Bacterial reworking of sedimentary lipids during sample storage

Grimalt, Joan O.; Torras, Ester; Albaigés, Joan

doi:10.1016/0146-6380(88)90096-4

Cited by 85 publications

(29 citation statements)

References 22 publications

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“…This approach assumes that the even-numbered long-chain nalkanes (C 20 − C 34 ) in marine sediments reflect microbial input or reworking of odd-numbered n-alkanes and thus an equal amount of odd numbered long-chain n-alkanes does not originate from terrestrial higher plant material. This approach is supported by laboratory experiments that found an alteration in hydrocarbon composition and significant input of even-numbered long-chain n-alkanes due to bacterial re-working (Grimalt et al, 1988) as well as soil studies that indicate a decrease in n-alkane odd over even predominance with soil depth due to microbial reworking (Buggle et al, 2010). Therefore, the sum of the odd-numbered C 27 to C 33 n-alkane homologues was corrected for the input of reworked n-alkanes by subtracting the sum of the even-numbered C 26 to C 34 n-alkane homologues by using: Villanueva et al, 1997) where A plant is the total amount of higher plant (non-reworked) nalkanes for each sample in ng/g and C 26 − C 34 the abundance of the individual n-alkanes in ng/g.…”

Section: Accumulation Rates Of N-alkanes and N-alkan-1-olsmentioning

confidence: 50%

Strengthening of North American dust sources during the late Pliocene (2.7 Ma)

Naafs

Hefter

Acton

et al. 2012

Earth and Planetary Science Letters

126

156

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a b s t r a c t a r t i c l e i n f oHere we present orbitally-resolved records of terrestrial higher plant leaf wax input to the North Atlantic over the last 3.5 Ma, based on the accumulation of long-chain n-alkanes and n-alkanl-1-ols at IODP Site U1313. These lipids are a major component of dust, even in remote ocean areas, and have a predominantly aeolian origin in distal marine sediments. Our results demonstrate that around 2.7 million years ago (Ma), coinciding with the intensification of the Northern Hemisphere glaciation (NHG), the aeolian input of terrestrial material to the North Atlantic increased drastically. Since then, during every glacial the aeolian input of higher plant material was up to 30 times higher than during interglacials. The close correspondence between aeolian input to the North Atlantic and other dust records indicates a globally uniform response of dust sources to Quaternary climate variability, although the amplitude of variation differs among areas. We argue that the increased aeolian input at Site U1313 during glacials is predominantly related to the episodic appearance of continental ice sheets in North America and the associated strengthening of glaciogenic dust sources. Evolutional spectral analyses of the n-alkane records were therefore used to determine the dominant astronomical forcing in North American ice sheet advances. These results demonstrate that during the early Pleistocene North American ice sheet dynamics responded predominantly to variations in obliquity (41 ka), which argues against previous suggestions of precession-related variations in Northern Hemisphere ice sheets during the early Pleistocene.

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Section: Accumulation Rates Of N-alkanes and N-alkan-1-olsmentioning

confidence: 50%

Strengthening of North American dust sources during the late Pliocene (2.7 Ma)

Naafs

Hefter

Acton

et al. 2012

Earth and Planetary Science Letters

126

156

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“…The traces of n-alkanes from C 23 to C 33 with no odd/even predominance (CPI ∼ 1) in all samples, except the most superficial one at 3 m depth, indicate fossil-or microbially derived hydrocarbons (Grimalt et al, 1988;Volkman et al, 1980). However, as UCM was not detected, the fossil component in the marine suspended particles was certainly very low.…”

Section: Sources Of Organic Matter In the Suspended Particles Of The mentioning

confidence: 92%

Carbon sources in suspended particles and surface sediments from the Beaufort Sea revealed by molecular lipid biomarkers and compound-specific isotope analysis

