Fish assemblage structure in the East China Sea and southern Yellow Sea during autumn and spring

Based on bottom trawl surveys in autumn 2000 and spring 2001, the fish assemblage structure in the southern Yellow Sea and the continental shelf of the East China Sea was analysed. Four groups of fishes were identified for each season by the two-way indicator species analysis (TWIA). Although seasonal migration caused a slight difference in fish assemblages between autumn and spring, two major groups of fishes, corresponding to the Yellow Sea and East China Sea were identified. Inshore and offshore groups were subsequently separated. Changes in water depth may be most important in the separation of the groups in the offshore waters of the East China Sea. Temperature affected the groupings between north and south, particularly in the central part of the Yellow Sea. Here, the cold water mass affected the species composition which was low in diversity and different from the other areas.     

Mesozooplankton dynamics in the northern Baltic Sea: implications of variations in hydrography and climate

An 18-year mesozooplankton time series from 1967 to 1984 fromthe SW coast of Finland, northern Baltic Sea, was studied inrelation to climatic parameters (air temperature, air pressure,precipitation, and wind speed and direction), freshwater dischargeand hydrographical factors (water temperature, salinity andwater column stability). Climatic factors influenced mesozooplanktoncommunity through their effects on hydrography. The averagewater salinity responded to fluctuations in river dischargewith a 1–2 year lag. River discharge was in turn regulatedby variations in atmospheric pressure and precipitation, whichoscillated on 3–5 year cycles. Shorter-term variationsin salinity and temperature were related to changes in the dominatmgwind directions. The seasonally adjusted residuals of totalmesozooplankton biomass, cladoceran biomass and those of manyof the dominant mesozooplankton species were significantly negativelycorrelated with salinity. The annual peaks of the most abundaiitcladoceran species and one of the most abundant calanoid speciesco-varied with the seasonal fluctuation of surface water temperature.Canonical correspondence analysis identified the mesozooplanktonspecies by their relationship to water stability: rotifers andcladocerans had their optima in warm and stabile conditions,while the nentic calanoid copepods were more abundant in relativelysaline and mixed conditions.     

Age,growth and reproduction of cutlassfishes Trichiurus spp. in the southern East China Sea

The cutlassfish is one of the most commercially important continental fishes in the East China Sea. However, the current classification of cutlassfishes is suboptimal and complicates fisheries management. This study investigated the growth and reproduction of three cutlassfish species in the southern East China Sea. Between August 2002 and September 2003, a total of 2717 specimens of Trichiurus japonicus, T. sp.2 (likely synonymous for T. nanhaiensis) and T. lepturus were collected monthly from Daxi, Anping, Nanfangao, Donggang and Xingang fishing ports. The von Bertalanffy growth model in preanal length (PL) resulted in PL (mm) for T. japonicus, PL(mm) for T. sp.2 and PL (mm) for T. lepturus. Their growths were significantly different between sexes for T. japonicus and T. sp.2 and among the three species. From macroscopic examination of ovaries, histological inspection of oocytes, and analyses of gonosomatic and hepatosomatic indices, T. japonicus was likely to spawn all year round, with two peaks in February–July and November–December. T. sp.2 spawned relatively later, between April and August. The length at sexual maturity of T. japonicus females was 264 mm PL or 746 mm total length. The sex ratios of T. japonicus and T. sp.2 were significantly different from 1 : 1 whereas T. lepturus showed no significant difference. The three species of trichiurids have different geographical distributions in this region.     

Phage spread dynamics in clonal bacterial populations is depending on features of the founder cell

Plate-cultured bacterial colonies are intriguing models to study host-parasite interactions in senescent populations. During the growth of bacteriophage-infected colonies there is a synchronous prophage induction episode among lysogenic cells that allows a dramatic but time-restricted amplification of viral particles. We report here that the dynamics of phage spread depends on the history of the lysogenic cell that establishes the clonal population, the duration of the pre-burst period being shorter when the founder, infected cell derives from older colonies. These results offer a physiologic explanation for the self-contained progression of the viral spread in closed environments, that ensures both viral dissemination but also survival of most of the host cells.     

