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1.
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.  相似文献   

2.
In this study,cored sediment samples collected by the Jiaolong Submersible at 6779 m depth from the hadal zone of the Yap Trench in May 2016 were sliced in 1-cm interval from top to bottom,and lipids in each sediment layer were quantitatively and qualitatively analyzed.The vertical distribution profiles of the lipids in the sediment sample,their main existing forms,and their possible sources were investigated.The results show that the concentration of lipid in the surface sediment was the highest with the carbon number from 12 to 27,dominated by medium and short-chain lipids.The total concentration of fatty acids in surface sediment was much higher than those in the offshore and deep-sea areas,being up to 325.77μg/g due to the funnel effect caused by the“V”terrain of the trench.Fatty acid 18:0 was the most abundant lipids in the sediment sample.Abnormal high concentrations of fatty acid 18:1ω7 and alkanes indicated the existence of hydrothermal fluids in the study area.In addition,saturated fatty acids and monounsaturated fatty acids existed mainly in free form,and polyunsaturated fatty acids existed mainly in bound form.Most of the alkanes were in bound form,and their major source was autochthounous input.The carbon number of alcohols in the sediment sample ranged from 12 to 20,mainly existed in bound form.The source of fatty acids was mainly autochthonous input,and the neutral lipids had both marine and terrestrial origin.This is the first study of lipids in hadal sediment of the Yap Trench.The results will promote deeper understanding of organic carbon cycle in marine environment.  相似文献   

3.
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4.
Spatial distribution patterns of the different life stages of Euphausia superba in the region of the South Shet- land Islands and southern Scotia Sea （Antarctica） were assessed based on scientific survey data collected in lanuary and February of 2010. Adults, eggs, nauplii, metanauplii, calyptopis I-Ill, and furcilia I-II were found in the investigation. The abundance of larvae averaged 1 172.8 ind./mz, with calyptopis I and II as the dominant stages. Habitat occupancy patterns varied among Euphausia superba at different stages, and three sub-regions were identified by cluster analysis. The degree of larval development increased from west to east. Larvae were not observed north of the South Shetland Islands. Calyptopis I was predominant in the water between Elephant Island and the South Orkney Islands, which featured no thermocline. Older stages, including calyptopis II and III and furcilia I and II, were common in north and northeast of the South Orkney Islands, which were characterized by high temperature and high chlorophyll concentration. Distri- bution and abundance of the early life stages of E. superba were associated with specific environmental con- ditions. According to Biota-Environment matching （BIOENV）, the distributions of E. superba larvae were correlated with a combination of temperature at the surface and 200 m, and 0-100 m integrated chlorophyll a concentration.  相似文献   

5.
Quantitative evaluation of the copepod feeding process is critical for understanding the functioning of marine food webs, as this provides a major link between primary producers and higher trophic levels. In this study, a molecular protocol based on quantitative polymerase chain reaction(qPCR) targeting 18S rDNA was developed and used to investigate the feeding and digestion rates of the copepod Acartia erythraea in a laboratory experiment using microalgae Thalassiosira weissflogii, Prorocentrum...  相似文献   

6.
The morphology of seven specimens of Chrysaora chinensis (Scyphomedusae, Semaestomae) obtained from four sites off the coast of Peninsular Malaysia was examined. Morphological characteristics of C. chinensis that encompasses structures such as the bell, tentacles, oral arms, stomach, manubrium, radial canals and gonads were described in detail. A total of 107 specimens that represented C. chinensis populations of four coastal areas of Peninsular Malaysia (East-Central, East-North, West-Central, and West-North) were also analysed for shape variation using geometric morphometric analysis. Procrustes superimposition, Principal Component Analysis (PCA) and Canonical Variate Analysis (CVA) were applied to the images of gastrovascular pouches of C. chinensis to extract the shape information. Independent contrasts were used for comparisons between shapes. There were no significant differences in shape variation between all the specimens based on the PCA results. However, CVA results showed shape variations between specimens taken from the four areas of Peninsular Malaysia, especially with higher magnitudes of Mahalanobis distances between the east and west coast areas, including between East-Central and East-North, but lower magnitudes were detected between the West-Central and West-North.  相似文献   

