title: Seasonal dynamics of cylindrospermopsin and cyanobacteria in two German lakes.
abstract: Cylindrospermopsin (CYN) is a potent hepatotoxin produced by different cyanobacteria of the order Nostocales. Questions of major concern are: which species produce CYN, which are the seasonal patterns of CYN dynamics and how are they regulated? Therefore, we studied for the first time the seasonal dynamics of particulate and dissolved CYN concentrations, cyanobacterial abundance and environmental factors in two German lakes over 2 years. Total CYN reached maximum concentrations of 0.34 and 1.80 microg L(-1) in Melangsee and Langer See, respectively. In both lakes, maxima of the dissolved CYN fraction occurred later in the season than those of the particulate fraction, and it reached higher concentrations. This indicates that CYN is poorly decomposed and accumulates in the water. The cyanobacterial community in both lakes included several potentially CYN-producing species that did not correlate with CYN concentrations. Significant correlations between the particulate CYN concentrations and species biovolume were only found for Aphanizomenon gracile (r(s)=0.803) in Langer See indicating that this species is a CYN producer. Different correlations of CYN with abiotic factors in the two lakes indicate the presence of further undetected CYN producers as well as different regulation mechanisms of their dynamics and the variability of CYN.
authors: Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department of Limnology of Stratified Lakes, Alte Fischerhuette 2, 16775 Stechlin, Germany. c.wiedner@igb-berlin.de
authors: Claudia
authors: C
authors: Wiedner
authors: Jacqueline
authors: J
authors: Rücker
authors: Jutta
authors: J
authors: Fastner
authors: Ingrid
authors: I
authors: Chorus
authors: Brigitte
authors: B
authors: Nixdorf
mesh_terms: D000470:Alkaloids; D001427:Bacterial Toxins; D044822:Biodiversity; D000458:Cyanobacteria / Q000145:classification / Q000254:growth & development / Q000378:metabolism*; D000087522:Cyanobacteria Toxins; D004784:Environmental Monitoring; D005618:Fresh Water / Q000737:chemistry*; D005858:Germany; D012621:Seasons; D014498:Uracil / Q000031:analogs & derivatives* / Q000032:analysis
chemical_list: D000470:Alkaloids; D001427:Bacterial Toxins; D000087522:Cyanobacteria Toxins; C089595:cylindrospermopsin; D014498:Uracil