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Calcium in sea water was determined of the samples taken from the Antarctic and Indian Oceans. Surface water commonly contains less calcium relative to chlorinity than does deep water. The tendency, however, is very faint in the Antarctic Ocean. In the surface waters, the Ca/Cl ratio is lower in the tropical and subtropical waters and the ratio well correlates with phosphate. The Ca/P ratio is calculated as 37 in atomic ratio. These may indicate that calcium is uptaken by organisms to make skeletal parts from surface water which is supersaturated with respect to calcite or aragonite. On the other hand, no definite correlationship between calcium and phosphate is found in subsurface water. This fact suggests that the regeneration process of calcium from organic debris is different from that of phosphate. The increase-rate of calcium in the abyssal water is estimated to be 0.18g at./(1 yr), which is due to the dissolution of calcium carbonate. The rate is about a half of total carbonate increase in the water. 相似文献
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《Deep Sea Research Part I: Oceanographic Research Papers》2007,54(10):1841-1851
An unusual region of high meso-scale turbulence has been identified in the Indian Ocean sector of the Southern Ocean. It has been shown that this is the result of eddy shedding from the Antarctic Polar Front. These eddies may dramatically affect the local distribution of marine organisms. To investigate this, the euphausiid community structure and species composition in the region of a cold eddy within the Antarctic Polar Frontal Zone (APFZ) was investigated during April 2005. Water masses within the core of the eddy were typically Antarctic, showing they had come from south of the Antarctic Polar Front. Results of numerical analyses indicate that the euphausiid community within the survey area consisted of three distinct groups: those in APFZ waters, those at the edge of the eddy and those in the core of the eddy. These results indicate that eddies generated by the interaction of the Antarctic Circumpolar Current with the South-West Indian Ridge play an important role in transporting Antarctic euphausiid species equatorward, thus contributing to the spatial heterogeneity of the zooplankton community within the region. 相似文献
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厄尔尼诺—南方涛动 ,由起源于太平洋的东—西正常大气环流和大洋条件改变所致 ,对现代气候产生的急剧影响已为人所熟知。然而 ,人们对于其在古气候环境中的作用及其长期影响还知之甚少。2 0 0 2年 7月 1 2日《Ｓｃｉｅｎｃｅ》刊出的两篇文章提供了远至更新世的厄尔尼诺—南方涛动的证据。与早期观点不同 ,作者认为厄尔尼诺实际上出现在冰期和全球气温下降时期 ,而不是在间冰期。美国南加利福尼亚大学ＬｏｗｅｌｌＳｔｏｔｔ领导的研究小组负责西太平洋的研究 ,ＬａｍｏｎｔＤｏｈｅｒｔｙ地球观测站的ＡｔｈａｎａｓｉｏｓＫｏｕｔａｖａ… 相似文献
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Cascading of cold Antarctic shelf water (ASW) initiates compensatory isopycnic upwelling of the warm Circumpolar Deep Water (CDW). The baroclinic/thermoclinic Antarctic slope front (ASF) is formed, and a mesoscale intrusive structure develops on the shelf edge and slope. Mesoscale processes when the ASF peaks are periodically accompanied by local baroclinic instability, which forms a smaller-scale intrusive structure. Therefore, the ASF is naturally subdivided into two layers according to the intrusion scales (vertical δН and horizontal L) and the horizontal parameters of the front (thermoclinity (TL)ρ and baroclinity γρ). Analysis of ASF intrusive layering due to the baroclinic factor supports the following conclusion: the higher the (TL)ρ of the ASF, the greater the intrusion intensity |δθ| (temperature anomaly amplitude), while an increase in γρ of the ASF leads to a decrease in intrusion scales δН and L. Frontal intrusions can be distinguished by a development degree. Regardless of the degree of development, all warm intrusions are characterized by vertical density stratification, while cold intrusions are characterized by density quasihomogeneity. According to field data, the ASF instability process is subdivided into four stages. When theASF is baroclinically unstable, the local baroclinic deformation radius RdL of the front is close in magnitude to the horizontal scale L of the intrusions that form, and their characteristic vertical scale δH is close to the typical vertical scale of front instability. 相似文献
