Turnover of recently assimilated carbon in arctic bryophytes

Citation

Street LE, Subke J, Sommerkorn M, Heinemeyer A & Williams M (2011) Turnover of recently assimilated carbon in arctic bryophytes. Oecologia, 167 (2), pp. 325-337. https://doi.org/10.1007/s00442-011-1988-y

Abstract
Carbon (C) allocation and turnover in arctic bryophytes is largely unknown, but their response to climatic change has potentially significant impacts on arctic ecosystem C budgets. Using a combination of pulse-chase experiments and a newly developed model of C turnover in bryophytes, we show significant differences in C turnover between two contrasting arctic moss species (Polytrichum piliferum and Sphagnum fuscum). 13C abundance in moss tissues (measured up to 1 year) and respired CO2 (traced over 5 days) were used to parameterise the bryophyte C model with four pools representing labile and structural C in photosynthetic and stem tissue. The model was optimised using an Ensemble Kalman Filter to ensure a focus on estimating the confidence intervals (CI) on model parameters and outputs. The ratio of aboveground NPP:GPP in Polytrichum piliferum was 23% (CI 9–35%), with an average turnover time of 1.7 days (CI 1.1–2.5 days). The aboveground NPP:GPP ratio in Sphagnum fuscum was 43% (CI 19–65%) with an average turnover time of 3.1 days (CI 1.6–6.1 days). These results are the first to show differences in C partitioning between arctic bryophyte species in situ and highlight the importance of modelling C dynamics of this group separately from vascular plants for a realistic representation of vegetation in arctic C models.

Keywords
Mosses; NPP:GPP ratio; 13C pulse-labelling; Carbon model; Carbon allocation; Photosynthesis; Autotrophic respiration; Mosses Arctic regions; Bryophytes; Climatic changes Arctic regions; Atmospheric carbon dioxide Environmental aspects

Journal
Oecologia: Volume 167, Issue 2