Impact of Kuroshio on the dissolved oxygen in the East China Sea region

A marine survey was conducted from 18 May to 13 June 2014 in the East China Sea (ECS) and its adjacent Kuroshio Current to examine the spatial distribution and biogeochemical characteristics of dissolved oxygen (DO) in spring. Waters were sampled at 10?25 m intervals within 100 m depth, and at 25?500 m beyond 100 m. The depth, temperature, salinity, and density (sigma- t ) were measured in situ with a conductivity-temperature-depth (CTD) sensor. DO concentrations were determined on board using traditional Winkler titration method. The results show that in the Kuroshio Current, DO content was the highest in the euphotic layer, then decreased sharply with depth to about 1 000 m, and increased with depth gradually thereafter. While in the ECS continental shelf area, DO content had high values in the coastal surface water and low values in the near-bottom water. In addition, a low-DO zone off the Changjiang (Yangtze) River estuary was found in spring 2014, and it was formed under the combined influence of many factors, including water stratification, high primary productivity in the euphotic layers, high accumulation/ sedimentation of organic matter below the euphotic layers, and mixing/transport of oceanic current waters on the shelf. Most notable among these is the Kuroshio intruded water, an oceanic current water which carried rich dissolved oxygen onto the continental shelf and alleviated the oxygen deficit phenomenon in the ECS, could impact the position, range, and intensity, thus the formation/destruction of the ECS Hypoxia Zone.     

Seasonal variability in dissolved oxygen in the Bohai Sea,China

Deoxygenation has frequently appeared in coastal ecosystems over the past century due to the joint influence of increasing anthropogenically induced nutrient in...     

Influence of Kuroshio water on the distribution of dissolved oxygen in the northern East China Sea

On the basis of the four-cruise investigation data of the Kuroshio by the R/V "Xiangyanghong 09", this paper lays stress on the discussion of the relationship between the Kuroshio current systems, the distribution of dissolved oxygen in the northern East China Sea (ECS) and seasonal variations.     

Variability of the Kuroshio in the East China Sea in 1995

INTRODUCTIONTherearemanyresearchworksabbottheKUrOShioVTanditSSeaSOnalvacationintheEastChinaho(GUan,1988;Nishizawaetal.,1982;TangandTaShiro,1993;SunandKaneko,1993;Yuanetal.,1990;Yuanetal.,1993;Yuanetal.,1994;Yuanetal.,1995;LiuandYuan,1997a,b).~previou...     

Ocean temperature responses to Typhoon Mstsa in the East China Sea

The MASNUM wave-tide-circulation coupled model, with 21 layers in the vertical and （1/8） °horizontal resolution, was employed to investigate the oceanic responses to Typhoon Mstsa which traversed the East China Sea （ECS） during the period of 4 - 6 August, 2005. Numerical experiment results are analyzed and compared with observation. The responses of the sea surface temperature （SST）, in a focused area of （27° -29°N, 121° - 124°E）, include heating and cooling stages. The heating is mainly due to warm Kuroshio water transportation and downwelling due to the water accumulation. In the cooling stage, the amplitude of the simulated cold wake （ -3℃ ）, located on the right side of this typhoon track, is compared quite well with that of the satellite observed SST data. The wave-induced mixing（Bv） plays a key role for the SST cooling. Bv still plays a leading role, which accounts for 36%, for the ocean temperature drop in the upper ocean of 0 - 40 m, while the upwelling is responsible for 84% of the cooling for the lower layer of 40 - 70 m. The mixed layer depth （MLD） increased quickly from 28 to 50 m in the typhoon period. However, the simulated MLD without the wave-induced vertical mixing, evolution from 13 to 32 m, was seriously underestimated. The surface wave is too important to be ignored for the ocean responses to a typhoon.     

黄、东海海域溶解无解机砷分布特征与化学形态

Distribution and chemical speciation of dissolved inorganic arsenic were examined in Yellow Sea and East China Sea. Results demonstrated that: (1) both As(III) and As(V) were detected, with As(V) domin...     

