Preliminary study of the retention mechanism of planktonic copepods in the Jiulong Estuary in China   总被引：1，自引：0，他引：1  

SHANG Xu  WANG Guizhong  LI Shaojing  GUO Donghui 《海洋学报(英文版)》2007,26(4):156-163

The horizontal and vertical distribution patterns of five planktonic copepods,Calanus sinicus, Acartia pacifica, Tortanus derjugini, Acartiella sinensis and Pseudodiaptomus poplesia, predominant in the Jiulong Estuary, were investigated from May 2003 to April 2004. The results showed that the distribution of these copepods was related to the tidal period but that each species had its own specific pattern. C. sinicus showed no tidal vertical migration behavior and was thought to be a non-resident species in this estuary. Among Acartia pacifica,T. derjugini,Acartiella sinensis, more individuals occurred in the surface than in the bottom waters during flood tide, and the pattern was reversed during ebb tide. The epibenthic copepod P. poplesia usually remained in the bottom waters in the upstream part of the estuary, but it displayed strong tidally-oriented vertical migration in the middle reaches of the estuary.Taking into account the hydrographic characteristics of the Jiulong Estuary,it was hypothesized that the planktonic copepods in this estuary had more or less adopted the mechanism of vertically migrating to the surface waters during flood tide in order to make use of the inflowing tide, and then sinking to the bottom during ebb tide to avoid being carried out of the estuary by net outflow.  相似文献   

黄海小拟哲水蚤(Paracalanus parvus)丰度的季节变化   总被引：1，自引：0，他引：1  

张芳  孙松  杨波  吉鹏 《海洋与湖沼》2006,37(4):322-329

根据2001年3、5、6、7、8、11月黄海6个航次的大容量采水器(59L)中浮游动物的样品资料,对小拟哲水蚤无节幼体及该种桡足幼体和成体丰度的时空分布格局进行了研究。结果表明,小拟哲水蚤桡足幼体和成体3月份在整个黄海测区内的丰度较低;5月份除山东半岛南岸三个高值站位,外海相对比近岸高;6、7月份的丰度水平最高,7月份航次中,丰度最高的站位可达10555ind/m3,整个测区内,海州湾内侧高于外侧;8月份,测区内的丰度分布相对均匀,丰度较低;11月份,测区小拟哲水蚤的分布相对也比较均匀。小拟哲水蚤无节幼体的丰度在黄海测区内的分布格局与该种桡足幼体及成体丰度的分布格局在3、5、6、7月份比较吻合,在8、11月份吻合程度较差。不同月份小拟哲水蚤的分布与温度、盐度、叶绿素a的关系不尽相同;其受温度的影响相对较大,受盐度、叶绿素a影响较小。  相似文献   

Pelagic processes and vertical flux of particles: an overview of a long-term comparative study in the Norwegian Sea and Greenland Sea     

B. von Bodungen  A. Antia  E. Bauerfeind  O. Haupt  W. Koeve  E. Machado  I. Peeken  R. Peinert  S. Reitmeier  C. Thomsen  M. Voss  M. Wunsch  U. Zeller  B. Zeitzschel 《International Journal of Earth Sciences》1995,84(1):11-27

Pelagic processes and their relation to vertical flux have been studied in the Norwegian and Greenland Seas since 1986. Results of long-term sediment trap deployments and adjoining process studies are presented, and the underlying methodological and conceptional background is discussed. Recent extension of these investigations at the Barents Sea continental slope are also presented. With similar conditions of input irradiation and nutrient conditions, the Norwegian and Greenland Seas exhibit comparable mean annual rates of new and total production. Major differences can be found between these regions, however, in the hydrographic conditions constraining primary production and in the composition and seasonal development of the plankton. This is reflected in differences in the temporal patterns of vertical particle flux in relation to new production in the euphotic zone, the composition of particles exported and in different processes leading to their modification in the mid-water layers.In the Norwegian Sea heavy grazing pressure during early spring retards the accumulation of phytoplankton stocks and thus a mass sedimentation of diatoms that is often associated with spring blooms. This, in conjunction with the further seasonal development of zooplankton populations, serves to delay the annual peak in sedimentation to summer or autumn. Carbonate sedimentation in the Norwegian Sea, however, is significantly higher than in the Greenland Sea, where physical factors exert a greater control on phytoplankton development and the sedimentation of opal is of greater importance. In addition to these comparative long-term studies a case study has been carried out at the continental slope of the Barents Sea, where an emphasis was laid on the influence of resuspension and across-slope lateral transport with an analysis of suspended and sedimented material.  相似文献   

