Revisiting Peruvian anchovy (Engraulis ringens) trophodynamics provides a new vision of the Humboldt Current system   总被引：6，自引：4，他引：2  

Pepe Espinoza  Arnaud Bertrand   《Progress in Oceanography》2008,79(2-4):215

The Peruvian anchovy or anchoveta (Engraulis ringens) forages on plankton and is a main prey for marine mammals, seabirds, fish, and fishers, and is therefore a key element of the food web in the Humboldt Current system (HCS). Here, we present results from the analysis of 21,203 anchoveta stomach contents sampled during 23 acoustic surveys over the period 1996–2003. Prey items were identified to the genus level, and the relative dietary importance of different prey was assessed by determination of their carbon content. Variability in stomach fullness was examined relative to the diel cycle, the distance from the coast, sea surface temperature, and latitude, using generalized additive models (GAMs). Whereas phytoplankton largely dominated anchoveta diets in terms of numerical abundance and comprised >99% of ingested prey items, the carbon content of prey items indicated that zooplankton was by far the most important dietary component, with euphausiids contributing 67.5% of dietary carbon followed by copepods (26.3%). Stomach fullness data showed that anchoveta feed mainly during daytime between 07h00 and 18h00, although night-time feeding also made a substantial contribution to total food consumption. Stomach fullness also varied with latitude, distance from the coast, and temperature, but with substantial variability indicating a high degree of plasticity in anchoveta feeding behaviour. The results suggest an ecological role for anchoveta that challenges current understanding of its position in the foodweb, the functioning of the HCS, and trophic models of the HCS.  相似文献   

Seagrass as the main food source of Neaxius acanthus (Thalassinidea: Strahlaxiidae), its burrow associates, and of Corallianassa coutierei (Thalassinidea: Callianassidae)     

Dominik Kneer  Harald Asmus  Jan Arie Vonk 《Estuarine, Coastal and Shelf Science》2008,79(4):620-630

Burrows of the thalassinidean shrimps Neaxius acanthus and Corallianassa coutierei are striking aspects in tropical seagrass beds of the Spermonde Archipelago, Indonesia. Burrow construction, behaviour, burrow type and associated commensal community were investigated to clarify the ecological role and food requirements of these shrimps and their commensals. Gut content analysis and stable-isotope data were used to unravel the food sources and the trophic interactions among the commensal community.Individuals of Neaxius acanthus were caught on Bone Batang Island. In narrow aquaria filled with sediment they constructed burrows resembling those found in the field. During burrow construction and maintenance only little sediment was brought to the surface, most was sorted and compacted to create a distinct lining. Maintenance work by single shrimps typically took about 5 min, after which the shrimp walked up to the entrance and rested for a similar period of time. There were no differences in behaviour between day and night. Intrasexual encounters inside the burrow were characterised by a high level of aggression and all resulted in one participant being driven out of the burrow. Intersexual encounters led to coexistence with both animals taking turns in burrow maintenance and guarding the entrance. Offered seagrass leaves were pulled underground, cut into pieces and eventually integrated into the lining. Burrows of Corallianassa coutierei resembled a deep U-shape. Chambers branching off halfway down and at the deepest point contained seagrass fragments. All steep parts of the burrow were lined similar to burrows of N. acanthus.No commensals were found associated with Corallianassa coutierei. However, burrows of Neaxius acanthus in the field typically contained a pair of shrimps, up to 8 individuals of the commensal bivalve Barrimysia cumingii and large numbers of gammarid amphipods. Other animals found associated with the burrow were the goby Austrolethops wardi, a palaemonid shrimp species and two species of tube-building polychaetes, one of which was also found as an epibiont on N. acanthus.Stable-isotope and gut content analyses indicate that the diet of Neaxius acanthus, its commensal Austrolethops wardi, and Corallianassa coutierei is mainly derived from detrital seagrass leaves, with a potential contribution of sediment organic matter and seagrass epiphytes. In contrast the isotopic signature of Barrimysia cumingii suggests the presence of symbiotic sulphide metabolism bacteria. This study underlines that, besides their interactions with the surrounding ecosystem, thalassinid shrimp burrows play an important role as a sub-habitat with a unique associated fauna.  相似文献   

