近三百年来长江口泥质区沉积环境变化及与低氧关系的初步分析

近年来全球大型河口区低氧事件频发,严重威胁环境和生态系统健康.因缺少长时间序列的观测资料,人们对历史时期河口陆架区域生态环境演化,尤其是低氧事件发生的历史认识不足.本文基于210Pb、137Cs和光释光测年技术,以长江水下三角洲现代低氧区沉积物柱状样为研究对象,通过分析沉积物的粒度参数、氧化还原敏感元素、TOC、TN和...     

Probable limits of sea ice extent in the northwestern Subarctic Pacific during the last glacial maximum

The article summarizes and analyzes published data on the distribution of sea-ice and open-ocean diatoms in 42 cores of bottom sediments from the northwestern part of the Subarctic Pacific that accumulated during the last glacial maximum (LGM). Based on micropaleontological records, the extent of winter sea ice during the LGM could be limited to the Okhotsk and Bering seas. During the warm season, the surface water masses from the open Subarctic Pacific spread widely in the marginal seas.     

Environmental changes in the Amur Bay (Japan/East Sea) during the last 150 years revealed by examination of diatoms and silicoflagellates

Siliceous unicellular microalgae — diatoms and silicoflagellates from sediments in Amur Bay were analyzed with high temporal resolution to examine changes over the last 150 years. The age of sediments was estimated from unsupported ²¹⁰Pb controlled by ¹³⁷Cs. Siliceous microalgae examined in each cm of two sediment cores demonstrated significant changes in the ecological structure of the assemblages that reflected changes in sedimentation conditions. During the years 1860–1910 the sediments accumulated under the great influence of river runoff. For about the next 50 years the number of freshwater species and marine benthic diatoms in sediments sharply declined, which is probably connected with the weakening of the effects of river runoff due to deforestation. Since the early 1960s the sedimentation conditions in the Amur Bay changed significantly. Marine planktonic diatoms and silicoflagellates began to prevail in sediments and this reflects increasing microphytoplankton productivity. One consequence of this was the formation of seasonal bottom hypoxia in Amur Bay. The ecological structure of diatom and silicoflagellate assemblages indicates that the sea level began to rise since the early 1960s and this corresponds to the water and air temperature increase in the area for that period. The obtained data suggest that the environmental changes over the last 150 years in Armur Bay are associated with the weakening of river runoff due to deforestation, sea level rise caused by global warming, and the increase of siliceous microplankton productivity that resulted in the formation of seasonal bottom hypoxia.

     

The dynamics of demographic indicators in Russia for the last half-century

This paper analyzes demographic data (the time series of the number of births and deaths for over 50 years in the 20th and 21st centuries). The properties of the time series are revealed, and some of them are explained. A comparison of data for men and women has resulted in the revelation that seasonal changes for women are more strongly evident than for men. The possible causes for the differences between the time series of the number of deceased men and women are discussed.     

Investigation of dynamic processes in the period of formation and development of the blocking anticyclone over European Russia in summer 2010

The blocking anticyclone (BA) observed in the summer of 2010 over the European part of Russia led to enormous economical damage, substantially increased the mortality of the population, and had serious negative consequences for human health. Dynamic processes in the troposphere, i.e., wave trains, which could contribute to anticyclone formation and sustenance, are investigated. In order to study these wave trains, three-dimensional Plumb vectors have been calculated and analyzed. It is shown that, in June 2010, three wave trains propagated eastward in the troposphere over the Atlantics. The first two wave trains, having reached Europe, continued to propagate in eastern and southeastern directions. Only the third wave train, upon reaching Europe, continued to propagate toward the northeast and, on June 17–19, entered northwestern Russia. The anticyclone, which started to form on June 18 precisely in this region, subsequently developed into a stable BA observed over European Russia up to mid-August. The propagation direction of the wave trains could change due to the formation of a double structure of the zonal flow in the troposphere. The wave trains are revealed in the middle of June in regions with increased cloudiness over the northwestern part of the Atlantic Ocean and over the northwestern and northern parts of the central United States. Eastwardpropagating wave trains, which could contribute to the intensification of the corresponding BAs that brought anomalously high temperatures to European Russia, were also revealed in July and August of 2010 and 1972. The calculated 10-day backward trajectories are analyzed to determine the character of motions of air particles that penetrated into the anticyclone over the region of Moscow during the 2010 summer in the period of its development.     