黄海南部和东海小黄鱼(Larimichthys polyactis)产卵场分布及其环境特征

根据2003～2005年和2007年4月份在黄海南部和东海海域进行的底拖网调查数据,分析了小黄鱼产卵场分布和产卵场环境特征等.结果表明,目前小黄鱼产卵场范围较过去有扩大,范围已经扩展到外海海域,产卵场可分为黄海南部产卵场和东海产卵场;其中黄海南部产卵场主要集中在33°00′～34°00′N,122°30′～124°00′E,产卵场最适水温范围为9.65～12.17℃,最适盐度范围为32.25～34.54,最适水深范围为29.74～76.49m;东海产卵场主要集中在30°30′～31°00′N,124°00′～125°00′E海域和30°30′～32°30′N,125°00′～126°00′E海域,产卵场最适水温范围为10.13～16.64℃,最适盐度范围为32.50～34.37,最适水深范围为40.23～85.61m;黄海南部和东海产卵场水温分布差异极显著(P<0.01);小黄鱼产卵场较过去发生较大变化的主要原因可能是在过度捕捞等扰动因素的影响下,小黄鱼对环境适应性明显提高.     

The hydrography of the southern Canada Basin, 2002

Physical and geochemical data collected in 2002 during a multi-disciplinary expedition across the southern Canada Basin are interpreted here to provide context for the biological program that included observations from the entire water column. The mixed layer was shallow (15–20 m) and depleted of nitrate, indicating it was the limiting nutrient. Below the mixed layer a strong, multi-layered halocline complex, consisting of Pacific-origin summer and winter waters and Atlantic-origin lower halocline water, occupied the water column down to ~200 m. Pacific and Atlantic-origin waters were shallower by 25–50 m in comparison to data collected in 1997/1998, suggesting a progressive decrease in Pacific-origin water extent. Fram Strait Branch waters were warmer everywhere in the southern Canada Basin, indicating the arrival of the pulse of anomalously warm Atlantic-origin water observed in the three upstream basins during the 1990s. The highest temperatures (1.13°C) were observed along the flank of the Northwind Ridge in the core of the topographically steered boundary current. Comparison with 1997/1998 observations showed that this pulse of anomalously warm water advanced ~430 km in 4 years with an apparent speed of ~0.34 cm/s. Observation of high temperatures at a station in the Canada Abyssal Plain suggest that the boundary current bifurcates north of the Northwind Ridge, with one branch continuing eastward into the basin and the other turning southward, following the ridge.     

Phylogenetic diversity of Synechococcus strains isolated from the East China Sea and the East Sea

Phylogenetic relationships among 33 Synechococcus strains isolated from the East China Sea (ECS) and the East Sea (ES) were studied based on 16S rRNA gene sequences and 16S–23S rRNA gene internal transcribed spacer (ITS) sequences. Pigment patterns of the culture strains were also examined. Based on 16S rRNA gene and ITS sequence phylogenies, the Synechococcus isolates were clustered into 10 clades, among which eight were previously identified and two were novel. Half of the culture strains belonged to clade V or VI. All strains that clustered into novel clades exhibited both phycoerythrobilin and phycourobilin. Interestingly, the pigment compositions of isolates belonging to clades V and VI differed from those reported for other oceanic regions. None of the isolates in clade V showed phycourobilin, whereas strains in clade VI exhibited both phycourobilin and phycoerythrobilin, which is in contrast to previous studies. The presence of novel lineages and the different pigment patterns in the ECS and the ES suggests the possibility that some Synechococcus lineages are distributed only in geographically restricted areas and have evolved in these regions. Therefore, further elucidation of the physiological, ecological, and genetic characteristics of the diverse Synechococcus strains is required to understand their spatial and geographical distribution.     

夏季黄东海中华哲水蚤种群分布、脂类含量和利用策略

度夏过程对黄东海中华哲水蚤其种群延续具有重要的意义。通过2011年08月黄东海现场调查航次研究了中华哲水蚤夏季种群的分布和脂类含量,探讨了中华哲水蚤度夏期间的能量利用策略。结果表明,夏季在黄海中部以及浙江近岸存在中华哲水蚤的密集分布区域。其中,黄海冷水团内的中华哲水蚤以C5期(平均为77.4%)个体为主,而冷水团周边及浙江近岸站位则主要由C5期(分别为32.3%和33.2%)和雌体(分别为41.3%和51.8%)组成。脂类含量结果显示,冷水团内的C5期中华哲水蚤的总脂含量最高(平均43.1μg/个),浙江近岸雌体的总脂含量(平均24.6μg/个)和黄海冷水团周边雌体的总脂含量(平均18.2μg/个)较低。在完全饥饿的假设下,冷水团内的C5期中华哲水蚤具有明显的代谢优势,其储存的脂类可以维持超过18天的代谢需求。而在浙江近岸以及冷水团周边,中华哲水蚤储存的脂类则只可维持3—6d的需求。由此推测,黄海冷水团内的C5期中华哲水蚤依靠储存的油脂和较低的摄食率度夏,而冷水团以外的种群则需要在适宜温度下积极摄食才能顺利度夏。     