坠落物体产生的冲击荷载对海底管线的损伤分析     

张海  刘蕊  王秀存  田英辉 《海洋技术学报》2008,27(1):77-80

提出了坠落物体产生的冲击荷载对海底管线的损伤一种简易可行的分析方法。对坠落物体进行分类,然后进行运动形式分析,求得冲击速度,根据动力问题控制方程,使用著名商业软件‘ANSYS/LS-DYNA’,‘LS-DYNA’是世界上最著名的通用显式动力分析程序,对实际的工程算例进行了仿真模拟分析。得到的计算结果与已有经验方程结果是基本一致的。该方法可以和一般风险分析方法一起用作海底管线损伤分析和保护措施校核分析。  相似文献   

Evaluating the efficacy of technical measures: a case study of selection device legislation in the UK Crangon crangon (brown shrimp) fishery     

Catchpole  Tom L.; Revill  Andrew S.; Innes  James; Pascoe  Sean 《ICES Journal of Marine Science》2008,65(2):267-275

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Behavioural adaptations in talitrids from two Atlantic beaches     

Claudia Rossano  Simone Gambineri  Lucia Fanini  Virginie Durier  Colette Rivault  Felicita Scapini 《Estuarine, Coastal and Shelf Science》2009

The aim of the present study was to test sun orientation and rhythmic activity of two sandhopper populations from two Atlantic macro-tidal beaches. A population from Le Verger beach (orientated to 346°, Ille et Vilaine, Brittany, France) and a population from Damgan (orientated to 195°, Morbihan, Brittany, France), were tested on the beach under clear sky discriminating for landscape vision. For both populations locomotor activity rhythm was recorded in the laboratory. The two beaches differed for climatic features, tidal range and for human use. Both talitrid populations resulted very well orientated toward the shoreline, and both used solar position and landscape vision to orient. However the multiple regression analysis of orientation with climatic features showed a different use of local cues by the two populations and a slight influence of tidal regime (ebbing and rising tide), in spite of the supralittoral zonation of sandhoppers. In the laboratory they showed a well defined rhythmic behaviour as well as a bimodal rhythmicity, explained as a tidal one. These results are a new brick in the complex picture of orientation and rhythm studies on sandy beach invertebrates.  相似文献   

防海胆食害藻礁的设计及实验研究     

田涛  张秀梅  张沛东  杨宝清  陈勇 《中国海洋大学学报(自然科学版)》2008,38(1):68-72

人工藻礁是进行藻场建设的重要手段,但由于海胆等食藻类生物的摄食,将会影响藻类的生长,从而影响人工藻场的建设效果.为解决人工藻场建设中海胆的食害问题,从礁体自身设计出发,实验设计了8种不同形状的藻礁,选用光棘球海胆和中间球海胆为实验对象,观察比较了不同形状藻礁对海胆攀爬的阻碍效果,实验发现:侧周面为锯齿形或侧周面缠挂多孔柔性材料的礁型可有效阻止海胆攀爬,起到防止海胆摄食礁顶藻类的目的.研究结果为人工藻礁的设计提供了参考依据.  相似文献   

扇贝多肽在体外对免疫细胞活性的影响及其抗紫外线的氧化损伤作用   总被引：9，自引：2，他引：9  

刘晓萍  王玉贞  韩彦弢  于业军  王跃军  王春波 《海洋与湖沼》2001,32(4):414-419

采用噻唑盐（MTT）比色方法研究在紫外线辐射损伤条件下扇贝多肽对免疫细胞的保护作用，并探讨扇贝多肽对胸腺细胞和脾细胞活性的影响，结果表明，扇贝多肽具有抗紫外线氧化损伤的作用，可减轻或抑制紫外线对胸腺细胞和脾细胞的氧化损伤，并且呈剂量依赖性，扇贝多肽在0.5%-10.0%的浓度范围内，其抗氧化能力随浓度的增高而增强，在正常条件下可显著增强免疫细胞的活性，并且可拮抗雌激素对免疫细胞的抑制作用。提示扇贝多肽不仅具有抗氧化损伤作用，而且具有免疫增强使用。  相似文献   

