scholarly journals Seasonal changes in the D  /  H ratio of fatty acids of pelagic microorganisms in the coastal North Sea

2016 ◽  
Vol 13 (19) ◽  
pp. 5527-5539 ◽  
Author(s):  
Sandra Mariam Heinzelmann ◽  
Nicole Jane Bale ◽  
Laura Villanueva ◽  
Danielle Sinke-Schoen ◽  
Catharina Johanna Maria Philippart ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Isotopic Composition ◽  
North Sea ◽  
Phytoplankton Bloom ◽  
Isotopic Fractionation ◽  
Spring Phytoplankton Bloom ◽  
Fractionation Factor ◽  
Culture Studies ◽  
Hydrogen Isotopic Composition

Abstract. Culture studies of microorganisms have shown that the hydrogen isotopic composition of fatty acids depends on their metabolism, but there are only few environmental studies available to confirm this observation. Here we studied the seasonal variability of the deuterium-to-hydrogen (D / H) ratio of fatty acids in the coastal Dutch North Sea and compared this with the diversity of the phyto- and bacterioplankton. Over the year, the stable hydrogen isotopic fractionation factor ε between fatty acids and water (εlipid/water) ranged between −172 and −237 ‰, the algal-derived polyunsaturated fatty acid nC20:5 generally being the most D-depleted (−177 to −235 ‰) and nC18:0 the least D-depleted fatty acid (−172 to −210 ‰). The in general highly D-depleted nC20:5 is in agreement with culture studies, which indicates that photoautotrophic microorganisms produce fatty acids which are significantly depleted in D relative to water. The εlipid/water of all fatty acids showed a transient shift towards increased fractionation during the spring phytoplankton bloom, indicated by increasing chlorophyll a concentrations and relative abundance of the nC20:5 polyunsaturated fatty acids, suggesting increased contributions of photoautotrophy. Time periods with decreased fractionation (less negative εlipid/water values) can potentially be explained by an increased contribution of heterotrophy to the fatty acid pool. Our results show that the hydrogen isotopic composition of fatty acids is a promising tool to assess the community metabolism of coastal plankton potentially in combination with the isotopic analysis of more specific biomarker lipids.

scholarly journals Seasonal changes in the D/H ratio of fatty acids of pelagic microorganisms in the coastal North Sea

2016 ◽  
Author(s):  
Sandra Mariam Heinzelmann ◽  
Nicole Jane Bale ◽  
Laura Villanueva ◽  
Danielle Sinke-Schoen ◽  
Katja Philippart ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Isotopic Composition ◽  
North Sea ◽  
Phytoplankton Bloom ◽  
Isotopic Fractionation ◽  
Spring Phytoplankton Bloom ◽  
Fractionation Factor ◽  
Culture Studies ◽  
Hydrogen Isotopic Composition

Abstract. Culture studies of microorganisms have shown that the hydrogen isotopic composition of fatty acids depends on their metabolism, but there are only few environmental studies available to confirm this observation. Here we studied the seasonal variability of the deuterium/hydrogen (D/H) ratio of fatty acids in the coastal Dutch North Sea and compared this with the diversity of the phyto- and bacterioplankton. Over the year, the stable hydrogen isotopic fractionation factor ε between fatty acids and water ranged between −172 ‰ and −237 ‰, the algal-derived polyunsaturated fatty acid nC20:5 being the most D-depleted and nC18:0 the least D-depleted fatty acid. The D-depleted nC20:5 is in agreement with culture studies, which indicates that photoautotrophic microorganisms produce fatty acids which are significantly depleted in D relative to water. The εlipid/water of all fatty acids showed a transient shift towards increased fractionation during the spring phytoplankton bloom, indicated by increasing chlorophyll a concentrations and relative abundance of the nC20:5 PUFA, suggesting increased contributions of photoautotrophy. Time periods with decreased fractionation (less negative εlipid/water values) can be explained by an increased contribution by heterotrophy to the fatty acid pool. Our results show that the hydrogen isotopic composition of fatty acids is a useful tool to assess the community metabolism of coastal plankton.

scholarly journals Oceanibulbus indolifex gen. nov., sp. nov., a North Sea alphaproteobacterium that produces bioactive metabolites

2004 ◽  
Vol 54 (4) ◽  
pp. 1177-1184 ◽  
Author(s):  
Irene Wagner-Döbler ◽  
Holger Rheims ◽  
Andreas Felske ◽  
Aymen El-Ghezal ◽  
Dirk Flade-Schröder ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Phylogenetic Analysis ◽  
Fatty Acid ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
North Sea ◽  
Sequence Similarity ◽  
Rrna Gene ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences

A water sample from the North Sea was used to isolate the abundant heterotrophic bacteria that are able to grow on complex marine media. Isolation was by serial dilution and spread plating. Phylogenetic analysis of nearly complete 16S rRNA gene sequences revealed that one of the strains, HEL-45T, had 97·4 % sequence similarity to Sulfitobacter mediterraneus and 96·5 % sequence similarity to Staleya guttiformis. Strain HEL-45T is a Gram-negative, non-motile rod and obligate aerobe and requires sodium and 1–7 % sea salts for growth. It contains storage granules and does not produce bacteriochlorophyll. Optimal growth temperatures are 25–30 °C. The DNA base composition (G+C content) is 60·1 mol%. Strain HEL-45T has Q10 as the dominant respiratory quinone. The major polar lipids are phosphatidyl glycerol, diphosphatidyl glycerol, phosphatidyl choline, phosphatidyl ethanolamine and an aminolipid. The fatty acids comprise 18 : 1ω7c, 18 : 0, 16 : 1ω7c, 16 : 0, 3-OH 10 : 0, 3-OH 12 : 1 (or 3-oxo 12 : 0) and traces of an 18 : 2 fatty acid. Among the hydroxylated fatty acids only 3-OH 12 : 1 (or 3-oxo 12 : 0) appears to be amide linked, whereas 3-OH 10 : 0 appears to be ester linked. The minor fatty acid components (between 1 and 7 %) allow three subgroups to be distinguished in the Sulfitobacter/Staleya clade, placing HEL-45T into a separate lineage characterized by the presence of 3-OH 12 : 1 (or 3-oxo 12 : 0) and both ester- and amide-linked 16 : 1ω7c phospholipids. HEL-45T produces indole and derivatives thereof, several cyclic dipeptides and thryptanthrin. Phylogenetic analysis of 16S rRNA gene sequences and chemotaxonomic data support the description of a new genus and species, to include Oceanibulbus indolifex gen. nov., sp. nov., with the type strain HEL-45T (=DSM 14862T=NCIMB 13983T).

