Physiological processes in mosses and lichens in response to local climate: Case study from the James Ross Island, Antarctics
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| Year of publication | 2010 |
| Type | Conference abstract |
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| Description | Abstract: In Antarctics, physiologically active state of moses and lichens depends on availability of liquid water, light and physiological temperature. In the field, photosynthesis of these poikilohydric organisms might be sensitively monitored by chlorophyll fluorescence. Fluorometric measurements are a part of our long-term research program aimed to the evaluation physiological response to local climate and manipulated warming using open top chambers (OTCs). Within 2007-2009, nine OTCs were established in the Northern part of the James Ross Island in a vicinity of the Czech Antarctic station Johann Gregor Mendel (63 o 50 S, 57o 50 W). The OTCs were installed over typical vegetation cover: (I) moss carpet (Bryum sp.) with several individual spots of lichen, (II) lichens Usnea antarctica and Umbilicaria decussata located on basaltic stones, (III) inicial stages of vegetation succession forming algal biofilms and tiny spots of microlichens on deglaciated stony substrates. Temperature sensors were installed and connected to a multichannel dataloggers. The sensors were put (a) into the height of 30 cm above surface, into the substrate to the depths of (b) 5, (c) 10, (d) 15 cm and also (e) into the surface cover (moss or lichen). Since 2007, the temperature data have been taken in a 30 min step. Additionaly, automatic weather station data recorded in the same interval are used to compare the OTC microclimate with reference outside climate. To estimate photosynthetic processes and physiologically active time in Bryum, several fluorometers were tested and used in the field: (1) modified PAM-210 fluorometer (Heinz Walz), (2) FluorPen FP-100 (Photon Systems Instruments), (3) Moni-PAM (Heinz Walz). The instruments measured effective quantum yield of photosynthetic processes in photosystem II (FPSII) as dependent on hydration/dehydration and microclimatic parameters. Using FPSII and apropriate data of photosynthetically active radiation (PAR), we evaluated diurnals of photosynthetic electron transport rate (ETR). Acknowledgenemts: ME-945 and KJB601630808. Theme 3: Polar ecosystems and biodiversity, Session: T3-6 Impact of climate change on polar terrestrial ecosystems. Time: Sometime between Thursday 10 June 16:00 and 17:30 h. |
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