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21.
运用MnO2纤维富集-228Ac b计数法测定了南沙海域两个测站3个时间点水柱的228Ra比活度, 得其值介于0.38至 3.60 Bq×m-3. 发现228Ra的分布能满足稳态条件. 采用一维稳态模型, 以228Ra-NO- 3法测得测站NS97-43, NS99-53(T1)和NS99-53(T2)的新生产力分别为4.4, 5.1和5.7 mmolC·m-2·d-1. 结合初级生产力的文献报道值, 计算得南沙海域的f比介于0.12~0.15. 相似文献
22.
南黄海和东海海水18O的组及其意义
O的组成及其意义 总被引：3，自引：0，他引：3
对2006年夏季采自南黄海和东海的海水进行了18O同位素组成的分析,结合温度与盐度的分布,探讨了影响研究海域海水δ18O分布的主要因素。结果表明,南黄海和东海海水的δ18O与盐度之间具有良好的线性正相关关系,据此确定出夏季黑潮水和陆地径流水的特征δ18O值分别为0.20‰—0.45‰和9.85‰。依据海水δ18O的分布,探讨了黑潮水、长江冲淡水和黄海冷水团对研究海区δ18O分布的影响,结果显示,夏季黑潮水仅影响到台湾东北部陆架坡折以外的海域,其影响路径可能以气旋式涡旋的形式出现;在长江口附近海域,长江径流水进入东海后,对长江口东北部海域的影响范围较其南部更为宽广,可到达济州岛西南部。在南黄海海域,海水δ18O的分布可清晰指示出南黄海冷水团的位置,黄海冷水团的形成可能与冬季的黄海暖流具有一定的联系。 相似文献
23.
对北太平洋亚热带环流区表层水中溶解态(＜0.2 μm)和颗粒态(≥0.2 μm)210 Po、210pb的含量、分布、停留时间及其在颗粒物清除迁出过程中的分馏效应开展了研究,结果表明,研究海域表层水中溶解态210Po、210Pb的比活度分别介于0.14 ～3.75和1.41 ～6.87 Bq/m3之间;颗粒态210Po、210Pb的比活度分别介于0.35 ～ 2.49和0.18 ～3.18 Bq/m3之间.溶解相和颗粒相中的210Po/210Pb不平衡状态呈现截然不同的特征,溶解相中210Po相对于210Pb呈亏损状态,而在颗粒相中则呈过剩状态,反映出210Po与210Pb生物地球化学行为的差异,210Po具有更强的颗粒(生物)活性.由稳态不可逆模型计算出溶解态和颗粒态210Po的平均停留时间分别为0.28、0.27 a;溶解态和颗粒态210Pb的平均停留时间分别为0.88、0.15 a.由清除速率常数法计算得到的溶解态210Po、210Pb在颗粒清除过程中的平均分馏因子为4.73,且该分馏因子随颗粒氮含量的增加呈增加的趋势.停留时间的差异以及明显大于1的分馏因子均表明,210Po、210Pb在颗粒清除过程中发生了明显的分馏,而分馏因子与颗粒氮(PN)之间存在的正相关关系则显示含氮组分对210 Po、210Pb的分馏起着一定的作用. 相似文献
24.
A combination of δ~(18)O and salinity data was employed to explore the freshwater balance in the Canada Basin in summer 2008.The Arctic river water and Pacific river water were quantitatively distinguished by using different saline end-members.The fractions of total river water,including the Arctic and Pacific river water,were high in the upper 50 m and decreased with depth as well as increasing latitude.In contrast,the fraction of Pacific river water increased gradually with depth but decreased toward north.The inventory of total river water in the Canada Basin was higher than other arctic seas,indicating that Canada Basin was a main storage region for river water in the Arctic Ocean.The fraction of Arctic river water was higher than Pacific river water in the upper 50 m while the opposite was true below 50 m.As a result,the inventories of Pacific river water were higher than those of Arctic river water,demonstrating that the Pacific inflow through the Bering Strait is the main source of freshwater in the Canada Basin.Both the river water and sea-ice melted water in the permanent ice zone were more abundant than those in the region with sea-ice just melted.The fractions of total river water,Arctic river water,Pacific river water increased northward to the north of 82°N,indicating an additional source of river water in the permanent ice zone of the northern Canada Basin.A possible reason for the extra river water in the permanent ice zone is the lateral advection of shelf waters by the Trans-Polar Drift.The penetration depth of sea-ice melted waters was less than 30 m in the southern Canada Basin,while it extended to 125 m in the northern Canada Basin.The inventory of seaice melted water suggested that sea-ice melted waters were also accumulated in the permanent ice zone,attributing to the trap of earlier melted waters in the permanent ice zone via the Beaufort Gyre. 相似文献
25.
