基于脂肪酸标记法和碳氮稳定同位素比值法的东海水母常见种的食性分析

采用脂肪酸标记法和碳氮稳定同位素比值法研究了东海6个水母常见种的食性。结果表明,6种水母的总脂肪酸含量都不高,说明作为饵料,水母不能够给捕食者提供较多的脂类营养物质。蝶水母(Ocyropsis crystallina)、瓜水母(Bero cucumis)和四叶小舌水母(Liriope tetraphylla)的脂肪酸组成较为相近,它们更多地通过捕食食物链获得有机质。同时,这几种小型水母摄食浮游植物(主要是硅藻和甲藻)比其它几种水母多;另外,它们对植食性桡足类也有一定的摄食。4月份墨绿多管水母(Aequorea coerulescens)主要通过腐生食物链获取有机质;另外,其对植食性桡足类也有一定的摄食。双生水母(Diphyidae spp.)参与腐生食物链也较多;另外,20:1+22:1含量较低指示了其对植食性桡足类几乎不摄食。蝶水母、瓜水母、四叶小舌水母和沙海蜇(Nemopilema nomurai)的δ13C更接近于陆源的C4植物的δ13C,说明其受陆源影响较大。δ15N特征结果表明,蝶水母、瓜水母和四叶小舌水母(Liriope tetraphylla)在浮游食物网中均处于较高营养级,沙海蜇虽个体较大,但由于其摄食器官较小,故其与这3种小型水母的营养地位相近。并且相对于其它几种水母,沙海蜇细菌脂肪酸标记更为明显。     

海洋浮游纤毛虫摄食研究综述

海洋浮游纤毛虫是海洋微食物环的重要组成部分,同时也是连接海洋微食物环和经典食物链的重要环节。研究海洋浮游纤毛虫的摄食情况对了解海洋浮游纤毛虫在海洋浮游生态系统物质循环和能量流动中的作用有重要意义。主要研究内容包括纤毛虫的食性、纤毛虫对不同饵料的摄食强度(摄食率、清滤率)和选择性、影响摄食的因素及摄食后的同化和排遗。海洋浮游纤毛虫食性的研究方法主要有两种,分别为体内饵料颗粒法和维持生长法。实验室内估算纤毛虫摄食率和清滤率主要有两种方法,分别为饵料浓度差减法和体内饵料颗粒增多法。可以用特定体积清滤率和特定生物量摄食率来比较不同种纤毛虫的清滤率和摄食率。已有研究结果表明,纤毛虫的饵料包括较小的纤毛虫、硅藻、甲藻、鞭毛虫、聚球藻、原绿球藻和细菌等。纤毛虫的摄食率范围为0.1—920 cells/(ciliate h),清滤率范围为0—110μL/(ciliate h)。纤毛虫对饵料的粒径和化学性质均有选择性。饵料浓度、温度、光线、扰动以及纤毛虫所处的生长阶段都会对纤毛虫的摄食率产生影响。不同种类纤毛虫对不同种类饵料的同化率(67%—79%)和消化时间(13.7 min—24 h)不同。     

基于脂肪酸标记的长江口海区浮游动物常见种食性分析

脂肪酸不仅是浮游动物的重要组分,也被作为生物标记来指示动物的食物组成及其之间的营养关系。本文运用脂肪酸标记法对长江口附近海区6个浮游动物常见种的食性进行了分析。研究结果表明,中华哲水蚤(Calanus sinicus)雌体和桡足幼体都表现出明显的植食性。但雌体中16:1ω7的含量要明显高于18:4ω3,表明雌体对硅藻的摄食较多;桡足幼体的18:4ω3要高于雌体,说明桡足幼体对甲藻的摄食较多。磷虾(Euphausia spp.)的多不饱和脂肪酸(PUFA)和ω3系列脂肪酸的含量很高,说明其作为饵料可以给摄食者提供较多的脂类营养物质。中华哲水蚤和磷虾较低的22:6ω3/20:5ω3比值说明他们的营养地位较低。箭虫(Sagitta spp.)的20:1和22:1脂肪酸含量很高,指示了其对植食性桡足类的摄食。蝶水母(Ocyropsis crystallina)、瓜水母(Bero cucumis)和四叶小舌水母(Liriopetetraphylla)的20:1+22:1脂肪酸所占比例较高,指示了其对植食性桡足类的摄食,但是水母类的总脂肪酸含量都很低。几种水母和箭虫的22:6ω3的含量要明显高于20:5ω3的含量,说明它们在浮游食物网中具有较高的营养地位。     