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Shizuo Tsunogai Shinichiro Noriki Koh Harada Taro Kurosaki Yasunori Watanabe Masaru Maedaa 《Journal of Oceanography》1986,42(2):83-90
Settling particles were collected at 1,460 m and 3,760 m depth in the Antarctic Ocean with sediment traps of time series type. The total deployment period of 40 days was divided into four terms of 10 days each. Seawater samples were collected both at deployment and retrieval of the traps at each site. During the 42 days the concentration of silicate in the surface water decreased by 32%, whereas those of nitrate and phosphate decreased by only 4–5%. The total particulate flux in the Antarctic Ocean is the largest among those hitherto observed in the world ocean. The time variation of the particulate flux at 1,460 m depth almost coincided with that at 3,760 m. The settling particles were comprised roughly of 80% biogenic silica, 15% organic matter and 5% other substances including sea salt. The clay fraction was only 0.05% at 1,460 m depth. The settling flux of biogenic silica agrees fairly well with the calculated rate of change in the concentration of silicate in the surface 100 m. Thus it is concluded that preferential propagation of diatoms reduces the concentration of silicate prior to other nutrients in the Antarctic Ocean. 相似文献
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Phytoplankton chlorophyll stocks in the Antarctic Ocean 总被引：5，自引：0，他引：5
Mitsuo Fukuchi 《Journal of Oceanography》1980,36(1):73-84
Phytoplankton chlorophyll stocks in the Indian sector of the Antarctic Ocean were estimated on the basis of published data collected from nine cruises of the Icebreaker,Fuji in 1965–1976, during routine observations of the Japanese Antarctic Research Expedition (JARE). Surface chlorophylla concentration, measured at 631 stations in waters south of 35°S, ranged from 0.01 to 3.01 mg m–3, At about half of the stations the values were less than 0.24 mg and at only 29 stations were high values more than 1.00 mg m–3 recorded. The levels of surface chlorophylla stocks were estimated in three groups; (1) data obtained on the southward leg through the eastern Indian sector (middle-late December), (2) those on the northward leg through the western Indian sector (late February–early March) and (3) those on the northward leg through the eastern Atlantic sector (late February–early March). Furthermore, mean values and standard deviations were calculated for each of six different water masses from north to south,i. e., subtropical water between 35°S and the Subtropical Convergence (STC) zone, water within the STC zone, Subantarctic Upper Water, water within the Antarctic Convergence (AC) zone, Antarctic Surface Water between the AC zone and 63°S, and Antarctic Surface Water south of 63°S. Mean values of surface chlorophylla concentrations for each of the six water masses on the three legs ranged from 0.15 to 0.58 mg m–3 and were comparable to those reported by other workers previously. Seasonal periodicity of phytoplankton chlorophyll stock is discussed. The surface chlorophyll stock in the oceanic water of the Antarctic Ocean does not seem to be so high as previously believed. 相似文献
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Polonik N. S. Ponomareva A. L. Eskova A. I. Shakirov R. B. Obzhirov A. I. Morozov E. G. 《Oceanology》2021,61(6):892-898
Oceanology - Methane concentrations were measured in the water layers on two transects crossing the central part of Bransfield Strait and along the Antarctic Sound. In the abyssal sea of the... 相似文献
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南极普里兹湾气旋的生消发展 总被引：3，自引：4，他引：3
利用1989～2000年现场观测的气象资料,特别是自1997年以来在南极考察船上接收的NOAA卫星极轨高分辨的卫星云图,研究了普里兹湾气旋的生消发展;提出了夏季绕极气旋进入普里兹湾内也会发展加强,在湾内东风带里也能生成气旋的新观点,修正了普里兹湾仅是气旋墓地的不全面说法,从而进一步完善了南极西风带绕极气旋和东风带上气旋生消发展的理论;研究了普里兹湾冰-气-海相互作用的机理,解释了气旋发生、发展的物理过程.用整体动力学输送法计算了进入普里兹湾980205号绕极气旋爆发性发展的能量交换,指出气旋在超过冰坝进入冰间湖可以获得巨大的热量,使气旋迅速发展成为具有南极特色的强风暴,风力达12级以上,平均风速为38m/s;瞬时最大风速达100m/s. 相似文献
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以Ritzwoller为首的一批地球物理学家公布了新的表示南极洲和南大洋底上地幔结构的层面X射线照相图件。对南半球 ,特别是对南极洲的地壳和地幔的研究程度很低。然而 ,正是这个地域在大地构造方面特别重要 ,因为这是冰大陆中的最大的地壳省区 ,而该大陆周围裂谷 (断裂 )的形成过程在主要海洋盆地的形成中起到了显著的作用。除此之外 ,现代的火山作用和新裂谷的产生能影响冰盖的稳定性 ,而很多现代的气候、海洋学和气象学特征与其有关。在所有地震波速度资料的基础上构筑的图件表明 ,东南极洲的地幔是一个具有高速地震波的区域 ,因此这里的地… 相似文献
