Abstract
Estimates of carbon gain were obtained based upon integration of previously published measurements of diel courses of CO2 exchange of seven lichen species in their natural tundra habitat. Total net photosynthetic CO2 uptake, CO2 loss by dark respiration, and the balance between these were calculated. The field measurements (146 observations of lichen sample diel courses on 26 d distributed over the growth periods from July through September in 1988 and 1989) were classed with respect to 5 types of weather conditions. The occurrence of these weather types during the growing season was established according to meteorological data. Combination of these data sets permits an estimate of seasonal carbon gain.Integrated photosynthetic carbon uptake was highest for the cyanobacterial Peltigera malacea, 1.5 times higher than for Dactylina arctica and 5 times higher than for the least productive Masonhalea richardsonii, both being green algal species. There was an essentially linear correlation across species between the sum of carbon uptake and short-term maximal rates of net photosynthesis, stressing the importance of photosynthetic capacity for carbon gain. Mean respiratory carbon loss for all of the species was ca. 33%.Three groups of species were determined with respect to estimated seasonal carbon balance: high productivity (carbon gain of 24.0–21.5% of thallus carbon content) which included D. arctica, P. malacea, P. aphthosa, and Thamnolia vermicularis, lowest productivity (6.8%) for M. richardsonii, and intermediate for Cetraria cucullata (15.9%) and Stereocaulon alpinum (14.6%). Seasonal carbon gain is related to the maximal possible thallus growth. Estimates of annual lichen biomass increase in typical tundra communities ranged from 47.2 gDW m–2 for dry to 10.8 gDW m–2 per season for moist Cassiope dwarf-shrub heath.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.