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Presented at the NABS Annual meeting, Athens, Georgia, 2003
in Ecotoxicology
Cyanotoxins, their role in the ecology of Mediterranean streams
M.A. Puig1, M. Aboal2, J. Vassallo1, P. Mateo3, and E. Perona3. 1Department of Aquatic Biogeochemistry, CEAB-CSIC, Acces Cala Sant Francesc 14, E-17300 Blanes, Spain, 2Departamento de Biologia Vegetal, Universidad de Murcia, E-30100 Murcia, Spain, 3Departamento de Biologia, Facultad de Ciencias, Universidad Autonoma de Madrid, Canto Blanco, E-28049 Madrid, Spain
The results obtained from a study of eleven reaches of five Mediterranean calcareous streams have shown that all the benthic communities of cyanobacteria produce toxins, which are present in running waters. Different bioassays carried out with bacteria and microalgae show the inhibitory capacity of cyanobacteria and their toxic crude extracts. At the same time the effect on primary and secondary consumers (mayflies, stoneflies and caddisflies) has been demostrated experimentally. As can be seen, such effects may be hepatotoxic and neurotoxic, perhaps even lethal in some species. In undisturbed conditions the levels of free hepatotoxins (microcystins) observed were usally lower, but in reaches punctually disturbed by nutrient inputs from urban and recreative activities high levels near 4ppb were recorded. If the network of effects of cyanobacteria is represented graphically, the bottom-up control of this type of stream ecosystem becomes evident, as well as the limit of possible water uses.
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