Lipids and their oxidation products as biomarkers for carbon cycling in the northwestern Mediterranean Sea: results from a sediment trap study

Marchand, Daphné; Marty, Jean-Claude; Miquel, Juan‐Carlos; Rontani, Jean‐François

doi:10.1016/j.marchem.2004.09.001

Cited by 45 publications

(28 citation statements)

References 64 publications

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“…Unfortunately, they are too labile to be used for this purpose. In contrast, autoxidation and photooxidation products of monounsaturated fatty acids, although produced much more slowly, are stable enough in the environment to act as markers of these processes Rontani, 2001, 2003;Marchand et al, 2005;Rontani et al, 2011). Singlet oxygen ( 1 O 2 )-mediated photooxidation of monounsaturated fatty acids involves a direct reaction of 1 O 2 with the carbon-carbon double bond by a concerted "ene" addition (Frimer, 1979) and leads to formation of hydroperoxides at each carbon of the original double bond with an allylic trans-double bond, which can subsequently undergo highly stereoselective radical allylic rearrangement (Porter et al, 1995;Fig.…”

Section: Choice Of Fatty Acid Degradation Tracers and Estimation Of Pmentioning

confidence: 99%

Degradation state of organic matter in surface sediments from the Southern Beaufort Sea: a lipid approach

et al. 2012

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Abstract. For the next decades significant climatic changes should occur in the Arctic zone. The expected destabilisation of permafrost and its consequences for hydrology and plant cover should increase the input of terrigenous carbon to coastal seas. Consequently, the relative importance of the fluxes of terrestrial and marine organic carbon to the seafloor will likely change, strongly impacting the preservation of organic carbon in Arctic marine sediments. Here, we investigated the lipid content of surface sediments collected on the Mackenzie basin in the Beaufort Sea. Particular attention was given to biotic and abiotic degradation products of sterols and monounsaturated fatty acids. By using sitosterol and campesterol degradation products as tracers of the degradation of terrestrial higher plant inputs and brassicasterol degradation products as tracers of degradation of phytoplanktonic organisms, it could be observed that autoxidation, photooxidation and biodegradation processes act much more intensively on higher plant debris than on phytoplanktonic organisms. Examination of oxidation products of monounsaturated fatty acids showed that photo-and autoxidation processes act more intensively on bacteria than on phytodetritus. Enhanced damages induced by singlet oxygen (transferred from senescent phytoplanktonic cells) in bacteria were attributed to the lack of an adapted antioxidant system in these microorganisms. The strong oxidative stress observed in the sampled sediments resulted in the production of significant amounts of epoxy acids and unusually high proportions of monounsaturated fatty acids with a trans double bond. The formation of epoxy acids was attributed to peroxygenases (enzymes playing a protective role against the deleterious effects of fatty acid hydroperoxides in vivo), while cis/trans isomerisation was probably induced by thiyl radicals produced during the reaction of thiols with hydroperoxides. Our results confirm the important role played by abiotic oxidative processes in the degradation of marine bacteria and do not support the generally expected refractory character of terrigenous material deposited in deltaic systems.

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Section: Choice Of Fatty Acid Degradation Tracers and Estimation Of Pmentioning

confidence: 99%

Degradation state of organic matter in surface sediments from the Southern Beaufort Sea: a lipid approach

et al. 2012

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“…1 and 3). Selected ion monitoring (SIM) analyses (using m/z 169, 183, 245 and 353) of silylated NaBH 4 -reduced neutral lipid extracts of particulate matter samples collected at the DYFAMED station (Ligurian Sea) 10 allowed us to detect significant amounts of the diols 1, 6, 7, 8 and 9 (Fig. 4).…”

Section: Characterization Of Isomeric Diols 1 6 7 8 and 9 In Naturmentioning

confidence: 99%

Characterization of isomeric allylic diols resulting from chlorophyll phytyl side‐chain photo‐ and autoxidation by electron ionization gas chromatography/mass spectrometry

Rontani

Aubert²

2005

Rapid Comm Mass Spectrometry

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The electron ionization (EI) mass spectral fragmentation of the trimethylsilyl derivatives of 3-methylidene-7,11,15-trimethylhexadecane-1,2-diol, Z- and E-3,7,11,15-tetramethylhexadec-3-ene-1,2-diols and Z- and E-3,7,11,15-tetramethylhexadec-2-ene-1,4-diols resulting from chlorophyll phytyl side-chain photo- and autoxidation was investigated. Different pathways (substantiated by deuterium labelling) were proposed in order to explain the main fragmentation observed. Then, some sufficiently specific fragment ions were selected and used to characterize these compounds in natural environmental samples.

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“…As a result, sedimentary MAs and MBs will be enriched in C 28 members compared to other steroidal biomarkers. It should be noted here that photooxidation/autoxidation products of D 5 -sterols such as ster-5-en-3,7-diols and ster-4-en-3,6-diols, recently identified in sediment trap samples and surface sediments from Mediterranean Sea, have also been proposed as potential sources for sedimentary steratrienes (Rontani and Marchand, 2000;Marchand et al, 2005). In this case, sedimentary MAs and MBs might also be formed readily from D 5 -sterols in the same way.…”

Section: Precursors Of Mas and Mbs In Sedimentsmentioning

confidence: 73%

Acid catalysed backbone rearrangement of cholesta-2,4,6-triene: On the origin of ring A and ring B aromatic steroids in recent sediments

Schüpfer

Finck

Houot

et al. 2007

Organic Geochemistry

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Rearrangement of cholesta-2,4,6-triene in the presence of p-toluenesulfonic acid in acetic acid at 70°C leads to 4-methyl-19-nor-cholesta-1,3,5(10)-triene and 1(10 ! 6)-abeo-14b-cholesta-5,7,9(10)-triene in less than 2 h. Postulated mechanisms of formation of these products are supported by molecular mechanics calculations of the relative stabilities of reaction intermediates. The results suggest that D 5,7 -sterols, the most common natural precursors of triunsaturated steroidal hydrocarbons in contemporary sediments, constitute another major source for monoaromatic A and B steroids in addition to D 5 -sterols.

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Lipids and their oxidation products as biomarkers for carbon cycling in the northwestern Mediterranean Sea: results from a sediment trap study

Cited by 45 publications

References 64 publications

Degradation state of organic matter in surface sediments from the Southern Beaufort Sea: a lipid approach

Degradation state of organic matter in surface sediments from the Southern Beaufort Sea: a lipid approach

Characterization of isomeric allylic diols resulting from chlorophyll phytyl side‐chain photo‐ and autoxidation by electron ionization gas chromatography/mass spectrometry

Acid catalysed backbone rearrangement of cholesta-2,4,6-triene: On the origin of ring A and ring B aromatic steroids in recent sediments

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