东海对台风云娜的海洋响应

Many typhoons pass through the East China Sea(ECS) and the oceanic responses to typhoons on the ECS shelf are very energetic. However, these responses are not well studied because of the complicated background oceanic environment. The sea surface temperature(SST) response to a severe Typhoon Rananim in August 2004 on the ECS shelf was observed by the merged cloud-penetrating microwave and infrared SST data. The observed SST response shows an extensive SST cooling with a maximum cooling of 3°C on the ECS shelf and the SST cooling lags the typhoon by about one day. A numerical model is designed to simulate the oceanic responses to Rananim.The numerical model reasonably simulates the observed SST response and thereby provides a more comprehensive investigation on the oceanic temperature and current responses. The simulation shows that Rananim deepens the ocean mix layer by more than 10 m on the ECS shelf and causes a cooling in the whole mixed layer. Both upwelling and entrainment are responsible for the cooling. Rananim significantly deforms the background Taiwan Warm Current on the ECS shelf and generates strong Ekman current at the surface. After the typhoon disappears, the surface current rotates clockwise and vertically, the current is featured by near inertial oscillation with upward propagating phase.     

东海海表面温度长期变化趋势研究

通过对卫星海表面温度资料的分析，研究了东海表面温度的长期变化趋势。发现东海存在41个月左右的变化周期，并与ENSO有一定的关系。海表面温度变异最大的区域在东海北部由长江口至济州岛南部区域。     

南海越南上升流区沉积物中溶解氧、锰和铁的垂直分布特征

2007年夏季航次对南海越南上升流区的三个站位进行现场采样,利用微电极技术测定了沉积物间隙水中的溶解氧(DO溶解氧分子)、锰(Mn2+)、铁(Fe2+)的浓度和氧化还原电位,估算了DO的通量、消耗速率和有机碳的消耗速率.在沉积物间隙水中DO浓度随深度的增加而迅速降低,渗透深度为9-48mm.在沉积物深处还检测到Mn2+和Fe2+.采用元素分析仪测定了沉积物中总有机碳(TOC)含量和总氮(TN)含量,三个站位沉积物中的TOC含量为0.7%-1.03%,TN含量为0.052%-0.10%,C/N为10.5-16.0.从C/N可以看出,该研究区域沉积物中的有机物有部分来源于陆源输入,其中一个站位位于湄公河冲淡水区域,其C/N最大.从氧化还原电位来看,三个站位的沉积环境都属于还原性环境.此研究首次测量了南海越南上升流区沉积物的氧化还原化学成分,对于认识该海区海底生物地球化学具有重要意义.     

春季东海溶存氧化亚氮的分布和海气交换通量

于2011年5至6月在东海采集不同深度海水样品,研究了其中溶存氧化亚氮(N2O)的分布并估算其海-气交换通量。结果表明,春季东海表层海水中溶存N2O浓度范围为6.31~11.88 nmol/L,平均值为(9.13±1.45)nmol/L;底层海水中N2O浓度范围为7.53~39.75 nmol/L,平均值为(13.71±7.76)nmol/L。随着深度的增加,N2O浓度逐渐升高。温度是影响春季东海N2O分布的主要因素,N2O浓度与温度呈负相关关系。长江冲淡水和黑潮水是东海N2O的重要来源。东海表层海水中N2O的饱和度范围为92.5%~139.3%,平均值为118.5%±10.3%,绝大多数站位都处于过饱和状态,因此,春季东海是大气N2O的净源。利用LM86公式和W92公式求得东海的海-气交换通量分别为(4.96±6.12)μmol/(m2·d)和(10.25±17.18)μmol/(m2·d),初步估算出东海年释放N2O通量约为0.061~0.127 Tg/a,占全球海洋释放总量的2.0%,远高于其所占的面积比0.2%。     

东海区域灾害性海浪长期预测方法研究

海浪预报具有复杂性、非线性和高维性等特点,而BP人工神经网络是处理非线性关系,进行科学预测行之有效的方法。本文中采用BP人工神经网络技术,以1985—2005年影响东海区的热带气旋、温带气旋和冷空气等相关要素为样本,建立东海区域灾害性海浪BP神经网络长期预测数值模型。通过模拟预测效果检验:该模型预测准确率超过85%,平均误差约为8%,满足实际预测要求。     

