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Impacts of eutrophication and water level change in turkish shallow lakes: a palaeolimnological approach utilizing plant remains and marker pigments

Levi, Eti Ester
Current study provides further understanding of plant macrofossil and sedimentary pigment utilization in comparison with modern and historical environmental variables. Moreover, it contributes to investigations for determining suitable macrophyte-based indices (water framework directive-WFD) that can be employed in Turkey. In total 44 small and mostly shallow lakes, covering the whole latitudinal gradient at western half of Turkey were sampled with snap-shot sampling and from another set of three large lakes cores were retrieved. Plant remains and pigments acquired from surface sediment samples showed significant accord to present-day plant and phytoplankton assemblages, respectively. Conductivity and trophic state were key environmental variables correlated with plants, also temperature and nutrients with phytoplanktonkton. Comparison of instrumental water-level data (40-100 years) with core samples from three lakes showed that effect of longer-term and pronounced water-level changes reflected in sediment record. Furthermore, employing plant remains in macrophyte-indice calculations increased the reliability of the results, which suggested that for shallow lakes, metrics based on species scores (including plant remains), and for deep lakes metrics using colonization depth may be more suitable. Being particularly useful for lakes in Mediterranean regions, that are especially vulnerable to hydrological constraints under climate change, these comparisons were conducted for the first time in Turkish shallow lakes and this study confirmed that sedimentary plant and phytoplankton remains are reliable indicators of environmental change. Furthermore, importance of conductivity, nutrients and temperature underpins the concerns on salinisation and eutrophication in Mediterranean region, supporting exacerbation of these problems as predicted by climate change projections.