Application of microwave-assisted extraction to the analysis of biomarker climate proxies in marine sediments

Kornilova, Oksana; Rosell-Melé, Antoni

doi:10.1016/s0146-6380(03)00155-4

Cited by 64 publications

(44 citation statements)

References 28 publications

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“…Alkenones were extracted from freeze-dried, homogenized aliquots of sediment using microwave-assisted extraction with dichloromethane and methanol (3:1, v-v;) 32 . Known concentrations of n-tetracontane (498%, Sigma 87096) were added as an internal standard.…”

Section: Methodsmentioning

confidence: 99%

Palaeoclimate reconstructions reveal a strong link between El Niño-Southern Oscillation and Tropical Pacific mean state

et al. 2013

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The El Niño-Southern Oscillation (ENSO) is one of the most important components of the global climate system, but its potential response to an anthropogenic increase in atmospheric CO 2 remains largely unknown. One of the major limitations in ENSO prediction is our poor understanding of the relationship between ENSO variability and long-term changes in Tropical Pacific oceanography. Here we investigate this relationship using palaeorecords derived from the geochemistry of planktonic foraminifera. Our results indicate a strong negative correlation between ENSO variability and zonal gradient of sea-surface temperatures across the Tropical Pacific during the last 22 ky. This strong correlation implies a mechanistic link that tightly couples zonal sea-surface temperature gradient and ENSO variability during large climate changes and provides a unique insight into potential ENSO evolution in the future by suggesting enhanced ENSO variability under a global warming scenario.

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Section: Methodsmentioning

confidence: 99%

Palaeoclimate reconstructions reveal a strong link between El Niño-Southern Oscillation and Tropical Pacific mean state

et al. 2013

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“…Alkenones were extracted from freeze-dried samples (1 to 2 g) using 12 mL of dichloromethane and methanol (3 : 1 v/v) in a CEM MARS microwave, following the protocol of Kornilova and Rosell-Melé (2003). Extraction was aided by heating to 70 • C over 2 min, holding the temperature for 5 min, and cooling below 30 • C before further processing.…”

Section: Alkenone-based Sea Surface Temperature Reconstructionsmentioning

confidence: 99%

Highly variable Pliocene sea surface conditions in the Norwegian Sea

et al. 2017

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“…Acidified solvent extraction, especially after an initial extraction with phosphate buffer (modified Bligh-Dyer) is considered to be superior for living biomass (Bligh and Dyer 1959;Sturt et al 2004;Lipp et al 2008), whereas ASE is traditionally used in sediments and soils where most GDGT proxy records are measured. During the course of this study, we incorporated other techniques including microwave-aided extraction (MAE) (Kornilova and Rosell-Melé 2003;Escala et al 2009) as well as bead beating (BB) and proteinase K treatments, which are common extraction methods for DNA in molecular microbial ecology (e.g., Zhou et al 1996;Miller et al 1999). …”

Section: Introductionmentioning

confidence: 99%

Comparison of extraction methods for quantitative analysis of core and intact polar glycerol dialkyl glycerol tetraethers (GDGTs) in environmental samples

Huguet¹,

Martens‐Habbena²,

Urakawa³

et al. 2010

Limnology & Ocean Methods

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Archaeal membranes are composed of core lipids called glycerol dialkyl glycerol tetraethers (GDGTs) that contain polar head groups (intact GDGTs) in living cells. The reliability of Archaeal membrane lipids in studies of paleogeochemistry, population distributions, and physiological state depend on efficient extraction and detection of these lipids. We compare existing methods for extraction of core and intact GDGTs so that they can be used as quantitative indicators of living archaeal biomass. We used an active culture of the marine archaeon, Nitrosopumilus maritimus, to document limitations of methods in current use and as a reference for methodological improvement. We found that all extractable GDGTs in the culture were intact and that acid hydrolysis is the only way to quantitatively recover GDGTs from exponentially growing cells. Because acid hydrolysis removes polar head groups, it is not suitable for analysis of intact lipids. In contrast to the culture, high recovery was achieved for intact and core lipids from environmental samples, including water column particles, sediments, and soils. The high recovery from environmental samples and the large portion of core GDGTs relative to intact GDGTs suggest that lipids in the environment are largely derived from dead or dying cells. Because previous studies measured core GDGTs without acid hydrolysis, lipids contained in living cells were not detected and thus these results do not reflect viable biomass. We present a method to accurately quantify living and relict GDGTs by choosing the most efficient extraction protocol and measuring core GDGTs in extracts before and after acid hydrolysis. Here we set out to develop a method to use I-GDGTs as quantitative tracers of viable cell abundance in the environment Sturt et al. 2004). Using traditional extraction techniques on cultures of the mesophilic marine crenarchaeota, Nitrosopumilus maritimus, we discovered that lipid yields per cell varied considerably depending on the extraction technique used. Whereas it is well known that membrane lipids of archaeal cells can be difficult to extract, there are no recent reports that quantify the efficiency of currently used extraction techniques. Moreover, researchers often give no rationale for choosing one extraction protocol over another. As applications of both core and intact GDGTs grow, it is important to compare and unify GDGT extraction techniques. We searched the literature for GDGT extraction methods and measured the efficiency and degree of polar head group loss for each method using a culture of exponentially growing N. maritimus that contained only I-GDGTs. We then analyzed samples from environments where GDGT-based proxies are commonly measured, including marine water column particles, marine sediments, and soils.We evaluated five basic techniques: solvent extraction with mild acid to enhance the lyses of archaeal cells (e.g., Bligh and Dyer 1959;Nishihara and Koga 1987), accelerated solvent extraction (ASE) (e.g., Huguet et al. 2007b; Kim et al. 2008), ...

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Application of microwave-assisted extraction to the analysis of biomarker climate proxies in marine sediments

Cited by 64 publications

References 28 publications

Palaeoclimate reconstructions reveal a strong link between El Niño-Southern Oscillation and Tropical Pacific mean state

Palaeoclimate reconstructions reveal a strong link between El Niño-Southern Oscillation and Tropical Pacific mean state

Highly variable Pliocene sea surface conditions in the Norwegian Sea

Comparison of extraction methods for quantitative analysis of core and intact polar glycerol dialkyl glycerol tetraethers (GDGTs) in environmental samples

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