东海水母类多样性分布特征

根据1997–2000年东海23°30'–33°00'N、118°30'–128°00'E海域4个季节海洋调查资料,从环境因素与优势种的聚集强度等不同侧面探讨了东海水母类多样性指数(H′)的分布特征及其成因。东海4季共发现水母类103种,主要分布在东海南部和北部外海。大部分水域水母物种多样性较高,且冬夏季高于春秋季,南部高于北部,外海高于近海。分析成因如下:(1)多样性指数与物种数密切相关,但与丰度相关性不显著。优势种的聚集导致个别海区物种多样性降低。春季五角水母(Muggiaeaatlantica)在浙江近海、秋季双生水母(Diphyeschamissonis)在长江口海域聚集,导致春秋季东海近海水母类多样性指数较低。(2)水温是影响多样性指数分布的主要环境因子,盐度是次要因子。冬春季多样性指数值与10m层水温相关,夏季与表层水温相关,秋季与10m层盐度相关。(3)多样性指数的分布还受不同水团的影响。春季、夏季和冬季多样性指数(H′)等值线分布全面反映了东海海流走向和水团的变化,是分析东海水团的良好指标。     

东海水母类丰度的动力学特征

本文根据1997-2000年东海23°30′-33°N、118°30′-128°E海域4个季节海洋调查资料,探讨了东海水母类数量变化特征和相应的动力学。结果表明:水母类是东海浮游动物的第三大类群,其丰度仅次于桡足类和海樽类;其数量有明显的季节变化,春季丰度最高(5·37ind·/m3),秋季次之(2·23ind·/m3),冬季(1·82ind·/m3),夏季最低(0·88ind·/m3);其平面分布特征为近海高于外海;其数量变化首先来自优势种大西洋五角水母(Muggiaeaatlantica)和双生水母(Diphyeschamissonis)的贡献,前者是近岸暖温种,后者是近岸暖水种;春季丰度变化与表层和底层盐度二元线性相关,夏季与底层水温相关,秋季与底层盐度相关,冬季与表层盐度相关,4季总丰度与10m层盐度相关。盐度是影响水母类数量变化的主要环境动力学因子,水温是次要因子;水母类高丰度区往往位于台湾暖流与长江径流交汇处偏冲淡水水团一侧。长江冲淡水在不同季节入海后的流向是决定高丰度分布区位置重要的动力学因子。该类浮游动物对沿海海域生物安全、生态安全和环境安全都有重要的影响,引起全球的普遍关注。     

东海浮游等足类和涟虫类的调查

根据1997~2000年东海(23°30′~33°00′N,118°30′~128°00′E)海域4个季节海洋调查资料,对东海浮游等足类和涟虫类种类的组成、数量变化及地理分布等特征作了探讨。结果表明,调查海域出现浮游等足类2种,其中圆柱水虱(Cirolanasp.)在东海等足类数量中具有绝对优势(占总丰度的98%),中国急游水虱(Tachaea chinensis)是稀有种。等足类主要在夏季出现,并分布在东海近海。浮游涟虫类主要分布在台湾海峡和东海南部海域。浮游涟虫类有4种,细长涟虫(Iphinoe tenera)和萨氏异涟虫(Heterocumasarsi)在3个季节出现,丰度和出现率较高,是东海涟虫类的常见种;无尾涟虫(Leueonsp.)在2个季节出现,丰度和出现率与前2个种相似,是次常见种。卵圆涟虫(Bodotria ovalis)仅出现在秋季,数量和出现率极低,是稀有种。细长涟虫、萨氏异涟虫和无尾涟虫都是暖水种。相比之下,无尾涟虫有更广泛的适温能力。卵圆涟虫在盐度较低的长江口出现,是一个近岸种。     

