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1.
长江口崇明东滩地貌发育过程中的活性铁变化及环境意义 总被引：1，自引：0，他引：1
利用2002—2003年在崇明东滩采得的CDS、CDM和CDN三个典型沉积物剖面样品,测定了其中的Fe3 、Fe2 、Fe3 /Fe2 以及有机碳、粒度等特征参数,分析了活性铁分布变化特征并对其沉积物氧化还原环境的变化进行了探讨。结果表明Fe3 含量在整个研究区域均是从表层向下逐渐递减的,Fe2 含量逐渐增加。从实验结果判断,所研究区域沉积环境上层以氧化环境为主,呈弱氧化型,中下层以还原环境为主。分析发现其分布变化受粒度、有机碳的影响,氧化还原界面与中、高潮滩划分界大致相当。 相似文献
2.
根据2015年5月对长江口及其邻近海域的生态环境调查资料, 探讨长江口春季表层沉积物总有机碳(TOC)、总氮(TN)、总磷(TP)和生源硅(BSi)4类生源要素的空间分布和来源。结果表明: 2015年春季长江口表层沉积物TOC、TN、TP和BSi平均含量分别为0.315%、0.041%、0.066%和0.450%, 其中, 沉积物中TOC、TN受到陆源输入和海洋自生输入双重影响, 且海洋自生组分的贡献较大, 二者空间分布均呈现南部分布最高并沿西北方向递减趋势; TP分布主要受陆源输入影响, 并呈西北向东南递减趋势; BSi来源于生物沉积, 总体呈现南部高、北部低的分布趋势。与2007年相比, 长江口表层沉积物有机碳、氮含量降低, 东南外海区域替代浑浊区域成为表层沉积物生源要素含量最高区域, 且陆源输入对长江口表层沉积物生源要素的贡献趋于减弱。 相似文献
3.
对2003年7月至9月采自北极楚科奇海域的4个站位表层沉积物及1个站位的柱状沉积物样品的总糖、总碳、有机碳、无机碳、总氮、总磷的含量进行了测定,并对其有机碳和有机氮同位素(1δ3C和1δ5N)的变化进行了研究,结果表明:北极楚科奇海域沉积物中的总糖与有机碳为明显的正相关关系,说明糖类是有机碳重要的组成部分;表层沉积物中TOC/TN平均值为9.273,1δ3C和1δ5N的平均值分别为-21.61‰和7.1‰,显示出表层沉积物中糖类物质以海洋藻类来源为主、混入部分陆源物质的分布特征;柱状样品不同深度沉积物中TOC/TN平均值为13.45,也反映出糖类物质为海洋自生和陆源输入共存的分布特征。 相似文献
4.
环雷州半岛近海表层沉积物有机碳分布及其控制因素分析 总被引：1，自引：0，他引：1
对环雷州半岛近海43个海底表层沉积物的总有机碳(TOC)、总氮(TN)、沉积介质条件(包括沉积物粒度)进行了分析,探讨了沉积物TOC、TN的区域分布特征以及影响有机碳分布的主要因素。结果表明,环雷州半岛近海海域海底表层沉积物有机碳含量在0~0.79%之间,平均值为0.26%。与中国其它近海海域相比,环雷州半岛大部分近海区域海底表层沉积物有机碳含量明显偏低,为有机质贫乏区,仅雷州半岛西南部流沙湾近海海域为TOC相对高值区。总氮含量也不高,在0.011%到0.100%之间,TOC与TN存在较强的正相关性,且平面上TOC与TN分布高度重合,显示氮元素主要以有机化合物形式存在。TOC/TN比值在5.1~14.3之间,表明沉积有机质具有陆源输入和海洋自生来源的混合特征,但以雷州半岛西侧北部及东侧中部海域受陆源有机质输入影响更大。大多数站位海底沉积物粒度构成以粉砂为主、粘土次之,少数站位以砂质沉积为主。沉积物有机碳含量与粘土及粉砂含量呈弱正相关性,与沉积物pH值、Eh值及砂含量呈弱负相关性,这表明海底沉积物有机质丰度受有机质来源输入、海底氧化还原状态和沉积水动力条件(沉积物粒度)等因素综合控制。 相似文献
5.
