Interannual and Spatial Variability of Cyanotoxins in the Prespa Lake Area, Greece

Valentini Maliaka,Elisabeth J Faassen,Miquel Lürling,Frank Van Oosterhout,Alfons J.P Smolders,Christian Fritz,Yvon J.M Verstijnen

doi:10.3390/w13030357

Abstract

The Prespa Lakes area in Greece—comprised partly of lake Great and lake Lesser Prespa and the Vromolimni pond—has a global importance for biodiversity. Although the waters show regular cyanobacteria blooms, assessments of water quality threats are limited. Samples collected in 2012 revealed scattered and low microcystin (MC) concentrations in Great Prespa (<0.2 μg MC L−1) whereas considerable spatial heterogeneity in both total chlorophyll (2.4–93 µg L−1) and MC concentrations (0.04–52.4 µg MC L−1) was detected in Lesser Prespa. In 2013, there was far less spatial variability of MC concentrations in Lesser Prespa (0.4–1.53 µg L−1), however in 2014, increased concentrations were detected near the lakeshore (25–861 µg MC L−1). In Vromolimni pond the MC concentrations were on average 26.6 (±6.4) µg MC L−1 in 2012, 2.1 (±0.3) µg MC L−1 in 2013 and 12.7 (±12.5) µg MC L−1 in 2014. In 2013, no anatoxins, saxitoxins, nor cylindrospermopsins were detected in Lesser Prespa and Vromolimni waters. Tissue samples from carps, an otter and Dalmatian Pelicans contained 0.4–1.9 µg MC g−1 dry weight. These results indicate that cyanotoxins could be a threat to the ecosystem functions of particularly Lesser Prespa and Vromolimni.

Highlights

The incidence and intensity of cyanobacterial blooms in freshwater systems are on the rise worldwide [1,2]
Tri-border basin shared by Albania, Greece and North Macedonia and encompasses two interlinked lakes; the deep lake Great Prespa and the relatively shallow lake Lesser Prespa [9]
The area is internationally recognized as a ”shelter” for endemic biodiversity and migratory birds, especially for the rare piscivorous Dalmatian Pelican (Pelecanus crispus) and Great White Pelican (Pelecanus onocrotalus), which have one of their largest colonies worldwide in Lake Lesser Prespa [9,12,13]

Summary

Introduction

The incidence and intensity of cyanobacterial blooms in freshwater systems are on the rise worldwide [1,2]. Like many other lakes worldwide, the water quality of the Prespa Lakes, has been affected by unsustainable human activities such as discharge of communal waste water, intensive agriculture and sedimentation of eroded matter These events have negative impacts on biodiversity [9]. The Prespa Lakes form a single high altitude (850 m.a.s.l) tri-border basin shared by Albania, Greece and North Macedonia and encompasses two interlinked lakes; the deep lake Great Prespa ( known as Macro Prespa) and the relatively shallow lake Lesser Prespa ( known as Mikri Prespa) [9] Both lakes together form one of the largest waterbodies and the first transboundary protected site within the Balkan area (Southeast Europe) [9,10]. There is a great need to prevent habitat deterioration, i.e., due to eutrophication and the development of toxic cyanobacteria blooms, and to stimulate conservation of the aquatic habitats in the Prespa area

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Conclusion