东海海域溶解氧垂直分布最大值的分析研究

本文讨论了１９８７年５～６月东海海域溶解氧垂直分布及其氧最大值分布特征。结果表明，春末在东海北部、中部的中层存在明显的溶解氧垂直分布最大值。氧最大值与冷水同存。本文对氧最大值及垂直结构与冷暖水入侵和温跃层关系进行了初步分析     

On a new Siphonophora from the East China Sea and South China Sea

In the course of identifying the samples of Siphonophora from the East China Sea and South China Sea, a new Siphonophora, Vogtia microsticella sp. nov. , was noted. The new species is distinguished from other five species in the genus in nectophore as follows: Parahorse-shoe shaped with five bluntly rounded projections, the two projections below the ostium, i. e. the basal projections, approach each other. The dorsal facet is smooth without any gelatinous prominence. Smaller are the nectosac and the ostium.     

Characteristic analysis on oxygen isotopic tracer in the East China Sea and waters to east of the Ryukyu－gunto

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Long-term series in ichthyoplankton: sole and sprat at French coast of the North Sea from 1975 to 1994

The sampling of eggs and larvae of sole and sprat at Gravelines (French part of the North Sea coast) since 1975 has produced a long-term series showing major interannual changes. Comparison of the results obtained on two species, one benthic and the other one pelagic, suggests some events affecting the environment that are also revealed by the holoplanktonic (appendicularia, chaetognatha) and meroplanktonic (cirripeda larvae) compartment. This study attempts also to distinguish general variations from more closely species-related fluctuations.     

Effects of dissolved oxygen and nutrients from the Kuroshio on hypoxia off the Changjiang River estuary

The intrusion of the Kuroshio into the East China Sea(ECS) affects the development of hypoxia off the Changjiang(Yangtze) River estuary; however, quantitative analysis of its impacts is lacking. In this study, the Regional Ocean Modeling Systems(ROMS) model coupled with the Carbon, Silicate and Nitrogen Ecosystem(Co Si NE) model was used to investigate the relative importance of dissolved oxygen(DO) and different nutrients(silicate, nitrate, and phosphate) in the Kuroshio on hypoxia in the ECS. ...     

东海大陆架区海胆分类研究

海胆是重要的大型海洋底栖生物类群之一，某些海胆既是人工养殖对象，又是捕捞对象。因此，对海胆进行分类研究，摸清其地理分布特点，对合理利用海胆资源以及生物多样性研究都可提供基本科学依据。 对我国海胆的分类学研究始于1948年，当时张凤瀛先生对青岛的6种海胆进行了描述(张凤瀛，1948)。1957年张凤瀛和吴宝铃先生对广东沿海的37种海胆进行了研究(张凤瀛等，1957)。张凤瀛先生等1964年在《中国动物图谱，棘皮动物门》中记录了30种我国常见海胆(张凤瀛等，1964)。廖玉麟先生在20世纪70年代对西沙群岛的棘皮动物进行了分类研究，其中包括26种海胆(廖玉麟，1978)。 中国科学院海洋研究所于1958-1982年在东海大陆架进行过多次的综合性海洋调查。调查范围:26°~33°45′N，122°~129°E。该海域的底栖生物种类繁多，多样性丰度高。本文对中国科学院海洋研究所历年采自东海大陆架的海胆进行了较系统的研究，共包括21种，隶属于7目、11科、17属。其中有11种在我国是首次记录。名录如下，有*者为新记录。     

