长江口桡足类数量分布与变动

于1999年枯水期(2～3月份)、丰水期(8月份)、2000年枯水期(2～3月份)对长江河口浮游动物桡足类采样调查,研究了长江河口桡足类的数量分布与变动.结果表明:1999年枯水期,桡足类在整个长江河口区的平均数量相对不大,为76ind/m3,但却占同期浮游动物平均数量的95.61%;1999年丰水期桡足类平均数量为254ind/m3,占同期浮游动物平均数量的84.29%;2000年枯水期桡足类平均数量为97ind/m3,占同期浮游动物总数量的84.46%.从优势度看,1999、2000年枯水期主要优势种为华哲水蚤(Sinocalanus sinensis);1999年丰水期主要优势种为火腿许水蚤(Schmackeria poplesia).虫肢歪水蚤(Tortanus vermiculus)、真刺唇角水蚤(Labidocera euchaeta)则在枯、丰水期均为优势种.从种类数看,桡点类在1999年、2000年枯水期均为14种,1999年丰水期为枯水期的近2倍,达25种.对于长江河口主要桡足类而言,华哲水蚤的季节变化明显,适宜生活在盐度较低水域.虫肢歪水蚤数量年际变化较大,其适盐范围比华哲水蚤较宽、较高.真刺唇角水蚤的适盐范围与虫肢歪水蚤相似且更高一些,但该种在枯水期数量较少,丰水期数量较多,变化显著,更适宜在较高温时生长.火腿许水蚤适盐范围宽,能适应很大范围盐度变化,枯水期数量少,丰水期数量大,较高温度生长良好.     

两种桡足类短期热冲击的高起始致死温度值

于2007年4月研究了亚热带海域近海种桡足类中华哲水蚤(Calanus sinicus Brodsky)和真刺唇角水蚤(Labidocera euchaeta Giesbrecht)在不同驯化温度下热冲击15、30、45 min后的24 h高起始致死温度(upper incipient lethal temperature,24-h UILT50).结果表明:(1)在相同驯化温度下,两种桡足类短期热冲击24-h UILT50随暴露时间的延长而降低;(2)在相同暴露时间下,两种桡足类短期热冲击24-h UILT50随驯化温度的上升均有不同程度的上升,但这种升高的趋势会随驯化温度的上升而变缓,且趋于一固定值后不再上升;(3)中华哲水蚤在暴露时间为15、30、45 min的24 h最高起始致死温度(ultimate upper incipient lethal temperature,24-h UUILT50)分别为31.7、31.0、30.3℃,真刺唇角水蚤在暴露15、30、45 min时的24-h UUILT50分别为36.5、36.0、35.4℃;(4)在相同驯化温度和暴露时间条件下,真刺唇角水蚤对短期热冲击的耐受性显著强于中华哲水蚤.     

长江口和杭州湾凤鲚胃含物与海洋浮游动物的种类组成比较

2009年6月—8月期间在长江口及杭州湾水域收集了1355尾的凤鲚（Coilia mystus）标本,对其胃含物进行分析,期间采用出现频率（F）、个数百分比（N）、重量百分比（W）、相对重要性指标（IRI）、优势度（Y）公式计算,并进行种类的相似性分析,同步采集了取样点附近的浮游动物,比较了凤鲚胃含物食谱与该海域浮游动物种类组成。结果表明：河口性的长额刺糠虾IRI 为703.25,%IRI为62.94%,远远超过其他种类,甚至超过任何一个桡足类优势种,因而是凤鲚食谱中的最重要的种类。凤鲚摄食的其他主要种类包括：火腿许水蚤（Schmackeria poplesia）（IRI = 261.04）,虫肢歪水蚤（Tortanus vermiculus）（IRI = 107.53）、真刺唇角水蚤（Labidocera euchaeta）（IRI = 27.27）。以上四种浮游动物重要性合计%IRI为98.36%。在主要食物种类占绝对优势。因而是凤鲚饵料中最重要的优势种。种类组成相似性分析结果显示：胃含物和海域浮游动物之间的相似度值大致在0.363—0.365之间;而两者桡足类之间的相似值在0.521—0.575之间。推测凤鲚对个体较小的桡足类摄食方法是过滤性摄食,对种类的选择性较低。而对个体较大的糠虾则是有选择性追逐摄食。     

