Cyanobacterial blooms and water quality in Greek waterbodies

Abstract

The cyanobacterial species composition of nine Greek waterbodies of different type and trophic status was examined during the warm period of the year (May-October). Cyanobacterial water blooms were observed in all waterbodies. Forty-six cyanobacterial taxa were identified, 11 of which are known to be toxic. Eighteen species are reported for the first time in these waterbodies, 8 of which are known to produce toxins. Toxin producing species were found in all of the waterbodies and were primarily dominant in bloom formations (e.g., Microcystis aeruginosa, Anabaena flos-aquae, Aphanizomenon flos-aquae and Cylindrospermopsis raciborskii). Cosmopolitan species (e.g., M. aeruginosa), pantropic (e.g., Anabaenopsis tanganyikae) and holarctic species (e.g., Anabaena flos-aquae) were encountered. Shallow, eutrophic waterbodies had blooms dominated by Microcystis species and were characterized by phytoplankton association M. Anabaena and Aphanizomenon species of association H were dominant in waterbodies with low dissolved inorganic nitrogen and thermal stratification in the summer. Total cyanobacterial biovolumes (CBV) ranged from 7 to 9,507 cm 3 m −3 and were higher than Alert Level 2 and Guidance Level 2 (10 cm 3 m −3 ; World Health Organization; WHO) in seven of the waterbodies. Chlorophyll a concentrations ranged from 6 to 90,000 mg m −3 and were higher than Alert Level 2 and Guidance Level 2 (50 mg m −3 ; WHO) in eight of the waterbodies. There is also an elevated risk of acute toxicosis (Guidance Level 3; WHO) in five waterbodies. Water of an undesirable quality, hazardous to humans and animals occurs in several Greek waterbodies.

Ecological impacts of global warming and water abstraction on lakes and reservoirs due to changes in water level and related changes in salinity

“…3e). Petaloti et al (2004) Precipitation, Prec (mm y and was dominated by cyanobacteria (Snowella lacustris) (Cooke et al, 2005;Vardaka et al, 2005). More recently, Ioakimidou (2010) observed that cyanobacteria dominated the phytoplankton community of the lake, accounting for more than 86% of total abundance.…”

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“…Sphaerocystis schroeteri and Microcystis aeruginosa performed the second peak in early autumn. The summer and autumn growth of Microcystis aeruginosa in eutrophic and hypertrophic lakes was reported to be characteristic by many authors (Naselli-Flores and Barone, 2000; Vardaka et al, 2005).…”

Isolation and preliminary characterization of cyanobacteria strains from freshwaters of Greece

“…In Greece, common bloom-forming cyanobacteria mainly belong to the genera Microcystis and Anabaena, followed by Cylindrospermopsis and Aphanizomenon [1,4,5]. In addition to the bloom-forming cyanobacteria, a wide range of less abundant and lesser-known cyanobacteria, such as, filamentous (e.g.…”

“…Pseudanabaena) or colonial (e.g. Aphanocapsa, Chroococcus, Cyanodictyon) nanoplanktonic (2-20 μm) species [4] and Synechococcustype picocyanobacteria (<2 μm) [6] are present in blooms that rarely become dominant, but can represent an important part of the total cyanobacterial biomass. Occasionally, benthic and/or periphytic cyanobacteria can be observed in phytoplankton.…”

“…In Greece, cyanobacteria diversity and toxicity is mainly known by field (e.g. [4,5,19]) and culture-independent 16S rRNA gene studies (e.g. [7]); only one publication [18] refers to Limnothrix cyanobacteria isolates.…”