Elevated atmospheric CO 2 affects decomposition of Festuca vivipara (L.) Sm. litter and roots in experiments simulating environmental change in two contrasting arctic ecosystems

• Published in: Global Change Biology
• Main Authors: ROBINSON, C.H., MICHELSEN, A., LEE, J.A., WHITEHEAD, S.J., CALLAGHAN, T.V., PRESS, M.C., JONASSON, S.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1997
• Subjects: Arctic
• Online Access: http://dx.doi.org/10.1046/j.1365-2486.1997.d01-133.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1365-2486.1997.d01-133.x; https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2486.1997.d01-133.x

Mass loss, together with nitrogen and carbon loss, from above‐ground material and roots of Festuca vivipara were followed for 13 months in a high Arctic polar semi‐desert and a low Arctic tree‐line dwarf shrub heath. Festuca vivipara for the study was obtained from plants cultivated at two different CO 2 concentrations (350 and 500 μL L –1 ) in controlled environment chambers in the UK. Each of the four resource types (shoots or roots from plants grown in elevated or ambient CO 2 concentrations) was subsequently placed in an experiment simulating aspects of environmental change in each Arctic ecosystem. Air, litter and soil temperatures were increased using open‐topped polythene tents at both sites, and a 58% increase in summer precipitation was simulated at the high Arctic site. Mass loss was greatest at the low Arctic site, and from the shoot material, rather than the roots. Shoots grown under an elevated CO 2 concentration decomposed more slowly at the high Arctic site, and more quickly at the low Arctic one, than shoots grown at ambient CO 2 . After 13 months, greater amounts of C and N remained in above‐ground litter from plants grown under elevated, rather than ambient, CO 2 at the polar semi‐desert site, although lower amounts of C remained in elevated CO 2 litter at the low Arctic ecosystem. In the high Arctic, roots grown in the 500 μL L –1 CO 2 concentration decomposed significantly more slowly than below‐ground material derived from the ambient CO 2 chambers. Elevated CO 2 concentrations significantly increased the inital C:N ratio, % soluble carbohydrates and α‐cellulose content, and significantly decreased the inital N content, of the above‐ground material compared to that derived from the ambient treatment. Initially, the C:N ratio and percentage N were similar in both sets of roots derived from the two different CO 2 treatments, but soluble carbohydrate and α‐cellulose concentrations were higher, and percentage lignin lower, in the elevated CO 2 treatments.The tent treatments significantly ...