海南岛西北沿岸海域浮游桡足类的分布及群落特征

为了解昌江沿岸海域生态系统的现状, 探讨海域环境因素对浮游动物的生存环境造成的影响。本文根据2008年11月至2009年7月在海南西部昌江沿岸水域21个测站、4个季度月调查所获的浮游桡足类样品数据, 对该海域浮游桡足类群落结构、分布、季节变化及影响因素进行了分析。本调查共鉴定出桡足类44种, 隶属4目17科24属, 其中秋季25种, 冬季23种, 春季22种, 夏季23种。本次调查共发现优势种6种, 分别是微刺哲水蚤(Canthocalanus pauper)、亚强次真哲水蚤(Subeucalanus subcrassus)、锥形宽水蚤(Temora turbinata)、刺尾纺锤水蚤(Acartia spinicauda)、椭形长足水蚤(Calanopia elliptica)和精致真刺水蚤(Euchaeta concinna), 优势种以近岸暖水种居多。浮游桡足类丰度季节变化明显: 冬季最高, 达409 ind./m³; 秋季次之, 为144 ind./m³, 春季为55 ind./m³, 夏季最低仅为17 ind./m³。其丰度的平面分布显示: 秋、冬季节分别在海区中部和南部形成明显密集区, 春、夏季节则大致呈现由外海向近岸逐渐递减的趋势。浮游桡足类的多样性指数(H')表现为夏季>春季>秋季>冬季, 春、夏季的均匀度指数(J')明显高于秋、冬季。本调查反映出该海区的桡足类群落具有热带—亚热带区系特征, 种类组成季节更替明显, 桡足类种群受海域水温和硅藻的影响明显, 受盐度影响不明显。     

小黄鱼育幼期吕泗渔场的饵料浮游动物特征

根据2008年6月在吕泗渔场(31.90°N-32.10°N、121.70°E-121.95°E)海域生态环境调查资料,分析了该区饵料浮游动物种类分布、优势种、数量分布、多样性等特征。结果表明:该区共出现饵料浮游动物31种(不含浮游幼体和腔肠动物),种类数和丰度均以桡足类占据优势;该区总生物量均值为845.54mg.m-3,其中大潮时为895.58mg.m-3,分布趋势为北部高于南部,小潮时为795.49mg.m-3,分布趋势为中部较高;6月吕泗渔场饵料浮游动物优势种分别是真刺唇角水蚤(Labidocera euchaeta)、中华哲水蚤(Calanus sini-cus)、小拟哲水蚤(Paracalanus parvus)、太平洋纺锤水蚤(Acartia pacifica)、火腿许水蚤(Schmackeria poplesia)、长轴螺(Peraclis reticulata)、长额刺糠虾(Acanthomysis longirostris);大潮时真刺唇角水蚤和中华哲水蚤优势度最高均为0.19,小潮时真刺唇角水蚤优势度最高为0.40;在吕泗渔场,6月饵料浮游动物生物量较高,优势种数较多,反映出该渔场小黄鱼饵料环境的稳定性,为小黄鱼幼体生长提供了良好的饵料条件。     

