太湖现代沉积物中磷的沉积通量及空间差异性   总被引：5，自引：0，他引：5  

朱广伟  秦伯强  高光 《海洋与湖沼》2007,38(4):329-335

在水文状况、水质状况、生态类型均显著不同的三个太湖典型湖区, 利用^210Pb定年测定了近百年来沉积物及磷的沉积通量.结果发现, 三个湖区磷的沉积通量及其变化规律相差很大.发生蓝藻水华暴发的梅梁湾近百年来沉积物和磷的沉积通量都比较小, 只是在近十几年来才有明显增加的趋势; 太湖上游的夹浦沉积物沉积速率近百年来持续增加, 只有表层有所下降, 但表层12cm沉积物中磷的沉积通量却显著下降; 处于太湖下游草型化的胥口湾湖区, 在20世纪60年代以前沉积物沉积通量呈增加趋势, 之后呈下降趋势, 磷的沉积通量则呈振荡下降趋势.研究表明, 太湖沉积物中磷的累积通量具有明显的空间异质性.  相似文献   

长江河口淡水端溶解态无机氮磷的通量   总被引：15，自引：1，他引：15  

傅瑞标  沈焕庭 《海洋学报》2002,24(4):34-43

1998年2和9月在长江河口淡水端连续观测了DIN(NO₃-,NO₂-,NH₄+),PO₄3-,流速和流向.结果表明,溶解态无机氮、磷浓度的时空变化较复杂;1998年2月NO₃-,NO₂-,NH₄+和PO₄3-的月通量分别为168241,974.4,19335和2648t,9月的月通量分别为905678,8317,5797和6281t;1998年NO₃-,NO₂-,NH₄+和PO₄3-年通量分别为497.1×104,3.911×104,10.22×104和4.155×104t.  相似文献   

台湾以东黑潮流量变异与冬季西北太平洋海洋-大气相互作用   总被引：5，自引：1，他引：5  

温娜  刘秦玉 《海洋与湖沼》2006,37(3):264-270

通过对历史资料进行奇异值分解、合成分析及相关分析,揭示了对应冬季台湾以东黑潮流量增强(减弱)时,西北太平洋海区异常失热(得热),北太平洋(北纬20°N以北)上空500hPa位势高度负异常(正异常);进一步证实了冬季西北太平洋海洋-大气相互作用是一个正反馈过程;发现了冬季台湾以东黑潮的暖平流作用可能是维持该正反馈过程进行的一个必要条件;通过超前和滞后相关及合成分析,提出从10月开始,台湾以东黑潮流量异常形成的暖平流作用会对冬季西北太平洋海区海洋-大气相互作用有贡献。  相似文献   

New directions in black carbon organic geochemistry   总被引：8，自引：0，他引：8  

C.A. Masiello   《Marine Chemistry》2004,92(1-4):201

In the past 30 years, the field of black carbon (BC) research has expanded broadly, stretching from its traditional core in the atmospheric sciences into oceanography, soil science, and even anthropology. Results produced in this period of expansion have been exciting: BC has been detected in many important geochemical pools, and interesting new research directions open as we learn about the role of this byproduct of biomass burning in the carbon cycle. Especially important research directions will be the quantification of BC loss processes (both biotic and abiotic), measurement of BC decomposition products in environmentally relevant reservoirs, and exploration of the interactions between BC and its host organo-mineral matrix, including the role of BC in pedogenesis.However, along with exciting results, we have also seen apparent discrepancies between BC studies. These discrepancies occur at least in part because of a lack of a common language, common methods, and a common model of BC. This paper lays out the framework many BC researchers use to understand the role of BC in the carbon cycle, discussing the ‘combustion continuum’ BC model and the methodological continuum that this model implies.  相似文献   

不同来源水沙对黄河入海泥沙通量的影响   总被引：6，自引：2，他引：6  

许炯心 《海洋与湖沼》2002,33(5):536-545

文中研究了黄河入海泥沙通量与流域上、中游不同来源区的水沙量之间的关系 ,并以年系列和洪水系列水文泥沙资料 ,建立了表达这一关系的经验统计模型。所建立的模型表明 ,来自不同来源区的泥沙 ,对于入海泥沙通量的影响是不同的。来自多沙细沙区的每 1t泥沙 ,输送入海的为 0 .85t(年系列 )和 0 .72t(洪水系列 ) ;而来自多沙粗沙区的每 1t泥沙 ,输送入海的仅为 0 .34t(年系列 )和 0 .2 1t(洪水系列 )。 70年代以来入海泥沙通量的减少 ,与多沙细沙区水土保持工作的开展有密切关系。将文中的模型与已建立的黄河流域水土保持减水、减沙模型相耦合 ,可以用来预测未来因人类活动和气候变化而使不同来源区的水沙进一步减少时 ,黄河入海泥沙通量的变化  相似文献   