外源对太湖河口沉积物有机质贡献的同位素示踪 总被引：2，自引：0，他引：2
分析了太湖流域不同土地利用类型土壤、河口表层沉积物及主要生物的有机碳含量和同位素分布特征,并利用端元混合法求取了陆源输入对湖泊沉积物有机质的贡献及分布。研究结果表明,流域表层土壤有机质δ13C受植物群落的δ13C值影响,不同植被类型的土壤有机质δ13C值存在差异。茶园、菜地、林地和农田δ13Corg平均值分别为-25.4‰、-25.8‰、-27.1‰和-28.1‰,其中茶园有机碳同位素值最高。河口表层沉积物有机碳同位素变化范围为-27.5‰～-25.1‰,平均值为-25.7‰。河口近岸区域表层沉积物δ13Corg偏低,且以河口为轴心向湖心逐渐增大,呈扇形条状分布,其分布主要受低δ13C值的陆源有机质输入影响。利用端元混合法求得近河口表层沉积物中陆源有机质贡献高达70%～80%,随着离岸距离的增加,陆源有机质贡献量逐渐减少。 相似文献
6.
南海南部中上新世以来沉积有机碳与古生产力变化 总被引：3，自引：1，他引：2
对南海南部ODP1143站上部150m的1005个沉积物样品进行了有机碳分析,求取中上新世3．5Ma以来表层生产力长期的演化趋势和短期的变化规律。有机碳含量、有机碳堆积速率和输出生产力在2．85～1．58Ma和0．9～0Ma两个时期呈现相对高值,反映具较高的古生产力,推测分别与上新世晚期北极冰盖形成和“中更新世革命”之后北极冰盖扩大事件密切相关。与有孔虫δ^18O记录对比,有机碳含量、有机碳堆积速率和输出生产力都显示在冰期增加,间冰期降低,反映了冰期具较高的表层生产力。冰期时较高的沉积物堆积速率和C／N比值反映低海平面时期陆源营养物质供应增加,是造成冰期表层生产力高的重要原因。同时推测冰期时低氧含量的底层水有利于有机物质的保存。频谱分析揭示,中上新世以来有机碳含量变化复杂,说明其变化除主要受到地球轨道周期变化的驱动外,还受到陆源物输入等其他因素的影响;而有机碳堆积速率和输出生产力主要受地球轨道周期变化的驱动。 相似文献
7.
台湾东部黑潮区海源碳的沉积物记录与近千年来生产力与气候变化的反演 总被引：1，自引：0，他引：1
本文基于对台湾以东黑潮主流区沉积物的粒度和定年，通过解析沉积物总有机碳及其同位素组成获取海源碳变化特征，首次报道了该海区近千年来的初级生产力与气候变化反演结果。研究显示，台湾以东黑潮主流区近千年来的平均沉积速率为34.44 cm/ka，沉积环境较为稳定。另外，台湾以东黑潮主流区沉积物中的总有机碳和总氮含量主要受台湾东部河流输入、海洋初级生产力的沉降过程、成岩作用和粒度效应影响。对沉积物海源碳的定量估算表明，近千年来台湾以东黑潮主流区沉积物中40.02%~73.88%的有机质为海源输入，陆源输送次之。同时，近千年来台湾以东黑潮主流区沉积物记录较好地反映了中世纪暖期、小冰期和现代暖期3个气候变化阶段。1150-1420年期间，沉积物中总有机碳、总氮和海源碳含量缓慢升高，较高的表层海水温度有利于海洋初级生产力水平的升高。1500-1840年期间，较低的表层海水温度和亚洲大陆风尘输送水平使得海洋初级生产力较低，同时台湾地区小冰期较高的降水量有利于台湾东部河流向海输送，增强的水动力条件可能会加强海底沉积物的东移，从而导致该区域沉积物中总有机碳含量的增加。进入现代暖期以来研究区的海水温度逐渐增暖，而东亚季风强度和降水量却表现出波动的年际变化特征，并体现在研究区1930-1950年和1970年期间沉积物的中值粒径、总有机碳和总氮含量的快速波动。 相似文献
8.
渤海中南部沉积物中生源要素的分布特征 总被引：3，自引：0，他引：3
从化学结合形式出发,对渤海中南部海区沉积物中OC、N、P、BSi等生源要素的含量进行调查分析,讨论了各生源要素的分布及其影响因素。结果表明:受陆源输入的影响,表层沉积物中各形态氮、磷及有机碳均呈现"近岸高,远岸低"的分布趋势,生物硅的含量分布则与海区浮游硅藻的分布趋势相一致;可交换态氮是总氮中较活跃的部分,占总氮的比例约为3.7%;固定态铵是总氮的主要组成部分,约占总氮的38.4%,其主要与有机质含量及黏土矿物组成有关;渤海表层沉积物中OC/BSi、ON/BSi以及OP/BSi的比值分别为2.38、0.19、0.03,低于Redfield比值,说明有机质优先于生物硅分解;OC/ON平均值在6.0~14.0之间,判断渤海沉积物中有机质受陆源输入和海洋自生共同影响;其中,有机碳主要以陆源输入为主,而有机氮在沉积物表层主要以陆源输入为主,在沉积物下层则主要来源于海洋自生。 相似文献
9.