Ocean circulation patterns and dust supply into the South Atlantic during the last glacial cycle revealed by statistical analysis of kaolinite/chlorite ratios

Multivariate statistical analysis on the kaolinite/chlorite ratios from 20 South Atlantic sediment cores allowed for the extraction of two processes controlling the fluctuations of the kaolinite/chlorite ratio during the last 130,000 yrs, (1) the relative strength of North Atlantic Deep Water (NADW) inflow into the South Atlantic Ocean and (2) the influx of aeolian sediments from the south African continent. The NADW fluctuation can be traced in the entire deep South Atlantic while the dust signal is restricted to the vicinity of South Africa. Our data indicate that NADW formation underwent significant changes in response to glacial/interglacial climate changes with enhanced export to the Southern Hemisphere during interglacials. The most pronounced phases with Enhanced South African Dust Export (ESADE) occurred during cold Marine Isotope Stage (MIS) 5d and across the Late Glacial/Holocene transition from 16 ka to 4 ka (MIS 2 to 1). This particular pattern is attributed to the interaction of Antarctic Sea Ice extent, the position of the westerlies and the South African monsoon system.     

Prediction of natural processes by the method of adaptive balance of causes

The problem of estimation of the future values of processes is studied as a problem of their adaptation to the known data of observations in the past. The method of adaptive balance of causes (ABC-method) is used for the construction of a dynamic model of the coefficients of influence. This model enables one to compute the current values of these coefficients according to the current correlation matrix determined as a result of reanalysis of the observed processes. We propose an ABC-model with variable coefficients of influence guaranteeing the optimal (from the viewpoint of accuracy) prediction of natural processes and present an example of its application.Translated from Morskoi Gidrofizicheskii Zhurnal, No. 5, pp. 53–63, September–October, 2004.This revised version was published online in May 2005 with corrections to cover date.     

近45年太平洋海浪特征分析

利用来自欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)将风浪、涌浪分离的具有较高时空分辨率的45年ERA-40海浪资料,对太平洋的海表风场、风浪、涌浪、混合浪的特征进行分析。研究发现太平洋大部分海域的涌浪波高、混合浪波高呈显著的逐年线性递增趋势,趋势分别为0.3—0.6cm.a 1、0.3—1.2cm.a 1;太平洋的涌浪在混合浪中四季皆起主导作用,涌浪指标的低值区主要集中在南北半球的西风带,太平洋赤道附近海域存在明显的涌浪池;北太平洋的风场与风浪场的相关系数好于南太平洋,风场与涌浪场的相关系数则是南太平洋好于北太平洋;研究还发现太平洋的浪场与Nino3指数有着密切的关系。     

近70年胶州湾水动力变化的数值模拟研究

采用无结构三角形网格海洋模式FVCOM,基于胶州湾不同年代的岸线和水深地形条件,建立胶州湾及其邻近海域各年代的三维潮汐潮流数值模型,从数值模拟角度分析和比较胶州湾不同年代纳潮量、潮汐潮流、水交换率等水动力参数的变化。结果表明:随着胶州湾水域总面积不断缩小,纳潮量在逐渐减小,2008年全湾的纳潮量相对于1935年减少了31.5%,约合3.9×108 m3;海湾流场结构变化很小,流速呈减小趋势;胶州湾欧拉余流"团团转"的多涡结构基本保持不变,最大值都发生在团岛附近;海湾的水交换能力趋弱,对整个胶州湾水体的半交换时间进行海湾平均,不同年代5套岸线下海湾的水体半交换时间分别是37.0 d,36.7 d,39.2 d,39.7 d和40.8 d。     