et al. 2013

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Molecular lipid biomarkers (hydrocarbons, alcohols, sterols and fatty acids) and compound-specific isotope analysis of suspended particulate organic matter (SPM) and surface sediments of the Mackenzie Shelf and slope (southeast Beaufort Sea, Arctic Ocean) were studied in summer 2009. The concentrations of the molecular lipid markers, characteristic of known organic matter sources, were grouped and used as proxies to evaluate the relative importance of fresh algal, detrital algal, fossil, C₃ terrestrial plants, bacterial and zooplankton material in the organic matter (OM) of this area. Fossil and detrital algal contributions were the major fractions of the freshwater SPM from the Mackenzie River with ~34% each of the total molecular biomarkers. Fresh algal, C₃ terrestrial, bacterial and zooplanktonic components represented much lower percentages, 17, 10, 4 and <1%, respectively. In marine SPM from the Mackenzie slope, the major contributions were fresh and detrital algal components (>80%), with a minor contribution of fossil and C₃ terrestrial biomarkers. Characterization of the sediments revealed a major sink of refractory algal material mixed with some fresh algal material, fossil hydrocarbons and a small input of C₃ terrestrial sources. In particular, the sediments from the shelf and at the mouth of the Amundsen Gulf presented the highest contribution of detrital algal material (60–75%), whereas those from the slope contained the highest proportion of fossil (40%) and C₃ terrestrial plant material (10%). Overall, considering that the detrital algal material is marine derived, autochthonous sources contributed more than allochthonous sources to the OM lipid pool. Using the ratio of an allochthonous biomarker (normalized to total organic carbon, TOC) found in the sediments to those measured at the river mouth water, we estimated that the fraction of terrestrial material preserved in the sediments accounted for 30–40% of the total carbon in the inner shelf sediments, 17% in the outer shelf and Amundsen Gulf and up to 25% in the slope sediments. These estimates are low compared to other studies conducted 5–20 yr earlier, and they support the increase in primary production during the last decade mainly because of the increase in the number of ice-free days and due to the strength and persistence of winds favouring upwelling

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“…The presence of these compounds in the sediments also indicates organic matter in advanced stage of degradation. 51 The unsaturated triterpenoid diploptene, found in nearly all hopanoid-producing bacteria was present in lower proportions relative to the hopanes. Trisnorhop-17(21)-ene (17 (H),21 (H)) of recent biogenic origin, was generally observed in low proportions, except in station 16 where it appeared as dominant amongst all other identified polycyclic triterpenoids.…”

Section: Triterpanesmentioning

confidence: 99%

“…17,50,51 From this group only in stations 3 and 11 the UCM/resolved NAH (U/R) ratio > 4 unambiguously indicates petrogenic contamination.…”

Section: Unresolved Complex Mixture (Ucm)mentioning

confidence: 99%

Non-aromatic hydrocarbons in recent sediments of Sepetiba and Ilha Grande Bays, Brazil

Figueiredo¹,

Wagener²,

Dagaut³

et al. 2008

J. Braz. Chem. Soc.

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Realizou-se uma investigação nas Baías de Ilha Grande e de Sepetiba sobre a natureza dos hidrocarbonetos não-aromáticos (NAH) em seus sedimentos. A mistura complexa não resolvida (UCM) constituiu de 50 a 90% da concentração dos NAH, que variou entre 2,5 µg g -1 e 193,8 µg g -1 . Na maior parte das amostras a distribuição dos n-alcanos foi unimodal com predomínio de compostos de número ímpar de átomos de carbono e máximos em nC 29 e nC 31 . Monolefinas ocorreram em baixas concentrações, enquanto as poliolefinas, incluindo isoprenoides ramificados e esqualeno, variaram entre 0,099 µg g -1 e 1,387 µg g -1 , com os baixos valores relativos aos NAH surgindo em áreas de forte influência continental e antrópica. C 27 -C 33 hopanos foram encontrados em todas as amostras, assim como houve predominância da configuração 17 (H),21 (H), característica de origem petrogênica.An investigation was conducted in Ilha Grande and Sepetiba Bays aiming at identifying the nature of non-aromatic hydrocarbons (NAH) in surface sediments. NAH concentrations ranged from 2.5 µg g -1 to 193.8 µg g -1 of which the major fraction (53 to 93%) was composed by unresolved complex mixture (UMC). In most samples n-alkane distribution was dominated by compounds of odd carbon number showing maxima in nC 29 and nC 31 . Mono-olefins were at low concentrations and the polyolefins including highly branched isoprenoids and squalene varied from 0.099 µg g -1 to 1.387 µg g -1 with lower values relative to NAH appearing in areas of strong terrestrial and anthropogenic influence. Hopanes between C 27 and C 33 were observed in all samples with the predominant configuration 17 (H),21 (H), characteristic of a petrogenic origin.

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Bacterial reworking of sedimentary lipids during sample storage

Cited by 85 publications

References 22 publications

Strengthening of North American dust sources during the late Pliocene (2.7 Ma)

Strengthening of North American dust sources during the late Pliocene (2.7 Ma)

Carbon sources in suspended particles and surface sediments from the Beaufort Sea revealed by molecular lipid biomarkers and compound-specific isotope analysis

Non-aromatic hydrocarbons in recent sediments of Sepetiba and Ilha Grande Bays, Brazil

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