基于稳定性同位素的普里兹湾南极大磷虾不同发育阶段食性转变分析

As one of the most common and dominant species in the Southern Ocean, Antarctic krill(Euphausia superba)play a significant role in food web structure and the process of energy flow. The diet of Antarctic krill in the Prydz Bay during austral summer of 2012/2013 was investigated and the ontogenetic shift in krill diet was evaluated using the stable isotope method. The nitrogen stable isotope values(δ~(15) N) of adults((2.78±0.58)‰) were much higher than those of juveniles((1.69±0.70)‰), whereas the carbon stable isotope values(δ~(13) C) of adults(–(28.26±1.08)‰) were slightly lower than those of juveniles(–(27.48±1.35)‰). Particulate organic matter(POM)from 0, 25, and 50 m depth combined(0/25/50 m) represented phytoplankton food items. The results showed that phytoplankton food items in surface water and mesozooplankton were two essential food items for Antarctic krill in the Prydz Bay during summer. POM(0/25/50 m) contributes 56%–69% and 26%–34% to the diet of juvenile and adult krill, respectively, whereas mesozooplankton composes 13%–34% and 58%–71% of the diet of juvenile and adult krill, respectively. Thus, an ontogenetic diet shift from POM(0/25/50 m), which consists mainly of phytoplankton, to a higher trophic level diet containing mesozooplankton, was detected. The capacity for adults to consume more zooplankton food items may minimize their food competition with juveniles, which rely mostly on phytoplankton food items. This suggests "diet shift with ontogeny" which may somehow help krill keep their dietary energy budget balanced and well adapted to the Antarctic marine ecosystem as a dominant species.     

南极夏季南设德兰群岛东部海域南极大磷虾的摄食策略

Euphausia superba is a key species in the Southern Ocean that serves as a link between primary production and higher trophic levels. To investigate the feeding strategies of E. superba from the eastern South Shetland Islands,fatty acid biomarkers, stable isotope signatures, and an incubation experiment were conducted. The results of the incubation experiment proved that adult E. superba mainly fed on 2–20 μm particles, demonstrating the importance of nanoplankton in their diet. Moreover, significant positive relationships between δ15 N and body size demonstrated that size-related dietary shifts were present in E. superba. Evidence from principal component analysis and the C16:1ω7/C18:4ω3 ratio showed that juveniles preferentially fed on dinoflagellates and adults were more likely to feed on diatoms. Fatty acid profiles in adult E. superba roughly mirrored the different trophic conditions and feeding strategies between stations. Adult E. superba at Stas D2-07, D5-07, DA-01 and DA-02 exhibited elevated levels of C16:1ω7, C18:4ω3, C18:1ω9 and C18:1ω9/C18:1ω7, indicating higher levels of feeding on both phytoplankton and higher trophic diets. In contrast, adult E. superba at Stas D1-03 and D1-04 were characterized by high levels of polyunsaturated fatty acids/saturated fatty acids ratios and low levels of C16:1ω7,C18:1ω7, C18:4ω3, C18:1ω9 and total fatty acids. We inferred that adult krill at Stas D1-03 and D1-04 still suffered from difficult dietary conditions after overwintering. The different dietary conditions between stations suggest a highly plastic feeding strategy of E. superba in the eastern South Shetland Islands.     

应用稳定同位素技术研究江苏近海食物网营养结构的季节性变化

本研究基于稳定同位素技术对江苏近海春、夏、秋季采集的不同生物类群(鱼类、甲壳类、头足类和底栖动物等)进行稳定同位素的分析,利用SIBER模型计算不同季节消费者的营养生态位,并计算出6种营养结构的量化指标.结果表明,3个季节的δ13C值、δ15N值均差异不显著(p>0.05).春季δ13C值范围为?24.47‰～?14....     

南极磷虾捕捞加工船利用现状及趋势分析

南极磷虾广泛分布于南极水域,资源储量非常丰富,是全球海洋中最大的单种可捕生物资源。文章梳理了全球南极磷虾捕捞加工船运行情况,剖析了主要国家南极磷虾开发利用及捕捞加工船的发展现状,选取了“福荣海”和“南极耐力”,对我国南极磷虾捕捞加工船与挪威渔船进行了对比分析,指出中国南极磷虾捕捞加工船的发展还存在专业化程度不高、生产模式存在问题且传统渔船捕捞方式有待改进以及船载加工技术有待进一步提高的问题。基于此,研究认为在未来中国应推进转型升级,形成新型南极磷虾捕捞加工渔船体系;强化产业素质,不断提升捕捞渔船渔具装备水平;完善加工环节,突破船载加工技术“瓶颈”,以期通过该研究能够对中国南极磷虾捕捞行业的发展提供帮助。     