江苏典型水域湖鲚食性对比分析

利用多目刺网于2017年9—11月在江苏典型水域长江南京段、高邮湖、洪泽湖、骆马湖及淮河江苏段采集湖鲚样品。通过胃含物鉴定以及测定摄食率、平均饱满指数、食物选择指数等指标,对比分析不同水域湖鲚的食性差异。结果表明:不同水域湖鲚皆为浮游动物食性,以枝角类和桡足类为主,偶尔出现轮虫和小型鱼虾;在摄食强度、食物选择性不同水域湖鲚并无显著性差异,但在食物组成上差异明显;洪泽湖湖鲚食物种类最多,高邮湖次之,长江最少;长江、洪泽湖、骆马湖水域湖鲚食物中,桡足类占优势,高邮湖中枝角类占优势;桡足类中,长江、高邮湖、洪泽湖水域湖鲚食物中以剑水蚤为主要优势种(数量百分比为29.2%～70.1%),骆马湖则以刺剑水蚤为主要优势种(数量百分比45.4%),淮河以剑水蚤、温剑水蚤为优势种(数量百分比18.6～18.9%);枝角类中高邮湖、洪泽湖、骆马湖、淮河水域湖鲚食物中象鼻溞为主要优势种,数量百分比76.9%～100.0%,长江水域湖鲚则以溞为主(数量百分比81.5%)。聚类分析表明,根据食性差异,5个不同水域湖鲚可以归为长江种群、高邮湖洪泽湖种群以及骆马湖淮河种群3个种群。     

长江口中华鲟幼鱼的食物组成及摄食习性

分析了2004年5-9月长江口水域中华鲟幼鱼的食物组成及摄食的月份变化.结果表明:长江口中华鲟幼鱼以底栖小型鱼类、多毛类和端足类为主要食物,兼食虾类、蟹类及瓣鳃类等小型底栖动物.幼鱼的摄食率和摄食强度较高,且摄食强度存在着月份变化.主要饵料生物组成有明显的月变化,且食物个体有逐渐增大的趋势,其中5月主食多毛类和蟹类,6月主食鱼类和端足类,7月为鱼类和多毛类,8月样本较少且为空胃,9月为鱼类和虾类.与历史资料进行比较发现,曾是幼鱼重要饵料的鲬类所占比例极小,其质量百分比仅占1.81%;而以前未曾记录的虾虎鱼类在食物中所占比例较高, 其质量百分比达50.54%;等足类以前也未曾记录,其出现频率达10.07%.     

纺锤水蚤摄食生态学研究进展

纺锤水蚤(Acartia)是温带、亚热带近岸水域优势的小型桡足类,在区域生态系统的物质循环与能量流通中起着重要作用。综述了国内外对纺锤水蚤食性、摄食机制、摄食影响因子及摄食转化效率的研究工作:纺锤水蚤为杂食性,偏爱高营养的动物性饵料,摄食浮游植物和微型浮游动物时分别采取滤食策略和伏击策略,摄食过程受到自身生理状态和环境因子的共同调节。其对食物的利用效率约为60%,其他40%通过Sloppy feeding和排泄等方式以溶解形式释放到海水中。目前摄食研究多以实验模拟为主,自然现场研究手段有限,分子生物学技术有望促进认识其在自然生态系统中的地位与作用。     

胶州湾六丝钝尾虾虎鱼的摄食生态特征

根据2011年2-11月在胶州湾海域进行的4个季节的底拖网调查,共收集624尾六丝钝尾虾虎鱼样品进行胃含物分析,对其摄食生态进行了初步研究.结果表明:六丝钝尾虾虎鱼摄食的饵料种类有40余种,其中优势饵料生物有日本鼓虾、经氏壳蛞蝓和细螯虾等.其食物组成存在明显的季节变化,除在4个季节均大量摄食虾类外,春季主要摄食腹足类,夏季主要以鱼类为食,秋季主要摄食虾类,冬季摄食桡足类和端足类等小型甲壳生物的比例较高,这主要与胶州湾饵料生物种类和数量的季节性变化有关.随着体长的增长,六丝钝尾虾虎鱼摄食的饵料生物由小型的桡足类逐渐转变为个体较大的经氏壳蛞蝓、绒毛细足蟹和日本鼓虾等,食物组成呈现出明显的体长变化.典范对应分析(CCA)表明,水温和盐度是影响六丝钝尾虾虎鱼摄食的主要因素,其次是体长和pH.     