北冰洋西部表层沉积物中生源组分及其古海洋学意义 总被引：4，自引：0，他引：4
通过对中国首次和第二次北极科学考察在北冰洋西部所采取的66个表层沉积物中生源组分的分析,探讨了该海区表层生产力变化与水团的相互关系。楚科奇海西南部呈现出高的有机碳和生源蛋白石含量,而中部和东部哈罗德浅滩至阿拉斯加沿岸,以及楚科奇海台、北风脊和加拿大海盆表现出低的有机碳和生源蛋白石含量。楚科奇海陆架区表层沉积物以底栖有孔虫为主,丰度低;而楚科奇海台、北风脊和加拿大海盆则以浮游有孔虫占绝对优势,丰度较高。生源组分的分布特征显然与通过白令海峡进入楚科奇海的三股太平洋水和大西洋次表层水相关。楚科奇海西侧沿富营养的阿纳德尔流方向的区域呈现出高的表层生产力。而东侧受寡营养的阿拉斯加沿岸流及阿拉斯加西北沿岸陆源物质输入的影响,呈现出低的表层生产力。北纬75°以北及加拿大海盆受海冰覆盖影响,也表现出最低的表层生产力。而受北大西洋次表层水的影响,楚科奇海陆架外侧高纬海域表现出较高的钙质生物生产力。表层沉积物中Corg/N比值及其分布反映楚科奇海表层沉积物中的有机碳以海洋自身来源为主,且主要受生物泵过程控制。有机碳和生源蛋白石含量呈现高的正相关关系,说明硅藻等浮游植物的初级生产力可能控制着生物泵对碳的吸收和释放。 相似文献
10.
渤海表层沉积物中的生物硅 总被引：1，自引：0，他引：1
采用0.1 mol/L HCl和1%Na2CO3两步连续提取法,对103个渤海表层沉积物样品的生物硅含量进行了分析,结果表明,渤海表层沉积物中生物硅含量范围为7.3~54.7 g/kg,均值31.5 g/kg,高于其他相关调查,原因可能是由于采用0.1 mol/L HCl提取过程中,破坏了生物硅表面的金属氧化膜。对沉积物生物硅含量的空间分布表征显示,莱州湾是沉积物生物硅的低值区、而渤海湾与辽东湾之间的河北沿岸海域是相对高值区,初步认为是陆源营养物质的输入与黄河泥沙长期不断输入干扰沉积环境的稳定性,造成了该海域表层沉积物生物硅分布差异。主成分分析显示,生物硅含量与沉积物黏粒含量、细粉砂、有机氮、有机碳的含量均呈极显著正相关(P0.01),进一步证实沉积物粒度特征和营养环境对生物硅积累的影响。 相似文献
11.
The analysis of the structure of the cryolithozone, facies, and thicknesses of the Quaternary sediments and the results of the physicochemical mathematical modeling of the modern shelf of the western part of the Laptev Sea support the influence of the Late Pleistocene glaciations on the heat conditions and the distribution of the permafrost in the area. A ～200-m thick glacier formed under aerial conditions from atmospheric precipitation represented the metamorphosed snow cover. According to the modeling, the long-living (from 60?50 to 10?4 ky) glacier reduced the thickness of the permafrost rocks in the reviewed shelf area for 280–360 m. The Holocene marine transgression additionally decreased the thickness from 50–140 m on the inner shelf to 220–350 m on the outer shelf. The modern submarine cryolithozone 450-0 m thick is wide-spread in the studied region from the coast to the shelf boundary (isobaths of 130–140 m), where it pinches out at a distance of ～380 km from the coast at a depth of ～250 m above the sea level. 相似文献
12.
We analyze the components of the carbon system of the Sevastopol bay waters and the balance of main sediment-forming substances
using the data of field investigations in 1998–2008. The interannual variations of total inorganic carbon and the equilibrium
partial pressure of carbon dioxide in the bay water are noted. An increase in the flux of carbon dioxide into the bay and
in the content of organic carbon in bottom sediments is revealed, and an explanation of this phenomenon is given. The priority
accumulation of organic carbon in the sediments of the bay is established. We assess the interannual variation in the relative
abundances of organic and inorganic carbon as an index of the carbon cycle stability. 相似文献
13.
We generalize and analyze the state of investigations of the influence of river waters on the hydrologic structure of the
Black Sea. Specific features of the water, regime and hydrography of rivers flowing into the sea, data on the discharge of
rivers, and intrayear and interyear variability of the discharge are presented. We discuss and analyze works studying the
transformation of river waters, routes of desalinized sea waters, and their influence on the thermohaline structure and dynamic
regime of the sea.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
14.
