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1.
应用实验室培养法测定了溶解无机氮(DIN)在胶州湾16个站位沉积物-海水界面上的交换速率。结果表明, NH4 -N,NO2 -N和NO3 -N的交换速率一般分别在-0.5~1.6,0.005~0.67, + - --2.0~2.8 mmol/(m2·d)范围内。由于间隙水中DIN主要以NH4 -N形态存在,DIN在胶州湾沉 +积物-海水界面上的交换以NH4 -N的扩散为主,在大部分站位表现为由沉积物向水体的释放, +NO3 -N主要来自NH4 -N的硝化反应,而NO2 -N是NH4 -N和NO3 -N之间化学转化过程的中 - + - + -间产物。考虑胶州湾沉积物类型, 在胶州湾沉积物-海水界面上的交换通量为9.68×108 DINmmol/d,是河流输入DIN的50%左右,可提供维持胶州湾初级生产力所需DIN的52%。  相似文献   

2.
胶州湾沉积物-海水界面硅的交换速率及其影响因素探讨   总被引：2，自引：1，他引：1  
采用实验室培养法在原位温度和溶氧条件下测定了胶州湾沉积物-海水界面硅的交换速率,并探讨了相关环境因子对界面交换速率的影响机制。结果表明,胶州湾沉积物-海水界面硅的交换表现为从沉积物向水体释放,其交换速率在947~4 889 μmol/（m2·d）范围内,平均速率为1 819 μmol/（m2·d）。表层沉积物中叶绿素a（Chl a）和总有机碳（TOC）是影响胶州湾沉积物-海水界面硅交换速率的主要环境因子,同时表层沉积物的含水率（φ）、生源硅（BSi）和粘土含量以及间隙水中溶解硅酸盐（DSi）对沉积物-海水界面硅的交换也有重要影响。由此可推知,胶州湾沉积物-海水界面硅的交换速率主要受生物活动和溶解-扩散双重过程调控,而表层沉积物粒度与底层水体中DSi对胶州湾硅的释放影响较小。  相似文献   

3.
胶州湾秋季表层海水pCO_2分布及水-气界面通量   总被引：1，自引：0，他引：1  
根据2007年11月31日在胶州湾走航连续观测所得pCO2数据,结合水文、化学和生物等要素的同步观测资料,对胶州湾海域pCO2分布及其影响因素进行了探讨。结果表明:秋季胶州湾表层海水pCO2实测值在315~720μatm之间,平均值为423μatm。东部海域由于有机物降解及李村河水输入的影响表现为大气CO2的源;西部海域由于浮游植物活动的影响为大气CO2的弱汇区;湾中部水交换较好的海域,浮游植物活动和有机物降解共同影响着pCO2的分布。总体来说,秋季胶州湾表现为大气CO2的弱源,海-气界面CO2交换速率在-5.94~23.15 mmol.m-2.d-1之间,平均值为2.87 mmol.m-2.d-1,由此可估算出秋季胶州湾可向大气释放940.74 tC。  相似文献   

4.
采用实验室培养法,在原位温度和溶氧条件下,研究了夏、冬季胶州湾沉积物-海水界面溶解无机氮(DIN)的迁移特征。结果表明,夏、冬季胶州湾沉积物-海水界面DIN主要以NO_3-N和NH_4-N的形态进行交换,夏季胶州湾沉积物表现为水体DIN的源,其交换通量为1.64×10~9 mmol/d,可以提供维持初级生产力所需氮的39.3%;而冬季沉积物表现为DIN的汇,其交换通量为–2.12×10~8 mmol/d。利用相关分析和主成分回归分析,研究界面不同形态DIN交换速率和底层环境因子的关系,结果表明,夏季胶州湾沉积物-海水界面DIN的交换主要受沉积物中有机质的矿化、底栖藻类的同化作用和扩散过程共同调控,而冬季则主要受内源有机质的矿化、底栖藻类的同化作用、吸附-解吸和扩散过程共同调控。  相似文献   

5.
依据2011年3月4日对胶州湾走航连续实测所得pCO2数据,结合水文、化学和生物等要素的同步实测资料,对胶州湾海域pCO2分布及其影响因素进行了初步探讨,并估算了3月海-气CO2通量。结果表明:3月胶州湾表层海水pCO2实测值在191～332μatm之间,平均值为278μatm,海-气CO2通量在-22.76～-7.13mmol·m-2·d-1,平均值为-14.2mmol·m-2·d-1,这一时期胶州湾从大气吸收约1.59×103t C,表现为大气CO2的强汇。生物活动是影响这一时期表层海水pCO2分布的主要原因。  相似文献   