近50 a来秀山岛岸线时空变化规律及其原因浅析

海岸线是十分重要的自然资源,海岸线的变化会影响生态平衡与人们的生活。本文以浙江省秀山岛1970、1980、2003、2008和2014年的遥感影像作为数据源,利用遥感和GIS技术方法,并采用DSAS的岸线分析方法揭示了秀山岛近50 a来岸线的时空变化规律。结果表明:在自然和人为的双重因素影响下,秀山岛的自然岸线和人工岸线发生大规模的变化,岸线长度总体上是减少的,共减少4 226 m,新增陆域面积2.491 km²;其中人工岸线减少了4 046 m,海塘面积增加1.971 km²,表现为大规模的向海推进,时空变化显著;自然岸线减少了214 m,主要是沙质岸线和淤泥质岸线的变化,整体表现为岸线小规模的后退,但是局部地区有向海推进的现象。     

Stable isotope analysis of Pacific salmon: insight into trophic status and oceanographic conditions over the last 30 years

Food web interactions and the response of Pacific salmon to physical processes in the North Pacific Ocean over interannual and interdecadal timescales are explored using naturally occurring stable isotope ratios of carbon (¹³C/¹²C) and nitrogen (¹⁵N/¹⁴N). Stable isotope analyses of five species of sexually mature North Pacific salmon from Alaska (Oncorhynchus spp.) cluster into three groups: chinook salmon (O. tshawytscha) have the highest values, followed by coho (O. kisutch), with chum (O. keta), sockeye (O. nerka), and pink (O. gorbuscha) together having the lowest values. Although detailed isotopic data on salmon prey are lacking, there are limited data on relevant prey items from areas in which they are found in high abundance. These data suggest that the characteristics of the sockeye, pink and chum we have analyzed are compatible with their diets including open ocean squid and zooplankton, which are in general agreement with stomach content analyses. Isotope relationships between muscle and scale show consistent relationships for both δ¹³C (R²=0.98) and δ¹⁵N (R²=0.90). Thus, scales, which have been routinely archived for many systems, can be used for retrospective analyses. Archived sockeye salmon scales spanning 1966–1999 from Red Lake, Kodiak Island, Alaska were analyzed for their stable isotope ratios of carbon and nitrogen. The δ¹⁵N record displays a decreasing trend of ˜3‰ from 1969–1982 and an increasing trend of ˜3‰ from 1982–1992, while the variations in δ¹³C are relatively minor. These trends may result from factors such as shifts in trophic level of feeding and/or feeding location, or may originate at the base of the food web via changes in processes such as nutrient cycling or primary productivity. Detailed studies on prey isotopic variability and its controls are needed to distinguish between these factors, and thus to improve the use of stable isotope analysis as a tool to learn more about present and past ecosystem change in the North Pacific and its relation to climatic change.     

Time series video analysis of bubble release processes at natural hydrocarbon seeps in the Northern Gulf of Mexico

This research quantifies the rate and volume of oil and gas released from two natural seep sites in the Gulf of Mexico: lease blocks GC600 (1200 m depth) and MC118 (850 m depth). Our objectives were to determine variability in release rates and bubble size at five individual vents and to investigate the effects of tidal fluctuations on bubble release. Observations with autonomous video cameras captured the formation of individual bubbles as they were released through partially exposed deposits of gas hydrate. Image processing techniques determined bubble type (oily, gaseous, and mixed: oily and gaseous), size distribution, release rate, and temporal variations (observation intervals ranged from 3 h to 26 d). A semi-automatic bubble counting algorithm was developed to analyze bubble count and release rates from video data. This method is suitable for discrete vents with small bubble streams commonly seen at seeps and is adaptable to multiple in situ set-ups. Two vents at GC600 (Birthday Candles 1 and Birthday Candles 2) were analyzed. They released oily bubbles with an average diameter of 5.0 mm at a rate of 4.7 bubbles s⁻¹, and 1.3 bubbles s⁻¹, respectively. Approximately 1 km away, within the GC600 seep site, two more vents (Mega Plume 1 and Mega Plume 2) were analyzed. These vents released a mixture of oily and gaseous bubbles with an average diameter of 3.9 mm at a rate of 49 bubbles s⁻¹, and 81 bubbles s⁻¹, respectively. The fifth vent at MC118 (Rudyville) released gaseous bubbles with an average diameter of 3.0 mm at a rate of 127 bubbles s⁻¹. Pressure records at Mega Plume and Rudyville showed a diurnal tidal cycle (24.5 h). Rudyville was the only vent that demonstrated any positive correlation (ρ = 0.60) to the 24.5 h diurnal tidal cycle. However, these observations were not conclusive regarding tidal effects on bubble release.     