深海锰结核中螺旋状超微生物化石的发现及其意义   总被引：24，自引：2，他引：24  

张富生  周旅复 《高校地质学报》1995,1(1):109-116

对东太平洋深海瘤状锰结核透射电的系统观察和分析表明，瘤状锰结核的包壳，即奇异叠层石的建造者米级的螺旋状微生物、螺旋状微生物体的菌落呈圆盘状至不规则分枝状，菌落主下陷，营养菌丝体呈辐射状从中央向周围生长，营养菌丝体的束宽度为１７－６０ｎｍ，呈双分叉。生殖菌丝体由粗细不等的螺旋状丝体组成。螺旋状丝体的宽度３－２５ｎｍ，长度为３６－２００ｎｍ。螺环宽度为２－４ｎｍ、螺旋状生殖丝体分太、孢囊呈球形，深陷于  相似文献   

The economics of the Swedish individual transferable quota system: Experiences and policy implications     

《Marine Policy》2016

Sweden and other European Union countries are currently carrying out extensive work aimed at improving the marine and freshwater environment. The adaptive management approaches typically used for this require the development of new policy instruments and measures when needed, but also evaluations of instruments and measures already in use or under way. This paper reports on a study of the Swedish individual transferable quota system introduced in 2009 for the pelagic fishery. The new system was motivated mainly by economic arguments and, thus, the need to get incentives right. Despite this, the design of the Swedish system weakened the intended incentive effects in several ways, compared with the foreign systems that served as models. Moreover, the information needed for future evaluations was not collected, even though the need for future evaluations had been expressed explicitly and the data needs for this could be identified at the time that the system was introduced.  相似文献   

Stakeholder participation in the management of North East Atlantic pelagic fish stocks: The future role of the Pelagic Regional Advisory Council in a reformed CFP     

Aukje Coers  Jesper Raakjær  Christian Olesen 《Marine Policy》2012,36(3):689-695

When the Regional Advisory Councils (RACs) were created during the last reform of the Common Fisheries Policy (CFP) in 2002, it was recognised that in addition to the five geographically orientated stakeholder lead advisory bodies, a separate RAC dedicated exclusively to pelagic fisheries was needed because of it being so distinctly different from other fisheries. Pelagic fishing is different mostly due to the fact that the targeted fish species behave in a unique manner by grouping in schools in mid-water unlike other commercially targeted fishes, which typically reside on or near the ocean floor. For this reason, as well as the fact that they are usually widely distributed, researching and managing this dynamic group of fishes across the borders of many countries requires a unique approach. Fortunately, despite these complexities, policy makers have succeeded to establish a reasonably well functioning management framework, which has lead to the situation that most pelagic fish stocks are harvested biologically sustainable. While a majority of Europe's fish stocks still need rebuilding, and the main aim accordingly is to reduce fishing mortality, the current focus for pelagic fish stocks is to improve the performance of already implemented Long Term Management plans in terms of their biological as well as social and economical objectives. This paper reflects upon experiences of the Pelagic Regional Advisory Council (PRAC) in its role as advisor to the EU institutions. Subsequently, in the context of ideas presented in the European Commission's Green paper, the authors discuss the future of the PRAC and conclude that its main development potential lies not with the current EU's CFP reform, but rather should be sought in a wider international context.  相似文献   

Zooplankton response to long-term liming: Comparison of 15 limed and 15 reference lakes in Sweden     

Gunnar Persson 《Limnologica》2008,38(1):1-13

Taxonomic composition and variation in density of zooplankton were studied since 1989 to investigate possible long-term effects of anthropogenic acidification and liming in Sweden (the Integrated Studies of the Effects of Liming in Acidified Water (ISELAW) programme). In the programme, 15 long-term (18-31 years) limed lakes were studied in parallel with 8 untreated circumneutral lakes (representing target conditions) and 7 acid lakes. Five-year means from these lakes were used to evaluate differences between the three lake groups. Water chemistry (including trace metals), phytoplankton, invertebrate predators and fish were also monitored. Older records from 8 of the limed lakes obtained during the acid period preceding the initial liming were compared with records from the limed period. The number of taxa more than doubled in 6 lakes after liming. Total present-day zooplankton biovolume showed insignificant differences between the neutral and limed groups, i.e., conformed with the target conditions. Trace metals, including inorganic aluminium, appeared in low concentrations in limed and neutral lakes whereas zooplankton in one acid lake was Al-intoxicated. Daphnid populations in 4 other lakes may suffer from effects of high Cd or Cu concentrations. “Bottom-up” regulation of the zooplankton biovolumes was indicated by positive regressions between total phosphorus-phytoplankton and phytoplankton-zooplankton. Corresponding tests showed no “top-down” regulation of zooplankton by fish and of phytoplankton by zooplankton. Biomasses of planktivorous fish were higher in the neutral reference lakes than in both the acid and the limed lake groups, but neither zooplankton density and biovolume nor mean body size were lower in the neutral references. A higher production and turnover of zooplankton in neutral reference lakes may explain similar densities and structure of zooplankton in spite of a heavier predation pressure.  相似文献   