利用脂肪酸标记法对南极罗斯海桡足类优势物种的食性研究

脂肪酸标记法是浮游动物食性研究的一种重要方法.将提取的脂质区分为中性脂和极性脂,可以进一步查明不同脂质在浮游动物食性研究中的作用.本研究通过分析不同脂质的脂肪酸构成,对2013年1月中国第29次南极考察期间在罗斯海采集的5种优势种桡足类的食性进行了研究.结果显示:5种桡足类的极性脂脂肪酸具有相似的组成,无法给出桡足类食性差异信息,食性信息主要体现于中性脂脂肪酸组成的差异.通过分析中性脂脂肪酸的组成信息,将5种桡足类的食性分为三类:Cala-noides acutus和Calanus propinquus主要摄食浮游植物,Metridia gerlachei及小型桡足类Oncaea curvata为杂食性种,Paraeuchaeta antarctica为肉食性种.本文的结果说明,在应用脂肪酸作为浮游动物食性标记的研究中,应尽量区分不同脂质种类的脂肪酸信息,从而得到更为精确的浮游动物食性信息.     

可见光和紫外线对浮游动物行为的影响

浮游动物在海洋食物链中处于中枢地位．大多数浮游动物摄食浮游植物,自身又是鱼类等高级摄食者的饵料,在食物链中起着承上启下的关键作用。而且微型浮游动物又是微食物环的重要组成部分。浮游动物存活、繁殖的成功与否决定于能否根据环境的变化调整自己的行为。因此,浮游动物行为的研究对理解浮游动物的生存策略和生态系统动力学具有重要意义,对浮游动物行为的研究逐渐成为浮游动物研究的热点问题之一．     

九龙江口潮间带大弹涂鱼食性及其消化管组织结构

本文对九龙江口北岸潮间带大弹涂鱼幼鱼和成鱼的食性作了周年分析,并观察了消化管的组织结构。大弹涂鱼所摄食的食物共有10个类群,其中生物类群至少有94种。主要摄食底栖硅藻和有机碎屑,系属植食性的底栖鱼类。个数百分比和出现频率百分组成较高的硅藻有布纹藻、菱形藻和舟形藻。摄食强度季节变化明显。体长42.4mm 以上,保持植食性不变,比肠长相对稳定。胃腺仅分布于贲门胃的粘膜层中,消化管的组织学特征与其食性相适应。     

湛江硇洲岛文昌鱼(Branchiostoma belcheri)的食性研究

于2006年4~7月在湛江硇洲岛海域采集文昌鱼,进行春夏季节不同性别、不同体长组等的胃含物观察分析。结果表明,湛江硇洲岛文昌鱼消化道残留食物成分以泥沙碎屑为主,可辨生物成分有34种,大部分为底栖硅藻,占58.8%,也有少量甲藻、瓣鳃类幼虫、底栖桡足类幼虫和原生动物等。春夏季节的文昌鱼的摄食喜好不尽相同,饵料生物的出现率随着季节的变化有所变化。不同性别文昌鱼的摄食喜好比较相近。文昌鱼到了性腺成熟后才开始进食动物性食物。研究结果表明,文昌鱼摄食藻类、微生物等而自身转化为其他动物的较高营养层次食物,在海洋食物网中具有一定的重要作用。     

