Abstract
A multi-proxy study of short sediment cores recovered in small, karstic Lake Estanya (42°02′ N, 0°32′ E, 670 m. a. s. l.) in the Pre-Pyrenean Ranges (NE Spain) provides a detailed record of the complex environmental, hydrological and anthropogenic interactions occurring in the area since medieval times. The integration of sedimentary facies, elemental and isotopic geochemistry, and biological proxies (diatoms, chironomids and pollen), together with a robust chronological control, provided by AMS radiocarbon dating and 210Pb and 137Cs radiometric techniques, enabled precise reconstruction of the main phases of environmental change, associated with the Medieval Warm Period (MWP), the Little Ice Age (LIA) and the industrial era. Shallow lake levels and saline conditions with poor development of littoral environments prevailed during medieval times (1150-1300 AD). Generally higher water levels and more dilute waters occurred during the LIA (1300-1850 AD), although this period shows a complex internal paleohydrological structure and is contemporaneous with a gradual increase of farming activity. Maximum lake levels and flooding of the current littoral shelf occurred during the nineteenth century, coinciding with the maximum expansion of agriculture in the area and prior to the last cold phase of the LIA. Finally, declining lake levels during the twentieth century, coinciding with a decrease in human pressure, are associated with warmer climate conditions. A strong link with solar irradiance is suggested by the coherence between periods of more positive water balance and phases of reduced solar activity. Changes in winter precipitation and dominance of NAO negative phases would be responsible for wet LIA conditions in western Mediterranean regions. The main environmental stages recorded in Lake Estanya are consistent with Western Mediterranean continental records, and show similarities with both Central and NE Iberian reconstructions, reflecting a strong climatic control of the hydrological and anthropogenic changes during the last 800 years.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 423-452 |
| Number of pages | 30 |
| Journal | Journal of Paleolimnology |
| Volume | 46 |
| Issue number | 3 |
| DOIs | |
| State | Published - Oct 1 2011 |
| Externally published | Yes |
Bibliographical note
Funding Information:Acknowledgments This research was funded through the projects LIMNOCAL (CGL2006-13327-C04-01), PALEO-DIVERSITAS (CGL2006-02956/BOS), GRACCIE (CSD2007-00067) supported by the Spanish Inter-Ministry Commission of Science and Technology (CICYT); and PM073/2007 provided by the Diputación General de Aragón. The Aragonese Regional Government and CAJA INMACULADA provided two travel grants for the analyses carried out at Univ. of Cádiz and EEZ-CSIC (Spain), and MARUM Centre (Univ. of Bremen, Germany). M. Morellón was supported by a PhD contract with the CONAI ? D (Aragonese Scientific Council for Research and Development). We are indebted to Anders Noren, Doug Schnurrenberger and Mark Shapley (LRC-University of Minnesota) for the 2004 coring campaign and Santiago Giralt and Armand Hernández (IJA-CSIC), as well as Alberto Sáez and J.J. Pueyo-Mur (University of Barcelona) for coring assistance in 2006. We also acknowledge Cristina Pérez Bielsa (IGME) for her help in water and short-core sampling, Joan Gomà and Roger Flower for their help with the identification of diatom species, and Marco Klann (MARUM Centre, Univ. of Bremen) for biogenic silica analyses. We are also grateful to EEZ-CSIC, EEAD-CSIC and IPE-CSIC laboratory staff for their collaboration in this research. We thank Dirk Verschuren and Santiago Giralt for their helpful comments and their criticism, which led to a considerable improvement of the manuscript.
Keywords
- Human impact
- Iberian Peninsula
- Lake Estanya
- Little Ice Age
- Medieval Warm Period
- Twentieth century
- Western Mediterranean
