Living on the edge: feeding of subtropical open ocean copepods   总被引：2，自引：0，他引：2  

Gustav-Adolf Paffenhöfer  Maria Grazia Mazzocchi  & Mimi W. Tzeng 《Marine Ecology》2006,27(2):99-108

The objective of this study was to provide quantitative information on environmental feeding rates of warm water oceanic epipelagic copepods. We determined clearance rates at 23 °C for various particle size ranges in shipboard studies in the western oligotrophic subtropical Atlantic Ocean for females of the calanoid species Clausocalanus furcatus and Mecynocera clausii. These in situ clearance rates were then applied to the various particle size ranges of environmental particle spectra of auto‐ and heterotrophs at different depths from three stations in the western Atlantic. After calculating the metabolic demands of each of these two copepod species and applying an assimilation efficiency of 90%, we determined that C. furcatus meets its metabolic demands in all six cases, and M. clausii in two of six cases. Clausocalanus furcatus would also meet its energy demands at 25 °C, where it is often found, while M. clausii at 20 °C, where it is regularly found, would cover its metabolic needs in four of six cases. It is hypothesized that these species, and most likely most of the other co‐occurring copepod species, are limited in their abundance by food availability, or, better said, are ‘living on the edge’ in relation to food abundance.  相似文献   

南极鳕鱼食性的初步研究   总被引：1，自引：0，他引：1       下载免费PDF全文

黄凤鹏  吴宝铃 《极地研究》1992,4(4):51-54

对 1 98 8年 1 2月 2 5 - 2 6日在长城站附近海区采集的南极鳕鱼胃含物进行了初步分析。结果表明食物的主要种类有底栖动物 6种和钩虾多种 ,浮游动物 3种 ,海藻 8种。底栖动物占食物量的 5 2 .82 % ,其中帽贝占 1 0 .77% ,钩虾类占 3 3 .78% ;浮游动物占 6 .74% ,其中磷虾占 5 .47% ;海藻占 3 5 .49% ,其中紫菜占 6 .3 5 % ,倒卵银杏藻占 1 8.96 %。鱼的体重与体长相关显著 ,相关系数是 0 .96。分析结果反映了南极鳕鱼的食物来源主要是底栖动物和海藻  相似文献   

Feeding ecology of the mud shrimp Solenocera melantho in the East China Sea          下载免费PDF全文

Hui Yu Li  Jian Zhong Ling  Li Ping Yan  Jia Hua Cheng  Fen Hu 《Marine Ecology》2016,37(2):380-391

The feeding habits of the mud shrimp Solenocera melantho were studied in the East China Sea by analysing 720 stomach contents and comparing diet composition and prey diversity among seasons, sexes and size classes. Feeding activity was linked to season and ovarian condition. The stomach fullness was high during spring and summer and low in fall. Females with advanced ovaries also displayed low stomach fullness, which suggests that feeding activity is affected by the reproductive cycle. The diet of S. melantho consisted of 42 different prey categories, primarily smaller crustaceans, Foraminifera, polychaetes, mollusks and fishes (larvae and eggs). Crustacea,Foraminifera and polychaetes together constituted the dominant prey groups, accounting for 75% of total prey abundance and >50% of total prey occurrence. Diet composition differed among seasons between sexes and size classes. Females and males consumed the same prey items but with different orders of importance. In terms of body size, the small shrimps preferred relatively small food items, such as Foraminifera and algae, whereas larger shrimps preferred polychaetes and crustaceans. Trophic diversity varied among the seasons within both sexes and size classes, with the highest values being observed in fall. Niche overlap was high within both sexes and size classes among seasons (0.6051–0.8740).  相似文献   

Food preferences and rhythms of feeding activity of two co‐existing demersal fish,the longspine snipefish,Macroramphosus scolopax (Linnaeus, 1758), and the boarfish Capros aper (Linnaeus, 1758), on the Mediterranean deep shelf          下载免费PDF全文

