Holocene climate and ecological impacts of the East Atlantic pattern (EA) and North Atlantic Oscillation (NAO) interplay in southwestern Atlantic Europe

The objective of the project is to characterize the spatial and temporal evolution, as well as their relationships, of the large-scale climate patterns that rule the climate variability of the Iberian Peninsula and the Azores Archipelago, with special regard on the Eastern Atlantic (EA) and the North Atlantic Oscillation (NAO) climate patterns, and their consequent impact on the aquatic and terrestrial ecosystems using a multiproxy approach applied to six lacustrine sediment records for the last 2,000 years. To achieve this obejctive, the project is subdivided in two subprojects: one centered on the climate reconstructions from inorganic proxies (physical properties, lithofacies, chemical and mineralogical composition) from the sediments, whereas the second subproject is foccused on characterizing the response of the lacustrine biota (molecular and isotopic organic matter composition, biogenic silica, pigments, diatoms, pollen, plan macrofossils, cladocerans, and chironomids) to climate and non-climate changes.

The achievement of this objective will provide insights on: a) the decadal climate dynamics of the coupling and uncoupling of the NAO and EA on different climate periods over the last 2,000 yr. These long-term assessment insights into the past can provide valuable information when considering climate change scenarios and the role played by these two climate patterns and their interaction. This is especially important when assessing under which climate conditions some extreme events (heatwaves, droughts, floods) are more prone to occur. b) the climate-induced dynamics of lacustrine ecosystems during the coupling and uncoupling of the climate modes over the last 2,000 yr. This is of paramount importance for assessing the effects of possible ecological regime shifts under the present day warming climate and for the design of correct management practices. The interannual climate variability of the North Atlantic-European sector is dominated by a relatively small number of large-scale climate patterns, such as the North Atlantic Oscillation NAO), the East Atlantic (EA), and the Scandinavian (SCAND) climate patterns. Therefore, hints on the short- and long-term evolutions of these climate patterns are of crucial importance since they play an important role on the evolution of key resources such as the water as well as the recurrence and intensity of extreme climate events, such as heatwaves, droughts and floods. The last IPCC report states that, for Southern Europe temperature will increase, hydrological resources will decrease and extreme climate events will be more prone to occur. This forecast do not provide hints on which climate conditions these climate scenarios will occur. This project intends to fill this gap by characterizing the decadal climate variability of the Iberian Peninsula as well as of the Azores Archipelago (the south center of action of the NAO) for the last 2,000 years. The project seeks to determine the decadal evolution of the NAO and EA and their relationship for the last millennia in order to establish under which climate conditions are the extreme climate events more prone to occur. The project will also characterize the ecological responses of lacustrine ecosystems to these modes of climatic variability and also to nonclimatic factors. Issues such as the resilience of the different lakes to environmental change, whether ecological regime shifts have taken place linearly or crossing tipping points, or the extent to which the different ecosystems can return to previous conditions when the climatic and non-climatic perturbations cease will also be assessed. All this information will be used used as a background for the implementation of correct management policies in the studied lake ecosystems, all of them under different types of environmental protection schemes.



  • Roberto Bao Casal (Universidade da Coruña)
  • Alberto Sáez (Universidad de Barcelona)
  • Ricardo Trigo (Universidade de Lisboa)
  • Armand hernández (Universidade de Lisboa)



Project Leader:




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