火腿伪镖水蚤对抑食金球藻中国株的摄食行为及摄食后的表现     

何学佳  韩棣棣  韩留玉  吕颂辉 《海洋学报(英文版)》2018,37(4):69-76

全球河口海域屡屡爆发褐潮,但我们对致因种抑食金球藻和浮游桡足类之间的营养关系还不甚清楚。我们就浮游桡足类火腿伪镖水蚤摄食抑食金球藻中国株的单种或混合饵料时的摄食行为和生长、发育等表现进行了研究。研究发现：火腿伪镖水蚤的无节幼体、桡足幼体和成体摄食单种抑食金球藻饵料时,摄食率和食物浓度之间的关系符合米氏方程。较之桡足类幼体和成体,无节幼体摄食抑食金球藻时的I_max（最大摄食率）值最大,同时大于其摄食中肋骨条藻的I_max值。通常情况下,火腿伪镖水蚤在摄食抑食金球藻和中肋骨条藻的混合饵料时避食抑食金球藻,但于无节幼体,这种情况并不明显。无节幼体摄食单种抑食金球藻饵料在无节幼体期末期死亡,无法进入桡足类幼体期,与饥饿状态下的个体相似。但是,饵料中抑食金球藻的存在对桡足幼体的生长无明显效应,但却极大地减少了成体的生殖率。我们的研究表明火腿伪镖水蚤无节幼体,在褐潮的控制中有潜在作用,然而,这种潜在控制作用由于桡足类种群的衰落难以持续。  相似文献   

Dietary separation between co-occurring copepods in a food-limited tropical coral reef of the Sanya Bay     

胡思敏  李涛  刘胜  黄晖 《海洋学报(英文版)》2020,39(4):65-72

Food differentiation among coexistent species in the field is important strategy for copepods to acquire materials and maintain population stabilization.In situ diet analysis of co-occurring six copepod species in coral waters of the Sanya Bay was conducted using a PCR protocol based on 18 S ribosomal gene.Various prey organisms were uncovered,including dinoflagellate,diatom,green algae and plant,protozoa and metazoan.All these spatially coexisting six species showed different dietary diversity,with the food niche breadth(B)ranging from 1.00(Temora turbinate in morning)to 10.68(Calanopia elliptica in night).While food overlap between all these copepods were low,with the average value of the diet niche overlap index being approximately 0.09.Even temporally co-existing species sampled from the same time point fed on different groups of prey items with the food overlap index of 0.04 to 0.07 in midday and night but 0 in morning.As the most important dominant copepod in the Sanya Bay,Subeucalanus subcrassus seems to be capable to regulate its feeding,by exhibiting a rhythm of herbivorous feeding in midday and carnivorous feeding in morning and night,to better coordinate with other competitors for utilization of food resources.For most copepods,none of the prey items belonged to the dominant phytoplankton in the ambient water,indicating that copepod can better their survival by widening the choice of potential food resources in food limited environment.The dietary separation observed here might be important strategy for copepod to maintain population stabilization and thriving in the Sanya coastal waters.  相似文献   

东海浮游翼足类(Pteropoda)环境适应类型的划分     

徐兆礼 《海洋与湖沼》2008,39(4)

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,采用浮游翼足类物种丰度和同步温、盐度数据,构造相关数学模型,计算其最适温度和最适盐度.同时参考生态特征分析,划分东海浮游翼足类物种生态类型.结果表明,东海浮游翼足类鉴定到种的共有20种.在翼足类优势种中,尖笔帽螺(Creseis acicula)和马蹄螔螺(Limacina trochiformis)是具有广温广盐特征的亚热带外海种;拟海若螺(Paraclione longicaudata)、球电螺(Cavolinia globulosa)和胖螔螺(Limacina inflata)是热带大洋种;强卷螺(Agadina syimpsoni)、厚唇螺(Diacria trispinosa)、龟螺(Cavolinia tridentata)和角长吻龟螺(C.longirostris var.angulata)是适温较低的亚热带外海种;其余都是典型的亚热带外海种.东海浮游翼足类总体上显示出典型的暖水性生态类型.拟海若螺和胖螔螺具有较小的盐度分布区间,是台湾暖流或黑潮暖流向北扩展的指示种.现代东海浮游翼足类优势种的地理分布,与古代东海底质沉积物分析结论相一致.浮游翼足类种类生态类型的划分在古海洋气象、海洋地质、海洋物理和海洋生物等学科研究中具有重要的意义.  相似文献