Stable isotope variability in macrophytes and sediments of two shallow lakes in Sicily: a first contribution for ecological monitoring

We present the first isotopic dataset for two shallow, slightly brackish Mediterranean lakes in Sicily colonised by Chara baltica (Lago Preola) and Najas marina (Lago Murana). Seasonal stable isotopes (δ13C, δ15N) and elements concentration (C%, N%) were measured in macrophytes and sediments over one year. Lago Murana sediments were more 13C-depleted than Lago Preola. Both lakes showed similar seasonality: 13C-enriched and 15N-depleted values in spring–summer, lower in autumn–winter. Greater seasonal variability in Preola indicates macrophyte-derived organic matter input to sediments, whereas Murana reflects run-off from surrounding pastures and vineyards. These results offer a preliminary framework for future work.