The last glacial-interglacial cycle in Lake Ohrid (Macedonia/Albania): testing diatom response to climate
Lake Ohrid is a site of global importance for palaeoclimate research. This study presents results of diatom analysis of a ca. 136 ka sequence, Co1202, from the northeast of the lake basin. It offers the opportunity to test diatom response across two glacial-interglacial transitions and within the La...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2010-10-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/7/3083/2010/bg-7-3083-2010.pdf |
| _version_ | 1818362476903792640 |
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| author | J. M. Reed A. Cvetkoska Z. Levkov H. Vogel B. Wagner |
| author_facet | J. M. Reed A. Cvetkoska Z. Levkov H. Vogel B. Wagner |
| author_sort | J. M. Reed |
| collection | DOAJ |
| description | Lake Ohrid is a site of global importance for palaeoclimate research. This study presents results of diatom analysis of a ca. 136 ka sequence, Co1202, from the northeast of the lake basin. It offers the opportunity to test diatom response across two glacial-interglacial transitions and within the Last Glacial, while setting up taxonomic protocols for future research. The results are outstanding in demonstrating the sensitivity of diatoms to climate change, providing proxy evidence for temperature change marked by glacial-interglacial shifts between the dominant planktonic taxa, <i>Cyclotella fottii</i> and <i>C. ocellata</i>, and exact correlation with geochemical proxies to mark the start of the Last Interglacial at ca. 130 ka. Importantly, diatoms show much stronger evidence in this site for warming during MIS3 than recorded in other productivity-related proxies, peaking at ca. 39 ka, prior to the extreme conditions of the Last Glacial maximum. In the light of the observed patterns, and from the results of analysis of early Holocene sediments from a second core, Lz1120, the lack of a response to Late Glacial and early Holocene warming from ca. 14.7&ndash;6.9 ka suggests the Co1202 sequence may be compromised during this phase. After ca. 7.4 ka, there is evidence for enhanced nutrient enrichment compared to the Last Interglacial, followed by a post-Medieval loss of diversity which is consistent with cooling, but not definitive. Taxonomically, morphological variability in <i>C. fottii</i> shows no clear trends linked to climate, but an intriguing change in central area morphology occurs after ca. 48.7 ka, coincident with a tephra layer. In contrast, <i>C. ocellata</i> shows morphological variation in the number of ocelli between interglacials, suggesting climatically-forced variation or evolutionary selection pressure. The application of a simple dissolution index does not track preservation quality very effectively, underlining the importance of diatom accumulation data in future studies. |
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| id | doaj.art-a3bdb8e6dd164cde84ba56b30e7ae3f9 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-13T21:33:12Z |
| publishDate | 2010-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-a3bdb8e6dd164cde84ba56b30e7ae3f92022-12-21T23:30:45ZengCopernicus PublicationsBiogeosciences1726-41701726-41892010-10-017103083309410.5194/bg-7-3083-2010The last glacial-interglacial cycle in Lake Ohrid (Macedonia/Albania): testing diatom response to climateJ. M. ReedA. CvetkoskaZ. LevkovH. VogelB. WagnerLake Ohrid is a site of global importance for palaeoclimate research. This study presents results of diatom analysis of a ca. 136 ka sequence, Co1202, from the northeast of the lake basin. It offers the opportunity to test diatom response across two glacial-interglacial transitions and within the Last Glacial, while setting up taxonomic protocols for future research. The results are outstanding in demonstrating the sensitivity of diatoms to climate change, providing proxy evidence for temperature change marked by glacial-interglacial shifts between the dominant planktonic taxa, <i>Cyclotella fottii</i> and <i>C. ocellata</i>, and exact correlation with geochemical proxies to mark the start of the Last Interglacial at ca. 130 ka. Importantly, diatoms show much stronger evidence in this site for warming during MIS3 than recorded in other productivity-related proxies, peaking at ca. 39 ka, prior to the extreme conditions of the Last Glacial maximum. In the light of the observed patterns, and from the results of analysis of early Holocene sediments from a second core, Lz1120, the lack of a response to Late Glacial and early Holocene warming from ca. 14.7&ndash;6.9 ka suggests the Co1202 sequence may be compromised during this phase. After ca. 7.4 ka, there is evidence for enhanced nutrient enrichment compared to the Last Interglacial, followed by a post-Medieval loss of diversity which is consistent with cooling, but not definitive. Taxonomically, morphological variability in <i>C. fottii</i> shows no clear trends linked to climate, but an intriguing change in central area morphology occurs after ca. 48.7 ka, coincident with a tephra layer. In contrast, <i>C. ocellata</i> shows morphological variation in the number of ocelli between interglacials, suggesting climatically-forced variation or evolutionary selection pressure. The application of a simple dissolution index does not track preservation quality very effectively, underlining the importance of diatom accumulation data in future studies.http://www.biogeosciences.net/7/3083/2010/bg-7-3083-2010.pdf |
| spellingShingle | J. M. Reed A. Cvetkoska Z. Levkov H. Vogel B. Wagner The last glacial-interglacial cycle in Lake Ohrid (Macedonia/Albania): testing diatom response to climate Biogeosciences |
| title | The last glacial-interglacial cycle in Lake Ohrid (Macedonia/Albania): testing diatom response to climate |
| title_full | The last glacial-interglacial cycle in Lake Ohrid (Macedonia/Albania): testing diatom response to climate |
| title_fullStr | The last glacial-interglacial cycle in Lake Ohrid (Macedonia/Albania): testing diatom response to climate |
| title_full_unstemmed | The last glacial-interglacial cycle in Lake Ohrid (Macedonia/Albania): testing diatom response to climate |
| title_short | The last glacial-interglacial cycle in Lake Ohrid (Macedonia/Albania): testing diatom response to climate |
| title_sort | last glacial interglacial cycle in lake ohrid macedonia albania testing diatom response to climate |
| url | http://www.biogeosciences.net/7/3083/2010/bg-7-3083-2010.pdf |
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