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EIMS Fragmentation Pathways and MRM Quantification of 7a/ß-Hydroxy-Dehydroabietic Acid TMS Derivatives.

https://arctichealth.org/en/permalink/ahliterature264371
Source
J Am Soc Mass Spectrom. 2015 Jul 3;
Publication Type
Article
Date
Jul-3-2015
Author
Jean-François Rontani
Claude Aubert
Simon T Belt
Source
J Am Soc Mass Spectrom. 2015 Jul 3;
Date
Jul-3-2015
Language
English
Publication Type
Article
Abstract
EI mass fragmentation pathways of TMS derivatives ?f 7a/ß-hydroxy-dehydroabietic acids resulting from NaBH4-reduction of oxidation products of dehydroabietic acid (a component of conifers) were investigated and deduced by a combination of (1) low energy CID-GC-MS/MS, (2) deuterium labeling, (3) different derivatization methods, and (4) GC-QTOF accurate mass measurements. Having identified the main fragmentation pathways, the TMS-derivatized 7a/ß-hydroxy-dehydroabietic acids could be quantified in multiple reaction monitoring (MRM) mode in sea ice and sediment samples collected from the Arctic. These newly characterized transformation products of dehydroabietic acid constitute potential tracers of biotic and abiotic degradation of terrestrial higher plants in the environment. Graphical Abstract ?.
PubMed ID
26138887 View in PubMed
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Electron ionization mass spectrometric fragmentation and detection of autoxidation products of 2,6,10,14-tetramethyl-7-(3-methylpent-4-enyl)-pentadec-5-ene in Arctic sediments.

https://arctichealth.org/en/permalink/ahliterature306153
Source
Rapid Commun Mass Spectrom. 2020 Aug 15; 34(15):e8816
Publication Type
Journal Article
Date
Aug-15-2020
Author
Jean-François Rontani
Lukas Smik
Simon T Belt
Author Affiliation
Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille France.
Source
Rapid Commun Mass Spectrom. 2020 Aug 15; 34(15):e8816
Date
Aug-15-2020
Language
English
Publication Type
Journal Article
Abstract
Some highly branched isoprenoid (HBI) alkenes are commonly used as proxies for palaeoceanographic reconstructions. However, there is a need to identify compounds that are sufficiently stable and abundant to be used as tracers of HBI oxidation in sediments. 2,6,10,14-Tetramethyl-7-(3-methylpent-4-enyl)-pentadec-5(Z/E)-en-4-ols resulting from 2,6,10,14-tetramethyl-7-(3-methylpent-4-enyl)-pentadec-5-ene appear to be useful for this purpose.
Comparison of electron ionization (EI) mass spectra and retention times with those of standards allowed formal identification of autoxidation products of 2,6,10,14-tetramethyl-7-(3-methylpent-4-enyl)-pentadec-5-ene. EI-MS fragmentations of TMS ethers of the main oxidation products (2,6,10,14-tetramethyl-7-(3-methylpent-4-enyl)-pentadec-5(Z/E)-en-4-ols) were deduced by gas chromatography/electron ionization mass spectrometry (GC/EI-MS), low-energy collision-induced dissociation tandem mass spectrometry (CID-MS/MS) and accurate mass measurements. These compounds were then quantified in Arctic sediment samples in MS/MS multiple reaction monitoring (MRM) mode using transitions based on the main fragmentation pathways elucidated.
2,6,10,14-Tetramethyl-7-(3-methylpent-4-enyl)-pentadec-5(Z/E)-en-4-ols were identified after autoxidation of the HBI alkene 2,6,10,14-tetramethyl-7-(3-methylpent-4-enyl)-pentadec-5-ene. Low-energy CID-MS/MS analyses and accurate mass measurements allowed the EI-MS fragmentation pathways of their trimethylsilyl (TMS) derivatives to be elucidated. Some specific fragment ions and chromatographic retention times were also useful for further characterization. As an application of some of the described fragmentations, TMS derivatives of these metabolites were characterized and quantified in MRM mode in Arctic sediments.
Due to their production in high proportions during autoxidation of their parent HBI diene, their apparent stability in sediments, and their specific EIMS fragmentations, (Z and E)-2,6,10,14-tetramethyl-7-(3-methylpent-4-enyl)-pentadec-5-en-4-ol TMS derivatives appeared to be useful tracers of HBI autoxidation in sediments.
PubMed ID
32315098 View in PubMed
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Electron ionization mass spectrometry fragmentation and multiple reaction monitoring quantification of bacterial metabolites of the sea ice biomarker proxy IP25 in Arctic sediments.

