The Sensitivity of High Altitude Lochs in Scotland to Climate Change and Atmospheric Pollution: A Preliminary Analysis Martin Kernan (Environmental Change Research Centre, UCL) The objectives of the EU Framework 5 EMERGE (European Mountain Lake Ecosystems: Regionalisation Diagnostics & Socio-Economic Evaluation) are to i) assess the status of remote mountain lakes throughout Europe following the requirements of the EU Water Framework Directives, ii) to provide an evaluation of the findings in ecological, environmental and socio-economic terms; iii) to provide decision makers with an overall understanding of remote mountain lakes so that appropriate policy and management measures can be taken at both European and national scales to ensure the sustainability of these ecosystems into the future. Workpackage 4 focuses on the biological response to environmental gradients. The intention is to model mountain species distribution and food web-structure in relation to the main geographical environmental gradients within Europe. The programme will involve a thorough survey of lakes in 12 ‘Lake Districts’ across Europe to assess the distribution of key organisms including those that provide a fossil record allowing changes through time to be inferred. This poster presents preliminary analyses of the data collected from 30 lochs in Scotland. These will be expanded to provide a more comprehensive assessment of Mountain Lake ecosystems in Scotland and will subsequently feed into to a pan-European study. Survey Site Selection Survey sites should to be headwater lakes above the theoretical treeline and greater than 0.5 hectares. Survey sites should represent - major geological gradients - altitudinal gradient Secondary considerations - size gradient and geographical distribution Sampling programme Littoral and pelagic Diatoms Macro-invertebrates Zooplankton Bacteria Chlorophyll a Water Chemistry Phytoplankton Surface Thermistor (1 year) Sediment (0-0.5 and cm) Diatoms Chironomids Pigments Cladocera SCPs Trace Metals Organic Pollutants CHEMISTRY & CATCHMENT ATTRIBUTES Following Redundancy Analysis with forward selection, Altitude, % bare ground (LC22), soil C:N, soil Bulk Density and Soil Depth explain 54% of the variation in water chemistry. DIATOM RESPONSE TO CHEMISTRY CCA of the diatom data constrained by the water chemistry data shows that 21.3% of the species variation is determined by alkalinity, total phosphorus and chloride. The main gradient is associated with alkalinity. Future work Further analysis of the distribution of different biological groups (e.g. diatoms, chironomids, zooplankton, invertebrates, bacteria, chlorophyll, phytoplankton etc) Examine chemical and morphological (altitude, size, geology, soil etc.) variation in Lake District to identify lake types. Examine variation in metals, POPs, geochemistry from core tops and bottoms. Direct gradient analysis of environmental gradients to examine how the biological groups respond to these Decompose variation into the unique variation attributable to key environmental parameters (climate, pollution, geography) Examination of core tops and bottoms – identify where spatial patterns of difference occur and relate these to changes in environmental drivers. This work was funded by the Commission of European Communities (EMERGE project -EVK1- CT The author acknowledges the contribution of Gina Clarke, Ron Harriman, Rachel Helliwell, Mike Hughes, David Livingstone, Gavin Simpson and Evzen Stuchlik Increasing dissimilarity between assemblages in core tops and core bottoms (15-17cm)