6.
根据交换速率连续函数计算法,应用实验室培养法测定了PO_4-P在胶州湾16个站位沉积物-海水界面上的交换速率。结果表明,PO_4-P的交换主要表现为由沉积物向水体的释放,其交换速率一般在 0.1～90 μmol·m~(-2)·d~(-1)范围内。根据 PO_4-P在不同类型沉积物-海水界面上的交换速率,估算出其在胶州湾海底沉积物-海水界面上的交换通量为 9.76×10~6mmol·d~(-1),仅占河流输入量的 24％,可提供浮游植物生长所需磷的 9％±3％。  相似文献   

7.
溶解无机态营养盐在渤海沉积物-海水界面交换通量研究   总被引：2，自引：0，他引：2  
了解无机态营养严在渤海沉积物-海水界面交换速率、通量基控制因素,于2002-08-06~08-24,应用船基沉积物培养方法,现场测定了硅酸盐(SiO3-Si)、磷酸盐(PO4-P)和溶解无机氮(DIN)在沉积物-海水界面上的交换速率(νN)和交换通量(FN)。结果显示,νSiO3-Si变化范围为2 220~4 317μmol.m-2.d-1,平均为3 466μmol.m-2.d-1,νPO4-P为0.4~77μmol.m-2.d-1,平均为39μmol.m-2.d-1,νDIN为667~2 167μmol.m-2.d-1,平均为1 308μmol.m-2.d-1,其中NH4-N和NO3-N的贡献分别为48%和47%左右。进一步分析表明,νSiO3-Si主要由溶解和扩散2个过程控制,前者决定于沉积物黏土矿物含量和含水率,后者决定于营养盐浓度和温度。νPO4-P主要由在以黏土为主的细颗粒和氢氧化铁上的吸附-解吸和扩散过程控制,前者分别决定于沉积物粒度和上覆水中DO浓度,而后者决定于间隙水与上覆水之间的浓度差。结果表明,FSiO3为2.59×1013mmol,FPO4为2.95×1011mmol,FDIN/SE为8.62×1012mmol。这样,为维持夏季渤海初级生产力,沉积物交换过程可提供大约65%的SiO3-Si、12%的PO4-P和22%的DIN,远远高于以河流径流为主的陆源排放。  相似文献   

8.
胶州湾毗邻青岛市区,是受人类活动影响显著的海湾。开展胶州湾水-气界面CO2通量研究,有助于厘清受人类活动严重干扰下的边缘海(湾)CO2源汇的控制机制。根据2013年4月在胶州湾走航连续观测所得pCO2数据,结合水文、化学和生物等要素的同步观测资料及以往本课题组获取的冬季2、3月份航次数据,对胶州湾海域pCO2分布及影响因素进行了分析探讨。结果表明:表层海水pCO2测得值在392~1 648μatm之间,平均值为496μatm。4月份胶州湾水体垂直混合均匀,且水柱对表层碳酸盐体系的影响显著。4月份胶州湾浮游生物初级生产弱于2、3月份,而生物的好氧呼吸作用要强于2、3月份。因此,生物好氧呼吸作用的增强是4月份胶州湾表现为大气CO2源的主要原因,同时温度升高也是导致胶州湾冬季到春季表层pCO2升高的重要因素,其影响程度仅次于生物好氧呼吸作用。总体来说,4月份胶州湾表现为大气CO2的源,水-气界面CO2交换通量在-8.22~490.68mmol·m-2·d-1之间,平均值为17.34mmol·m-2·d-1。  相似文献   

9.
桑沟湾和胶州湾沉积物耗氧率研究   总被引：2，自引：0，他引：2  
为评价浅海海域底层在碳元素生物地化循环中的作用,采用现场取样培养法测定了黄海桑沟湾和胶州湾的沉积物耗氧率。桑沟湾5月和8月的沉积物耗氧率分别为15和24 mmol.m-2.d-1;胶州湾8月的沉积物耗氧率为18 mmol.m-2.d-1。回归分析表明,2个湾的沉积物耗氧率分别与沉积物表层的有机碳和总氮含量正相关。取呼吸商为0.8,得到桑沟湾底层对有机碳的矿化率占水层初级生产力的102%(5月)和67%(8月),胶州湾底层对有机碳的矿化率占水层初级生产力的28%(8月)。取桑沟湾颗粒有机碳的生物沉积速率为236 mg.m-2.d-1,得到底层对有机碳的埋置效率为40%(5月)和3%(8月),埋置的有机碳占水层初级生产力的69%(5月)和2%(8月);胶州湾颗粒有机碳的自然沉积速率为251 mg.m-2.d-1,底层对有机碳的埋置效率为32%(8月),埋置的有机碳占水层初级生产力的13%(8月)。  相似文献   