https://arctichealth.org/en/permalink/ahliterature290191
Source
Rapid Commun Mass Spectrom. 2018 May 30; 32(10):775-783
Publication Type
Journal Article
Date
May-30-2018
Author
Jean-François Rontani
Claude Aubert
Simon T Belt
Author Affiliation
Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France.
Source
Rapid Commun Mass Spectrom. 2018 May 30; 32(10):775-783
Date
May-30-2018
Language
English
Publication Type
Journal Article
Abstract
3,9,13-Trimethyl-6-(1,5-dimethylhexyl)tetradecan-1,2-diol and 2,8,12-trimethyl-5-(1,5-dimethylhexyl)tridecanoic acid appear to be produced during the bacterial metabolism of IP25 , a highly branched isoprenoid lipid often employed for past Arctic sea ice reconstruction. Characterization and quantification of these metabolites in sediments are essential to determine if bacterial degradation may exert a significant influence on IP25 -based palaeo sea ice reconstructions.
Electron ionization mass spectrometry (EIMS) fragmentation pathways of 3,9,13-trimethyl-6-(1,5-dimethylhexyl)tetradecan-1,2-diol and 2,8,12-trimethyl-5-(1,5-dimethylhexyl)tridecanoic acid trimethylsilyl (TMS) derivatives were investigated. These pathways were deduced by: (i) low-energy collision-induced dissociation (CID) gas chromatography/tandem mass spectrometry (GC/MS/MS), (ii) accurate mass measurement, and (iii) deuterium labelling.
CID-MS/MS analyses, accurate mass measurement and deuterium-labelling experiments enabled us to elucidate the EIMS fragmentations of 3,9,13-trimethyl-6-(1,5-dimethylhexyl)tetradecan-1,2-diol and 2,8,12-trimethyl-5-(1,5-dimethylhexyl)tridecanoic acid TMS derivatives. Some specific fragment ions useful in addition to chromatographic retention times for further characterization could be identified. As an application of some of the described fragmentations, the TMS derivatives of these metabolites were characterized and quantified in MRM mode in different Arctic sediments.
EIMS fragmentations of 3,9,13-trimethyl-6-(1,5-dimethylhexyl)tetradecan-1,2-diol and 2,8,12-trimethyl-5-(1,5-dimethylhexyl)tridecanoic acid TMS derivatives exhibit specific fragment ions, which appear to be very useful for the quantification of these bacterial metabolites of the palaeo tracer IP25 in sediments.
PubMed ID
29508936 View in PubMed
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Electron ionization mass spectrometry fragmentation and multiple reaction monitoring quantification of bacterial metabolites of the sea ice biomarker proxy IP25 in Arctic sediments.

https://arctichealth.org/en/permalink/ahliterature295001
Source
Rapid Commun Mass Spectrom. 2018 May 30; 32(10):775-783
Publication Type
Journal Article
Date
May-30-2018
Author
Jean-François Rontani
Claude Aubert
Simon T Belt
Author Affiliation
Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France.
Source
Rapid Commun Mass Spectrom. 2018 May 30; 32(10):775-783
Date
May-30-2018
Language
English
Publication Type
Journal Article
Keywords
Alkenes - analysis - metabolism
Arctic Regions
Bacteria - metabolism
Gas Chromatography-Mass Spectrometry - methods
Geologic Sediments - microbiology
Ice Cover - microbiology
Spectrometry, Mass, Electrospray Ionization - methods
Tandem Mass Spectrometry - methods
Terpenes - analysis - metabolism
Trimethylsilyl Compounds - analysis - metabolism
Abstract
3,9,13-Trimethyl-6-(1,5-dimethylhexyl)tetradecan-1,2-diol and 2,8,12-trimethyl-5-(1,5-dimethylhexyl)tridecanoic acid appear to be produced during the bacterial metabolism of IP25 , a highly branched isoprenoid lipid often employed for past Arctic sea ice reconstruction. Characterization and quantification of these metabolites in sediments are essential to determine if bacterial degradation may exert a significant influence on IP25 -based palaeo sea ice reconstructions.
Electron ionization mass spectrometry (EIMS) fragmentation pathways of 3,9,13-trimethyl-6-(1,5-dimethylhexyl)tetradecan-1,2-diol and 2,8,12-trimethyl-5-(1,5-dimethylhexyl)tridecanoic acid trimethylsilyl (TMS) derivatives were investigated. These pathways were deduced by: (i) low-energy collision-induced dissociation (CID) gas chromatography/tandem mass spectrometry (GC/MS/MS), (ii) accurate mass measurement, and (iii) deuterium labelling.
CID-MS/MS analyses, accurate mass measurement and deuterium-labelling experiments enabled us to elucidate the EIMS fragmentations of 3,9,13-trimethyl-6-(1,5-dimethylhexyl)tetradecan-1,2-diol and 2,8,12-trimethyl-5-(1,5-dimethylhexyl)tridecanoic acid TMS derivatives. Some specific fragment ions useful in addition to chromatographic retention times for further characterization could be identified. As an application of some of the described fragmentations, the TMS derivatives of these metabolites were characterized and quantified in MRM mode in different Arctic sediments.
EIMS fragmentations of 3,9,13-trimethyl-6-(1,5-dimethylhexyl)tetradecan-1,2-diol and 2,8,12-trimethyl-5-(1,5-dimethylhexyl)tridecanoic acid TMS derivatives exhibit specific fragment ions, which appear to be very useful for the quantification of these bacterial metabolites of the palaeo tracer IP25 in sediments.
PubMed ID
29508936 View in PubMed
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The emergence of modern sea ice cover in the Arctic Ocean.

