Mixing ratio and species affect the use of substrate-derived CO2 by Sphagnum

Limpens, J., Robroek, B. J M, Heijmans, M. M P D and Tomassen, H. B M (2008) Mixing ratio and species affect the use of substrate-derived CO2 by Sphagnum. Journal of Vegetation Science, 19 (6), 841-848. (doi:10.3170/2008-8-18456).

Abstract

Question: Can mixing ratio and species affect the use of substrate-derived CO₂ by Sphagnum? Location: Poor fen in south Sweden and greenhouse in Wageningen, The Netherlands. Methods: Two mixing ratios of Sphagnum cuspidatum and S. magellanicum were exposed to two levels of CO₂ by pumping CO₂ enriched and non-enriched water through aquaria containing the species mixtures in the greenhouse. Results: Enhanced CO₂ stimulated the production of S. cuspidatum, but only in aquaria co-dominated by S. magellanicum, coinciding with higher CO₂ concentrations in the water layer. The denser growing S. magellanicum seemed to reduce gas escape from the water, resulting in accumulation of dissolved CO₂. Adding CO ₂ did not affect species replacement. Conclusions: The use of substrate-derived CO₂ forSphagnum production depended on species identity and mixing ratio. The effect of mixing ratio on CO₂ concentrations in the water layer suggests that species composition may affect both the efficiency with which substrate-derived CO₂ is trapped and subsequently used. This could result in hitherto unexplored feedbacks between vegetation composition and gas exchange.

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Contributors

Author: B. J M Robroek

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