抛锚撞击水下管汇的数值模拟研究     

娄敏  王艳红  明海芹 《海洋工程》2016,34(4):38-46

船舶抛锚撞击水下管汇会影响到管汇的正常作业,基于ANSYS/LS-DYNA动力学分析软件,建立锚-水下管汇-海床土体的三维有限元模型,对抛锚碰撞水下管汇的过程进行数值仿真。通过求解水下管汇受碰撞后的等效应力、应变的时间历程及受撞击部位的凹陷损伤深度,发现最大等效应力点出现在管汇与锚接触位置处,管汇的碰撞部位最终发生凹痕变形。同时讨论锚与管汇接触面的形状以及海床土体对水下管汇损伤程度的影响,当冲击能量相同时,锚与水下管汇的碰撞接触面积越小,水下管汇的损伤深度就越大;当锚与管汇接触的接触面积相同时,冲击能量越大,水下管汇的损伤变形越大。海床土体的剪切弹性模量对管汇的凹陷损伤深度以及最大等效应力影响与冲击能量有关,海床土体的内摩擦角对管汇的碰撞影响较小。  相似文献   

白藜芦醇对饥饿条件下厚壳贻贝(Mytilus coruscus)抗氧化能力的影响          下载免费PDF全文

陈传悦  谢兵  孙闻婧  廖智  严小军  张晓林 《海洋与湖沼》2023,54(1):266-275

饥饿胁迫引起的肥满度下降及收割延迟是导致贻贝养殖产量下降的主要原因之一。探究白藜芦醇(Resveratrol,RES)对饥饿条件下贻贝抗氧化能力的影响,揭示贻贝对饥饿胁迫的响应机制,对指导贻贝健康养殖具有重要意义。在饥饿胁迫条件下,分别采用10、20、50、100μmol/LRES处理厚壳贻贝,9d后采集贻贝组织样品并进行氧化应激指标检测。结果表明,饥饿胁迫显著增加厚壳贻贝组织中丙二醛(MDA)含量,同时显著降低过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)、碱性磷酸酶(AKP)和酸性磷酸酶(ACP)活性和还原性谷胱甘肽(GSH)含量。RES处理后,厚壳贻贝组织中MDA含量显著降低,但随着RES浓度的增加显著升高;性腺和鳃中CAT、SOD、GSH-PX、AKP、ACP活性和GSH水平、后闭壳肌中CAT、AKP活性和GSH水平以及外套膜中CAT、SOD、GSH-PX、ACP活性和GSH水平均随着RES处理浓度的增加先升高后降低。此外,10或20μmol/LRES处理能显著减轻饥饿胁迫引起的贻贝性腺中滤泡降解、配子退化及鳃丝纤毛脱落及结构受损;且各组贻贝后闭壳肌和外套膜组织形态学无明显变化。研究结果表明饥饿胁迫能显著抑制厚壳贻贝的抗氧化能力,但10或20μmol/LRES处理可减轻饥饿胁迫诱导的脂质过氧化和组织氧化应激损伤,且厚壳贻贝对饥饿胁迫诱导的氧化应激损伤表现出一定的组织差异性。  相似文献   

基于遥感和GIS的建筑物震害损失评估方法研究与实现   总被引：9，自引：0，他引：9  

王龙  王晓青  丁香  窦爱霞 《地震》2007,27(4):77-83

介绍了一种使用遥感技术进行震后损失快速评估的方法,评估流程包括震害提取和损失评估两个部分。评估方式根据需求可以分为基于震害指数的评估和基于图像分类结果的评估两种模式,前者通过震害指数与烈度的关系得到地面居民住地的宏观震害情况,结合地震应急数据进行建筑物损失评估;后者采用图像处理技术,选取典型震害样本以图像分类技术得到地面居民住地的分级分类的震害结果,然后计算参数进行损失评估。损失评估的计算根据震害提取模式而不同。这种遥感震害评估方法和计算流程结合了遥感和GIS技术,以满足实际工作需求目标,提高了震害提取的自动化程度,实现多人工作模式,通过有效率的人机交互来提高遥感震害评估的速度。  相似文献