Autonomous in situ measurement of daily courses of the net CO2 exchange rate in a moss from alpine environment ( Short Communication )

Moss-dominated vegetation type is considered one of the the most productive community type in treeless alpine environments in European mountains. In this study, net carbon exchange rate (NCER) of alpine moss Polytrichum commune was measured by automatic CO2 exchange station unit. Samples of mosses were collected in a mountains from the site located above tree line (1420 m a.s.l.), and transferred to Brno, Czech Republic. Then the cluster of moss (23 cm in diameter, 30 cm in depth) including dead parts was placed into open measuring chamber end exposed to local climate for two weeks in autumn 2019. The chamber closed by a transparent lid repeatedly each 20 min and NCER measured by the system. Data on photosynthetically active radiation (PAR), relative air humidity (RH), and moss temperature (T) were recorded as well. Maximum/ minimum dark respiration reached 1.0 and 0.2 mmol (CO2) m-2 s-1. The highest NCER was found - 0.6 mmol (CO2) m-2 s-1 was caused by photosynthesis of moss clump at the temperature within the range of 14.5-17.5°C and 100% of relative air humidity.