Size-fractionated 210Po and 210Pb, in the size fractions 0.4 μm, 2 μm and 10 μm, were examined to determine the seasonal variability of particulate fluxes in Xiamen Bay. Good correlations between 210Po and particulate organic carbon (POC) or non-Particulate Organic Matter (nPOM) suggested that 210Po can be used to trace the export fluxes of POC and nPOM. Both steady-state (SS) model and nSS model were used to evaluate fluxes of size-fractionated 210Po, results showed that nSS model was better than the SS model in coastal areas. Based on the nSS model, size-fractionated POC fluxes decreased with increasing particle size. For the particle size studied, maximum POC fluxes occurred in autumn, followed by spring, winter, and summer. Fluxes of nPOM were an order of magnitude higher than the corresponding size-fractionated POC fluxes. Differences between size-fractionated nPOM fluxes indicated that hydrodynamic conditions were the main factor regulating transportation of particulate out of the inner Bay. In winter most particulates, including 10 μm particles, were transported under the strongest hydrodynamic conditions. In contrast, only a fraction of the 2 μm particulates were transported from the inner Bay in spring. This study suggested that 210Po is a powerful tracer of seasonal particulate export in coastal seas. 相似文献
26.
Size-fractionated 210Po and 210Pb, in the size fractions >0.4 μm, >2 μm and >10 μm, were examined to determine the seasonal variability of particulate fluxes
in Xiamen Bay. Good correlations between 210Po and particulate organic carbon (POC) or non-Particulate Organic Matter (nPOM) suggested that 210Po can be used to trace the export fluxes of POC and nPOM. Both steady-state (SS) model and nSS model were used to evaluate
fluxes of size-fractionated 210Po, results showed that nSS model was better than the SS model in coastal areas. Based on the nSS model, size-fractionated
POC fluxes decreased with increasing particle size. For the particle size studied, maximum POC fluxes occurred in autumn,
followed by spring, winter, and summer. Fluxes of nPOM were an order of magnitude higher than the corresponding size-fractionated
POC fluxes. Differences between size-fractionated nPOM fluxes indicated that hydrodynamic conditions were the main factor
regulating transportation of particulate out of the inner Bay. In winter most particulates, including >10 μm particles, were
transported under the strongest hydrodynamic conditions. In contrast, only a fraction of the <2 μm particulates were transported
from the inner Bay in spring. This study suggested that 210Po is a powerful tracer of seasonal particulate export in coastal seas. 相似文献
27.
九龙江河口区溶解态、颗粒态铀同位素的地球化学行为 总被引：1，自引：1，他引：0
对九龙江河口区枯、丰水期水体中溶解态、颗粒态铀同位素地球化学行为的研究表明,溶解态铀与盐度存在良好的正相关关系,证实枯、丰水期该河口区水体中的铀均是保守行为。在低盐度区域（Ｓ＜１０）,~２３８Ｕ主要以颗粒态形式存在,颗粒态~２３８Ｕ所占份额随盐度增加而降低。~（２３８）Ｕ之条件分配系数介于 １． ２ × １０~３～１． ５ ×１０~５ｄｍ~３／ｋｇ之间,它与盐度呈负相关关系,但与悬浮颗粒物浓度无相关关系存在。枯水期悬浮颗粒物上~２３４Ｕ／~２３８Ｕ_Ａ．Ｒ．与盐度的负相关关系为河口区悬浮颗粒物中~２３４Ｕ的优先沥取理论提供了有力的证据。 相似文献
28.
南极普里兹湾及其邻近海域溶解有机碳的分布 总被引：5，自引：0，他引：5
中国南极科学考察第16航次期间(1999年11月～2000年4月),在南极普里兹湾及邻近海域的不同站位与水深采集海水样品用于溶解有机碳测定,通过高温催化氧化法完成样品的分析.结果表明,在调查期间,南极普里兹湾及其邻近海域各测站上层水体(0～100m)溶解有机碳浓度的变化范围为14.3～181.1μmol/dm3,平均为52.5μmol/dm3,该变化幅度比Ross海、太平洋等海域的相应值略大.溶解有机碳垂直分布的特征是0大于25大于50大于100m,即随深度的增加溶解有机碳浓度逐渐减小,与生物活动在垂直方向上的强弱变化相关.根据200m以深水柱溶解有机碳的垂直分布,可确定研究海域难降解溶解有机碳的浓度为40.4μmol/dm3,与其他研究所报道的数值(～42μmol/dm3)相近.上层水体(0～100m)过剩溶解有机碳的空间分布显示,64°S以北海域溶解有机碳过剩较多,而64°S以南海域则过剩溶解有机碳较少.溶解有机碳浓度与分布特征显示,普里兹湾及其邻近海域溶解有机碳浓度与南大洋其他海域相当,具有低溶解有机碳的一般特征.溶解有机碳浓度的空间分布呈现由西南向东北方向逐渐增加的趋势,这可能与南极陆架夏季上层水的北向扩展有关.生物活动及水体运动是研究海域溶解有机碳分布的主要影响因素. 相似文献
29.
本文阐述了在中国第 1 6次南极科学考察期间 ( 1 999/ 2 0 0 0南半球夏季 )运用3H 胸腺嘧啶核苷示踪法研究南极普里兹湾及其邻近海域细菌生产力的分布特征。结果表明 :该海区细菌生产力比较低 ,变化范围在 4.5- 1 91ngC·dm- 3·h- 1 ,平均为 5 0 .4ngC·dm- 3·h- 1 ,其水平与Ross海相当。细菌生产力的变化较好地反映了浮游植物变化的特性 ,BP与PP的比值为 0 .41。表层水体中BP与DOC的分布特征呈反相关关系。普里兹湾及邻近海域细菌生产力、初级生产力及溶解有机碳之间的关系表明 ,细菌的活动受浮游植物活跃程度及其它环境条件的影响 相似文献
30.