20世纪南极菲尔德斯半岛毛皮海豹食谱比例变化的同位素混合模型比较分析

稳定同位素比值分析已成功用于示踪动物的食物来源研究,近年来已发展了多个同位素混合模型用于计算混合物中多来源物质的组成比例。本文以过去百年来南极菲尔德斯半岛南极毛皮海豹(Arctocephalus gazella)毛发的C、N同位素数据为基础,运用同位素混合模型中的欧几里得距离法、线性模型和贝叶斯模型进行计算、分析和比较,得到毛皮海豹食谱中南极磷虾(Euphausia superb)、南极电灯鱼(Electrona antarctica)和尼氏裸灯鱼(Gymnoscopelus nicholsi)所占比例随时间的变化趋势。各模型计算得出的结果可分为两组,分别是欧几里得距离法公式(1)和(2)的结果,表现为近百年来毛皮海豹食谱中Euphausia superb比例与其毛发稳定N同位素比值呈同步上升的趋势;第二组为欧几里得距离法公式(3)、线性模型和贝叶斯模型的结果,Euphausia superb比例与毛皮海豹毛稳定N同位素比值呈反相关关系。综合对比研究区域气候、海冰环境变化背景和已有的南极磷虾种群密度调查资料分析,第二组模型结果与实际情况较为相符,可用于讨论食物比例的时间变化趋势。近百年来,菲尔德斯半岛毛皮海豹食谱中Euphausia superb的比例显著下降,很可能是由于区域气候快速变暖和海冰的消退造成的。本文的计算结果指示西南极半岛气候变暖已显著影响到区域海洋食物链变化。     

地球上最成功的生物物种——南极磷虾

南极磷虾，又名大磷虾或南极大磷虾，是一种生活在南极洲水域的磷虾。它是一种海洋甲壳类动物，它的眼柄基部、头部和胸的两侧和腹部的下面长着一粒粒金黄色的、略带红色的球形发光器，当它们受到惊吓时，发光器就能发出像萤火虫那样的磷光来。     

基于氮稳定同位素的九龙江口鱼类营养级研究

采用氮稳定同位素技术对2013年6—8月九龙江口采集到的隶属于13目42科61属共71种鱼类的营养级进行研究。结果表明,九龙江口鱼类的δ15 N值跨度较大,介于7.23‰~14.66‰之间。以菲律宾蛤仔(Ruditapes philippinarum)为基准生物估算出鱼类的营养级介于1.70~3.89之间,营养级最低与最高的鱼类分别为少牙斑鲆(Pseudorhombus oligodon)与多鳞鱚(Sillago sihama)。与Fishbase同种鱼类的营养级数据进行比较,83.1%的鱼类的营养级均值处于Fishbase同种鱼类的营养级范围内,但81.7%的鱼类的营养级均值比Fishbase同种鱼类的营养级均值略低;与传统的胃含物分析结果比较,58.3%的鱼类的营养级在0.5个营养级的误差范围内。基于氮稳定同位素估算的鱼类营养级较低的原因可能与本研究样品中低龄鱼及幼鱼比例较大有关。与其他方法相比,稳定同位素法在研究体型较小的幼鱼和低龄鱼营养级更具优势。鱼类营养级随其个体大小的变化明显,但存在种的差异性:不同体长的髭缟鰕虎鱼(Tridentiger barbatus)和绿鳍鱼(Chelidonichthys kumu)的营养级跨度较大,分别为1.54和1.43;而鳓(Ilisha elongata)等的营养级则跨度较小,这可能与不同鱼类的食性变化有关。     

