The possible metabolic role of C37 alkenones in Emiliania huxleyi

Epstein, B.; Dhondt, Steven; Hargraves, Paul E.

doi:10.1016/s0146-6380(01)00026-2

Cited by 85 publications

(57 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since the degree of unsaturation varies as a function of growth temperature, it has been speculated that alkenones have a role in regulating membrane fluidity (e.g., Prahl and Wakeham, 1987;Brassell, 1993). More recently, it has been suggested that E. huxleyi uses alkenones for metabolic storage (Bell and Pond, 1996;Epstein et al, 2001) or that their biosynthesis might be associated with the function of the coccolith-producing compartment (CPC) (Sawada and Shiraiwa, 2004). The hypothesis that alkenones serve as energy reserves has recently been corroborated by Eltgroth et al (2005) who furthermore found evidence that alkenones as well as polyunsaturated long-chain alkenoates and alkenes (PUL-CA) are synthesised in the chloroplast and subsequently packaged into lipid bodies and exported to the cytoplasm.…”

Section: Implications For the Metabolic Role Of Alkenones And Their Amentioning

confidence: 99%

Carbon isotopic fractionation during a mesocosm bloom experiment dominated by Emiliania huxleyi: Effects of CO2 concentration and primary production

Benthien

Zondervan

Engel

et al. 2007

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

We investigated the effect of CO 2 and primary production on the carbon isotopic fractionation of alkenones and particulate organic matter (POC) during a natural phytoplankton bloom dominated by the coccolithophore Emiliania huxleyi. In nine semi-closed mesocosms ($11 m 3 each), three different CO 2 partial pressures (pCO 2 ) in triplicate represented glacial ($180 ppmv CO 2 ), present ($380 ppmv CO 2 ), and year 2100 ($710 ppmv CO 2 ) CO 2 conditions. The largest shift in alkenone isotopic composition (4-5&) occurred during the exponential growth phase, regardless of the CO 2 concentration in the respective treatment. Despite the difference of $500 ppmv, the influence of pCO 2 on isotopic fractionation was marginal (1-2&). During the stationary phase, E. huxleyi continued to produce alkenones, accumulating cellular concentrations almost four times higher than those of exponentially dividing cells. Our isotope data indicate that, while alkenone production was maintained, the interaction of carbon source and cellular uptake dynamics by E. huxleyi reached a steady state. During stationary phase, we further observed a remarkable increase in the difference between d 13 C of bulk organic matter and of alkenones spanning 7-12&. We suggest that this phenomenon is caused mainly by a combination of extracellular release of 13 C-enriched polysaccharides and subsequent particle aggregation induced by the production of transparent exopolymer particles (TEP).

show abstract

Section: Implications For the Metabolic Role Of Alkenones And Their Amentioning

confidence: 99%

Carbon isotopic fractionation during a mesocosm bloom experiment dominated by Emiliania huxleyi: Effects of CO2 concentration and primary production

Benthien

Zondervan

Engel

et al. 2007

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

show abstract

“…Growing concerns about specific proxies for continental palaeotemperature and progress in the alkenone proxy for palaeo sea surface temperature (e.g., Volkman et al, 1980;Marlowe et al, 1984;Brassell et al, 1986;Prahl et al, 1989;Sikes et al, 1991;Conte et al, 1992;Rontani et al, 1997;Sonzogni et al, 1997;Herbert et al, 1998;Mü ller et al, 1998;Teece et al, 1998;Prahl et al, 2000;Epstein et al, 2001;Harada et al, 2006;Zhao et al, 2006) 0146-6380/$ -see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016All rights reserved.…”

Section: Introductionmentioning

confidence: 99%

“…/j.orggeochem.2007 have led to numerous studies of alkenone distributions and their relationship with temperature in limnic environments (Li et al, 1996;Thiel et al, 1997;Innes et al, 1998;Sheng et al, 1998;Wang and Zheng, 1998;Zink et al, 2001;Sun et al, 2004;Chu et al, 2005;D'Andrea and Huang, 2005;Theissen et al, 2005;Liu et al, 2006). Studies of the marine environment indicate that the U K 0 37 temperature relationships for the species C. lamellosa, I. galbana, E. huxleyi and G. oceanica differ significantly from each other (Marlowe et al, 1984;Brassell, 1993;Volkman et al, 1995;Sawada et al, 1996;Conte et al, 1998;Epstein et al, 1998Epstein et al, , 2001Yamamoto et al, 2000;Versteegh et al, 2001;Prahl et al, 2006a,b). Conte et al (1998) emphasized the importance of variations in alkenone based calibrations among different alkenone-synthesizing species and populations.…”

Section: Introductionmentioning

confidence: 99%

Calibration of alkenone unsaturation index with growth temperature for a lacustrine species, Chrysotila lamellosa (Haptophyceae)

Sun¹,

Chu

Liu

et al. 2007

Organic Geochemistry

View full text Add to dashboard Cite

“…It has been suggested that alkenones and associated compounds participate in the buoyancy of cells (Fernandez et al, 1994), somehow regulate membrane fluidity, or are associated with formation of coccoliths (Sawada and Shiraiwa, 2004). Some recent studies suggest that alkenones are metabolic storage lipids and that their metabolic utilisation is not a source of error in the temperature estimation (Epstein et al, 2001;Sawada and Shiraiwa, 2004). Whatever their exact physiological role, the important point here is their rate of turnover.…”

Section: Modelling An Alkenone Temperature Proxymentioning

confidence: 99%

Modelling an alkenone-like proxy record in the NW African upwelling

Giraud

2006

Biogeosciences

View full text Add to dashboard Cite

Abstract.A regional biogeochemical model is applied to the NW African coastal upwelling between 19 • N and 27 • N to investigate how a water temperature proxy, alkenones, are produced at the sea surface and recorded in the slope sediments. The biogeochemical model has two phytoplankton groups: an alkenone producer group, considered to be coccolithophores, and a group comprising other phytoplankton. The Regional Ocean Modelling System (ROMS) is used to simulate the ocean circulation and takes advantage of the Adaptive Grid Refinement in Fortran (AGRIF) package to set up an embedded griding system. In the simulations the alkenone temperature records in the sediments are between 1.1 and 2.3 • C colder than the annual mean SSTs. Despite the seasonality of the coccolithophore production, this temperature difference is not mainly due to a seasonal bias, nor to the lateral advection of phytoplankton and phytodetritus seaward from the cold near-shore waters, but to the production depth of the coccolithophores. If coretop alkenone temperatures are effectively recording the annual mean SSTs, the amount of alkenone produced must vary among the coccolithophores in the water column and depend on physiological factors (e.g. growth rate, nutrient stress).

show abstract

The possible metabolic role of C37 alkenones in Emiliania huxleyi

Cited by 85 publications

References 25 publications

Carbon isotopic fractionation during a mesocosm bloom experiment dominated by Emiliania huxleyi: Effects of CO2 concentration and primary production

Carbon isotopic fractionation during a mesocosm bloom experiment dominated by Emiliania huxleyi: Effects of CO2 concentration and primary production

Calibration of alkenone unsaturation index with growth temperature for a lacustrine species, Chrysotila lamellosa (Haptophyceae)

Modelling an alkenone-like proxy record in the NW African upwelling

Contact Info

Product

Resources

About