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  • 1
    Electronic Resource
    Electronic Resource
    Ontogenetic and seasonal changes in lipid and fatty acid/alcohol compositions of the dominant Antarctic copepods Calanus propinquus, Calanoides acutus and Rhincalanus gigas (1994)
    Springer
    Marine biology 118 (1994), S. 637-644 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lipid compositions of the dominant Antarctic copepods Calanoides acutus, Rhincalanus gigas and Calanus propinquus from the Weddell Sea have been investigated in great detail. Copepods were collected during summer in 1985 and late spring/early winter in 1986. The analyses revealed specific adaptations in the lipid biochemistry of these species which result in very different lipid components. The various copepodite stages of C. acutus synthesize wax esters with long-chain monounsaturated moieties and especially the alcohols consisted mainly of 20:1(n-9) and 22:1(n-11). R. gigas also generates wax esters, but with moieties of shorter chain length. The fatty alcohols consisted mainly of 14:0 and 16:0 components, while the major fatty acids were 20:5, 18:4 and 22:6, of which 18:4 probably originated from dietary input. In contrast, C. propinquus accumulates triacylglycerols, a very unusual depot lipid in polar calanoid copepods. Major fatty acids in C. propinquus were the long-chain monounsaturates 22:1(n-9) and 22:1(n-11), which may comprise up to 50% of total fatty acids. In C. acutus and C. propinquus there was a clear increase of long-chain fatty acids with increasing developmental stage. In contrast, the fatty acid and alcohol composition of the R. gigas copepodite stages were characterized by the dominance of the polyunsaturated fatty acids as well as high amounts of the monounsaturates 18:1(n-9) and 16:1(n-7). There was a considerable decrease of the dietary fatty acid 18:4(n-3) towards the older stages during summer; in late winter/early spring 18:4 was only detected in very low amounts. This tendency was also found in the other two species, but was less pronounced. In all three species dry weight and lipid content increased exponentially from younger to older stages. The highest portion of wax esters, or of triacylglycerols in C. propinquus, was found in the adults. Dry weight and lipid content were generally higher during summer. In late winter/early spring the variability was more pronounced and lipid-rich specimens showed a selective retention of long-chain monounsaturated fatty acids, whereas in lipid-poor specimens these fatty acids were very much depleted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00347511
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  • 2
    Electronic Resource
    Electronic Resource
    On the lipid biochemistry of polar copepods: compositional differences in the Antarctic calanoids Euchaeta antarctica and Euchirella rostromagna (1995)
    Springer
    Marine biology 123 (1995), S. 451-457 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During austral summer of 1985 different developmental stages (CIII, CIV, CV, females, males) of the Antarctic copepod Euchaeta antarctica and females of Euchirella rostromagna were collected in the southeastern Weddell Sea to determine their lipid contents and compositions. For E. antarctica the analyses revealed a strong ontogenetic accumulation of lipids towards the older copepodids with highest lipid contents in late CV stages and adults. The females of E. rostromagna had moderate lipid levels. The most striking difference between these two species concerns their lipid class compositions. E. antarctica deposited predominantly wax esters, whereas in E. rostromagna the major lipid class consisted of triacylglycerols, an unusual storage lipid in polar marine copepods. Principal fatty acids in E. antarctica were the monounsaturates 18:1(n-9) and 16:1(n-7), especially in the lipid-rich stages, while the polyunsaturated fatty acids 20:5(n-3) and 22:6(n-3), usually membrane lipids, dominated in the lipid-poor stages. The wax ester moieties in E. antarctica consisted almost entirely of 14:0 and 16:0 fatty alcohols. Major components in E. rostromagna were the fatty acids 18:1(n-9), 16:0, 20:5(n-3) and 22:6(n-3). The potential of fatty acids and alcohols as typical trophic markers is rendered largely insignificant in the two species due to catabolic processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349224
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  • 3
    Electronic Resource
    Electronic Resource
    Cd uptake by intact wheat plants (1978)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 1 (1978), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract. An investigation of the uptake of Cd by intact wheat plants has been carried out. The accumulation of Cd in the roots as a function of time and external Cd concentration was determined. Since the transport of Cd to the grains and shoots was found to be small, only uptake into the root was examined further. An appreciable fraction of the Cd absorbed by the roots can be desorbed and consequently constitutes the freely diffusible and exchangeable fraction.The effect of temperature and of metabolic inhibitors on the absorption provides evidence that another Cd fraction is taken up by metabolically mediated processes. The absorption of this Cd fraction was found to be inhibited by Cu and Zn. The inhibitory effect of Cu and Zn on Cd absorption was comparable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1978.tb02042.x
