کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5163667 | 1379923 | 2009 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Hydrogen isotope fractionation in freshwater and marine algae: II. Temperature and nitrogen limited growth rate effects
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
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چکیده انگلیسی
Zhang and Sachs [Hydrogen isotope fractionation in freshwater algae: I. Variations among lipids and species. Organic Geochemistry 38, 582-608, 2007] demonstrated that algal lipid δD values track water δD values with high fidelity (R2 > 0.99), but that D/H fractionation varied among lipids and algal species. Here we report on the influence of temperature and nitrogen limitation on D/H fractionation in lipids from cultured microalgae. Two species of freshwater green algae, Eudorina unicocca and Volvox aureus, were grown in batch culture at 15 °C and 25 °C. Increased D/H fractionation of 2â4â°/°C occurred at the higher temperature in all lipids analyzed. The marine diatom Thalassiosira pseudonana was grown in continuous culture under nitrogen replete (NR) and nitrogen limited (NL) conditions, resulting in a growth rate that was 4.4 fold lower under the latter conditions. The fatty acid content of NL cells was approximately 4 fold higher than in NR cells, whereas the sterol content was similar in both. While sterols from the NL culture were enriched in deuterium by 37â° relative to the NR culture, fatty acids from both cultures had similar δD values, implying that D/H fractionation during isoprenoid (branched) lipid synthesis is affected by nitrogen limitation, but D/H fractionation during acetogenic (linear) lipid synthesis is not. Cross-talk of the precursor isopentenyl diphosphate between the cytosolic MVA and plastidic DOXP/MEP synthetic pathways is a plausible mechanism for the observed D/H differences between isoprenoid and acetogenic lipids. This preliminary study highlights the need to consider both the type of lipid and potential changes in growth conditions in paleoenvironmental studies using lipid D/H ratios.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Organic Geochemistry - Volume 40, Issue 3, March 2009, Pages 428-439
Journal: Organic Geochemistry - Volume 40, Issue 3, March 2009, Pages 428-439
نویسندگان
Zhaohui Zhang, Julian P. Sachs, Adrian Marchetti,