CYANOBACTERIAL TOXINS - Cyanobacteria - page 562

Figure 26: Bloom of Aphanizomenon fl os - aquae in a lake in Surrey, UK. Picture courtesy John Burns (Cyanolab), Mark Schneegurt
(Wichita State University) and Cyanosite (www.cyanosite.bio.purdue.edu).
Color image of this figure appears in the color plate section at the end of the topic.
blooms of A . fl os - aquae and P . agardhii were shown to be responsible for the death of fi sh and a cow,
respectively in Denmark (Henriksen, 2001).
Three Turkish lakes Sapanca, Iznik and Taskisi were analysed for the contents of MCs in relation
to the depth profi les. MCs were detected at depths of 15 and 25 m at concentrations of 3.65 µg L -1
MC-LR equivalents in Lake Sapanca where the surface waters did not contain any MCs. On the
other hand, Lake Taskisi water samples revealed two unidentifi ed MCs equal to a concentration of
2.43 µg L -1 MC-LR equivalents (Albay et al ., 2003). The occurrence of toxic blooms of M . aeruginosa
in the Kucukcekmece lagoon (Istanbul, Turkey), the concentration of MC in waters and biomass
of the bloom, factors affecting bloom of M . aeruginosa have been described for the fi rst time over a
period of three years (Albay et al ., 2005). The MC content of fi ltered water samples ranged between
0.06 and 24.2 µg L -1 MC-LR equivalents. A temperature of 24ºC and 28.5ºC favoured the highest MC
concentration (>3 µg L -1 ) and the highest biomass (>30 mg L -1 ), respectively corresponding with a total
N:P ratio of 7:1. The highest concentration of M . aeruginosa biomass was 173 mg L -1 and MC content of
24.2 µg L -1 MC-LR equivalents and highest salinity (8.8%) were measured concurrently in the lagoon.
Of the 79 pond waters tested, 39 of them showed the growth of HABs with varying abundance of
Microcystis , Planktothrix and Anabaena . The total MC concentrations ranged between <0.1 µg L -1 and
up to 1000 µg L -1 . More than half samples contained MC levels of >10 µg L -1 that is ten times more
than the permissible limit prescribed by WHO posing imminent danger for human health.
Comparative population dynamics of two Planktothrix -dominated Dutch freshwater lakes,
i.e. Lake Tjeukemeer and Lake Klinckenberg revealed that in the former the concentration of MCs
persisted throughout summer (with maximum concentrations of up to 30 µg L -1 ) with P . agardhii as
the dominant species whereas in the latter the maximum MC content of 140 µg L -1 persisted for a
short duration with dominance of P . rubescens (Janse et al ., 2005). Spree, Dahme and Havel are three