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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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海洋生态系统净生产力 （net ecosystem production，NEP） 表示总初级生产力 （gross primary production，GPP） 和呼吸作用 （respiration，R） 过程之间的差异，它对碳收支平衡、海洋生态系统营养状态乃至气候变化等研究具有十分重要的指示意义。影响海洋 NEP 的因素有细菌、浮游生物、温度、太阳辐射、海冰融化、水团迁移、富营养有机质排放以及海水酸化等。目前计算 NEP 的方法可分为实验培养测定及数据模型计算两种。溶解氧培养法及同位素标记法等是经典的培养测定方法，但存在误差较大且重现性较差等问题。数据模型计算即借助养分质量平衡、响应面模型、O2/Ar 示踪等方法，通过将现场实测数据和生物地球化学模型结合，进行高时间分辨率的连续性观测，这也是目前测算 NEP 的主流应用手段。然而，相较于发达国家，我国在 NEP 的研究设备、技术、测定方法等方面仍存在一定差距。今后的研究重点将是建立 NEP 指标与表征海洋环境、气候变化之间的耦合关系以及 NEP 测定方法的改进，这将有助于深入理解和探索全球变化背景下海洋生态系统响应机制及变化趋势。 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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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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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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James K. McElroy 《Marine Policy》1984,8(3):239-258
The historical development of the fisheries for seals, whales, finfish and krill in the Antarctic is outlined. Particular emphasis is given to the development of the Antarctic krill fishery, the continued exponential expansion of which is causing increasing concern among fishery biologists and economists. The main prospects for fisheries development in the Antarctic lie with Antarctic krill and the stocks of baleen whales that are now recovering satisfactorily. Because of their ecological coupling, the existing pattern of exploitation implies that trade-offs between krill and whales have already begun and may soon significantly affect the future economic benefits that could be derived from this ecosystem. Thus important management decisions that will affect the future size and shape of these two fisheries must be faced now. 相似文献
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本文介绍了南极中山锚地的选择条件,勘测实施过程及水文、气象特点,并对测量区域作了分析研究与评价,科学地确定了适合科考船抛锚的锚地,致使“雪龙”船首次在中山锚地抛锚试抛成功,结束了中山站附近海域无锚地的历史。 相似文献
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巴勒尼群岛沿着南极洲维多利亚地延伸达1 6 0km ,并向北延伸到新西兰海底山脉的南端。其中最南部的是斯特尔岛 (长 44km)。起码在最近半个世纪 ,岛上未见到喷发。在其他海岛中 ,记录到火山活动的有巴基岛 ( 1 83 9和1 899年 )和杨岛 ( 1 83 9年 )。2 0 0 1年 6月 1 2日 ,美国华盛顿冰况观测中心的EuDowling在研究罗斯海中的冰况时 ,根据来自卫星“NOAA 1 4、NOAA 1 5和NOAA 1 6”的资料 ,发现了面积达 2 0× 2 0 0km2 的异常云彩 ,其底部边缘悬挂在斯特尔岛上空。其顶部位于近 6 0 0 0m的高空 ,主要由冻结的水汽组成 (温度为 -5 3℃ )… 相似文献
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The characteristic low-frequency oscillation of the sea surface temperature anomaly (SSTA) of ENSO related regions, Nino 1 + 2, Nino 3, Nino 4 and Nino West, and the Southern Oscillation index (SOI) is analyzed with the method of maximum entropy spectrum. Antarctic sea ice is divided into 4 regions, i. e. East Antarctic is Region Ⅰ (0°-120° E), the region dominated by Ross Sea ice is Region Ⅱ (120° E-120° W), the region dominated by Ross Sea ice is Region Ⅲ (120° W-0°), and the whole Antarctic sea ice area is Region Ⅳ. Also, the month-to-month correlation series of the sea ice with ENSO from contemporary to 5-years lag is calculated. The optimum correlation period is selected from the series. The characteristics and the rules obtained are as follows.1. There are a common 4-years main period of the SSTA of Ninos 1 + 2,3 and 4, a rather strong 4-years secondary period and a quasi-8-years main period of that of Nino West. There are also 1. 5 and 2 to 3-years secondary periods of that of all 4 Nin 相似文献
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《African Journal of Marine Science》2013,35(1):1101-1108
Ocean-ecosystem models are generally based upon the linkages among highly aggregated taxonomic (e.g. "phytoplankton", "zooplankton") or ataxonomic groups. This paper concentrates on the nature of a single linkage between two aggregations. The connection is rich in complexity, which is difficult to detect. The resolution of this difficulty needs to arise from greatly expanded empirical studies. 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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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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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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Data needs for ecosystem modelling 总被引：1，自引：0，他引：1