کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6445547 | 1640830 | 2014 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Alkenone distribution in Lake Van sediment over the last 270Â ka: influence of temperature and haptophyte species composition
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
زمین شناسی
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![عکس صفحه اول مقاله: Alkenone distribution in Lake Van sediment over the last 270Â ka: influence of temperature and haptophyte species composition Alkenone distribution in Lake Van sediment over the last 270Â ka: influence of temperature and haptophyte species composition](/preview/png/6445547.png)
چکیده انگلیسی
Fossil long-chain alkenones have been used for several decades to reconstruct past ocean surface water temperatures and gained recent interest as a paleotemperature proxy for continental lake settings. However, factors besides temperature can affect alkenone distributions in haptophyte algae, and alkenone compositions can differ between haptophyte species. Alkenone-biosynthesizing haptophyte algae are genetically much more diverse in lakes than in the marine realm, and species-level variations in alkenone compositions could have implications for alkenone paleothermometry. Here, we performed a paired analysis of alkenone distributions and haptophyte species compositions using ancient DNA in up to 270Â ka-old sediments of Lake Van in Turkey to reveal a possible species-effect on fossil alkenone distributions and paleotemperature estimates. The same predominant haptophyte in Lake Van today prevailed also since the last â¼100Â ka. However, a calibration of alkenone paleotemperature especially in the oldest analyzed intervals is complicated due to a more complex haptophyte species composition predominated by a haptophyte (LVHap_6), which is phylogenetically different from sequences recovered from currently existing lakes including Lake Van and from haptophyte species existing in culture. The predominance of LVHap_6 coincided with the presence of alkenone MeC38:3 and relatively high MeC37:3/4 (2.4) and MeC38:4/5 ratios (3.0). Uk37 index values in the sediment core over the last 270Â ka reflect relative changes in past temperature and are additionally linked to haptophyte species composition. A sustained period of high salinity, as indicated by pore-water salinity measurements, could potentially have triggered the succession of haptophytes as sources of alkenones in Lake Van.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Quaternary Science Reviews - Volume 104, 15 November 2014, Pages 53-62
Journal: Quaternary Science Reviews - Volume 104, 15 November 2014, Pages 53-62
نویسندگان
Marie-Ãve Randlett, Marco J.L. Coolen, Mona Stockhecke, Nadine Pickarski, Thomas Litt, Cherel Balkema, Ola Kwiecien, Yama Tomonaga, Bernhard Wehrli, Carsten J. Schubert,