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  • 11
    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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  • 12
    Electronic Resource
    Electronic Resource
    Changes in lipids during the development of Calanus finmarchicus s.l. from Copepodid I to adult (1987)
    Springer
    Marine biology 96 (1987), S. 511-518 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The total lipid and wax ester content as well as the fatty acid and alcohol composition of all copepodid stages and adults of Calanus finmarchicus s.l. were investigated at different locations in the North Sea in 1983 and 1984. Total lipid and the wax ester proportion increased exponentially until Copepodid V. The females were sometimes lower in lipids than the Stage V. The wax ester proportion reached about 90% of total lipids in males and Copepodid V and up to 40% in Copepodid I. The major fatty acids were 16:0, 20:5, and 22:6 and the major fatty alcohols were 16:0, 20:1 and 22:1. At one station the 18:4 acid became one of the dominant acids, because of a Phaeocystis sp. bloom, indicating that the fatty acids of the diet are incorporated mostly unchanged into the lipids of the copepods. The other main fatty acids 20:1 and 22:1 are probably synthesized de novo, serving as precursors for the principal alcohols 20:1 and 22:1. Their levels decreased in the younger stages due to increases in 16:0 alcohol. The fatty alcohol-forming enzyme seems to be specific for saturated and monounsaturated acids, which may be synthesized de novo or derived from diet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397968
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  • 13
    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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  • 14
    Electronic Resource
    Electronic Resource
    The North East Water polynya (Greenland Sea) (1994)
    Springer
    Polar biology 14 (1994), S. 483-490 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The nutrient and phytoplankton distributions in the North East Water polynya (NEW) were determined in June 1991. At Norske Øer Ice Barrier (the polynya's southern boundary), water was upwelled, but vertical instability precluded the development of phytoplankton blooms. Along the length of the northward coastal current, part of the anticyclonic circulation in this area, the vertical stability increased to the north by the input of melt water and solar heating. This caused a gradual increase in phytoplankton biomass and a decrease in nutrient concentrations until, in the northernmost area, nitrate was depleted at the surface, and sub-surface maxima of chlorophyll a were observed. The band of high chlorophyll a concentrations extending from this area to the south along the eastern margin of the polynya was interpreted as the presence of phytoplankton advected by the local circulation. The phytoplankton communities, consisting mainly of flagellates and diatoms, were typical for the beginning of phytoplankton development in ice-covered areas. They seemed to be partially released from melting ice. Three communities were distinguished, which represented, firstly, the upwelled water and its northern extension, secondly, an area of high phytoplankton biomass in the northwestern part of the polynya, and thirdly, the pack-ice region. The major taxa co-occurred at all stations, with only their relative importance changed. The nutrient concentrations in the NEW were different from those in the adjacent areas. The low nitrate values of about 4 μM in the upper 70 m, found to be representative for the beginning of the growth season, imposed limitations on the overall phytoplankton production. Therefore, fertilization mechanisms such as upwelling along the Norske Øer Ice Barrier are important for local nutrient replenishment during the period of active phytoplankton growth. Eventually, silicate and phosphate supplied in higher concentrations by jets of the Arctic outflow may also support phytoplankton production, although these nutrients were not limiting during this study. The high-nutrient jets were detected in the upper 100 m of the water column at the eastern boundary of the polynya.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239053
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  • 15
    Electronic Resource
    Electronic Resource
    Automatic method for the determination of ortho-phosphate and total dissolved phosphorus in the marine environment (1987)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 326 (1987), S. 354-357 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary An automatic method for the determination of ortho-phosphate in seawater is described. It is based on the original molybdenum blue method and is very sensitive because of the very small dilution of samples by reagents. An all-glass reaction manifold is proposed, the use of plastic material should be avoided as far as possible. The described method may also be used in a slightly modified version for the determination of total dissolved phosphorus, when samples are first digested with peroxidisulfate. Orthophosphate and total dissolved phosphorus can be determined exactly in the concentration range from 0.01–5 μg at P/l with a sampling frequency of 30 h−1.
    Notes: Zusammenfassung Für die Bestimmung von ortho-Phosphat in Seewasser wird eine automatische Methode beschrieben, die auf der üblichen Molybdänblaumethode basiert und sehr empfindlich ist, weil die Proben mit einer sehr geringen Menge Reagenz verdünnt werden. Für die Reaktionseinheit wird ein Allglassystem vorgeschlagen, der Einsatz von Plastikmaterial sollte weitgehend vermieden werden. Die beschriebene Methode ist in leicht modifizierter Form auch für die Bestimmung von gelöstem Gesamt-Phosphor geeignet, wenn die Proben zuvor mit Peroxodisulfat aufgeschlossen werden. Die Methode liefert bei einer Probenfrequenz von 30 h−1 für ortho-Phosphat und gelösten Gesamt-Phosphor genaue Ergebnisse im Bereich von 0,01–5 μg at P/1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00469784
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  • 16
    Electronic Resource
    Electronic Resource
    Semi-automated methods for the determination of particulate phosphorus in the marine environment (1980)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 301 (1980), S. 14-16 
    Details
    ISSN: 1618-2650
    Keywords: Best. von Phosphor in Wasser ; Spektralphotometrie, AutoAnalyzer, Meerwasser, partikulärer Phosphor, Mo-Komplex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary After filtration of sea water through glass fiber filters, the filters with the residue are digested by heating with sulphuric acid and hydrogen peroxide. The following determination of phosphate is based on the formation of a phosphomolybdenum complex. It has been modified in such a way that the phosphorus content of the samples can be determined with a continuous-flow system with the TechniconAutoAnalyzer direct after digestion. Two methods are described for different sensitivities of 0.1–10μmol P · l−1.
    Notes: Zusammenfassung Der Rückstand bei Filtration von Meerwasser durch Glasfaserfilter wird mit Schwefelsäure und Wasserstoffperoxid aufgeschlossen. Die anschließende Phosphatbestimmung basiert auf der Bildung eines Phosphormolybdän-Komplexes. Sie wurde modifiziert, so daß der Phosphor-Gehalt der Proben sofort nach Aufschluß mit dem Durchflußsystem des Technicon-AutoAnalyzers bestimmt werden kann. Zwei Methoden mit unterschiedlicher Empfindlichkeit (von 0,1–10μmol P · l−1) werden beschrieben.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00481264
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  • 17
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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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  • 18
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    The impact of dissolved organic carbon and bacterial respiration on pCO2 in experimental sea ice (2016)
    Elsevier
    Details
    Publication Date: 2016-02-01
    Print ISSN: 0079-6611
    Electronic ISSN: 1873-4472
    Topics: Geosciences , Physics
    Published by Elsevier
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  • 19
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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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  • 20
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    Contribution of humic substances to the dissolved nitrogen pool in the Greenland Sea (1993)
    Elsevier
    Details
    Publication Date: 1993-02-01
    Print ISSN: 0304-4203
    Electronic ISSN: 1872-7581
    Topics: Geosciences
    Published by Elsevier
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