水团混合及其稳定同位素成分的变化

水团的概念，一般是指在海洋中由同一源地形成的，物理、化学性质和运动状态基本一致的水体。水团本身是均匀、稳定的，但彼此之问则存在比较明显的差别。     

基于稳定同位素技术的光背团水虱食性分析

为了探究光背团水虱的食性特征,本研究利用碳、氮稳定同位素技术于2015年冬季和2016年夏季对广西北海廉州湾红树林中光背团水虱及其食物来源的碳、氮稳定同位素比值（δ13C值和δ15N值）进行分析。结果显示,冬季和夏季光背团水虱的δ13C值大小范围为-22.85‰~-21.87‰,平均值为（-22.46±0.35）‰;δ15N值大小范围为11.02‰~12.85‰,平均值为（11.88±0.56）‰;光背团水虱的δ13C值、δ15N值变化范围较小,表明其食物来源较为简单。单因素方差分析结果显示,冬季与夏季光背团水虱的平均δ13C值差异不显著（P>0.05）,而夏季的δ15N值普遍高于冬季δ15N值,差异显著（P<0.05）;不同生长阶段的光背团水虱δ13C值、δ15N值会随着体长的增长而增大,差异显著（P<0.05）,表明光背团水虱在生长的过程中可能发生了食性转变。光背团水虱的δ13C值与浮游生物的δ13C值相近,而与红树植物δ13C值差距较远,说明光背团水虱主要以浮游生物为食物来源。基于R语言稳定同位素混合模型（SIAR）计算结果显示,冬季和夏季各粒径级别浮游生物对不同生长阶段的光背团水虱的贡献率趋势基本一致,表现为1.2~25 μm粒级的浮游生物对光背团水虱平均贡献率最高,其次为25~50 μm粒级,粒径大于100 μm的浮游生物对体长小于5.5 mm的光背团水虱贡献率较低,对体长大于5.5 mm的光背团水虱的贡献率随着体长增大而相应增大,说明不同生长阶段的光背团水虱食性有差异。对光背团水虱食性分析的结果可为深入研究团水虱爆发的原因及危害红树林的作用机理提供基础资料。     

Inferring trophic variation for Antarctic krill(Euphausia superba) in the Antarctic Peninsula from the austral fall to early winter using stable isotope analysis

The Antarctic krill(Euphausia superba) is a key species in the Southern Ocean ecosystem and an important link in the food web of the Antarctic ecosystem. The trophic information for this species during the transition from the austral fall to the winter is important to understand its poorly known overwintering mechanisms. However, the few studies on the topic differ in their results, in terms of both spatial and temporal variables. We investigated the size dependence and monthly and regional variation in δ~(13) C and δ~(15) N values of adult krill in the Antarctic Peninsula, in the austral fall(April to May) and the early winter(June). We aimed to examine the trophic variations of krill occurred during this period, and the relationship between krill and their feeding environment in the Antarctic marine ecosystem. The following results were obtained:(1) no significant relationship was observed between size and the δ13 C value of krill, but the δ15 N value of krill presented a remarkable association with size;(2)the δ13 C values of krill increased during the austral fall, but no remarkable variation existed at the onset of winter,and the δ15 N values were not significant different during this period;(3) mean δ15 N values of krill differed significantly between the Bransfield Strait and the South Shetland Islands. Our data imply that adult krill present size-, season-, and region-dependent trophic variation during the transition from austral fall to early winter in the Antarctic Peninsula.     

青岛湾潮间带活体底栖有孔虫Ammonia aomoriensis (Asano,1951)壳体δ18O值的季节变化

近岸浅水底栖有孔虫是陆架海区古环境重建的重要手段,但是至今对其活体的研究非常缺乏。2014年6月至2015年5月对青岛湾潮间带活体底栖有孔虫Ammonia aomoriensis进行了连续12个月的采样,用虎红染色以确认活体。对壳径范围在200~550μm的活体壳体,以每增加50μm壳径为一组,进行δ18O测试。结果显示,A.aomoriensis壳体δ18O的月平均值的季节变化趋势与温度和盐度一致,与温度反相关,与盐度正相关,即青岛湾A.aomoriensis壳体δ18O值受温度和海水δ18O的影响,其壳体δ18O值表现出了很好的季节性波动。但是A.aomoriensis壳体δ18O的变化滞后于所测温度和盐度约2个月,其记录的是虫体在生长周期内在真实钙化温度下分馏所得的δ18O值。     

南极大磷虾粉对点带石斑鱼幼鱼氟蓄积的影响

为研究南极大磷虾(Euphausia superba)粉对点带石斑鱼幼鱼氟蓄积和生长的影响,作者通过饲养点带石斑鱼(Epinephelus malabaricus)幼鱼(初始体质量为(3.50±0.30)g,体长(5.5±0.3)cm)100 d,在基础日粮中添加0%(对照组)、2%、4%和6%的南极大磷虾粉制成4组饲料,饲料中氟质量分数分别为145.81、202.71、257.53和317.60 mg/kg。结果显示:南极大磷虾粉中的氟在点带石斑鱼幼鱼组织中的分布程度,以脊椎骨和鳃中为最高,氟质量分数分别为(58.020~114.380)mg/kg和(46.029~123.874)mg/kg,其次是皮(含鳞片)((44.127~88.761)mg/kg),再次是肝((7.654~18.248)mg/kg),而肌肉中氟蓄积最低((3.352~3.999)mg/kg);脊椎骨、皮(含鳞片)和鳃中氟含量随饲养时间的延续而产生蓄积,且与饲料中南极大磷虾粉的水平呈正相关,肝中氟含量随饲养时间延续而产生蓄积,但与南极大磷虾粉的水平无相关性,肌肉中氟含量与饲养时间和南极大磷虾粉水平均无相关性;100 d时,4%组和6%组的特定生长率处于最高水平,且显著高于对照组(P0.05)。本研究表明在饲料中添加4%~6%南极大磷虾粉,对点带石斑鱼幼鱼生长具有明显的促进作用。     