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Ed Sobey 《Journal of Oceanography》1975,31(6):235-242
Composite pictures of the areal extent of Antarctic sea ice derived from satellite photographs, show that the growth and the rate of growth of the pack ice compare favorably to the values previously estimated on other bases. Anomalous growth patterns are found in the Weddell Sea. Possible causes of this anomaly include surface and subsurface advection of ice crystals. The rate of retrogradation of the pack ice is found to exceed the rate of progradation. 相似文献
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《Marine Policy》2001,25(1):1-11
Australia will include the Australian Antarctic Territory in its November 2004 submission to the Commission on the Limits of the Continental Shelf. It is the first Claimant State to attempt delimitation of an extended continental shelf zone there. This paper investigates the complexity of Australia's Antarctic maritime boundaries from political, legal and practical perspectives that have hitherto been purely hypothetical. It concludes that the practical component is achievable, though complex, and will serve as a precedent for other Antarctic Claimant States. Irrespective of whether or not the submission succeeds, it will serve as a valuable lesson, legally and politically. 相似文献
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Liu Jianhua 《海洋学报(英文版)》1993,12(3):425-429
Analysis of gravity data based on the Airy isostasy, magnetic depth estimates and few seismic refraction data taken together indicates a thinning of the crust between the Antarctic Peninsula and the East Antarctic craton below the Filchner and Ronne ice shelves. 相似文献
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Reproductive resilience of ice‐dependent Antarctic silverfish in a rapidly changing system along the Western Antarctic Peninsula 
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下载免费PDF全文 The Western Antarctic Peninsula (wAP) is globally one of the systems most heavily impacted by climate change, notably steep declines in sea ice extent. In forage species, reproductive resilience to change is particularly important because population fluctuations are rapidly communicated through the system via trophic interactions. The reproductive traits of the ice‐dependent forage species Antarctic silverfish (Pleuragramma antarctica) from different areas along the wAP and at the tip of the Antarctic Peninsula were investigated through macroscopic and histological analyses of gonads, with the aim to assess its reproductive potential and to test for spatial differences in fecundity and spawning season. Fish samples were collected in late summer off Charcot Island, in Marguerite Bay and off Joinville Island; no fish were caught in the central wAP. Samples from Charcot Island and Marguerite Bay consisted of adults in developing gonad stage, whereas those from Joinville consisted almost exclusively of juveniles. Mean GSI was relatively low (2–3%) and similar in both sexes, as specimens were still far from being actively reproducing. Developing females exhibited two discrete, though partially overlapping modes of oocytes of different size, with vitellogenic oocytes measuring 0.5–1.0 mm. Absolute and relative fecundity ranged between 3000 and 12,000 eggs per female and between 80 and 190 eggs·g?1, with a strong relationship between absolute fecundity and body size. These results were consistent with a single population at Charcot Island and Marguerite Bay and indicated substantial reproductive potential, which may mitigate population isolation and reductions in habitat availability but cannot ultimately offset catastrophic loss of spawning habitat linked to sea‐ice retreat. 相似文献
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Records of icebergs near New Zealand are noted, and their implications on the interpretation of ice‐rafted sediments are discussed. 相似文献
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至今在南极洲的冰盖之下发现了 77个湖泊。其中最大的一个 (面积近 2万km2 )是前苏联科学家在“东方”站附近 4km厚的冰层之下发现的 ,并命名东方湖。这个呈半月形弯曲的淡水湖具有强烈切割的湖底 ,局部深度可达 10 0 0m。在 2 0 0 0年 ,英国布里斯托尔大学的MSiegert及其同事们对湖泊进行了 3次无线电测量工作。结果显示 ,在湖泊的西部和北部边缘 ,尽管温度很低 ,每年要融化几乎 1 0cm厚的冰层 (融解温度低于正常是由于上覆冰盾的巨大压力 )。由于融解水在冰盖底部重新冻结 ,使它的底部增厚 ,但这发生在相反的岸边。就这样 ,湖水缓慢地环… 相似文献