BSc. Project (BS303)

Duncan Hull (1996) Bachelor of Science Project (BS303). Supervisors: John H. Tallis and Jac A. Potter

The regulation of CO2 efflux from a sub-arctic heathland


The effects of climatic changes on CO2 efflux from a sub-arctic heathland in Swedish Lappland (Abisko Naturvetenskapliga) were studied using Infra-Red Gas Analysis (IRGA). Climatic changes of increased precipitation and soil temperatures were simulated with open-topped polythene tents and an external water supply. Two complete diel cycles of simulated climatic change and were recorded showing increased CO2 efflux of up to 20% over the control. The results provide evidence to support the hypothesis that increased soil temperature and precipitation could lead to increased CO2 emissions from arctic and sub-arctic ecosystems.

The results are discussed with reference to the availability of soil nutrients as a regulatory factor of CO2 efflux from sub-arctic heathlands.


  1. Jac A. Potter, Malcolm C. Press, Terry V. Callaghan and John A. Lee. (1995) Growth responses of Polytrichum commune and Hylocomium splendens to simulated environmental change in the sub-arctic. New Phytologist 131 (4) 533-541. DOI:10.1111/j.1469-8137.1995.tb03089.x (See the acknowledgements section at the end of this paper for an honourable mention of a humble field worker: yours truly. One of the absolut best summer jobs I've ever had!)
  2. W. D. Billings, J. O. Luken, D. A. Mortensen, K. M. Peterson (1982) Arctic tundra: A source or sink for atmospheric carbon dioxide in a changing environment? Oecologia 53:7-11
  3. W. D. Billings, J. O. Luken, D. A. Mortensen, K. M. Peterson (1983) Increasing atmospheric carbon dioxide: possible effects on arctic tundra Oecologia 58:286 - 289. DOI:10.1007/BF00377129
  4. David S. Jenkinson, D. E. Adams and A. Wild (1991) Model estimates of CO2 emissions from soil in response to global warming Nature 351(6234):304-306. DOI:10.1038/351304a0
  5. Charles D. Keeling, J.F.S. Chin and T.P.Whorf (1996) Increased activity of northern vegetation inferred from atmospheric CO2 measurements. Nature 382:146-149.. DOI:10.1038/382146a0
  6. Anders Michelsen, Sven Jonasson, Darren Sleep, Mats Havström, Terry V. Callaghan (1996) Shoot biomass, δ13C, nitrogen and chlorophyll responses of two arctic dwarf shrubs to in situ shading, nutrient application and warming simulating climatic change Oecologia 105:1-12. DOI:10.1007/BF00328785
  7. Anders Michelsen, Inger K. Schmidt, Sven Jonasson, Chris Quarmby, Darren Sleep (1996) Leaf 15N abundance of subarctic plants provides field evidence that ericoid, ectomycorrhizal and non-and arbuscular mycorrhizal species access different sources of soil nitrogen Oecologia 105:53-63. DOI:10.1007/BF00328791
  8. K.J. Nadelhoffer , A.E. Giblin, Gaius R. Shaver and A.E. Linkins. (1992) Microbial processes and plant nutrient availability in arctic soils In Arctic Ecosystems in a Changing Climate: An Ecophysiological Perspective F. Stuart Chapin III, James F. Reynolds, Ellen W. Chu, Josef Svoboda, Gaius R. Shaver and Robert L. Jefferies. Academic Press, San Diego, CA. pp.281-300
  9. S. F. Oberbauer, C. T. Gillespie, W. Cheng, R. Gebauer, A. Sala Serra, J. D. Tenhunen (1992) Environmental effects on CO2 efflux from riparian tundra in the northern foothills of the Brooks Range, Alaska, USA Oecologia 92(4):568-577. DOI:10.1007/BF00317851
  10. Walter C. Oechel, Steven J. Hastings, George Vourlrtis, Mitchell Jenkins, George Riechers and Nancy Grulke. (1993) Recent change of Arctic tundra ecosystems from a net carbon dioxide sink to a source Nature 361(6412):520-523. DOI:10.1038/361520a0
  11. Andrew N. Parsons, Malcolm C. Press, Philip A. Wookey, J.M. Welker, Clare H. Robinson, Terry V. Callaghan and John A. Lee (1995) Growth-Responses of Calamagrostis lapponica to Simulated Environmental-Change in the Sub-Arctic. Oikos 72(1), 61-66.
  12. A.F.W. Schimper. (1903) Plant geography upon a physiological basis Clarendon Press, Oxford, UK
  13. D.B.O. Savile. (1960) Limitations of the Competitive Exclusion Principle Science 132(3441):1761. DOI:10.1126/science.132.3441.1761