7.
The food sources of aquacultured Apostichopus japonicus and the trophic levels of organisms in a sea cucumber(A. japonicus) and prawn(Penaeus japonica) polyculture system in a saltwater pond in Zhuanghe, Liaoning Province were examined using carbon and nitrogen stable isotopes. Across organisms, δ13C ranged from(–25.47±0.20)‰ to(–16.48±0.17)‰(mean±SD), and δ15N ranged from(4.23±0.49)‰ to(12.44±0.09)‰. The δ13C and δ15N contents of A. japonicus, P. japonica and Fenneropenaeus chinensis were comparatively higher than those of other organisms. Values of δ13C and δ15N revealed that P. japonica, Hemigrapsus sanguineus and Neomysis japonica comprised the largest component of the diet of A. japonicus. The mean trophic level of the organisms in this saltwater pond polyculture system was(2.75±0.08). P. japonica, A. japonicus, F. chinensis,Synechogobius hasta and Neomysis japonica were in the 3rd trophic level(2–3); jellyfish, H. sanguineus and zooplankton were in the 2nd trophic level(1–2); and Enteromorpha prolifera, benthic microalgae, periphyton and suspended matter primarily consisting of phytoplankton, bacteria and humus were in the primary trophic level(0–1).  相似文献   

8.
With the decline of fish stocks, the proportions of economically important invertebrates like crustaceans and cephalopods have increased in the Bohai Sea. The community structure and trophic level of economically important invertebrates were analyzed using the bottom trawl survey data collected by the Yellow Sea Fisheries Research Institute in the Bohai Sea in May and August of 1958–1959, 1982, 1992–1993, 2004, 2009 and 2015. A total of 37 species of economically important invertebrates, belonging to 5 orders, 24 families, were captured. The biomass densities of economically important invertebrates in the Bohai Sea displayed an overall downward trend from 1982 to 2015. Oratosquilla oratoria and Loligo spp. were the most dominant species in the past 30 years, the biomass proportion of O. oratoria increased gradually in both May and August from 1982 to 2015. Moreover,biodiversity indices of economically important invertebrates in the Bohai Sea appeared to decline from 1982 to2004 and then increased in 2015. Similarly, the mean trophic level of economically important invertebrates declined from 1982 to 2004 and increased slightly in 2015. Overall, although the proportions of invertebrates have increased, the biomass densities in the Bohai Sea have displayed an overall downward trend from 1982 to 2015.The increases in the biodiversity and trophic level of economically important invertebrates after the 2000 s,possibly benefit from stock enhancement projects implemented by governments at different levels and national fishery management measures such as the "double-control" of the total number and engine power of fishing vessels and summer moratorium of fishing.  相似文献   

9.
Feeding activities provide necessary nutrition and energy to support the reproduction and development of fish populations. The feeding ecology and dietary plasticity of fish are important factors determining their recruitment and population dynamics. As a top predator, Japanese Spanish mackerel(Scomberomorus niphonius) supports one of the most valuable fisheries in China. In this study, the feeding ecology and diet composition of Japanese Spanish mackerel spawning groups were analysed based on samples collected from six spawning grounds along the eastern coastal waters of China during spring(March to May) in 2016 and 2017. Both stomach contents and stable isotope analysis were conducted. Stomach content analysis showed that spawning groups of Japanese Spanish mackerel mainly fed on fish, consuming more than 40 different prey species. Diets were significantly different among sampling locations. The most important prey species were Stolephorus in Fuzhou, Japanese anchovy Engraulis japonicus in Xiangshan, Euphausia pacifica in Lüsi, sand lance Ammodytes personatus in Qingdao and Weihai, and Leptochela gracilis in Laizhou Bay. Stable isotope analysis showed that the trophic level of Japanese Spanish mackerel was relatively high and generally increased with latitude from south to north. In the 1980 s, the diet of Japanese Spanish mackerel was dominated solely by Japanese anchovies in the eastern coastal waters of China. The results in the present study showed that the importance of Japanese anchovies declined considerably, and this fish was not the most dominant diet in most of the investigated waters. Both the spatial variations in diet composition and changes in the dominant diet over the long term indicated the high adaptability of Japanese Spanish mackerel to the environment. Combining the results of stomach analysis and stable isotope analysis from different tissues provided more comprehensive and accurate dietary information on Japanese Spanish mackerel. The study provides essential information about the feeding ecology of Japanese Spanish mackerel and will benefit the management of its populations in the future.  相似文献   