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  • 4
    Electronic Resource
    Electronic Resource
    Gas-liquid chromatographic method for the determination of marine was esters according to the degree of unsaturation
    Amsterdam : Elsevier
    Journal of Chromatography A 513 (1990), S. 327-332 
    Details
    ISSN: 0021-9673
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/S0021-9673(01)89450-4
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  • 5
    Electronic Resource
    Electronic Resource
    Diet-induced changes in the fatty acid composition of Arctic herbivorous copepods: Experimental evidence of trophic markers
    Amsterdam : Elsevier
    Journal of Experimental Marine Biology and Ecology 182 (1994), S. 97-110 
    Details
    ISSN: 0022-0981
    Keywords: Alcohol ; Arctic ; Copepod ; Fatty acid ; Feeding ; Lipid ; Trophic marker
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0022-0981(94)90213-5
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  • 6
    Electronic Resource
    Electronic Resource
    Lipids in Arctic benthos: does the fatty acid and alcohol composition reflect feeding and trophic interactions? (1997)
    Springer
    Polar biology 18 (1997), S. 53-61 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Arctic benthic organisms of various taxa (Anthozoa, Polychaeta, Pantopoda, Crustacea, Echinodermata) were collected on the shelves off northeast Greenland, Spitsbergen and the western Barents Sea. Their fatty acid compositions were generally characterised by the predominance of the polyunsaturated fatty acids 20:5(n-3) and 22:6(n-3) together with the saturated fatty acid 16:0, which reflect the dominance of phospholipids. The fatty acid compositions of most benthic specimens were influenced by fatty acids of dietary origin. High amounts of the fatty acid 16:1(n-7), typical of diatoms, were found in different taxa from the northeast Greenland shelf. The 18:4(n-3) fatty acid, often typical of non-diatom input, was only dominant in Ophiopholis aculeata from the Spitsbergen shelf. In some taxa small amounts of wax esters were detected with alcohol moieties similar to those of the dominant Arctic copepods. The occurrence of intact wax esters, as well as the wax ester typical fatty acids 20:1(n-9) and 22:1(n-11), also suggested ingestion of large herbivorous copepods. An unusual fatty acid composition was found for most brittle stars, due to a ratio of the 18:1(n-9) and (n-7) fatty acid isomers below 1 with lowest ratios of 0.1. A similar low ratio was also detected in the polychaete Onuphis conchylega. The extremely low portions of the 18:1(n-9) fatty acid are striking, since carnivores are generally characterised by high levels of this fatty acid. A clear gradient from low 18:1(n-9) to (n-7) ratios in suspension feeders, via predatory decapods, to higher ratios in the scavenging amphipods was a major characteristic of the benthic species. Our investigations showed that lipid analyses can give important hints on trophic relationships of benthic species and may serve as means to establish the intensity of pelagic-benthic coupling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003000050158
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  • 7
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    Stable isotope and fatty acid markers in plankton assemblages of a saline lake: seasonal trends and future scenario (2015)
    Oxford University Press
    Details
    Publication Date: 2015-05-24
    Description: Plankton fractions from a saline lake in Argentina were studied using a combined trophic marker approach. A strong seasonality of biomarkers was characteristic for the different fractions, particularly the variations in the 18:4( n – 3) and 20:4( n – 3) fatty acids and the 13 C values. The primary production in the lake was mainly driven by diatoms, reflected by the close relation of 13 C, chlorophyll a and diatom fatty acid markers. The combined approach of 13 C and 20:4( n – 3) enabled processes in the lipid metabolism of the copepod Boeckella poopoensis to be inferred. The polyunsaturated fatty acid 22:6( n – 3) and the 15 N separated the trophic levels in this food web with copepods at higher trophic level. Nutritional stress and omnivory of B. poopoensis partially explained the 15 N variations in mesozooplankton. The 15 N signature was probably driven by cyanobacteria in the microplankton and by microbial processes in the nanoplankton fraction. Warmer temperatures may favour the saturation of microalgae fatty acids and the abundance of plankton groups richer in saturated fatty acids. The tendency to unsaturation in mesozooplankton at colder temperatures was probably influenced by diet and metabolic requirements. Future temperature increase and eutrophication-like processes may increase the importance of cyanobacterial and bacterial markers under climate change scenarios.
