Diurnal changes in photosynthetic activity of the biological soil crust and lichen: Effects of abiotic factors (Petuniabukta, Svalbard)

• Main Authors: Sehnal Luděk, Barták Miloš, Váczi Peter
• Format: Article in Journal/Newspaper
• Language: English
• Published: Masarykova univerzita 2014
• Subjects: Spitsbergen; lichen; biological soil crusts; photosynthesis; fluorescence; effective quantum yield; Cladonia rangiferina; Nostoc sp; Špicberk; lišejník; biologická půdní krusta; photosyntéza; effektivní kvantový výtěžek; Svalbard; Petuniabukta
• Online Access: https://is.muni.cz/publication/1230155

In polar ecosystems, primary producers have to cope with a very harsh climate that limits the time available for growth and biomass production. In this study, diurnal measurement of photosynthetic processes in biological soil crust and a lichen were carried out in Petuniabukta, Spitsbergen. For field measurements, a method of induced fluorescence of chlorophyll was used. Measurements of photosynthetic activity were taken as repetitive measurements of effective quantum yield of photosystem II (PhiPSII). The short-term field measurements were carried out for 10 days in summer 2014. PhiPSII was recorded each 5 minutes as well as microclimatic data (air temperature, air humidity, photosynthetically active radiation - PAR). The microclimatic parameters were recorded by a datalogger. In general, physiological activity of both biological soil crust and a lichen showed daily courses. Tested lichen was Cladonia rangiferina and the most dominant species in biological soil crust was Nostoc sp. Typically, most of PhiPSII values ranged 0.6 – 0.7 in both model organisms. The results have shown that photosynthetic activity was strongly correlated with all observed abiotic factors in both study objects. Particularly important was the relation found between PAR and PhiPSII in biological soil crust. When the biological soil crust was exposed to high PAR doses of irradiation (about 2300 micromol m-2 s-1) photoinhibition of primary processes of photosynthesis was observed as PhiPSII decrease, while photosynthetic activity of lichen remained at same level. Furthermore, it has been demonstrated increasing that in situ photosynthetic activity increased in both biological soil crust and lichen with a decrease in temperature. Byly sledovány primární fotoszntetické procesy biologické půdní krusy a lišejníku. Studie byla uskutečněna v terénu na Špicberkách. In polar ecosystems, primary producers have to cope with a very harsh climate that limits the time available for growth and biomass production. In this study, diurnal measurement ...