10.
General nutrient components including moisture, ash, crude protein, lipid and carbohydrate, inorganic elements, photosynthetic pigments, amino acids and fatty acids of Bangia sp. were analyzed and compared with Porphyra yezoensis. The results indicated that the content of protein, total amino acids and free amino acids accounted for 47.2% , 42.6% and 3.3% in dried Bangia sp. , respectively, all essential amino acids were present in relatively high levels and desirable composition. Lipid was 1.8%, in which the eicosapentaenoic acid (EPA) reached 50.5% . In per 100 g dried material, the content of chlorophyll, carotenoids, phycoerythrin and phycocyanin accounted for 766, 208, 4 600 and 2963 mg, respectively. Inorganic elements necessary for human body were found to be abundant in Bangia sp. The results showed that the nutritive value of Bangia sp. was the highest among algae reported so far, and the industry of Bangia sp. was provided with significant economic importance and developing potential.  相似文献   

11.
Bacterial communities of different respiratory types were isolated from a marine sediment in a multiple chemostat system in an attempt to obtain bacterial cultures representative of the sediment. The fatty acid distribution of a mixed culture of sulphate-reducing bacteria isolated from this system showed a good correlation with the lipid distribution of the zone of maximum sulphate-reduction activity within the sediment. Both distributions had significant concentrations of C14 : 0, iso and anteiso C15 : 0, C16 : 0, C16 : 1ω7 and C18 : 1ω7. This was in contrast to the lipid profile of Desulfovibrio desulfuricans obtained by batch enrichment, which was dominated by iso C17 : 1ω7 fatty acids and correlated poorly with the sediment. The bacterial community cultured from the sediment was further differentiated according to respiratory types (aerobic, facultative aerobic and facultative anaerobic) by growth in a chemostat under defined conditions. The fatty acid distributions of these communities were sufficiently different to enable the various respiratory types to be recognized by their particular fatty acid composition. Cyclopropyl fatty acids (?17 and ?19) were present in significant levels only in the aerobic bacteria, while the facultative aerobes had significantly higher C18 : 1ω7 than the other cultures and the facultative anaerobic community was the only culture to have significant amounts of C12 : 0. The fatty acid distribution of Loch Eil sediment over the range C12-19 seemed to be predominantly of bacterial origin and were relatively abundant to a depth of 6 cm. The concentration of cyclopropyl fatty acids was highest in the oxidized surface sediments and decreased with depth as anaerobic conditions began to dominate, indicating that these fatty acids may only be indicative of aerobic sedimentary bacteria. In contrast to the fatty acids characteristic of bacteria, those fatty acids in the range C20-30 attributed to a terrestrial input were found in relatively constant concentrations over the whole 0–12 cm depth profile.  相似文献   

12.
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。  相似文献   

13.
Variations in egg volume and fatty acid (FA) content through embryogenesis were evaluated in Uca species from Inhaca island, Mozambique. Egg volume increased 96.1%, 93.3%, 84.2%, 92.9%, 96.3%, respectively, in Uca annulipes, Uca inversa, Uca urvillei, Uca chlorophthalmus and Uca vocans (p < 0.05). Fatty acid content decreased through embryogenesis, showing its importance as fuel during embryonic development. Major fatty acids were 16:0, 18:0, 16:1n-7, 18:1n-9, 18:1n-7, 18:2n-6, 20:5n-3 and 20:4n-3. Unsaturated fatty acids (UFA) and saturated fatty acids (SFA) were used up at a similar rate for U. annulipes and U. inversa contrarily to the other three species. Within the UFA, MUFA were more consumed than PUFA for all species except U. chlorophthalmus. The high values detected for fatty acid trophic markers (essential C18 and C20 PUFAs) and odd-numbered fatty acid suggest that Uca species occupy medium trophic level, primarily omnivores and scavengers/detritivores consuming algae common in the intertidal habitats. The fatty acid consumption pattern during embryonic development was essentially similar between species with some variation as expected, as FA content varies within species mainly due to female feeding ecology, nutritional and physiological conditions, differential demands on resource allocation and geographic and seasonal variations in embryonic development.  相似文献   

