2012-2015. Summary : Limiting factors for plant development in the Antarctic Peninsula such as: low summer temperature, short growing season and low liquid water and soil availability are being dramatically modified by the accelerated regional warming (average air temperature increases 2.6°C over the last 50 years). This environmental change is correlated with a significant increase in plant size, coverage and population number of Deschampsia antarctica and Colobanthus quitensis. In spite of several publications describing the effects of regional climate change on Antarctic plant populations, there is limited information on the eco-physiological and biochemical basis that explain growth and expansion of these plant populations. Thus, the general objective of this proposal is: 1. To create an international research core-group in Plant Ecophysiology to study and divulge plant responses to increase temperature and CO2 in order to unravel the biological basis for plants population expansion under the current climate change scenario in the Maritime Antarctica. The specific Research objectives are: 1. To study the effect of warming on seed maturation, germination, plant establishment and growth in the field and laboratory. These effects will be associated with plant physiological performance at different plant levels: freezing tolerance, nutrient uptake, plant metabolism and carbon balance. 2. To study the effect of water availability on plants exposed to local warming in the field and in the laboratory. 3. To evaluate the interaction between warming and CO2 enrichment under laboratory and biotron conditions. 4. To study the effect of warming on microbiological diversity of the vascular plants rhizosphere and associate warming driven changes in the micro-biota diversity with soil nutrient availability. Field and laboratory experiments will be conducted applying an increase in the air temperature (3-5°C) over two growing seasons. Because of their complexity, harsh Antarctic conditions (such as extremely high winds) and logistic difficulties in the field, the studies on the combination of increased temperature and CO2 enrichment will be conducted under growth chamber and BIOTRON where field conditions will be recreated. The studies will focus on understanding the effects of these treatments at the reproductive (seed formation, maturation, and germination), plant growth and development, metabolic (photosynthesis and respiration), and nutritional levels (changes in soil nutrient availability and plant nutrient uptake). Besides, the influence of warming treatments on soil microorganism biodiversity using a metagenomic approach and the effect of the putative change in the microbiota on nutrient recycling will be assessed. This inter-institutional (UFRO, UdeC, UM) proposal involving plant ecologists, physiologists, and molecular biologist with soil chemists and microbiologist will create a multidisciplinary research group with critical mass and wide vision to deal with Antarctic Plant Ecophysiology in a deep and synergistic way. Externalization of our activities will be done through workshops to secondary school teachers and scientific scholar groups using established networks such as Explora and the educational program of INACH. Additionally, we will establish a permanent stand at a Natural History Museum which will exhibit the study set up and results of this field experience. Finally, we will seek international cooperation and networking using established channels such as SCAR research programs like AntETR (Antarctic Ecosystems: Adaptations, Thresholds and Resilience) and finally, UNIS (University of Centre Svalbard) who had vast experience in terrestrial ecology in the Arctic.