The oxygen minimum zone in the Arabian Sea during 1995

This paper focuses on the characteristics of the oxygen minimum zone (OMZ) as observed in the Arabian Sea over the complete monsoon cycle of 1995. Dissolved oxygen, nitrite, nitrate and density values are used to delineate the OMZ, as well as identify regions where denitrification is observed. The suboxic conditions within the northern Arabian Sea are documented, as well as biological and chemical consequences of this phenomenon. Overall, the conditions found in the suboxic portion of the water column in the Arabian Sea were not greatly different from what has been reported in the literature with respect to oxygen, nitrate and nitrite distributions. Within the main thermocline, portions of the OMZ were found that were suboxic (oxygen less than ∼4.5 μM) and contained secondary nitrite maxima with concentrations that sometimes exceeded 6.0 μM, suggesting active nitrate reduction and denitrification. Although there may have been a reduction in the degree of suboxia during the Southwest monsoon, a dramatic seasonality was not observed, as has been suggested by some previous work. In particular, there was not much evidence for the occurrence of secondary nitrite maxima in waters with oxygen concentrations greater than 4.5 μM. Waters in the northern Arabian Sea appear to accumulate larger nitrate deficits due to longer residence times even though the denitrification rate might be lower, as evident in the reduced nitrite concentrations in the northern part of the basin. Organism distributions showed string relationships to the oxygen profiles, especially in locations where the OMZ was pronounced, but the biological responses to the OMZ varied with type of organism. The regional extent of intermediate nepheloid layers in our data corresponds well with the region of the secondary nitrite maximum. This is a region of denitrification, and the presence and activities of bacteria are assumed to cause the increase in particles. ADCP acoustic backscatter measurements show diel vertical migration of plankton or nekton and movement into the OMZ. Daytime acoustic returns from depth were strong, and the dawn sinking and dusk rise of the fauna were obvious. However, at night the biomass remaining in the suboxic zone was so low that no ADCP signal was detectable at these depths. There are at least two groups of organisms, one that stays in the upper mixed layer and another that makes daily excursions. A subsurface zooplankton peak in the lower OMZ (near the lower 4.5 μM oxycline) was also typically present; these animals occurred day and night and did not vertically migrate.     

秋季东海溶解态和颗粒态氨基酸的分布与组成*

本文对2012年秋季中国东海31个站位的海水样品中溶解态氨基酸（THAA）和颗粒态氨基酸（PAA）的分布与组成进行了研究。结果表明：表层海水中溶解游离氨基酸(DFAA)的平均浓度为0.12±0.04 μmol/L (0.06~0.19 μmol/L),溶解结合氨基酸(DCAA)的平均浓度为0.61±0.51 μmol/L (0.15~1.79 μmol/L),PAA的平均浓度为0.11±0.06 μmol/L (0.02~0.27 μmol/L)。THAA的水平分布特点大致为近岸高、远岸低;PAA的水平分布特点是近岸海域向远海海域分布呈现逐渐减小的趋势。THAA的垂直分布特点是由表层向底层逐渐降低。DCAA、PAA与Chl-a有很好的相关性,而DFAA与Chl-a的相关性不明显。东海表层海水中THAA的主要组分是天门冬氨酸、谷氨酸、丝氨酸、甘氨酸、苏氨酸及丙氨酸,PAA的主要组分是天门冬氨酸、谷氨酸、丝氨酸、甘氨酸、丙氨酸及亮氨酸。在表层海水中氨基酸是作为一个整体而对海洋生物地球化学过程产生影响的。     

Sediments in the East China Sea

This paper describes measurements of sediments during the 2000-2001 Asian Seas International Acoustic Experiment in the East China Sea. A number of techniques were used to infer properties of these sediments, including gravity and piston cores, subbottom profiling using a water gun, long-range sediment tomography, and in situ measurement of conductivity. Historical data from echosounder records and cores showed two regions of surficial sediments in the experimental area: a silty area to the west and a sandy area to the east. The tomography, cores, and water-gun measurements confirm the two surficial sediment regions seen in the historical data and also indicate that the subbottom structure at the experimental site consists of a thin (0-3 m thick) layer of sandy sediment directly beneath the sea floor. Below this layer, there is an extensive package of sediment with relatively uniform acoustic attributes. Core analysis shows that the surface sediment layer varies in compressional wave speed from a low near 1600 m/s in the west side of the experiment area to 1660 m/s in the east side of the experiment area. Long-range sediment tomography inversions show a similar spatial variation in the surface layer properties. In addition, the layer thickness as determined from tomography is consistent with the estimates from subbottom profiling.