14.
《Marine Chemistry》2001,73(1):53-64
Antarctic hyperiid (Themisto gaudichaudi, Hyperia macrocephalus, and Primno macropa) and gammarid amphipods (Eusirus perdentatus and Orchomene rossi) were collected near Elephant Island, located in the South Shetland Islands, during January and February 1997 and 1998. Polar lipid (PL) was the major lipid class in all amphipods (58–88% of total lipid), except for T. gaudichaudi in which triacylglycerol (TAG) was dominant (62%). Cholesterol was the major sterol in the gammarid amphipods (89–91% of total sterols), and the hyperiid P. macropa (70%). The hyperiids T. gaudichaudi and H. macrocephalus had a more diverse sterol composition including trans-dehydrocholesterol, desmosterol, 24-nordehydrocholesterol, 24-methylcholest-5,22E-dien-3β-ol, 24-methylenecholesterol, and stanols (mostly cholestanol). Eicosapentaenoic acid [EPA, 20:5(n−3)] and docosahexaenoic acid [DHA, 22:6(n−3)] were the major polyunsaturated fatty acids (PUFA) in all amphipods. The PUFA octadecapentaenoic acid [18:5(n−3)] was not detected in 1997 samples, but comprised 0.3–1.2% in all 1998 samples. The PUFA 18:4(n−3) comprised 0.2–4.2% in all samples from both years. Very long chain PUFA (VLC-PUFA) (C24 and C26) were not detected in the one 1997 sample but comprised 0.6–2.8% of total fatty acids in almost all 1998 amphipods. Monounsaturated fatty acids included 18:1(n−9)c, 18:1(n−7)c, and 16:1(n−7)c. Principal saturated fatty acids in all amphipods were 16:0, 14:0, and 18:0. Examination of biomarker lipids has helped clarify trophic interactions for these Antarctic amphipods, and revealed annual differences in their food sources.  相似文献   

15.
南极大磷虾（Euphausia superba）为南大洋生态系统中的关键种，也是南极生态系统食物网中的重要枢纽。该种秋冬季转换期的营养信息对于理解其知之甚少的越冬机制非常重要。但关于此方面的少数研究在时空变化上仍存在着差异。为此，我们调查了南极半岛秋季（4-5月）和冬季（6月）磷虾成体δ13C和δ15N值的个体、月份及区域性差异。我们的目标旨在检验该期间磷虾的营养变化以及磷虾与其在南极海洋生态系统中的摄食环境之间的关系。结果如下：（1）磷虾δ13C值与体长之间无显著关系，但δ15N值与体长之间则存在显著相关性；（2）秋季磷虾δ13C值呈现增长趋势，但冬初季节并无显著变化，此期间δ15N值无显著不同；（3）布兰斯菲尔德与南设得兰群岛之间的δ15N平均值显著不同。我们的数据表明南极半岛秋至初冬转换期间磷虾成体营养呈现个体、季节性及区域性变化。  相似文献   

16.
通过对神狐海域表层5个沉积物样品进行脂肪酸组成及其碳同位素分布特征测试和研究,结果表明总脂肪酸含量分布为5.14~8.99 μg/g,碳数分布范围从C12到C32,类型包括正构饱和脂肪酸、支链脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸和类异戊二烯酸等计48种;样品中饱和的短链脂肪酸主要来自细菌与浮游生物,而长链饱和脂肪酸来自陆源高等植物,其比例表明研究海域中海洋细菌与浮游生物输入量远远大于陆源高等植物的输入。支链脂肪酸10me16:0与单不饱和脂肪酸18:1ω9、16:1ω9主要来自硫酸盐还原菌,而单不饱和脂肪酸16:1ω7很大可能来源于硫氧化菌,比较相对含量得出神狐海域表层沉积物为还原环境。样品中检测出8种类异戊二烯酸,主要是植烷酸和17,21-ββ二升藿烷酸,及少量的姥鲛酸,推测为叶绿素a和细菌微生物的共同贡献。  相似文献   