Paolo Carpentieri  Natalia Serpetti  Francesco Colloca  Alessandro Criscoli  Giandomenico Ardizzone 《Marine Ecology》2016,37(1):106-118

The feeding behaviour of two potentially competing species, the longspine snipefish, Macroramphosus scolopax, and the boarfish Capros aper was examined. While both species are very abundant along the Mediterranean coast and are regularly caught by demersal trawlers, they are of no commercial value. The diets of boarfish and longspine snipefish were investigated from samples collected between January 2001 and May 2002. Variations in the diet with fish size and season, as well as diet overlap and diversity were explored. Mysid shrimps, amphipods and gastropods were the most important food items in the diet of longspine snipefish. During ontogenetic development, M. scolopax occupies different trophic levels: the diet shifts from being predominantly composed of mysids (Anchialina agilis, Lophogaster typicus, Erythrops sp., Leptomysis spp.) in the smaller longspine snipefish [<6.5 cm total length (TL)] towards decapods (Anapagurus laevis) and amphipods (Leucothoe incisa, Eusirus longipes, Hyperidea) in the larger individuals (>6.5 cm TL). Crustacean decapods and copepods were the most important prey in the stomachs of boarfish. Mysids (Lo. typicus), euphausiids and nematodes were present in the larger individuals (>8 cm TL). A more generalist diet, still containing copepods, crustacean decapods, gastropods (Limacina retroversa) and a large variety of amphipods (e.g. Phtysica marina, Stenotoe bosphorana) and mysids (e.g. A. agilis, Leptomysis spp., Erythrops sp.), dominated the diet of C. aper between 2 and 8 cm TL. Diet overlap between longspine snipefish and boarfish was very low and the differences in stomach species diversity were explained by season and fish size.  相似文献   

Connectivity and stock composition of loggerhead turtles foraging on the North African continental shelf (Central Mediterranean): implications for conservation and management          下载免费PDF全文

Sami Karaa  Fulvio Maffucci  Imed Jribi  Marco Alberto Bologna  Marco Borra  Elio Biffali  Mohamed Nejmeddine Bradai  Sandra Hochscheid 《Marine Ecology》2016,37(5):1103-1115

The loggerhead turtle, Caretta caretta, is a highly migratory species with a complex life cycle that involves a series of ontogenetic habitat shifts and migrations. Understanding the links amongst nesting populations and foraging habitats is essential for the effective management of the species. Here we used mixed stock analysis to examine the natal origin of loggerhead turtles foraging on the North African continental shelf off Tunisia, one of the most important Mediterranean neritic habitats. An 815‐bp fragment of the mitochondrial DNA control region was sequenced from 107 individuals sampled from 2007 to 2009. No temporal variation in haplotype frequencies was detected. Juveniles (n = 87) and adults (n = 23) exhibited weak but significant genetic differentiation that resulted in different stock compositions. Libya was the main source population but the proportion of turtles from this rookery was higher in adults (median = 80%) than in juveniles (median = 35%). Western Greece was the second most important contributing population. Juvenile stock composition derived from mixed stock analysis and the estimates produced by numerical simulation of hatchling dispersion in the Mediterranean Sea were significantly correlated, supporting the recent theory that loggerheads imprint on possible future neritic habitats during the initial phase of their life. This association was not significant for adults, suggesting that other factors contribute to shaping their distribution. Overall, our results show that human activities on the South Tunisian continental shelf pose an immediate threat to the survival of the Libyan rookery.  相似文献   