三座南亚热带大型水库敞水区桡足类群落结构比较

于2000-2002年对南亚热带三座大型水库:新丰江水库、公平水库和飞来峡水库敞水区桡足类进行了定性定量采样.三座水库桡足类种类数较少,共检出桡足类4科10属14种,其中8种哲水蚤,5种剑水蚤和1种猛水蚤.主要分布在广东省水库的我国特有种舌状叶镖水蚤(Phyllodiaptomus tunguidus)和广布性种类右突新镖水蚤(Neodiaptomus schmackeri)是出现频率较高的哲水蚤种类,温中剑水蚤(Mesocyclops thermocyclopoides)、台湾温剑水蚤(Thermocyclops taihokuensis)和博平近剑水蚤(Tropocycl opsbopingi)是出现频率较高的剑水蚤种类.水库的流域面积、滞留时间、鱼类捕食和营养状态是影响水库桡足类种类组成和数量的重要因素.三座水库桡足类种类数与水库流域面积大小存在正相关关系.随着水库营养水平的升高,桡足类密度和生物量也相应增加,但是大型哲水蚤的优势度降低,而剑水蚤和桡足类幼体的优势度上升.水力滞留时间很短是引起飞来峡水库桡足类种群波动的主要因素.水库捕食性鱼类对甲壳浮游动物的选择性捕食,对桡足类种类影响较小,对桡足类成体密度影响较大.由于地区差异和鱼类捕食强度等因素的影响,桡足类种类多样性与水体营养状态之间存在不确定性.     

The family Pontellidae (Crustacea: Copepoda) in la Ventosa Bay, Oaxaca, México: systematies and basic ecology

A study on ecological records of planktonic copepods from The Ventosa Bay, Oaxaca, Mexico is presented. Five species were identified: Labidocera acuta, L. lubbockii, Pontella agassizi, P. tenuiremis and Pontellina plumata. The most abundant species was L. acuta and their copepodite stages conforming the 95.7% of Pontellids, followed by L. lubbockii 4.09%; other species were less than one percent. The reproductive success of L. acuta is probably favored by its resistance to the changes in temperature and salinity, because of it is an eurytherme and euryhaline organism. Total density of this family was between 18 and 472 copepods/100 m3 in 1987 and 1988. Nevertheless in 1992 and 1993 the density was between 490 to 123,030 copepods/100 m3. This copepod density increment could be related local phenomenon (upwelling) at the beginning and end of the year.     

长足大竹象消化道不同分段菌群异质性及竹木质纤维素降解能力

[目的]长足大竹象Cyrtotrachelus buqueti消化道共生菌群参与了竹纤维素的降解.本研究旨在揭示长足大竹象幼虫消化道不同分段共生菌群异质性及木质纤维素的降解能力.[方法]通过对16S rRNA测序对长足大竹象幼虫消化道分段口器(YB)、前肠(YFG)、中肠(YMG)和后肠(YHG)进行菌群组成分析及功能...     

Polyunsaturated fatty acids in zooplankton: variation due to taxonomy and trophic position

1. Food quality has major effects on the transfer of energy and matter in food webs, and essential long‐chained polyunsaturated fatty acids (PUFAs) can affect the quality of phytoplankton as food. In a study of oligotrophic lakes in north‐western Sweden, we investigated the fatty acid composition of four planktonic cladocerans and two calanoid copepods, representing herbivorous and carnivorous species. We also collected seston samples. 2. The proportions of long‐chain PUFAs in the organisms increased with their increasing trophic position. Thus, both their quality as food for other organisms, as well as their requirement for fatty acids (FAs), differed among taxa and depended on their trophic position. 3. We found taxon‐specific differences in the FA composition of zooplankton that were not related to sestonic FA composition. This implies that the variation in zooplankton FA composition is constrained by phylogenetic origin, life history characteristics, or both. 4. The cladoceran taxa contained 12–23% eicosapentaenoic acid (EPA) but only 0.9–2.1% docosahexaenoic acid (DHA) of the total FA content. In contrast, the calanoid copepods contained 7–11% EPA and 14–21% DHA. Thus, our results show that differences in the PUFA content among zooplankton species could have repercussions for both food web structure and function.     

