Alkenone distribution in Lake Van sediment over the last 270 ka: influence of temperature and haptophyte species composition
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 al...
| Main Authors: | , , , , , , , , , |
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| Format: | Journal Article |
| Published: |
Pergamon
2014
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| Online Access: | http://hdl.handle.net/20.500.11937/42613 |
| _version_ | 1848756468725055488 |
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| author | Randlett, M. Coolen, Marco Stockhecke, M. Pickarski, N. Litt, T. Balkema, C. Kwiecien, O. Tomonaga, Y. Wehrli, B. Schubert, C.J. |
| author_facet | Randlett, M. Coolen, Marco Stockhecke, M. Pickarski, N. Litt, T. Balkema, C. Kwiecien, O. Tomonaga, Y. Wehrli, B. Schubert, C.J. |
| author_sort | Randlett, M. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | 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 270 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 ~100 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. Thepredominance of LVHap_6 coincided with the presence of alkenone MeC38:3 and relatively highMeC37:3/4 (2.4) and MeC38:4/5 ratios (3.0). Uk37 index values in the sediment core over the last 270 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. |
| first_indexed | 2025-11-14T09:12:41Z |
| format | Journal Article |
| id | curtin-20.500.11937-42613 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:12:41Z |
| publishDate | 2014 |
| publisher | Pergamon |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-426132017-09-13T16:03:55Z Alkenone distribution in Lake Van sediment over the last 270 ka: influence of temperature and haptophyte species composition Randlett, M. Coolen, Marco Stockhecke, M. Pickarski, N. Litt, T. Balkema, C. Kwiecien, O. Tomonaga, Y. Wehrli, B. Schubert, C.J. 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 270 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 ~100 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. Thepredominance of LVHap_6 coincided with the presence of alkenone MeC38:3 and relatively highMeC37:3/4 (2.4) and MeC38:4/5 ratios (3.0). Uk37 index values in the sediment core over the last 270 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. 2014 Journal Article http://hdl.handle.net/20.500.11937/42613 10.1016/j.quascirev.2014.07.009 Pergamon unknown |
| spellingShingle | Randlett, M. Coolen, Marco Stockhecke, M. Pickarski, N. Litt, T. Balkema, C. Kwiecien, O. Tomonaga, Y. Wehrli, B. Schubert, C.J. Alkenone distribution in Lake Van sediment over the last 270 ka: influence of temperature and haptophyte species composition |
| title | Alkenone distribution in Lake Van sediment over the last 270 ka: influence of temperature and haptophyte species composition |
| title_full | Alkenone distribution in Lake Van sediment over the last 270 ka: influence of temperature and haptophyte species composition |
| title_fullStr | Alkenone distribution in Lake Van sediment over the last 270 ka: influence of temperature and haptophyte species composition |
| title_full_unstemmed | Alkenone distribution in Lake Van sediment over the last 270 ka: influence of temperature and haptophyte species composition |
| title_short | Alkenone distribution in Lake Van sediment over the last 270 ka: influence of temperature and haptophyte species composition |
| title_sort | alkenone distribution in lake van sediment over the last 270 ka: influence of temperature and haptophyte species composition |
| url | http://hdl.handle.net/20.500.11937/42613 |