National-scale metacommunity dynamics of carabid beetles in UK farmland

1. Understanding the wide-scale processes controlling communities across multiple sites is a foremost challenge of modern ecology. Here, data from a nation-wide network of field sites are used to describe the metacommunity dynamics of arable carabid beetles. This is done by modelling how communities are structured at a local level, by changes in the environment of the sampled fields and, at a regional level, by fitting spatial parameters describing latitudinal and longitudinal gradients. 2. Local and regional processes demonstrated independent and significant capacities for structuring communities. Within the local environment, crop type was found to be the primary determinant of carabid community composition. The regional component included a strong response to a longitudinal gradient, with significant increases in diversity in an east-to-west direction. 3. Carabid metacommunities seem to be structured by a combination of species sorting dynamics, operating at two different, but equally important, spatial scales. At a local scale, species are sorted along a resource gradient determined by crop type. At a wider spatial scale species appear to be sorted along a longitudinal gradient. 4. Nation-wide trends in communities coincided with known gradients of increased homogeneity of habitat mosaics and agricultural intensification. However, more work is required to understand fully how communities are controlled by the interaction of crops with changes in landscape structure at different spatial scales. 5. We conclude that crop type is a powerful determinant of carabid biodiversity, but that it cannot be considered in isolation from other components of the landscape for optimal conservation policy.     

Formation of nuclear HSF1 granules varies depending on stress stimuli

In concert with the stress-induced activation of human heat shock factor 1 (HSF1), the factor becomes inducibly phosphorylated and accumulates into nuclear granules. To date, these processes are not fully understood. Here, we show that although stress caused by the proteasome inhibitors MG132 and clasto-lactacystine beta-lactone induces the expression of Hsp70, the formation of HSF1 granules is affected differently in comparison to heat shock. Furthermore, proteasome inhibition increases serine phosphorylation on HSF1, but to a lesser extent than heat stress. Our results suggest that, depending on the type of stress stimulus, the multiple events associated with HSF1 activation might be affected differently.     

Simulation of drifting seaweeds in East China Sea

Drifting seaweeds plays a major role in areas where they are present. We describe a computer model, JeoSim that clarifies the roles of those seaweeds in relation to their transport using particle-tracking algorithm. The Euler rule with trapezoidal approximation, used to calculate drifting paths, is implemented in JeoSim in discrete events fashion in order to simulate the path and movement of seaweeds. Pre-processing of the ocean currents is done with the Princeton Ocean circulation Model (POM). Simulated current constitutes the data that provides force and directions for the calculations of drifting paths. Along with the implementation of the particle-tracking algorithm in discrete event fashion, the originality of the JeoSim software lies in its Object Oriented architecture which makes it especially suited to perform simulation of living, cross scale systems with complex behavior. Behavior of drifting seaweeds of the Sargasso family has been implemented in JeoSim, and experimented in East China Sea following a drifting seaweed collection campaign in May 2002. Despite a relatively low resolution ocean currents data, simulated results compare well with the observed distribution.     

Mesozooplankton and copepod community structures in the southern East China Sea: the status during the monsoonal transition period in September

A field sampling was conducted before the onset of the northeasterly monsoon to investigate the copepod community composition during the monsoon transition period at the northern coast of Taiwan (East China Sea). In total, 22 major mesozooplankton taxa were found, with the Calanoida (relative abundance: 66.36%) and Chaetognatha (9.44%) being the most abundant. Mesozooplankton densities ranged between 226.91 and 2162.84 individuals m^?3 (mean?±?SD: 744.01?±?631.5 individuals m^?3). A total of 49 copepod species were identified, belonging to 4 orders, 19 families, and 30 genera. The most abundant species were: Temora turbinata (23.50%), Undinula vulgaris (17.92%), and Acrocalanus gibber (14.73%). The chaetognath Flaccisagitta enflata occurred at all 8 sampling stations, providing a 95% portion of the overall chaetognath contribution. Amphipoda were abundant at stations 4 and 5, with Hyperioides sibaginis and Lestigonus bengalensis being dominant, and comprising about 50% of all amphipods. Chaetognath abundance showed a significantly negative correlation with salinity (r?=?0.77, p?=?0.027), whereas mesozooplankton group numbers had a significantly positive correlation with salinity (r?=?0.71, p?=?0.048). Densities of four copepod species (Calanus sinicus, Calocalanus pavo, Calanopia elliptica and Labidocera acuta) showed a significantly negative correlation with seawater temperature. Communities of mesozooplankton and copepods of northern Taiwan varied spatially with the distance to land. The results of this study provide evidence for the presence of C. sinicus in the coastal area of northern Taiwan during the early northeast monsoon transition period in September.     