红海湾远海梭子蟹Portunus pelagicus的食物组成及营养位置分析

利用稳定同位素技术;分析了2015年5月在红海湾海域采集的远海梭子蟹Portunus pelagicus及其潜在食物的碳（δ13C）和氮（δ15N）稳定同位素比值;通过稳定同位素混合模型（SIAR）;估算不同食物对远海梭子蟹食性的相对贡献。结果表明:远海梭子蟹的δ13C值在-18.1‰~-14.1‰之间;δ15N值的范围为9.8‰~13.8‰;平均值分别为-16.9‰±1.3‰和12.1‰±2.3‰。δ13C和δ15N值的变化范围均较大;表明远海梭子蟹食物来源广泛、多样。远海梭子蟹的食物主要由双壳贝类、螺类、鱼类、头足类、虾类、蟹类和藻类组成。SIAR模型计算结果显示:藻类为远海梭子蟹的主要食物;其平均贡献为32.5%;双壳贝类的相对食性贡献为21.9%;虾类、螺类、鱼类和蟹类的平均贡献差异较小;分别为9.7%、9.7%、9.6%和9.3%;头足类的贡献最低;仅为7.3%。此外;根据δ15N值及营养位置的计算公式得出:远海梭子蟹在红海湾海域位于2.91±0.68营养级。远海梭子蟹的7类潜在食物中;藻类的营养位置最低;为1.21±0.58;其次为双壳贝类;为2.00±0.25;蟹类、螺类、虾类和鱼类的营养位置分别为2.85±0.33、2.87±0.26、3.01±0.16和3.08±0.18;头足类的最高;为3.41±0.17。     

采用碳氮稳定同位素技术对黄海中南部鳀鱼食性的研究

根据2005年4~5月在黄海和长江口海域进行的春季底拖网调查,应用稳定同位素方法研究了黄海中南部鳀鱼(Engraulis japonicus)及其可能摄食饵料的碳氮稳定同位素比值,结果表明:(1)黄海中南部鳀鱼的食物组成为不同粒径的浮游动物、太平洋磷虾(Euphausia pacifica)和仔稚鱼,其中以粒径为500~900μm的浮游动物为主,贡献比例占61%~84%;仔稚鱼贡献比例占16%~21%,较传统胃含物方法分析的结果小;(2)黄海中部海域鳀鱼的碳氮稳定同位素比值平均值较南部海域高,原因可能与各海域的能量来源不同或存在微食物环有关,也可能与不同海域鳀鱼的能量转换途径不一样,即与食物链长短不一有关.     

黄海中部太平洋磷虾的大小组成和丰度分布的季节变化及其与环境因子的关系

The seasonal size structure and spatial abundance distributions of Euphausia pacifica populations were investigated in the central part of southern Yellow Sea from August 2009 to May 2010.The abundance and biomass of E.pacifica were higher in spring and summer,and lower in autumn and winter.The mean abundance and biomass(calculated by carbon)were 74.94 ind./m~3 and 8.23 mg/m~3,respectively.Females with total length(TL)ranging between 10 and 19 mm in summer had a substantial contribution to the population biomass,whereas larvae of TL of 3–7 mm in spring were the main contributor to the population abundance.The sex ratio(female:male)showed a female bias in four seasons.Its value peaked in summer,and then decreased in autumn,spring,and winter successively.Cohort analysis revealed that the length-frequency distribution of E.pacifica could be characterized as one group with large animals(mean TL12 mm)accompanied by one or two subgroups of small individuals(mean TL7 mm).Regarding the spatial distribution,juveniles and adults of E.pacifica tend to concentrate in relatively deep water with low temperature(～11℃)and high salinity(32),whereas its larvae showed more abundance in inshore water with rich chlorophyll a,low salinity(32),and warm temperature(11℃),especially in summer and autumn.Associations changed seasonally between stage-specific abundance and environmental factors.