MULTI-ARC · Training in multi-scale approaches to understanding carbon dynamics in Arctic and upland systems

Final Activity Report Summary - MULTI ARC (Training in multi-scale approaches to understanding carbon dynamics in Arctic and upland systems)

Northern high latitude systems contain large stores of carbon in soils and vegetation, yet these regions are experiencing some of the greatest warming from climate change. Understanding the processes driving the carbon cycling and the sensitivity to warming of cycling in these regions is therefore of major global importance. The MULTIARC project trained six early stage career fellows (EST) in cross-disciplinary and multi-scale approaches to understanding carbon dynamics in Arctic and upland ecosystems. The overarching aims were to: 1. quantify carbon fluxes in catchments representing different stages of development from systems of low carbon storage to those with significant carbon pools 2. compare these carbon dynamics along multiple transitions 3. understand how 'upstream' components of carbon cycling, e.g. plant traits or microbial functioning, drove downstream changes in carbon dynamics of catchments 4. provide understanding of their sensitivity to future environmental perturbations. To achieve this, six EST fellows worked within one of five work packages (WPs) that covered a broad spectrum of scales and incorporated the major processes and drivers of system carbon dynamics, as well as modelling, and undertook joint training at the Abisko scientific research station, i.e. a sub-Arctic station in northern Sweden. The advances made included using a catchment of contrasting climate and snow melt as a proxy for climate change to show that plant productivity and timing of bud burst and seasonal shoot growth was often less responsive to changes in snow melt timing than initially thought. Furthermore, larger scale assessment of vegetation carbon balance, in particular using eddy-flux towers ascertained the extent to which photosynthesis and respiration at the level of the species and functional type drove community gas exchange. Critical factors determining the annual C-balance at the landscape scale were therefore identified. Work also advanced understanding of how decomposition processes controlled catchment scale carbon cycling. This work revealed similarity in decomposition traits between different plant organs among a wide range of subarctic lowland species that could ultimately provide data to quantify ecosystem level litter carbon dynamics. Furthermore, the work revealed how climate warming might not only directly affect litter carbon dynamics, but also indirectly by changing community composition of invertebrate soil animals. Detailed datasets on hydrological carbon fluxes from a sub-Arctic catchment were also produced and revealed the hydrological controls on export of weathering products and that only small amounts of carbon export occurred per unit catchment area, with dissolved inorganic carbon being by far the most important flux compared to dissolved inorganic carbon. Overarching these field based studies were modelling activities. Here, temperature downscaling provided a novel model of the surface, air and temperature distribution in the Abisko region and microclimatic variability was explored in the context of past climate change using the long-term, i.e. from 1913 to 2010, climatological record from the Abisko scientific research station. This was then expanded to understand the vegetation, soil and climate relationships in the bioclimatic model around the region. Throughout this work all six fellows undertook a series of training activities to maximise their development. These included induction and annual network meetings and annual training needs analyses which informed an annual research training programme. Fellows also undertook ongoing identification of research needs, attendance at formal taught courses both at the fellows' hosts and at other institutes and learning though informal and experiential training, yearly submissions of training progress reports, nine months joint field training over three years at the Abisko scientific research station, annual career development plans and attendance and presentations at national and international conferences.

Data: CORDIS, © European Union