Large-Scale Smoke Haze over the European Part of Russia and Belorus in July 2016

Izvestiya, Atmospheric and Oceanic Physics - The smoke haze over the European part of Russia (EPR) and Belorus in July 2016 has been studied with the use of aerosol optical thickness (AOT) data...     

台湾岛周边海域近16a来海平面变化研究

利用1992年10月至2008年6月的卫星高度计融合资料对台湾岛周边海域（20°～28°N,117°～124°E）多年海平面变化进行分析.研究结果表明：（1）采用改进的月平均水位周期信号的谱分析方法计算多年来台湾岛周边海域海平面年均上升速率为0.34±0.02 cm/a,与该海域内的潮位站结果较为一致.（2）台湾岛周边海域海平面高度变化以1 a周期变化为主,其次为0.5 a、准2 a周期变化.（3）通过计算海平面异常的标准差得出多年来台湾海峡西南部海域海平面波动最为激烈.（4）分析了台湾岛周边海域海平面4个季节的变化情况,指出台湾岛周边海域海平面季节变化的主要驱动力是风场.     

Genetic variability analysis in five populations of the sea cucumber Stichopus (Apostichopus) japonicus from China,Russia, South Korea and Japan as revealed by microsatellite markers

The genetic structure of populations of the sea cucumber Stichopus (Apostichopus) japonicus was investigated using 10 microsatellite markers. In all, 152 individuals from five natural populations were collected from Aomori, Japan (JA and JR), Yosu, South Korea (KY), Dalian, China (CD) and Vladivostock, Russia (RV). A total of 145 alleles were found at 10 loci. The number of alleles per locus ranged from 9 at PSC03 to 20 at SCZ06, with an average of 14.5. Average H_o and H_e ranged from 0.260 (JR) to 0.434 (JA) and from 0.654 (RV) to 0.778 (KY), respectively. No significant differences at A, H_o and H_e were found, indicating similar genetic diversity in the five populations. A single allele was found at the PSC05 locus in the RV population. Of the 50 loci, 42 significantly deviated from Hardy–Weinberg equilibrium, all showing heterozygote deficiency. The genetic distances were all relatively great, ranging from 0.497 (between JA and KY) to 1.029 (between KY and JR). This suggests the five populations are genetically distinct. Cluster analysis indicated that JA, KY and CD form one branch and RV and JR another in the UPGMA tree. A hypothesis is proposed for the evolution of the Japanese red sea cucumbers and the genetic relationship among the populations.     

黄河口近60年来潮流特征演化过程

本文利用 1962 年、1986 年以及 2015 年的三个典型年代的实测资料建立黄河口数学模型,并对河口潮流场和潮流特征进行模拟,借用 MATLAB 软件进行分潮调和分析,得到黄河口近 60 年潮流特征以及各个阶段的潮流演化过程,得出以下结论：（1） 1962 年河口流场较为平整,有明显切变锋形态,该阶段存在两个较为明显的高流速区并且潮流在河口处呈现为往复流;（2） 1986 年黄河三角洲岸线曲折多拐,从湾湾沟到清水沟滋生了多个小型高流速区群,并且潮流在滨海处呈现往复流的形态而在远海处为旋转流; （3） 2015 年涨落潮时潮流在河口处形成明显的环流,此时在沿线凸出沙嘴处会形成 3 个明显的高流速区,并且潮流在大部分区域呈现旋转流而在河口东北向远海处部分区域呈现往复流的特征.     

