HR: 14:40h
AN: C33A-05    [Abstracts]
TI: Seasonal Snow Cover in Tundra Environments:Patterns, Processes and Scaling.
AU: * Baxter, R
EM: robert.baxter@durham.ac.uk
AF: Institute of Ecosystem Sience,School of Biological and Biomedical Sciences, University of Durham., Science Laboratories, South Road, Durham, DH1 3LE, United Kingdom
AU: Olofsson, J
EM: johan.olofsson@emg.umu.se
AF: Department of Ecology and Environmental Science, Umeå University., SE - 901 87, Umeå., Umeå., SE - 901 8, Sweden
AU: Huntley, B
EM: brian.huntley@durham.ac.uk
AF: Institute of Ecosystem Sience,School of Biological and Biomedical Sciences, University of Durham., Science Laboratories, South Road, Durham, DH1 3LE, United Kingdom
AU: Wiltshire, A J
EM: a.j.wiltshire@durham.ac.uk
AF: Institute of Ecosystem Sience,School of Biological and Biomedical Sciences, University of Durham., Science Laboratories, South Road, Durham, DH1 3LE, United Kingdom
AU: Sayer, D R
EM: d.r.sayer@durham.ac.uk
AF: Institute of Ecosystem Sience,School of Biological and Biomedical Sciences, University of Durham., Science Laboratories, South Road, Durham, DH1 3LE, United Kingdom
AU: Wookey, P A
EM: philip.wookey@stir.ac.uk
AF: School of Biological and Environmental Sciences, University of Stirling., University of Stirling, Stirling, FK94LA, United Kingdom
AU: Cook, J G
AF: Institute of Ecosystem Sience,School of Biological and Biomedical Sciences, University of Durham., Science Laboratories, South Road, Durham, DH1 3LE, United Kingdom
AU: Blyth, E M
EM: emb@ceh.ac.uk
AF: Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxford, OX10 8BB, United Kingdom
AU: Fox, A M
EM: a.m.fox@sheffield.ac.uk
AF: Institute of Ecosystem Sience,School of Biological and Biomedical Sciences, University of Durham., Science Laboratories, South Road, Durham, DH1 3LE, United Kingdom
AU: Harding, R J
EM: rjh@ceh.ac.uk
AF: Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxford, OX10 8BB, United Kingdom
AB: Landscape-scale patterning of depth and duration of snow cover is the single most important meso-scale variable controlling biological systems in the Arctic, and is the primary determinant of landscape-scale ecosystem heterogeneity. Duration of snow-lie also determines length of the plant growing season and is a primary determinant of the dynamics of soil temperature, soil moisture, depth of freezing and heat flux. Duration and extent of these seasonal effects have major impacts upon both plant communities and the soils with which they are associated, generating landscape mosaics ranging from exposed snow-free ridges to depressions characterised by deep snow accumulation. Our primary objective has been, through a suite of measurements, models, and appropriate up-scaling methodologies, to provide the understanding of biogeochemical processes in tundra regions required to answer a number of basic questions about the impacts of global warming upon tundra ecosystems and the potential magnitudes of any positive feedbacks. Given that in the mosaic that forms the Tundra landscape depth and duration of snow cover are primary determinants of thermal and hydrological regimes, and hence indirectly of soil biogeochemical processes plus vegetation composition and cover, we hypothesised: (i) That a change in depth/duration of snow-lie will, as a result of direct effects upon soil thermal and hydrological regimes, alter the thermal balance of the soil and hence result indirectly in altered seasonal dynamics of soil biogeochemistry. (ii) That changes in seasonal soil biogeochemical dynamics and vegetation growth and development will, together with direct effects of changes in depth/duration of snow-lie, result in altered seasonal and annual ecosystem carbon and energy budgets. (iii) That the sign and magnitude of alterations in soil biogeochemical dynamics and trace-gas fluxes, resulting from climate change, will differ between components of the landscape mosaic that occupy contrasting hydro- topographic positions. (iv) That the relative contributions to trace-gas flux of individual elements of the landscape mosaic, and the differential impacts of altered climate upon them, can be integrated and up-scaled in a manner that will provide significant improvements over current spatially-non-explicit models. Here we present the key results of this 4 year programme of research related to the hypotheses posed above, carried out at Abisko, northern Sweden. In particular we will concentrate upon a series of manipulations of snow- lie across different facets of the tundra landscape upon plants (e.g. phenology, degree of herbivory, litter decomposition) and soils (soil moisture, freezing, nutrient mineralisation rates) and together, integrated impacts upon carbon exchange between landscape and atmosphere. The work will placed in the context of likely consequences of climatic change across this tundra landscape, in terms of a potentially altered snow-lie.
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0718 Tundra (9315)
DE: 0736 Snow (1827, 1863)
DE: 0740 Snowmelt
DE: 0793 Biogeochemistry (0412, 0414, 1615, 4805, 4912)
SC: Cryosphere [C]
MN: 2007 Fall Meeting