https://arctichealth.org/en/permalink/ahliterature258476
Source
Nat Commun. 2014;5:5608
Publication Type
Article
Date
2014
Author
Jochen Knies
Patricia Cabedo-Sanz
Simon T Belt
Soma Baranwal
Susanne Fietz
Antoni Rosell-Melé
Author Affiliation
1] Department of Marine Geology, Geological Survey of Norway, NO-7491 Trondheim, Norway [2] Centre for Arctic Gas Hydrate, Environment and Climate (CAGE), Department of Geology, University of Tromsø, NO-9037 Tromsø, Norway.
Source
Nat Commun. 2014;5:5608
Date
2014
Language
English
Publication Type
Article
Abstract
Arctic sea ice coverage is shrinking in response to global climate change and summer ice-free conditions in the Arctic Ocean are predicted by the end of the century. The validity of this prediction could potentially be tested through the reconstruction of the climate of the Pliocene epoch (5.33-2.58 million years ago), an analogue of a future warmer Earth. Here we show that, in the Eurasian sector of the Arctic Ocean, ice-free conditions prevailed in the early Pliocene until sea ice expanded from the central Arctic Ocean for the first time ca. 4 million years ago. Amplified by a rise in topography in several regions of the Arctic and enhanced freshening of the Arctic Ocean, sea ice expanded progressively in response to positive ice-albedo feedback mechanisms. Sea ice reached its modern winter maximum extension for the first time during the culmination of the Northern Hemisphere glaciation, ca. 2.6 million years ago.
PubMed ID
25429795 View in PubMed
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Group 2i Isochrysidales produce characteristic alkenones reflecting sea ice distribution.

https://arctichealth.org/en/permalink/ahliterature303778
Source
Nat Commun. 2021 01 04; 12(1):15
Publication Type
Journal Article
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, Non-U.S. Gov't
Date
01-04-2021
Author
Karen Jiaxi Wang
Yongsong Huang
Markus Majaneva
Simon T Belt
Sian Liao
Joseph Novak
Tyler R Kartzinel
Timothy D Herbert
Nora Richter
Patricia Cabedo-Sanz
Author Affiliation
Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, 02912, USA. karen_wang@brown.edu.
Source
Nat Commun. 2021 01 04; 12(1):15
Date
01-04-2021
Language
English
Publication Type
Journal Article
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, Non-U.S. Gov't
Abstract
Alkenones are biomarkers produced solely by algae in the order Isochrysidales that have been used to reconstruct sea surface temperature (SST) since the 1980s. However, alkenone-based SST reconstructions in the northern high latitude oceans show significant bias towards warmer temperatures in core-tops, diverge from other SST proxies in down core records, and are often accompanied by anomalously high relative abundance of the C37 tetra-unsaturated methyl alkenone (%C37:4). Elevated %C37:4 is widely interpreted as an indicator of low sea surface salinity from polar water masses, but its biological source has thus far remained elusive. Here we identify a lineage of Isochrysidales that is responsible for elevated C37:4 methyl alkenone in the northern high latitude oceans through next-generation sequencing and lab-culture experiments. This Isochrysidales lineage co-occurs widely with sea ice in marine environments and is distinct from other known marine alkenone-producers, namely Emiliania huxleyi and Gephyrocapsa oceanica. More importantly, the %C37:4 in seawater filtered particulate organic matter and surface sediments is significantly correlated with annual mean sea ice concentrations. In sediment cores from the Svalbard region, the %C37:4 concentration aligns with the Greenland temperature record and other qualitative regional sea ice records spanning the past 14 kyrs, reflecting sea ice concentrations quantitatively. Our findings imply that %C37:4 is a powerful proxy for reconstructing sea ice conditions in the high latitude oceans on thousand- and, potentially, on million-year timescales.
PubMed ID
33397905 View in PubMed
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High contributions of sea ice derived carbon in polar bear (Ursus maritimus) tissue.