Ice-rafted volcanic ash in the South Atlantic sector of the Southern Ocean during the last 100,000 years

Eucampia antarctica (Castr.) Mangin abundance curves for two piston cores from the western Agulhas Basin (southeast Atlantic sector of the Southern Ocean) were used to place volcanic glass shard and ice-rafted debris abundance curves into a stratigraphic framework for the last 100,000 years. A direct correlation is shown between increased abundance of E. antarctica, tephra and ice-rafted debris; low abundances are often characterized by calcareous sediment in the northern core. Peaks in abundance of E. antarctica have been interpreted as an indication of glacial periods and the increased ice-rafted debris and tephra during glacial periods is evidence for an ice-rafted origin for the tephra.Microprobe geochemical analysis of volcanic glass shards provides no single distinct source for the ash. The geochemical data is consistent, but not definitive, with a primary source in the Scotia Arc and a minor source from Bouvet Island. Between core correlations of geochemically “fingerprinted” dispersed tephra zones were not successful due to variability of glass shard geochemistry and limited sample size.     

近200年桑沟湾养殖海域柱状沉积剖面的污染有机质记录与评价

通过对取自桑沟湾南部和北部养殖海域2个站位的柱状沉积物样品进行TOC和TN测定,分析了桑沟湾沉积物中TOC和TN的分布情况,结合沉积物年代序列的测定,估算了工业革命之前、之中及规模化养殖之后桑沟湾海域沉积物中水生有机碳和总氮的含量,并对近200年来桑沟湾养殖海域有机质沉积情况进行了评价。结果显示:19世纪70年代以前,TOC含量较稳定,TN含量随深度增加而缓慢降低;19世纪70年代至20世纪70年代,TOC,TN含量波动均较大;20世纪70年代以后,TOC含量逐渐减小并趋于稳定,TN含量随养殖规模的扩大显著增加,且扇贝养殖区表层沉积物中TOC,TN的含量均低于海带养殖区。近200年桑沟湾沉积物中有机质来源变化趋势为混源-陆源-混源,近40年来的规模化养殖明显增加了水生有机碳及水生总氮在TOC和TN中所占比例。对桑沟湾沉积物中有机质污染评价结果显示,大规模的养殖活动增加了底质中沉积物TOC和TN的含量,海带筏式养殖对沉积物中的TN造成了一定的累积性自身污染。     

Evolution of the North Atlantic Current and Barents Ice Sheet as revealed by grain size populations in the northern Norwegian Sea during the last 60 ka

The grain size distribution of bulk sediment samples was decomposed in a core to reconstruct paleoceanographic evolution over the past 60 ka in the northern Norwegian Sea. The results show that sediments consisted of 3–4 grain populations derived from the North Atlantic Current (NAC) and Barents Ice Sheet (BIS). The grain size data suggest three palaeoceanographic evolution stages: (1) an environment affected by BIS and NAC and changed with the interstadial/stadial transition in phase with the Greenland ice-core record at 60–31 ka BP, during which discharge of icebergs and the content of the coarsest population containing ice-rafted debris (IRD) in the sediments increased significantly during stadial, while the fine silt population containing volcanic glasses increased with the enhancement of NAC during the interstadial; (2) an extreme environment controlled by BIS at 31–13 ka BP. BIS reached to its maximum at about 31 ka BP and the turbid plumes that formed at the leading edge of BIS contributed to a significant increase in the clayey population in sediments. Icebergs drained into the northern Norwegian Sea with periodical calving of the BIS at 31–19 ka BP. Subsequently, the ablation of the BIS discharged massive floods with clayey sediments and icebergs into the Norwegian Sea at 19–13 ka BP, resulting in a constant increase in clay and IRD in sediments; and (3) a marine environment similar to the present one under the strong influence of NAC following the complete melting of the BIS after 13 ka BP, NAC is the dominant transport agent and no IRD occurred in sediments. The fine silt populations containing volcanic glasses transported by NAC significantly increased.