    Print ISSN: 0142-7873
    Electronic ISSN: 1464-3774
    Topics: Biology
    Published by Oxford University Press
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  • 8
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    Lipid turnover reflects life-cycle strategies of small-sized Arctic copepods (2016)
    Oxford University Press
    Details
    Publication Date: 2016-11-27
    Description: This study aimed at understanding how life-cycle strategies of the primarily herbivorous Pseudocalanus minutus and the omnivorous Oithona similis are reflected by their lipid carbon turnover capacities. The copepods were collected in Billefjorden, Svalbard, and fed with 13 C labeled flagellates and diatoms during 3 weeks. Fatty acid (FA) and fatty alcohol compositions were determined by gas chromatography, 13 C incorporation was monitored using isotope ratio mass spectrometry. Maximum lipid turnover occurred in P. minutus , which exchanged 54.4% of total lipid, whereas 9.4% were exchanged in O. similis . In P. minutus , the diatom markers 16:1(n-7), 16:2(n-4) and 16:3(n-4) were almost completely renewed from the diet within 21 days, while 15% of the flagellate markers 18:2(n-6), 18:3(n-3) and 18:4(n-3) were exchanged. In O. similis , 15% of both flagellate and diatom markers were renewed. P. minutus exhibited typical physiological adaptations of herbivorous copepod species, with a very high lipid turnover rate and the ability to integrate FAs more rapidly from diatoms than from flagellates. O. similis depended much less on lipid reserves and had a lower lipid turnover rate, but was able to ingest and/or assimilate lipids with the same intensity from various food sources, to sustain shorter periods of food shortage.
    Print ISSN: 0142-7873
    Electronic ISSN: 1464-3774
    Topics: Biology
    Published by Oxford University Press
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  • 9
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    Planktonic trophic interactions in a human-impacted estuary of Argentina: a fatty acid marker approach (2014)
    Oxford University Press
    Details
    Publication Date: 2014-05-09
    Description: Few studies have been made on planktonic food webs of temperate ecosystems, especially those from the Southern Atlantic Ocean, using molecular biomarkers. The fatty acid compositions of suspended particulate matter (SPM), microplankton and mesozooplankton were studied during summer and winter at a sewage-impacted and a control site in the Bahía Blanca Estuary (Argentina). The aim was to identify trophic relationships on a spatial and seasonal scale and to detect allochthonous inputs to the food web. Fatty acid trends were consistent with the seasonal succession of the plankton community structure supporting our underlying hypothesis that regional seasonality is mostly responsible for changes in fatty acid composition. Sewage had no clear impact on the fatty acids and may not be a significant source of SPM in the estuary. However, at the sewage site the composition of the SPM was more related to terrestrially derived compounds, diatoms and bacteria, and mesozooplankton fatty acids suggested grazing on terrestrial components and on diatoms over flagellates. Saltmarshes likely have a crucial role as the main contributors to the organic fraction of SPM followed by plankton. The seasonal fatty acid pattern of the mesozooplankton indicated different feeding strategies suggesting an active feeding mode during summer and a more terrestrially associated diet in winter. The fatty acid trophic marker approach provided relevant information to clarify planktonic trophic interactions and to trace the origin of organic matter in this highly dynamic temperate coastal system.
    Print ISSN: 0142-7873
    Electronic ISSN: 1464-3774
    Topics: Biology
    Published by Oxford University Press
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  • 10
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    Arctic pelagic amphipods: lipid dynamics and life strategy (2015)
    Oxford University Press
    Details
    Publication Date: 2015-07-28
    Description: Polar regions are characterized by a strong seasonality in primary production and distinct fluctuations in food supply. The storage of energy in the form of lipids is expected to follow a seasonal pattern; however, year-round observations are lacking. The seasonal variations of lipid classes and fatty acid compositions of four pelagic amphipods have been investigated. Individuals were collected at various depths during summer and winter expeditions to the Fram Strait and Svalbard archipelago (78°–81°N). Our results show a year-round dominance of wax esters and triacylglycerols over phospholipids for Themisto abyssorum , Themisto libellula , Themisto compressa and Cyclocaris guilelmi . High levels of the Calanus -marker fatty acids 20:1 and 22:1 (both isomers) during summer and winter indicated that all four species are part of the Calanus -based food web. Specific fatty acid trophic markers for diatoms and flagellates indicated that the lipid-based energy transfer could be traced back to the respective algal sources. We found a distinct difference between animals collected from very deep and shallow waters, which indicates that the lipid reservoir of these amphipods and their biochemical modifications seem to buffer seasonal variations in available prey and to allow an active, predatory life-style year-round in Arctic waters.
    Print ISSN: 0142-7873
    Electronic ISSN: 1464-3774
    Topics: Biology
    Published by Oxford University Press
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