scholarly journals Coupling δ<sup>2</sup>H and δ<sup>18</sup>O biomarker results yields information on relative humidity and isotopic composition of precipitation – a climate transect validation study

2015 ◽  
Vol 12 (12) ◽  
pp. 3913-3924 ◽  
Author(s):  
M. Tuthorn ◽  
R. Zech ◽  
M. Ruppenthal ◽  
Y. Oelmann ◽  
A. Kahmen ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Isotopic Composition ◽  
Validation Study ◽  
Leaf Water ◽  
Deuterium Excess ◽  
Air Humidity ◽  
Leaf Wax ◽  
Relative Air Humidity ◽  
Paleoclimate Reconstructions ◽  
Hydrogen Isotopic Composition

Abstract. The hydrogen isotopic composition (δ2H) of leaf waxes, especially of n-alkanes (δ2Hn-alkanes), is increasingly used for paleohydrological and paleoclimate reconstructions. However, it is challenging to disentangle past changes in the isotopic composition of precipitation and changes in evapotranspirative enrichment of leaf water, which are both recorded in leaf wax δ2H values. In order to overcome this limitation, Zech M. et al. (2013) proposed a coupled δ2Hn-alkanes–δ18Osugar biomarker approach. This coupled approach allows for calculating (i) biomarker-based "reconstructed" δ2Hδ18O values of leaf water (δ2Hδ18Oleaf water), (ii) biomarker-based reconstructed deuterium excess (d-excess) of leaf water, which mainly reflects evapotranspirative enrichment and which can be used to reconstruct relative air humidity (RH) and (iii) biomarker-based reconstructed δ2Hδ18Oprecipitation values. Here we present a climate transect validation study by coupling new results from δ2H analyses of n-alkanes and fatty acids in topsoils along a climate transect in Argentina with previously measured δ18O results obtained for plant-derived sugars. Accordingly, both the reconstructed RH and δ2Hδ18Oprecipitation values correlate highly significantly with actual RH and δ2Hδ18Oprecipitation values. We conclude that compared to single δ2Hn-alkane or δ18Osugar records, the proposed coupled δ2Hn-alkane–δ18Osugar biomarker approach will allow more robust δ2Hδ18Oprecipitation reconstructions in future paleoclimate research. Additionally, the proposed coupled δ2Hn-alkane–δ18Osugar biomarker approach allows for the establishment of a "paleohygrometer", more specifically, the reconstruction of mean summer daytime RH changes/history.

scholarly journals The effect of temperature, salinity and growth rate on the stable hydrogen isotopic composition of long chain alkenones produced by <I>Emiliania huxleyi</I> and <I>Gephyrocapsa oceanica</I>

2006 ◽  
Vol 3 (1) ◽  
pp. 113-119 ◽  
Author(s):  
S. Schouten ◽  
J. Ossebaar ◽  
K. Schreiber ◽  
M. V. M. Kienhuis ◽  
G. Langer ◽  
...  
Keyword(s):  
Growth Rate ◽  
Isotopic Composition ◽  
Emiliania Huxleyi ◽  
Effect Of Temperature ◽  
Fractionation Factor ◽  
Substantial Impact ◽  
The Impact ◽  
Hydrogen Isotopic Composition ◽  
Long Chain ◽  
Gephyrocapsa Oceanica

Abstract. Two haptophyte algae, Emiliania huxleyi and Gephyrocapsa oceanica, were cultured at different temperatures and salinities to investigate the impact of these factors on the hydrogen isotopic composition of long chain alkenones synthesized by these algae. Results showed that alkenones synthesized by G. oceanica were on average depleted in D by 30 compared to those of E. huxleyi when grown under similar temperature and salinity conditions. The fractionation factor, αalkenones-H2O, ranged from 0.760 to 0.815 for E. huxleyi and from 0.741 to 0.788 for G. oceanica. There was no significant correlation of αalkenones-H2O with temperature but a positive linear correlation was observed between αalkenones-H2O and salinity with ~3 change in fractionation per salinity unit and a negative correlation between αalkenones-H2O and growth rate. This suggests that both salinity and growth rate can have a substantial impact on the stable hydrogen isotopic composition of long chain alkenones in natural environments.

scholarly journals Changes in structural and functional diversity of nematode communities during a spring phytoplankton bloom in the southern North Sea

2004 ◽  
Vol 52 (4) ◽  
pp. 281-292 ◽  
Author(s):  
Jan Vanaverbeke ◽  
Maaike Steyaert ◽  
Karline Soetaert ◽  
Véronique Rousseau ◽  
Dirk Van Gansbeke ◽  
...  
Keyword(s):  
Functional Diversity ◽  
North Sea ◽  
Phytoplankton Bloom ◽  
Spring Phytoplankton Bloom ◽  
Nematode Communities ◽  
Southern North Sea
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