Format: ORAL

Beatriz Fernndez-Marn1, Alicia V. Perera-Castro2, Miren Irati Arzac1, Laura Daz-Jimnez2, Abel Torre1, Jos Vicente Albero Molina3, Joan Riba4, Jos Manuel Laza5, Leire Ruiz5, Jose Luis Vilas5, Mara Leo6, Nagore G. Medina7, Asuncin de los Ros8, Jaime Purtolas2, gueda M. Gonzlez-Rodrguez2, Jos Ignacio Garca-Plazaola1.

1 Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Leioa, Spain 2 Department of Botany, Ecology and Plant Physiology, University of La Laguna (ULL), Tenerife, Spain 3 Agencia Estatal de Meteorlogía (AEMET), Málaga, Spain 4 Unidad de Tecnología Marina (UTM-CSIC), Barcelona, Spain 5 Department of Physical Chemistry, University of the Basque Country (UPV/EHU), 6 Department of Soil, Plant and Environment Quality Department, Instituto de Ciencias Agrarias (ICA-CSIC), Madrid, Spain 7 Department of Biology, Universidad Autónoma de Madrid (UAM), Madrid, Spain 8 Department of Biogeochemistry and microbial ecology, Museo Nacional de Ciencias Naturales (MNCN-CSIC), Madrid, Spain

Maritime Antarctica (Antarctic Peninsula plus adjacent archipelagos) is one of the richest vegetated areas in Antarctica, with 189 and 59 species of lichen and of bryophytes respectively, but also one of the most fragile regions. After a period of decreasing temperature in the last 20y, in Maritime Antarctica this trend is currently shifting. Changes in air temperature induce variations in the type, frequency and timing of precipitation but predictions show high uncertainty regarding their direction and extent for this region. Furthermore, while occult precipitation (fog, snow, or rain with strong wind) is probably a key source of available water for the ecosystem, its occurrence and relevance are, so far, understudied. Thus, we aimed at evaluating how changes in water availability may affect the ecophysiological performance of some of the most prominent photosynthetic species of the antarctic tundra, with especial emphasis on horizontal precipitation and on lichen and moss flora. For this purpose, we have (i) monitored the potential contribution of occult precipitation to the ecosystem, (ii) studied anatomical and physicochemical properties of the thalli involved in the capture, absorption and retention of water and (iii) evaluated interspecific differences to deal with periods of water restriction, as well as biophysical and physiological traits involved on them. Our preliminary results reveal that (i) occult precipitation is potentially very relevant for terrestrial vegetation in Antarctica, particularly at moderated elevations (200m asl); (ii) there are important interspecific differences in the wettability of thalli surfaces and in their capability to delay desiccation; (iii) there are significant interspecific differences in the longevity of thalli in the dry state. This research is part of DROPLET: project supported by a 2022 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation; and included in the Spanish Antarctic Campaign 2023/2024 organised by the CPE and funded by the MCIN.