V. A. Ivanov S. P. Lyubartseva N. Mikhailova N. B. Shapiro 《Physical Oceanography》2001,11(6):509-524
We analyze the results of numerical calculations performed according to the three-dimensional interdisciplinary model of an
ecological system of the Black-Sea shelf zone near the estuary of the Danube. The complete system of equations of hydrothermodynamics
is solved together with transport equations of the advection-diffusion-reaction type used to describe the transformation of
a substance (nitrogen) between the components of the characteristic vectors of the ecosystem: plankton, detritus, and biogenic
elements (nitrates). We describe the distinctive features of the circumcontinental distribution of components obtained as
a result of numerical experiments and present arguments for the conclusion that the ecosystem of the Danube estuary water
area plays the role of a buffer zone between the press of the Danubian biogenic pollutions and the neighbouring areas of the
shelf zone and open sea.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
15.
Relationship between the path of the Kuroshio in the south of Japan and the path of the Kuroshio Extension in the east 总被引：2，自引：0，他引：2
A relationship between paths of the Kuroshio and Kuroshio Extension (KE) is investigated, using the satellite-derived altimetry
dataset of 1993–2008. When the Kuroshio takes the nearshore nonlarge meander path or typical large meander path and resultantly
goes through the deeper channel (about 2500 m) of the Izu-Ogasawara Ridge, the KE path adopts a relatively stable state with
the two quasi-stationary meanders. On the other hand, when the Kuroshio takes the offshore nonlarge meander path and then
passes over the shallower part of the Ridge (about 1000 m), the KE path tends to be convoluted, i.e., an unstable state. 相似文献
16.
Ten years of semistationary studies of the interaction of the ice cover and the coastal relief of the Kandalakhsa Gulf in the White Sea allowed us to reveal the peculiarities of these processes in the warm and cold years and the mechanisms of the origination of ice forms, including ice tents, which govern the character of the tidal flats. Three dynamic fast ice zones are distinguished by their geomorphological location, morphology, and ice dynamics. The dependence of the mechanisms and volumes of the enrichment of the fast ice in the sediments on the coastal zone??s relief was established. At the coast of the Kindo Peninsula (Velikaya Salma Strait), the ice mostly contains fine-sandy sediments. Coarser sediments, including boulders, are occasional and frozen into the ice at the contact of the fast ice and the bottom. At the expense of the ice??s spreading by 4?C6 times in the warm years and 2?C4 times in the cold years, several thousand tons of sediments mostly from the tidal flat??s surface (100?C700 m3 from 1 km of coast in the wide tidal flats and <50 m3 on the steep coasts) are delivered to the water area. 相似文献
17.
I. E. Timchenko A. A. Primalenny V. D. Yarin E. F. Vasechkina E. M. Igumnova 《Physical Oceanography》2001,11(4):367-378
We use many-year archival observations of hydrologic and hydrobiologic state of the Sea of Azov for the identification of
the structure of a model of its ecosystem. The ecosystem model, supplemented with expert estimates of bioresource consumption
(fish reserve), contamination level, and possible ecologic fines for violation of the sea natural state, is formalized by
the method of system dynamics. Hereat, the major part of influence functions is found in terms of observational data with
application of self-organization algorithms. We also present the results of simulated experiments with the model of the ecosystem,
which enable us to analyse scenarios of its behaviour under the influence of various external factors (wind, river discharge,
water exchange with the Black Sea, etc.).
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
18.
E. L. Vinogradova 《Oceanology》2008,48(4):483-492
The spatiotemporal variability of the hydrochemical composition of the riverine runoff in nearmouth areas is presented using the example of selected rivers of the Arctic Basin. The temporal dynamics of the riverine nutrient runoff are mainly determined by the seasonal and interseasonal variations in the drainage basins. The spatial variations in the chemical composition of riverine waters in the near-mouth areas are mainly caused by the dynamics of the water flow and the river bed relief and, to a lesser degree, by biochemical processes. It is shown that the variations in the nutrient composition of the waters in near-mouth areas are comparable in magnitude to those at the river-sea geochemical barriers. 相似文献
19.
The methodology and the first results of the computations of the volumes, masses, and growth rates of the sedimentary body of the buried Black Sea basin are presented. Their temporal evolution reflects the regional paleogeodynamics, in particular, the reorientation of the vector of the relative movement of the Arabian and Eurasian lithospheric plates and the related intensification of their collision in the late Miocene-Pliocene. 相似文献
20.
Izvestiya, Atmospheric and Oceanic Physics - Analysis of the temporal variations of the virtual heights of the sporadic E layer (h?ES) determined from ionograms with increased accuracy (1... 相似文献