17.
除草剂San9785在高EPA后棘藻品系筛选中的应用   总被引：1，自引：0，他引：1       下载免费PDF全文
邹立红  张学成 《海洋学报》2003,25(3):98-103
后棘藻(Ellipsoidion sp.)是一种高脂海洋微藻,采用微生物筛选平板的方法,利用多不饱和脂肪酸EPA合成的阻断剂——除草剂San9785对紫外线诱变的后棘藻细胞进行了高EPA个体的筛选,气相分析结果显示,在检测的8株筛选品系中,5株EPA含量高于出发藻种,平均提高了121.6%,另3株EPA含量低于出发藻种,平均降低的量为12.6%,EPA含量最高的品系达到总脂肪酸的26.22%,比出发藻种提高了212%.提示除草剂San9785可以作为一种高效筛选压力,选育多不饱和脂肪酸含量丰富的微藻品系.  相似文献   

18.
利用超声波破碎技术在1 mol/L HCl-CH3OH 溶液中提取小球藻脂肪酸并酯化,并用气相色谱和气质联用仪对其进行定量和定性分析,鉴定出 C14:0, C16:2, C16:1, C16:0, C18:2, C18:1, C18:3, C18:0, C20:0共9种脂肪酸,其中不饱和脂肪酸占总脂肪酸的65%.6份平行样的相对标准偏差为6.04%~9.84%,样品加标回收率范围为77.0%~122.6%,各种脂肪酸甲酯的仪器检测限<0.3 ng.初步探讨了脂肪酸甲酯在弱极性色谱柱上的保留时间规律  相似文献   

19.
野生对虾与养殖对虾脂肪酸组成和含量的比较   总被引：3，自引：0，他引：3       下载免费PDF全文
野生中国对虾(Penaeus chinensis)脂肪酸的组成类似于其他的海洋动物,即雌、雄虾的肝胰脏和肌肉中,棕榈酸(16:0)和n-3族高不饱和脂肪酸(如20:5n-3和22:6n-3)占优势。野生虾体内含有的脂肪酸种类,尤其是高不饱和脂肪酸的种类多于养殖虾。野生虾肝胰脏中主要脂肪酸为16:0(20.0～22.5%),18:0(2.5～2.9%),18:1 n-9(12.3～14.0%),18:2 n-6(2.4～2.6%),20:5 n-3(6.1～6.6%)和22:6 n-3(7.1～7.5%)。肌肉中的主要脂肪酸种类大致与肝胰脏中相同。养殖虾中除了18:2 n-6(6.3～13.0%)高于和16:l(3.6～4.2%)低于野生虾外,其余的基本类似。野生虾比养殖虾有较高水平的n-3族和较低水平的n-6族不饱和脂肪酸,且野生虾n-3/n-6族脂肪酸的比率同样大于养殖虾。  相似文献   

20.
Rates of daily egg production, moulting and egg hatching success, as well as total lipid content and composition of Calanoides carinatus, were measured in the region of the southern Angola Curre nt SAC), the Angola-Benguela Front (ABF) and the coastal upwelling area of the northern Benguela Current (NBC) system during February–March 2002. There were distinct differences in the vertical distribution, growth characteristics, lipid content and composition of populations in the SAC/ABF and NBC regions, indicative of different physiological states. Whereas in the NBC, C. carinatus was actively growing in response to elevated chlorophyll a levels associated with coastal upwelling, it comprised deep-living C5 copepodids with very large wax ester reseves (c. 40–50% dry mass) and extremely low metabolism in the SAC/ABF, suggesting diapause. This study provides the first data on lipid composition (lipid classes, fatty acids and alcohols) of this copepod in the region; in particular, the diapausing C5 contained high-levels of long-chain, mono-unsaturated fatty acids (23% of all fatty acids) and alcohols (69% of all fatty alcohols) in addition to trophic markers of diatoms, viz. 16:1(n-7) and 20:5(n-3). Based on total lipidcontent, the maximum survival time of the diapausal component of C. carinatus was estimated to be 149–192 days, whereas active surface-dwelling C5s and females could not survive for more than 10 days without feeding.  相似文献   

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