长江口海域真刺唇角水蚤的分布及其对全球变暖的响应

基于1959和2002年在长江口28°00′—32°00′N、122°00′—123°30′ E海域4个季节8个航次的海洋调查资料,分析了长江口海域真刺唇角水蚤的水平分布和季节变化特征及其对气候变暖的响应.结果表明：长江口海域真刺唇角水蚤平均丰度在夏秋季较低、冬春季较高,冬季真刺唇角水蚤的出现率最高,春、夏季具明显的集群性;盐度是影响真刺唇角水蚤水平分布的主要因素,该种分布的最适温度约16 ℃,最适盐度在12～20,属暖温性咸淡水种;与1959年相比,2002年长江口海域真刺唇角水蚤丰度明显降低,这可能与全球变暖有关,可作为长江口海洋变暖的一个重要指示种.春季真刺唇角水蚤的高丰度值出现在长江口最大浑浊带水域,这对于维持该水域渔场功能和生态系统的其他功能具有重要意义.     

Feeding habits of the Oligocene bristlemouth fish Scopeloides glarisianus (Teleostei: Stomiiformes: Gonostomatidae)

The dietary habits of the Oligocene fish Scopeloides glarisianus (Agassiz) are presented on the basis of functional morphology, in comparison with their recent relatives (Gonostoma spp.) as well as fossil materials from localities in Poland (Lubenia, B?a?ova), Ukraine (Ljubizhnja), the Czech Republic (Lou?ka), and the northern Caucasus in Russia and Abkhazia. Analogous to the recent relatives from the genus Gonostoma, S. glarisianus fed on crustaceans such as ostracods and copepods, the larger specimens preying on small fishes. Fishes remains preserved within the alimentary canal region are usually represented by smaller individuals of the same species; accordingly, the cannibalistic behaviour of the adult S. glarisianus is thereby documented. The remains of the alimentary canal and the peritoneum are identified.     

蝗虫消化道结构的比较研究

采用扫描仪分析方法对10种蝗虫消化道形态结构进行了观察比较,发现蝗虫不同类群个体其中肠占消化道总长的比例依进化地位呈现递增趋势,胃盲囊和后肠则呈递减趋势.这种趋势可能是随着蝗虫类群的进化,中肠在消化道所占的比例逐渐增大,对食物的消化吸收能力逐渐增强,与之相应的是胃盲囊呈退化趋势,同时后肠所排泄的残渣逐渐减少,导致蝗虫消化道形态发生适应性变化的结果.     

Food patch size, food concentration and grazing efficiency of the harpacticoid Paramphiascella fulvofasciata (Crustacea, Copepoda)

Harpacticoid copepods are known as important grazers on primary producers. The underlying factors for their food selectivity and grazing efficiency are however far from well known. For instance, their patchy distribution in the marine environment is well documented but how meiofaunal organisms cope with the spatial distribution/accessibility of the available food resources is less clear.In the present study a laboratory experiment was conducted to test the grazing efficiency of Paramphiascella fulvofasciata (Copepoda, Harpacticoida) on the epipelic diatom Seminavis robusta applied in recipients of different area and in various concentrations. Diatoms were enriched in the stable isotope ¹³C in order to trace food uptake and copepods were left to graze for 4 days.We found that the grazing efficiency of P. fulvofasciata was diatom concentration-dependent. A lower diatom uptake at lower diatom densities illustrated this clear functional response. On the contrary, there was no significant effect of the area per se where the copepods could graze upon. The lack of a significant effect of area is mainly due to the high variability in uptake that was recorded in some treatments. Although P. fulvofasciata is a very motile copepod, known as endobenthic and epibenthic species, it was able to concentrate on food uptake at the bottom of the experimental unit as there was no significant difference in uptake between treatments with different water heights in the units. In addition, it was found that a diatom concentration of about 140 000 cells/cm² favours egg production of P. fulvofasciata.     

