First report of the cyanobacterium Aphanizomenon ovalisporum Forti in two Greek lakes and cyanotoxin occurrence

Abstract

Aphanizomenon ovalisporum is reported for the first time in Greece, in two warm, monomictic lakes. Aphanizomenon ovalisporum was dominant constituting 99 and 58% of the total cyanobacterial biomass in lakes Lysimachia and Trichonis, respectively. Trichomes were solitary (length 60-700 μm), were narrowed slightly at the ends, had a few terminal hyaline cells and had cells containing gas vesicles (length 2.5-6.9, width 2.4-5.1 μm). Heterocytes, spherical or ellipsoidal (length 4.4-10.5, width 2.41-5.1 μm) and akinetes (length 16.0-27.8, width 6.0-15.9 μm) were located in the middle of the trichome. High performance liquid chromatography (HPLC) analysis detected microcystin-LR (MC-LR) and a putative anabaenopeptin in the L. Lysimachia sample. The sestonic MC-LR concentration was 0.9 μg L-1. The origin of MC-LR in L. Lysimachia is discussed. The other cyanobacteria present were Pseudanabaena sp. and Planktothrix mougeotii (1% of the total cyanobacterial biomass). © The Author 2005. Published by Oxford University Press. All rights reserved.