红沿河海域常见水母的食物组成分析——基于稳定同位素和脂肪酸标记法

为了探究不同种类水母对浮游食物网的摄食影响,采用碳氮稳定同位素和脂肪酸标记法,研究分析了渤海红沿河海域常见的4种小型水母(伞径直径5 cm:卡玛拉水母Malagazzia carolinae、球形侧腕水母Pleurobrachia globosa、帽铃水母Tiaricodon coeruleus、半球美螅水母Clytia hemisphaerica和3种大型水母(伞径10—200cm:沙海蜇Nemopilema nomurai、海月水母Aurelia aurita)和白色霞水母Cyanea nozakii)的食物组成。结果表明,不同种类水母的食物组成存在差异。其中卡玛拉水母、球形侧腕水母、帽铃水母、半球美螅水母和白色霞水母均偏肉食食性,食物组成中动物性食物所占比例更高,高于海月水母与沙海蜇。在食物粒径谱上,帽铃水母和半球美螅水母较大粒径的食物比例均高于小粒径的悬浮有机物(POM)比例。卡玛拉水母和球形侧腕水母各个粒径食物比例接近。大型水母中,白色霞水母的食物中大粒径的浮游动物的比例高于海月水母,更高于沙海蜇。由此看来,小型水母和大型的白色霞水母的暴发会直接影响大中型浮游动物数量,海月水母的暴发对不同大小的浮游生物均会产生一定的影响。而沙海蜇的暴发会大量摄食1 mm的小型浮游生物和POM,对大中型浮游动物以及更高营养层生物(鱼类等)的影响可能是通过蜇伤以及饵料竞争导致的。因此,不同种类水母暴发对浮游生物的影响存在差异。本研究从摄食角度初步探究了水母对海洋生态系统物质循环和能量流动的影响,为水母暴发的灾害防治提供了数据支持。     

黄河口黄盖鲽的食性及摄食的季节性变化

923尾黄河口黄盖鲽Pseudo pleuronectes yokohamae(Gunther)成鱼的胃含物分析结果表明,黄盖鲽系广食性、底栖生物食性,主要摄食多毛类、软体动物类、棘皮动物类、甲壳类及腔肠动物类50余种食物,它终年摄食,仅在产卵期间稍有减弱,其食物类群及种类组成均有明显的季节性变化,表明鱼类的摄食与食物保障密切相关.     

东海区短鳄齿鱼摄食生态的初步研究

根据2008年5月～ 2009年2月“东海区主要渔场重要渔业资源的调查与评估(26°00′～ 35°00′N,120°00′～126°30′E)”课题调查的渔获样品,对东海区短鳄齿鱼(Champsodon snyderi)的摄食生态进行了初步研究.结果表明:东海区短鳄齿鱼属于浮游动物食性,兼食游泳动物;其主要饵料生物为太平洋磷虾(Euphausia pacifica)、细螯虾(Leptochela gracilis)、七星底灯鱼(Benthosema pterotum)和麦氏犀鳕(Bregmaceros macclellandi);主要食物种类的优势度随体长段不同而变化,食物种类分化明显,符合“最佳摄食理论”;短鳄齿鱼食物种类的季节替代明显,更替率尤以春季为高,达100％,其余三季相对接近;不同区域出现的饵料生物的种类自北而南递增,区域间食物种类的相似性系数均低于50％,表明短鳄齿鱼食物种类的区域差异明显,其中又以北部与其他两区的差异最大;短鳄齿鱼的年空胃率为16.34％,不同季节、区域和体长组的空胃率变动幅度也较小;短鳄齿鱼的年平均胃饱满指数为27.13‰,四季呈高低相间分布,并以冬季最高春季最低;平面分布与空胃率态势相同,自北而南递增,不同体长组的胃饱满指数差距甚小.     

Energy profiling of demersal fish: A case-study in wind farm artificial reefs

The construction of wind farms introduces artificial hard substrates in sandy sediments. As Atlantic cod (Gadus morhua) and pouting (Trisopterus luscus) tend to aggregate in order to feed around these reefs, energy profiling and trophic markers were applied to study their feeding ecology in a wind farm in the Belgian part of the North Sea. The proximate composition (carbohydrates, proteins and lipids) differed significantly between liver and muscle tissue but not between fish species or between their potential prey species. Atlantic cod showed to consume more energy than pouting. The latter had a higher overall energy reserve and can theoretically survive twice as long on the available energy than cod. In autumn, both fish species could survive longer on their energy than in spring. Polyunsaturated fatty acids were found in high concentrations in fish liver. The prey species Jassa and Pisidia were both rich in EPA while Jassa had a higher DHA content than Pisidia.Energy profiling supported the statement that wind farm artificial reefs are suitable feeding ground for both fish species. Sufficient energy levels were recorded and there is no indication of competition.     