10.
系统考察2014年4月胶州湾海水中甲烷的氧化速率。通过一系列的海水培养实验,采用气相—稳定同位素比值质谱仪(GC-IRMS)追踪了培养样品中δ13 CH4的变化,计算了胶州湾海水的甲烷氧化速率(MOX)。结果表明:胶州湾表层水中甲烷的氧化速率的变化范围为3.7~255.5nmol·L~(-1)·d~(-1),平均值为(104.7±89.7)nmol·L~(-1)·d~(-1)。底层水中甲烷的氧化速率的变化范围为38.2~227.1nmol·L~(-1)·d~(-1),平均值为(148.9±76.2)nmol·L~(-1)·d~(-1)。总体而言,在胶州湾东部和西部,特别是海泊河口、洋河河口附近的水域,表层海水中甲烷氧化速率的分布都明显呈现出近岸高,远岸低的趋势。胶州湾甲烷的氧化速率与溶解无机碳浓度的变化以及甲酸的含量呈较明显的线性正相关。根据甲烷氧化速率估算出胶州湾氧化甲烷的量为1.15×108 mol/a,该值相当于胶州湾甲烷海-气通量的6.4~14.3倍。  相似文献   

11.
Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding.  相似文献   

12.
Grain size and water content in box-core sediments from the Clarion-Clipperton fracture zone (C-C zone) in the northeast equatorial Pacific were analyzed in detail to understand the downcore variations across a hiatus between Quaternary and Tertiary layers. Grain-size distributions in the topmost core sediments show two modes: a coarse mode (peaked at 50 μm) and a fine mode (at 2-25 μm). The coarse mode disappears gradually with depth accompanied by the dissolution of siliceous fossil tests, whereas the fine mode coarsens due to the formation of authigenic minerals. Water content increases abruptly across a color boundary between an upper pale brown layer and a lower dark brown layer that is the hiatus between Quaternary and Tertiary layers. Abundant smectites and microvoid molds, which are created by the prolonged fossil dissolution in the underlying sediment, are attributed for the abrupt downcore variation of water content. Overall variations in grain size and water content in the topmost core sediments in the western C-C zone are possibly constrained by the dissolution of biogenic siliceous fossils. Variations in geotechnical properties related to these changes must be considered in the design of nodule collectors.  相似文献   

13.
This article concerns an interrelation between the sea levels and the western boundary flow near a tectonic boundary in a local zone in the Northwestern Pacific. In this zone, sea level variations at stations located on the coast facing the Pacific are studied to find the interrelation between variations of the Kurosio flow as an index of the distance of the flow axis off a specific coast. The result is discussed after data processing of the monthly means of the sea levels, and a notice is taken of variations caused by active crustal upheavals during a seismic event, a local earthquake.  相似文献   

14.
This study tests the hypothesis that the in situ void ratio of surficial marine sediments may be predicted from shear wave velocity-depth data with a reliability equal to that of other methods currently available. Shear wave velocity is fundamentally controlled by the number of grain-to-grain contacts per unit volume of material and by the effective stress across those contacts. In this study, three previously established empirical formulae are used to predict void ratio from velocity-depth data. Field data were acquired along a transect off the northern Californian coast across which water depth increased from 35 to 70 m and seafloor sediment type varied from sand to silty-sand, respectively. A towed seafloor sled device was used to collect shear wave refraction data, and a marked, systematic decrease in velocity was observed along the line, ranging from 35-70 m/s for the coarse, near-shore material to 25-40 m/s for the finer, offshore deposits. Void ratios predicted from these velocities were compared with data measured directly from box-core samples. Of the formulae used for prediction, two agree remarkably well with the control data. Both predicted and control values increase from 0.6-0.8 for the sandy material to 1.1-1.5 for the silty-sand. Thus, this study does not disprove the hypothesis set and demonstrates the potential of field shear wave velocity-depth data as a means of delineating spatial variation in void ratio for surficial marine sediments in a remote, nondestructive manner.  相似文献   

15.
Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease (0.84% ～ 1.88%) of organic carbon content from the upper reaches to the estuary.δ13C values of particulate organic carbon was in the range of -24.9×10-3 to -26.6×10-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ13C and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs (soil organic matter) among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream.  相似文献   

16.
Current trends of development of satellite derived bathymetry (SDB) models rely on applying calibration techniques including analytical approaches, neuro-fuzzy systems, regression optimization and others. In most of the cases, the SDB models are calibrated and verified for test sites, that provide favorable conditions for the remote derivation of bathymetry such as high water clarity, homogenous bottom type, low amount of sediment in the water and other factors. In this paper, a novel 3-dimensional geographical weighted regression (3GWR) SDB technique is presented, it binds together methods already presented in other studies, the geographically weighted local regression (GWR) model, with depth dependent inverse optimization. The proposed SDB model was calibrated and verified on a relatively difficult test site of the South Baltic near-shore areas with the use of multispectral observations acquired by a recently launched Sentinel-2 satellite observation system. By conducted experiments, it was shown that the proposed SDB model is capable of obtaining satisfactory results of RMSE ranging from 0.88 to 1.23[m] depending on the observation and can derive bathymetry for depths up to 12m. It was also shown, that the proposed approach may be used operationally, for instance, in the continuous assessment of temporal bathymetry changes, for areas important in the context of ensuring local maritime safety.  相似文献   

