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Description
The study of global climate changes is a topic of great scientific and public interest, promoted through international, European and national research programs. That present-day human activity contributes to global climate changes is generally acknowledged, although the extent of this contribution remains a matter of contention. The need for understanding the mechanisms that control present and future climate changes has triggered a revolution in geosciences because this understanding is based on the study of climate variability in the recent geological past. In this respect, understanding the causes of abrupt climate changes of the past, how these changes reflected over large areas and what effects they had to the biosphere and general landscape is a key to foreseeing future changes and their potential effects. This project aims at using a variety of cave and karst deposits from Romania for the paleoclimatic and paleoenvironmental reconstructions with a focus on abrupt climate changes. Selected cave sites from Romania will be compared with cave sites from Norway, where abrupt cooling episodes in the past are known to cause cessation of deposition in caves due to permafrost formation and ice-sheet expansion.
The project will establish a Center of Excellence in speleological research in Romania through the participation of three academic partners: the “Emil Racovita” Institute of Speleology, the LITHOS Research Centre, University of Bucharest, and the “Babes-Bolyai” University in Cluj-Napoca. The “KARSTHIVES” Centre will establish a long-term collaboration with the University of Bergen that shall strengthen the previous cooperation. The center will gather highly qualified researchers from fields such as geology, geochronology, palaeontology, geography, biology, physics, etc. and allow for financial and logistical resources to support a significant number of young MS and PhD students as well as young researchers at postdoctoral level.
Summary of project results
The KARSTHIVES project proposed an integrated approach based upon the analysis of the various paleoclimate archives from caves and karst deposits. The most important are the stable isotopes, chemical and mineralogical variations in speleothems (calcite formations in caves), magnetic properties of sediments, fossil species and faunal associations, stable isotopes of the underground ice accumulations. Most of these are relevant for the paleoclimate evolution at regional scale and their radiometric datings allow signal calibration and comparative analysis of the different time-series. The combination of the data measured from various deposits within the same cave or karst area allowed: (1) to overcome the limitations of some dating methods; (2) to carry out time-series analyses taking into account regional or global climate records and to identify the regional constrains of climate oscillations. The data are to be calibrated by isotope analysis of newly-precipitated calcite in laboratory-caves correlated with the monitoring of both surface weather conditions and underground microclimate and physical parameters. The conversion of the variations of isotope from cave deposits into variations of temperature or other parameters (precipitation source, vegetation cover, biological activity in soil) was used to validate and/or develop new models for abrupt climate oscillations at millennial or centennial scales.
The project activities were largely focused on systematic research of several key paleontological cave sites such as Pestera Ursilor, Pestera Muierilor, Pestera Bisericuta, etc. In all these sites, systematic excavations were carried out. They were complemented by various line of research such as stratigraphy, geochronology, ancient DNA, etc. Basically, all selected sites were analyzed for the whole range of paleoclimatic indicators available which has offered a more complete image of the succession of climatic changes in the past ~50,000 years. In ice caves such as the Scarisoara Glacier (Romania) and Svarthammarhola (Norway), the combined analyses of ice geochemistry and organic matter (e.g. pollen) trapped in the ice blocks also contributed to a better understanding on climatic variations in the last 10,000 years or so. The ancient DNA from Romanian caves contributed to unfold that Initial Upper Palaeolithic humans in Europe had recent Neanderthal ancestry. This contributes to studies on human mobility and the origin of modern humans, and illustrates how research in the fields of biogeosciences, physical geography, and (paleo)ecology interact with each other as well as with anthropology.
Since the project was a “basic research” one, it did not address immediate or direct beneficiaries. Indirectly, our results (>40 published papers, including several in mainstream journals such as Nature, Quaternary Science Reviews, Quaternary Geochronology, etc.) have improved the general knowledge on abrupt climate changes in Central-Eastern Europe. They have also shown how the integration of multiple proxies encountered in caves can offer a broader picture of the short-term climatic oscillations and the effects they might had on the extinction or migration of different animal species, as well as the changes of their respective biotopes. Aside from the general scientific achievements, the project has allowed the foundation of a new laboratory for stable isotope analysis at the ERIS, as well as infrastructure improvements at the existing laboratories of project partners. This is important as it creates the grounds for future research and for the secondary aim of the project which was to establish a Center of Excellence in speleological research.
Summary of bilateral results
The bilateral cooperation between the Norwegian partner and all three Romanian institutions has been already in place for more than 10 years. With this project it was strengthened by adding new sites for study in both countries, as well as new analytical avenues. It is worth mentioning that the project has contribute to enhance the infrastructure of the Cosmogenic Isotope Laboratory at the Norwegian partner.