Eco‐physiological repercussions of dietary arachidonic acid in cell membranes of active tissues of the Gray whale

The radiation of the mammalian land species that became the baleen whales happened about 27–34 Mya. Mammals require omega 6 fatty acids for reproduction. With this long exposure to the omega 3‐rich marine food chain, the Gray whale (Eschrichtius robustus) might be expected to have lost its requirement for omega 6 fatty acids. We report an unexpectedly high content of omega 6 arachidonic acid (ArA) in the Gray whale liver and muscle lipids. This whale migrates 10,000 km from the cold polar, omega 3 oil‐rich food chain to that of the breeding lagoons of the tropical waters. The food web of tropical waters is a source of omega 6 fatty acids, which are hardly present in the cold polar food web. We suggest the reason for this longest of migrations from cold to warm waters is to meet the requirement for omega 6 fatty acids for mammalian reproduction and brain growth. This extreme conservation of omega 6 fatty acids in Gray whale biology has critical implications for mammalian biology and especially for whale conservation.     

Transfer of lipids from plankton to blubber of harp and hooded seals off East Greenland

Sub-Arctic marine ecosystems are some of the most productive ecosystems in the world's oceans. The capacity of herbivorous zooplankton, such as Calanus, to biosynthesize and store large amounts of lipids during the short and intense spring bloom is a fundamental adaptation which facilitates the large production in these ecosystems. These energy-rich lipids are rapidly transferred through the food chain to Arctic seals. The fatty acids and stable isotopes from harp seal (Phoca groenlandica) and hooded seal (Cystophora cristata) off East Greenland as well as their potential prey, were analysed. The results were used to describe the lipid dynamics and energy transfer in parts of the East Greenland ecosystem. Even if the two seal species showed considerable overlap in diet and occurred at relatively similar trophic levels, the fatty acid profiles indicated that the bases of the food chains of harp and hooded seals were different. The fatty acids of harp seals originate from diatom-based food chain, whereas the fatty acids of hooded seals originate from dinoflagellate and the prymnesiophyte Phaeocystis pouchetii-based food chain. Stable isotope analyses showed that both species are true carnivores on the top of their food chains, with hooded seal being slightly higher on the food chain than harp seal.     

脂肪酸标志物在海洋生态系统营养关系研究中的应用

脂肪酸在食物链传递过程中相对保守,可以作为标志物示踪研究海洋生物间的营养关系.脂肪酸标志物属于营养学标志物的一种,是海洋生态系统营养关系研究中很有发展前景的分析方法之一.总结概括了目前国际上应用较广泛的脂肪酸标志及脂肪酸标志体系的建立过程、近年来脂肪酸标志物在海洋生态系统营养关系研究中的应用领域,展望了脂肪酸标志法的应...     

Trophic relations of capelin Mallotus villosus and polar cod Boreogadus saida in the Barents Sea as a factor of impact on the ecosystem

The purpose of the study is to assess the role of trophic relations of the dominant pelagic fishes capelin and polar cod in the Barents Sea with regard to distribution and accessibility as prey for the Atlantic cod in warm years (2004–2005). Unlike in the previous period, during these warm years a dramatic increase of the polar cod population resulted in a northwards expansion of the feeding grounds where overlapping of polar cod and capelin concentrations was observed. This caused an increased competition for copepods, which are the main food item for young fish. In the areas dominated by polar cod the shortage of copepods forced immature capelin to switch to the chaetognath Sagitta, which affected their fatness negatively.During the warm years the feeding grounds of Atlantic cod also expanded, to a large degree caused by the shortage of their main food, the capelin. In 2004–2005 the cod formed feeding concentrations in the north and northeast Barents Sea where they fed on the capelin. In this area the consumption of polar cod by cod increased, and in some local areas the polar cod practically replaced the capelin in the diet of cod. In general polar cod in the diet of Atlantic cod were more important in the northern than in the southern part of the Barents Sea. The fatness of cod was extremely low during the whole spring–summer period (until August), and after the feeding period the fatness index of the Atlantic cod became lower than the average long-term autumn value.     