17.
As a part of the environmental impact assessment studies, geotechnical properties of sediments were determined in the Central Indian Basin. The undrained shear strength and index properties of the siliceous sediments were determined on 20 box cores of uniform dimension collected from various locations in five preselected sites. The maximum core length encountered was 41 cm and most of the sediments were siliceous oozes consisting of radiolarian or diatomaceous tests. The shear strength measurements revealed that surface sediments deposited in recent times (0-10 cm) have a shear strength of 0-1 kPa; this value increases with depth, reaching 10 kPa at 40 cm deep. Older sediments have greater strength because of compaction. Water content varies in the wide range of 312-577% and decreases with depth. The clay minerals such as smectite and illite are dominant and show some control over water content. Wet density, specific gravity, and porosity do not indicate any notable variation with depth, thereby indicating a uniform, slow rate of sedimentation. The average porosity of sediments is 90.2%, specific gravity 2.18, and wet bulk density 1.12 g/cm 3 . Sediments exhibit medium to high plasticity characteristics, with the average plasticity index varying between 105% and 136%. Preliminary studies on postdisturbance samples showed an increase in natural water content and a decrease in undrained shear strength of sediments in the top 10- to 15-cm layer.  相似文献   

18.
The rare earth element (REE) distribution in nine deep-sea ferromanganese nodules and their associated siliceous sediments from the Central Indian Ocean Basin (CIOB) have been studied to elucidate the REE relationship among them. Total REE concentration varies from 398-928 ppm in the nodules and 137-235 ppm in the associated sediments, suggesting two- to four-fold enrichment in the nodules compared to associated sediments. REE of nodules and their associated sediments show a positive correlation, suggesting REE are supplied from a common source such as seawater. The positive correlation between REE of nodules and sediments from the CIOB is contrary to the competitive scavenging of REE between nodules and sediment in the equatorial Pacific Ocean. REEs in the nodules are carried by Fe, P, and Ti, whereas in the sediment they are carried by P and Mn phases. A similar REE fractionation pattern with middle REE enrichment over heavy and light REE in both the nodules and their associated sediment suggest fractionation is independent of REE abundance and their carrier phases.  相似文献   

19.
Detailed acoustic surveys of benthic sediments were conducted in July 1995 and September 1998 in the vicinity of Humboldt Bay, California. During these surveys, a band of enhanced acoustic backscatter was observed offshore from the bay entrance, approximately parallel to the isobaths, in water depths ranging from 16-24 m. In order to assess the cause of the increase in backscatter levels, a more comprehensive study was conducted in August and September 1999 using 100 kHz side-scan sonar, bottom grab sampling and underwater video recording. New observations indicated that a dense population of sand dollars ( Dendraster excentricus ) coincided with the enhanced backscatter band. Compared to the two previous acoustic studies, the central section of the band expanded westward by 180 m and the southern section of the band shifted eastward by 160 m, possibly resulting from a change in the biological or physical factors which influence the location and breadth of sand dollars. The relationship between high sand dollar abundance and enhanced acoustic backscatter was further verified in the nearshore region off Samoa Beach California, where a dense, banded population of sand dollars was previously observed. Video footage confirmed the presence of a band of sand dollars, also nominally parallel to the isobaths, in water depths of 8-15 m. A band of enhanced backscatter coincided with the dense sand dollar population. The identification of dense aggregations of sand dollars through enhanced acoustic backscatter could lead to the use of acoustic techniques to study sand dollar distributions and abundance.  相似文献   

20.
Vast reserves of marine minerals are known to occur within the Mexican Exclusive Economic Zone. These reserves include: (1) heavy mineral placers rich in titanium and iron along the coast of San Antonio del Mar, Baja California and the southern States of Oaxaca and Guerrero; (2) phosphorites, which represent the only source for superphosphate fertilizers along the Pacific coast off the Baja California peninsula and the Gulf of Tehuantepec; and (3) manganese oxide deposits in nodule and crusts located adjacent to the Clarion-Clipperton Zone and containing high concentrations of Cu + Ni + Co (up to 1.9%), which are essential for the steel and super-alloy industries. Few but important efforts toward surveying these deposits have been carried out by Mexican and international researchers. Relevant data generated by these investigations are reviewed here and put together in a single document. Adequate knowledge of Mexican mineral resources is essential for the development of management strategies when offshore mining starts during this century. Thus, the review discusses the economics inherent to ocean mining in Mexico, setting baselines for future exploration and development activities in the Mexican Exclusive Economic Zone.  相似文献   

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