ERTDI Report 55 (D. Taylor et al)
Summary: Synthesis Report of the ERTDI-funded project: 2002-W-MS-17
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This report synthesises findings from the EPA/ERTDI-funded research project Identification of Reference-Status for Irish Lake Typologies using Palaeolimnological Methods and Techniques (IN-SIGHT, project 2002-W-MS-17). IN-SIGHT commenced on 1 January 2003 with the aim of assisting the Government of Ireland meet some of its obligations under the EU Water Framework Directive (WFD). In particular, the project aimed to test the ecological status of a representative selection of Candidate Reference Lakes (CRLs), or lakes that potentially provide extant examples of reference (or anthropogenically little disturbed) conditions. The project also aimed at reconstructing biological reference conditions for examples of the main types of impacted lakes.
The project was entirely located within the Irish EcoRegion (EcoRegion number 17). EcoRegions are relatively large extents of land and water that contain characteristic and geographically distinct assemblages of plants and animals and their habitats. The Irish EcoRegion comprises the island of Ireland and proximate smaller islands.
Work Package (WP) 1 of IN-SIGHT reviewed existing relevant information and sediments relating to lakes in the Irish EcoRegion and identified a representative selection of 35 lakes from a total of 76 CRLs. WP2 determined the presence or absence of anthropogenic pressures at the selected CRLs. Sediment cores were obtained from the deepest part of each of the 35 CRLs during the summer of 2003 and dated according to down-core variations in Spheroidal Carbonaceous Particle (SCP) concentrations. SCPs are produced solely by fossil-fuel burning. Variations in the amounts of SCPs accumulating in lake sediments over time provide a relatively cheap and reliable means of dating those sediments, because they can be related to documented variations in industrial activity. Sediment core samples were also analysed for their diatom content and chemistry. Sediment core samples were assessed using a variety of techniques to determine the nature of biological and chemical changes at each site. The degree of biological change between a core top sample (associated with present-day conditions) and a core bottom sample (associated with pre-industrial reference conditions) from each sampled CRL was assessed. In cases where biologically important floristic changes were evident from the diatom data, sediment chemistry and CORINE land cover data were used to identify possible human-induced drivers. In particular, the processes of acidification, eutrophication and sediment inwash were examined. <...>