Availability of cadmium and zinc from sewage sludge to the flounder, Platichthys flesus, via a marine food chain

This paper examines the potential availability to a demersal fish of cadmium and zinc associated with digested sewage sludge, via a food chain as well as directly from the sludge, and the tissue distribution and possible excretion of any accumulated cadmium and zinc. Radioactive tracer techniques were used in order to follow the food chain transfer of the metals. Flounder (Platichthys flesus) accumulated cadmium both directly from sludge (delivered in newly ingested unassimilated gutfuls in the amphipods) and in assimilated form from the tissues of the amphipod crustacean Corophium volutator that had been feeding on a sludge-sediment mixture. Cadmium from both sources could be excreted by the fish. The concentration of cadmium within the whole fish increased as the input of cadmium in the diet increased. Zinc, similarly, is available to the flounder both directly from sludge and from zinc accumulated in C. volutator. Only a limited increase in net accumulation of zinc by the flounder was observed upon increased inputs of zinc through the diet, perhaps indicating some regulation of body zinc concentration by the flounder.     

Availability of cadmium and zinc from sewage sludge to the flounder, Platichthys flesus, via a marine food chain

This paper examines the potential availability to a demersal fish of cadmium and zinc associated with digested sewage sludge, via a food chain as well as directly from the sludge, and the tissue distribution and possible excretion of any accumulated cadmium and zinc. Radioactive tracer techniques were used in order to follow the food chain transfer of the metals. Flounder (Platichthys flesus) accumulated cadmium both directly from sludge (delivered in newly ingested unassimilated gutfuls in the amphipods) and in assimilated form from the tissues of the amphipod crustacean Corophium volutator that had been feeding on a sludge–sediment mixture. Cadmium from both sources could be excreted by the fish. The concentration of cadmium within the whole fish increased as the input of cadmium in the diet increased. Zinc, similarly, is available to the flounder both directly from sludge and from zinc accumulated in C. volutator. Only a limited increase in net accumulation of zinc by the flounder was observed upon increased inputs of zinc through the diet, perhaps indicating some regulation of body zinc concentration by the flounder.     

Dominant amphipods of Posidonia oceanica seagrass meadows display considerable trophic diversity

Gut content examination and trophic markers (fatty acids, stable isotopes of C and N) were combined to delineate the diet of the dominant species of amphipods from Mediterranean Posidonia oceanica seagrass meadows and to highlight trophic diversity among this community. Our results indicate that, although all dominant species heavily relied on macroalgal epiphytes, considerable interspecific dietary differences existed. Carbon stable isotope ratios notably showed that some of the amphipod species favored grazing on epiphytes from leaves or litter fragments (Apherusa chiereghinii, Aora spinicornis, Gammarus aequicauda), while others such as Dexamine spiniventris preferred epiphytes from rhizomes. The remaining amphipods (Caprella acanthifera, Ampithoe helleri and Gammarella fucicola) readily consumed both groups. In addition, SIAR modeling suggested that most species had a mixed diet, and relied on several food items. Fatty acid analysis and gut contents revealed that contributions of microepiphytic diatoms and of benthic and suspended particulate organic matter to the diet of amphipods were anecdotal. None of the examined species seemed to graze on their seagrass host [low 18:2(n‐6) and 18:3(n‐3) fatty acids contents], but Gammarus aequicauda partly relied on seagrass leaf detritus, as demonstrated by the lesser ¹³C‐depletion of their tissues. Overall, our findings suggest that amphipods, because of their importance in the transfer of organic matter from primary producers and detritus to higher rank consumers, are key items in P. oceanica‐associated food webs.     

2种东风螺软体部和生殖腺脂肪酸组成研究

利用气相色谱-质谱(GC-MS)联用技术测定了野生台湾东风螺(Babylonia formosae),方斑东风螺(Babylonia areolata)及养殖方斑东风螺软体部和生殖腺脂肪酸组成及其含量.结果表明,2种贝软体部和生殖腺的15种主要脂肪酸中,不饱和脂肪酸(UFA)含量较饱和脂肪酸(SFA)含量高.野生台湾东风螺、方斑东风螺及养殖方斑东风螺软体部的UFA质量分数分别为68.22%、67.23%和76.05%: 其软体部SFA质量分数分别为28.16%,28.23%和21.53%.多不饱和脂肪酸(PUFA)质量分数高,n-3PUFA和n-6PUFA质量分数占总脂肪酸的39.20%～64.53%,其中二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)质量分数占总脂肪酸的13.82%～34.22%,养殖方斑东风螺的质量分数最高.研究发现,2种东风螺,特别是养殖的小型方斑东风螺,不仅具有较高的营养价值,且是EPA和DHA理想的提取原料.