https://arctichealth.org/en/permalink/ahliterature290049
Source
PLoS One. 2018; 13(1):e0191631
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
2018
Author
Thomas A Brown
Melissa P Galicia
Gregory W Thiemann
Simon T Belt
David J Yurkowski
Markus G Dyck
Author Affiliation
Marine Ecology and Chemistry, Scottish Association for Marine Science, Oban, United Kingdom.
Source
PLoS One. 2018; 13(1):e0191631
Date
2018
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Keywords
Animals
Arctic Regions
Carbon - metabolism
Ecosystem
Ice Cover
Seawater
Ursidae - metabolism
Abstract
Polar bears (Ursus maritimus) rely upon Arctic sea ice as a physical habitat. Consequently, conservation assessments of polar bears identify the ongoing reduction in sea ice to represent a significant threat to their survival. However, the additional role of sea ice as a potential, indirect, source of energy to bears has been overlooked. Here we used the highly branched isoprenoid lipid biomarker-based index (H-Print) approach in combination with quantitative fatty acid signature analysis to show that sympagic (sea ice-associated), rather than pelagic, carbon contributions dominated the marine component of polar bear diet (72-100%; 99% CI, n = 55), irrespective of differences in diet composition. The lowest mean estimates of sympagic carbon were found in Baffin Bay bears, which were also exposed to the most rapidly increasing open water season. Therefore, our data illustrate that for future Arctic ecosystems that are likely to be characterised by reduced sea ice cover, polar bears will not only be impacted by a change in their physical habitat, but also potentially in the supply of energy to the ecosystems upon which they depend. This data represents the first quantifiable baseline that is critical for the assessment of likely ongoing changes in energy supply to Arctic predators as we move into an increasingly uncertain future for polar ecosystems.
Notes
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PubMed ID
29360849 View in PubMed
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Nordic Seas polynyas and their role in preconditioning marine productivity during the Last Glacial Maximum.

https://arctichealth.org/en/permalink/ahliterature295106
Source
Nat Commun. 2018 Sep 27; 9(1):3959
Publication Type
Journal Article
Date
Sep-27-2018
Author
Jochen Knies
Denizcan Köseoglu
Leif Rise
Nicole Baeten
Valérie K Bellec
Reidulv Bøe
Martin Klug
Giuliana Panieri
Patrycja E Jernas
Simon T Belt
Author Affiliation
Geological Survey of Norway, NO-7491, Trondheim, Norway. jochen.knies@ngu.no.
Source
Nat Commun. 2018 Sep 27; 9(1):3959
Date
Sep-27-2018
Language
English
Publication Type
Journal Article
Abstract
Arctic and Antarctic polynyas are crucial sites for deep-water formation, which helps sustain global ocean circulation. During glacial times, the occurrence of polynyas proximal to expansive ice sheets in both hemispheres has been proposed to explain limited ocean ventilation and a habitat requirement for marine and higher-trophic terrestrial fauna. Nonetheless, their existence remains equivocal, not least due to the hitherto paucity of sufficiently characteristic proxy data. Here we demonstrate polynya formation in front of the NW Eurasian ice sheets during the Last Glacial Maximum (LGM), which resulted from katabatic winds blowing seaward of the ice shelves and upwelling of warm, sub-surface Atlantic water. These polynyas sustained ice-sheet build-up, ocean ventilation, and marine productivity in an otherwise glacial Arctic desert. Following the catastrophic meltwater discharge from the collapsing ice sheets at ~17.5 ka BP, polynya formation ceased, marine productivity declined dramatically, and sea ice expanded rapidly to cover the entire Nordic Seas.
Notes
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PubMed ID
30262866 View in PubMed
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8 records – page 1 of 1.