New insights into Holocene hydrology and temperature from lipid biomarkers in western Mediterranean alpine wetlands
Alpine regions of the Mediterranean realm are among the most climatically sensitive areas in the world. Thus, alpine wetlands from the southern Iberian Peninsula, in the westernmost part of the Mediterranean region, are highly sensitive sensors of environmental changes. Difficulties have surfaced in...
| Published in: | Quaternary Science Reviews |
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| Main Authors: | , , , , , |
| Other Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | unknown |
| Published: |
Elsevier BV
2020
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| Subjects: | |
| Online Access: | http://hdl.handle.net/10261/225051 https://doi.org/10.1016/j.quascirev.2020.106395 https://doi.org/10.13039/501100000780 https://doi.org/10.13039/501100003329 https://doi.org/10.13039/501100011011 |
| Summary: | Alpine regions of the Mediterranean realm are among the most climatically sensitive areas in the world. Thus, alpine wetlands from the southern Iberian Peninsula, in the westernmost part of the Mediterranean region, are highly sensitive sensors of environmental changes. Difficulties have surfaced in separating controls by temperature and/or precipitation in previous paleoenvironmental studies from alpine environments in this area. We present a Holocene biomarker record (n-alkanes and long-chain diols) from a high elevation lake, Laguna de Río Seco (LdRS), in the south of the Iberian Peninsula, which contributes to the identification of these forcing mechanisms. The hydrological history of the area, primarily water availability and evapotranspiration, is reconstructed by means of the n-alkane record, including the indices of average chain length, portion aquatic, and carbon preference index, as well as hydrogen isotopes (δD) of aquatic (δD) and terrestrial (δD) n-alkanes. Temperatures are also estimated using the algae derived long-chain diols. We interpret δD and δD fluctuations as showing changes in the source and amount of precipitation throughout the LdRS record. An Atlantic precipitation source appears to have predominated during the early-middle Holocene, but an occasional Mediterranean influence with an isotopic enrichment in precipitation is detected in the middle-late Holocene that is likely related to the setting of the current atmospheric pattern in southeastern Iberia under the joint control of the North Atlantic Oscillation (NAO) and the Western Mediterranean dynamics, such as the Western Mediterranean Oscillation (WeMO). Our new record from LdRS is consistent with a generalized trend of a humid early-middle Holocene with low temperature variability, evolving towards an arid middle-late Holocene with abrupt temperature changes. In addition to these long-term trends during the last ∼10,500 years, two phases of climate instability, evidenced by abrupt depletions in δD, have been identified at the end ... |
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