域进行比较后发现,白令海中心海盆是一个高营养盐、低生物量、低新生产力、低f比值的海域,它与白令海陆架区以及其他上升流海域具有明显不同的生态特征,白令海中心海盆应属HNLC海域.国家自然科学基金(批准号:90411016);; 国家重点基础研究发展计划项目(批准号:2005CB422305);; 教育部新世纪优秀人才计划(批准号:NCET-04-0593)资助项

Uranium Series Disequilibrium in Naked Rocks from Huoshaoyu Island, Xiamen

用HPGeγ谱方法测定了厦门火烧屿裸露岩石天然放射性核素40 K、2 2 8Ra、2 2 8Th、2 3 8U、2 2 6Ra和2 10 Pb含量 ,对其铀系不平衡关系进行了讨论 ,发现钍系核素2 2 8Ra和2 2 8Th基本上是平衡的 ,而大部分样品2 2 6Ra相对于2 3 8U、2 10 Pb相对于2 2 6Ra亏损。由此推论 ,水体作用下岸边岩石中2 2 6Ra直接进入水体 ,可以是海水中2 2 6Ra的一个来源 ;岸边岩石中2 2 2 Rn逸出后 ,衰变为2 10 Pb再进入水体 ,可以是海水中2 10 Pb的一个来源 【英文摘要】 The natural radionuclides in naked rocks from Huoshaoyu island of Xiamen were measured by means of HPGe (spectroscopy,and the 40K, 228Ra, 228Th, 238U, 226Ra and 210Pb were detected. Based on a discussion on the disequilibrium of uranium series, it is found that in most samples 226Ra relative to 238U and 210Pb relative to 226Ra are deficient. It can thus be concluded that the migration of 226Ra from the coastal rocks into seawater by water leaching is a ...国家自然科学基金项目 ( 4 0 0 760 2 4)资

ANALYSIS OF ECOSYSTEM INCORPORATED WITH WATER-CIRCLE SYSTEM IN INLAND BASIN OF NORTHWEST CHINA

西北内陆盆地生态环境特别脆弱 ,生态环境与水资源息息相关。该文将内陆河流域作为水循环 -生态复合系统 ,分析了复合系统的结构、功能和水循环特点 ,对于流域水资源开发和生态环境保护有一定指导意义。 【英文摘要】 The ecosystem, closely related to water resources, is very vulnerable in inland basin of northwest China. The paper takes inland basin as a composite ecosystem incorporated with water-circle system. The structure and function of ecosystem are analyzed, simultaneously, the characteristics of water-circle system are discussed, which are helpful for exploiting water resources and protecting eco-environmen

九龙江河口区水体中--（238）U、--（234）Th地球化学行为的研究

对采自九龙江河口区盐度介于0~21.97的10个表层水样，铀、钍同位素的测定结果表明，九龙江河口区水体中溶解态的（238）u含量与盐度之间存在着良好的相关关系，其相关系数可达0.972，表明九龙江河口区水体中的（238）u呈现保守行为。当S＝0时，溶解态（234）u/（238）u放射性比值为1.19和1.55（两份水样）；而当S＝0.90~21.97时，该比值＝1.02~1.14，分别呈现河水及河口水铀同位素组成的特征。对于颗粒态铀，其（238）u含量则介于0.50~9.83x10（-3）bQ/dM3，且随盐度的增大而呈逐步降低的趋势。九龙江河口区水体中（234）TH的地球化学行为属于非保守行为，不可逆稳态清除模型计算的结果表明，当盐度介于9.76~17.07时，（234）TH相对于化学清除的停留时间为6~19d，远低于盐度为0和21.97所对应的停留时间（分别为203d及117d），反映了在该盐度范围内，胶体絮凝沉降对溶解态234TH的快速清除作用国家自然科学基

Bacterial productivity in the Prydz Bay and its adjacent waters, Antarctic

Bacterial productivity was measured using 3H-thymidine methods in the Prydz Bay and its adjacent waters in the Southern Ocean during the 16th National Antarctic Research Expedition of China (CHINARE). The results showed that bacterial productivity in our study areas ranged from 4.5 to 191 ngC·dm -3·h -1, with an average of 50.4 ngC·dm -3·h -1. These values were comparable to those reported for the Ross Sea. The mean ratio of bacterial productivity to primary productivity in our study area..

加拿大海盆河水组分的平均停留时间

通过对西北冰洋海水中18O,226Ra,228Ra的分析,应用δ18O-S-PO*示踪体系计算了水体中河水组分和海冰融化水组分的份额,并根据陆架区与深海盆228Ra/226Ra)A.R.与河水组分之关系的差异估算海盆区河水组分的平均停留时间.结果表明,加拿大海盆的河水份额明显高于陆架区,证实该海盆是陆架所输送河水的主要储存区.楚科奇陆架、波弗特陆架水体中的228Ra活度浓度介于0.16～1.22Bq/m3之间,比中、低纬度陆架区的数值来得低,反映出海冰融化水的影响.陆架水228Ra/226Ra)A.R.与河水组分份额之间具有良好的线性正相关关系,而加拿大海盆水体的228Ra/226Ra)A.R.落在该拟合线下方,反映出水体离开陆架区往深海盆运移过程中228Ra的放射性衰变损失.根据陆架水与海盆水228Ra/226Ra)A.R.与河水组分份额之关系的差异估算出加拿大海盆河水组分的平均停留时间为5.0～11.0a.该停留时间决定了北大西洋深层水形成区域上层水体淡化对北冰洋入海径流响应的滞后时间.教育部新世纪优秀人才基金(批准号:NCET-04-0593);; 中国首次北极科学考察专项基金资助项

The sources of the upper and lower halocline water in the Canada Basin derived from isotopic tracers

Seawater samples were collected in the water column from the Canada Basin aboard RV Xuelong in August 1999. Concentrations of d D, d 18O, nutrients (NO3-, PO43-, SiO32-) and dis-solved oxygen were measured, along with hydrographic parameters (salinity and temperature). Our results showed that the upper layer of the water column was characterized by the occurrence of the upper halocline water (UHW) and the lower halocline water (LHW). The UHW was associ-ated with a salinity of 33.1 (~150m depth) and maximum...This work was supported by the Chinese First Arctic Expedition Foundation

The mean residence time of river water in the Canada Basin

Seawater was collected from the western Arctic Ocean for measurements of (18)O, (226)Ra and (228)Ra. The fractions of river runoff and sea ice melt-water in water samples were estimated by using delta (18)O-S-PO* tracer system. The mean residence time of river water in the Canada Basin was calculated based on the relationship between (228)Ra/(226)Ra)(A.R.) and the fractions of river runoff in the shelf and deep ocean. Our results showed that the river runoff fractions in the Canada Basin were significantly higher than those in the shelf regions, suggesting that the Canada Basin is a major storage region for Arctic river water. (228)Ra activity concentrations in the Chukchi shelf and the Beaufort shelf ranged from 0.16 to 1.22 Bq/m(3), lower than those reported for shelves in the low and middle latitudes, indicating the effect of sea ice melt-water. A good positive linear relationship was observed between (228)Ra/(226)Ra)(A.R.) and the fraction of river runoff for shelf waters, while the (228)Ra/(226)Ra)(A.R.) in the Canada Basin was located below this regressive line. The low (228)Ra/(226)Ra)(A.R.) in the Canada Basin was ascribed to (228)Ra decay during shelf waters transporting to the deep ocean. The residence time of 5.0-11.0 a was estimated for the river water in the Canada Basin, which determined the time response of surface freshening in the North Atlantic to the river runoff into the Arctic Ocean