黄海和东海营养盐分布及其对浮游植物的限制

根据1997～1999年黄海和东海4个季节的现场调查资料,分析探讨了黄海、东海的营养盐分布特征及其对浮游植物生长的限制状况．结果表明,在长江口以东及其东北部海域终年存在一个范围很大的营养盐高值区．分析表明,这些营养盐主要来自长江冲淡水的扩展及苏北沿岸流的输送．此外,还获得了1998年长江流域特大洪水期间,迄今被观测到的长江冲淡水中营养盐的最大扩展范围,计算并研究了黄海、东海上层水中Si／N／P比值,结果表明,黄东海上层水中Si／N比值较高,Si不会成为黄东海浮游植物生长的限制因子;但在南黄海南部尤其是西南部、东海近岸及长江口以东海域,N／P比值很高(>30),说明与一般海洋环境的情况不同,黄海、东海有很大一部分海域浮游植物的生长受磷限制,而不是受氮限制．     

东海栉水母(Ctenophora)生态特征

根据1997~2000年东海23°30′~33°00′N、118°30′~128°00′E海域4个季节海洋调查资料,对东海栉水母数量变化和地理分布特征作了探讨。结果表明,东海栉水母平均丰度秋季(6.3 ind.(100m3)-1)>春季(1.6 ind.(100 m3)-1)>冬季(1.4 ind.(100 m3)-1)>夏季(0.6 ind.(100 m3)-1)。调查海域鉴定到种的栉水母共有6种,其中球型侧腕水母(Pleurobrachia globosa)是东海的主要种类;掌状风球水母(Hormiphora palnata)和瓜水母(Beroe cucumis)是常见种;带水母(Cestumsp.)是次常见种;蝶水母(Ocyropsis crystalline)和卵型瓜水母(Beroe avata)是稀有种。东海栉水母系暖水性浮游动物类群,其数量变化与东海暖流势力活动过程中的携带有密切的联系。球型侧腕水母分布较为广泛,是适应环境能力较强的种类;掌状风球水母、蝶水母和卵型瓜水母相反,仅适应有限的环境;瓜水母和带水母适应能力介于以上两类栉水母之间。     

东海竹筴鱼的食性

以2008年5月、8月、11月和2009年2月东海灯光围网采集到的453条东海竹筴鱼为研究对象,对其胃含物进行分析,应用K-W非参数检验、卡方检验、聚类分析等方法,对不同季节和发育阶段条件下东海竹筴鱼的食性进行研究.结果表明:东海竹筴鱼的饵料生物有124种(包括未鉴定种),浮游甲壳类和小型鱼类为其主要饵料类群.优势饵料生物依次是麦氏犀鳕(IRI％=39.2％)、长尾类糠虾幼体(IRI％=18.4％)、短尾类大眼幼体(IRI％ =7.6％)和太平洋磷虾(IRI％=6.6％)等.季节和叉长对东海竹筴鱼的摄食强度均有显著影响(P＜0.01),东海竹筴鱼春季摄食强度最高,而冬季最低;叉长140 ～ 159 mm的竹筴鱼摄食强度最高,叉长45～99 mm的幼鱼的摄食强度较高,其余叉长的鱼摄食强度相对较低.聚类分析结果表明,叉长100 mm是东海竹筴鱼摄食取向的拐点.东海竹筴鱼四季的平均营养级为3.51,属于低级肉食性鱼类.     

东海浮游枝角类生态学研究

根据1997~2000年在东海23°30′~33°00′N、118°30′~128°00′E海域4个季节的海洋调查资料,探讨了东海浮游枝角类生态特征、数量变化和相应的动力学。结果表明,枝角类丰度夏季最高(17.16 ind.(100 m3)-1),秋季(14.68 ind.(100 m3)-1)次之,春季(0.63 ind.(100 m3)-1)较低,冬季该类未出现。春、夏、秋季的肥胖三角氵蚤(Evadne tergestina)和夏季的鸟喙尖头氵蚤(Penilia avirostris)是影响枝角类数量分布的主要种;春、夏、秋季枝角类总丰度与盐度呈负线性相关关系,与水温相关关系不显著。枝角类较高丰度区常位于沿岸淡水水团与其他水团交汇处偏沿岸水一侧。其数量变化动力主要来自沿岸冲淡水势力,特别是长江冲淡水势力的消长。枝角类在东海出现率较低,有一定的集群性,较高丰度的分布基本上局限在冲淡水势力影响范围内,其高丰度的水域是沿岸水团的一个重要标志。