一种新型海-气湍流通量参数化方案的模式测试     

班军梅  胡艳冰  李煜斌  徐小慧  孙燕 《海洋学报》2010,32(6):72-82

将一种新型湍流通量参数化方案代入到大气环流模式CAM3中,对比分析了模式改进前后模拟的风应力、感热通量、潜热通量和降水的全球分布,以及风应力、潜热通量和降水的纬向平均。结果表明:改进后模式的模拟结果更接近ERS、ERA40湍流通量数据和CMAP综合降水数据,其中对西风带上洋面风应力、亚洲季风区的潜热通量和降水改进明显。由于该新型湍流通量参数化方案直接由整体理查逊数、空气动力学粗糙度和热力学粗糙度参数化稳定度参数,避免了通过循环迭代计算Obukhov长度,计算效率得到提高。  相似文献   

颗粒物质和微量金属在东海北部的沉积通量   总被引：1，自引：1，他引：1       下载免费PDF全文

詹滨秋  黄华瑞  庞学忠  李鹏程  宋金明  任建伟 《海洋与湖沼》1993,24(1):51-58

于1990年运用沉积物捕捉器采样,实测了东海北部(32.00°N,126.00°E)海域颗粒物质和微量金属(Cu,Pb,Zn,Cr,Fe,Mn和Al)的海洋垂直通量。结果表明,颗粒物质的沉积通量随深度和季节而变化,明显地受上升流的影响。沉积的颗粒物质以0.45—63μm的小颗粒为主;Cu和Zn主要以有机物形式作垂直转移,Pb,Cr,Fe和Mn主要以弱键结合形式作垂直转移,Al则以硅酸盐的形式作垂直转移。沉积物中,颗粒Cu,Fe,Mn和Al以0.45—63μm的颗粒为主;颗粒Pb和Cr以大于63μm的颗粒为主;0.45—63μm和大于63μm的颗粒Zn在沉积物中占相近的比例。  相似文献   

Nitrogen cycling in deep-sea sediments of the Porcupine Abyssal Plain, NE Atlantic   总被引：2，自引：0，他引：2  

Jenny Brunnegrd  Sibylle Grandel  Henrik Sthl  Anders Tengberg  Per O.J. Hall 《Progress in Oceanography》2004,63(4):159-181

Rates of transformation, recycling and burial of nitrogen and their temporal and spatial variability were investigated in deep-sea sediments of the Porcupine Abyssal Plain (PAP), NE Atlantic during eight cruises from 1996 to 2000. Benthic fluxes of ammonium (NH₄) and nitrate (NO₃) were measured in situ using a benthic lander. Fluxes of dissolved organic nitrogen (DON) and denitrification rates were calculated from pore water profiles of DON and NO₃, respectively. Burial of nitrogen was calculated from down core profiles of nitrogen in the solid phase together with ¹⁴C-based sediment accumulation rates and dry bulk density. Average NH₄ and NO₃-effluxes were 7.4 ± 19 μmol m⁻² d⁻¹ (n = 7) and 52 ± 30 μmol m⁻² d⁻¹ (n = 14), respectively, during the period 1996–2000. During the same period, the DON-flux was 11 ± 5.6 μmol m⁻² d⁻¹ (n = 5) and the denitrification rate was 5.1 ± 3.0 μmol m⁻² d⁻¹ (n = 22). Temporal and spatial variations were only found in the benthic NO₃ fluxes. The average burial rate was 4.6 ± 0.9 μmol m⁻² d⁻¹. On average over the sampling period, the recycling efficiency of the PON input to the sediment was 94% and the burial efficiency hence 6%. The DON flux constituted 14% of the nitrogen recycled, and it was of similar magnitude as the sum of burial and denitrification. By assuming the PAP is representative of all deep-sea areas, rates of denitrification, burial and DON efflux were extrapolated to the total area of the deep-sea floor (>2000 m) and integrated values of denitrification and burial of 8 ± 5 and 7 ± 1 Tg N year⁻¹, respectively, were obtained. This value of total deep-sea sediment denitrification corresponds to 3–12% of the global ocean benthic denitrification. Burial in deep-sea sediments makes up at least 25% of the global ocean nitrogen burial. The integrated DON flux from the deep-sea floor is comparable in magnitude to a reported global riverine input of DON suggesting that deep-sea sediments constitute an important source of DON to the world ocean.  相似文献   

北戴河海滩泥沙捕获实验及其初步结果分析   总被引：2，自引：1，他引：2  

印萍  金永德  吕京福  胡泽建  王景川  丁明祥 《海岸工程》2003,22(2):67-77

介绍了利用泥沙捕获器观测破波带泥沙垂直分布结构的现场实验方法和基本程序，以及利用实验结果计算泥沙通量的方法。研究表明，近岸带泥沙运移通量及其在垂向上的分布受破波带相对位置和海滩地形变化的影响。在破波点附近，波浪的搅动和流场作用强，泥沙运移通量增大，泥沙在波浪的作用下可以大量进入垂直水体以悬移和跃移的方式运移。在本实验中，破波点附近的泥沙在距海底100cm的垂直水体中运移，通量垂向向上逐渐减小。远离破波点，泥沙运移通量和进入垂直水体的高度明显下降。在地形变化复杂的有坝海滩，沙坝顶部的泥沙运移通量最大，泥沙进入垂直水体运移的机率增加，而在沙坝问的沟槽内，波浪和海流作用减弱，泥沙通量和垂向进入水体运移的比例下降。  相似文献   

Study on the carbon flux in the South China Sea     

Han Wuying  Lin Hongying  Cai Yanya 《海洋学报(英文版)》1996,15(1):85-92

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