Microclimate impacts of passive warming methods in Antarctica: Implications for climate change studies

• Published in: Polar Biology
• Main Authors: Bokhorst, Stef, Huiskes, Ad H.L., Convey, Peter, Sinclair, Brent J., Lebouvier, Marc, Van De Vijver, Bart, Wall, Diana H.
• Other Authors: Department of Animal and Plant Sciences Sheffield, University of Sheffield Sheffield, Netherlands Institute of Ecology, British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Department of Biology, University of Western Ontario (UWO), Ecosystèmes, biodiversité, évolution Rennes (ECOBIO), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Department of Bryophyta and Thallophyta - National Botanic Garden of Belgium, National Botanic Garden of Belgium, Colorado State University Fort Collins (CSU), IPY project TARANTELLA; Netherlands Polar Programme, BAS 'Polar Science for Planet Earth'; IPEV Programme 136 ECOBIO et 405 DIVCRO; Zone Atelier CNRS; NSF OPP; McMurdo LTER; SCAR 'Evolution and Biodiversity in Antarctica'
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: Antarctica; Climate change; Climate warming; Extreme event; Open top chamber; Passive warming chambers; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Antarctic; Antarc*; Polar Biology
• Online Access: https://hal.archives-ouvertes.fr/hal-00699731; https://doi.org/10.1007/s00300-011-0997-y

International audience Passive chambers are used to examine the impacts of summer warming in Antarctica but, so far, impacts occurring outside the growing season, or related to extreme temperatures, have not been reported, despite their potentially large biological significance. In this review, we synthesise and discuss the microclimate impacts of passive warming chambers (closed, ventilated and Open Top Chamber--OTC) commonly used in Antarctic terrestrial habitats, paying special attention to seasonal warming, during the growing season and outside, extreme temperatures and freeze-thaw events. Both temperature increases and decreases were recorded throughout the year. Closed chambers caused earlier spring soil thaw (8-28 days) while OTCs delayed soil thaw (3-13 days). Smaller closed chamber types recorded the largest temperature extremes (up to 20 C higher than ambient) and longest periods (up to 11 h) of above ambient extreme temperatures, and even OTCs had above ambient temperature extremes over up to 5 consecutive hours. The frequency of freeze-thaw events was reduced by *25%. All chamber types experienced extreme temperature ranges that could negatively affect biological responses, while warming during winter could result in depletion of limited metabolic resources. The effects outside the growing season could be as important in driving biological responses as the mean summer warming. We make suggestions for improving season-specific warming simulations and propose that seasonal and changed temperature patterns achieved under climate manipulations should be recognised explicitly in descriptions of treatment effects.