Diet composition of Belone belone (Linnaeus, 1761) (Pisces: Belonidae) in the Aegean Sea

The objective of this study was to determine the monthly dietary pattern in migratory garfish and to improve our understanding in the seasonality of prey choice. Gut contents of 597 Belone belone specimens collected from the eastern Aegean Sea (Turkey) were analyzed: 79.2% contained food in their guts and 20.8% had empty guts. Crustaceans (36.7%) were the most important prey with a 36.7 index of relative importance (%IRI). Especially brachyurans (13.0%) and copepods played a major role (10.1%), followed by teleosts (26.1%) and other food categories (23.3%) (much of which was of terrestrial origin, including insects). Nannocalanus minor, Clausocalanus arcuicornis, Temora stylifera, Labidocera wollastoni and Oncea media were important copepods found in the guts of B. belone specimens. Analysis of variance of the monthly weight data indicated no significant seasonal differences, except for January and February.     

Characteristics of digestive enzymes of calanoid copepod species from different latitudes in relation to temperature, pH and food

In calanoid copepods it is poorly understood how enzymatic activities and patterns are affected by abiotic and biotic factors. Such knowledge, however, is crucial to assess metabolic functioning and performance of organisms in different habitats. Therefore, our study focuses on digestive enzyme activities in relation to temperature, pH and food in the Arctic species Calanus glacialis and in Centropages hamatus and Temora longicornis from the North Sea. Enzyme activities were measured over a range from 0 to 70 °C (lipases/esterases, proteinases) and pH 5 to 9 (proteinases). In all species, relative proteinases activity peaked at 40/50 °C and pH 6; relative lipases/esterases activity peaked at 30 °C. Between 0 and 20 °C, lipase activity of C. glacialis was higher (40-70% of maximum) than that of the boreal copepods (25-64%), which suggests thermal adaptation of the lipid metabolism in the polar species. Incubating C. glacialis with the diatom Thalassiosira weissflogii showed (i) that enzyme activities increased especially in the alkaline range and (ii) that enzyme patterns, revealed by gel electrophoresis, differed from that of starving individuals, indicating that feeding induced enzyme expression. Such studies, linking abiotic and biotic conditions to enzyme functioning, can help elucidating the capacity of copepods to respond to environmental changes.     

Copepod and microzooplankton grazing in mesocosms fertilised with different Si:N ratios: no overlap between food spectra and Si:N influence on zooplankton trophic level

We hypothesized that the trophic level of marine copepods should depend on the composition of the protist community. To test this hypothesis, we manipulated the phytoplankton composition in mesocosms and measured grazing rates of copepods and mesozooplankton in those mesocosms. Twelve mesocosms with Northeast Atlantic phytoplankton were fertilised with different Si:N ratios from 0:1 to 1:1. After 1 week, ten of the mesocosms were filled with natural densities of mesozooplankton, mainly calanoid copepods, while two remained as mesozooplankton-free controls. Both before and after the addition of copepods there was a positive correlation of diatom dominance with Si:N ratios. During the second phase of the experiment, copepod and microzooplankton grazing rates on different phytoplankton species were assessed by a modification of the Landry-Hassett dilution technique, where the bottles containing the different dilution treatments were replaced by dialysis bags incubated in situ. The results indicated no overlap in the food spectrum of microzooplankton (mainly ciliates) and copepods. Ciliates fed on nanoplankton, while copepods fed on large or chain-forming diatoms, naked dinoflagellates, and ciliates. The calculated trophic level of copepods showed a significantly negative but weak correlation with Si:N ratios. The strength of this response was strongly dependent on the trophic levels assumed for ciliates and mixotrophic dinoflagellates.