温度对厚壳贻贝(Mytilus coruscus)鳃组织纤毛结构及摄食率的影响机制研究     

梁泽玮  李伟业  殷小龙  徐羡  孙闻婧  王雪儿  陈传悦  廖智  严小军  张晓林 《海洋与湖沼》2024,55(2):471-478

纤毛是着生在贻贝鳃上感知外界物理和化学信号并帮助食物转运的一类重要细胞结构, 温度的变化会改变纤毛的形态和生理生化特征, 从而影响贻贝的摄食行为。为探究不同温度下厚壳贻贝的摄食率变化, 以及温度对纤毛的形态、酶活和相关基因表达的影响, 实验设置16、26和32 °C三种温度处理厚壳贻贝, 处理24 h后测定1 h内每个处理组的摄食率, 同时采用组织学方法对各处理组鳃上的纤毛形态结构进行观察,并测定鳃组织的抗氧化酶活力和纤毛相关基因tekt1、tekt2、tekt3、tekt4、caf58、caf100、dnah、rsph99和ift74的表达变化。实验结果显示, 32 °C处理组厚壳贻贝的摄食率显著低于其他两组(P<0.05), 且32 °C处理组贻贝鳃上的前纤毛、侧纤毛以及纤毛细胞受损严重并部分脱落, 血腔间隙破损暴露, 而其余两组鳃上纤毛形态较为正常; 不同温度处理下鳃组织的过氧化氢(H₂O₂)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)活力呈现温度特异性; 与16 °C处理组相比, 26 °C处理组中除tekt4和ndah外其他7个纤毛相关基因表达均显著上调, 32 °C处理组除tekt1外其余8个基因表达均显著下调(P<0.05)。上述结果表明, 32 °C高温处理对贻贝鳃上纤毛造成严重损伤, 导致纤毛运动、纤毛再生和纤毛感知功能均受到一定程度的抑制,从而影响食物颗粒的运输, 造成摄食率的降低。  相似文献   

Grazing on microcystin-producing and microcystin-free phytoplankters by different filter-feeders: implications for lake restoration     

Luis M. Dionisio Pires  Babette M. Bontes  Larysa Samchyshyna  Jacco Jong  Ellen Van Donk  Bas W. Ibelings 《Aquatic Sciences - Research Across Boundaries》2007,69(4):534-543

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沙漠地区资源高精度三维地震勘探技术应用     

吴守华 《中国煤田地质》2006,18(3):57-59

内蒙古毛乌素沙漠西南边缘勘探区，地表大部分为固定、半周定沙丘．少部分为随季风流动的供状沙丘及新月型沙丘，地形起伏剧烈。该勘探区存在着检波器耦合难、实施变脱难、地震浒号屏蔽作用姓、心始记录面貌差、干扰波复杂、资料处理难度大等问题。为此采取了加长检波器尾锥、加大井深和药量、综合应用多种静校正技术以及与提高信噪比为主的资料处理流程等技术措施，经验证术措施采用合理，勘探成果准确可靠。  相似文献   

Temporal variation in feeding rhythms in a tidal marsh population of the common goby <Emphasis Type="Italic">Pomatoschistus microps</Emphasis> (Kroyer, 1838)     

Henrietta Hampel  Andre Cattrijsse 《Aquatic Sciences - Research Across Boundaries》2004,66(3):315-326

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海洋尖尾藻的摄食   总被引：2，自引：0，他引：2  

安鑫龙  李雪梅  李亚宁 《海洋技术学报》2012,31(1):100-102

海洋尖尾藻(Oxyrrhis marina)是世界广布的一种赤潮原因甲藻。以亚心形扁藻(Platymonas subcordiformis)和米氏凯伦藻(Karenia mikimotoi)等6种海洋微藻为饵料对海洋尖尾藻的摄食进行了显微观察。结果表明:海洋尖尾藻的摄食方式为滤食,整个摄食过程分为水流形成和胞吞作用两个阶段;水流形成依靠海洋尖尾藻整个细胞围绕饵料藻旋转实现,胞吞器官为纵沟;每个海洋尖尾藻细胞内可同时容纳饵料藻一至数个。此外,分属于不同门类的供试藻均能被海洋尖尾藻摄食。  相似文献