title: Microcystins and cyanophyte extracts inhibit or promote the photosynthesis of fluvial algae. Ecological and management implications.
abstract: The ecological influence of cyanotoxins on aquatic biota remains unclear despite the numerous published references on toxicological and sanitary problems related with cyanophyte proliferation. The effects of microcystins and cyanophyte extracts on the photosynthesis of the algae that belong to two taxonomic groups, Rhodophyta and Bacillariophyta, were studied in an attempt to elucidate their role in the intraspecific competence and physiognomy of fluvial communities. The data showed that both cyanobacteria extracts and pure microcystin-LR affected the photosynthetic activity of all the tested organisms, diatoms (Fistulifera pelliculosa, Gomphonema parvulum, Nitzschia frustulum and Stephanodiscus minutulus) and red algae (Chroothece richteriana) at environmentally relevant concentrations. Effects varied with strains and time, and promoted or inhibited photosynthesis. The microcystins and the other compounds present in cyanobacteria extracts may explain the competence effects observed in nature, especially in calcareous environments where they predominate, and after disturbing events like heavy rains or floods, which may destroy cyanophyte mats and release toxic or inhibitory compounds in a seasonal scale pattern.
authors.affiliation: Laboratory of Algology, Faculty of Biology, Espinardo Campus, Murcia University, Murcia, E-30100, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: García-Espín
authors.affiliation: Multidisciplinary Teaching and Research Unit, Faculty of Sciences, Juriquilla Campus, National Autonomous University of México, Querétaro, C. P. 76230, Mexico.
authors.forename: Enrique A
authors.initials: EA
authors.lastname: Cantoral
authors.affiliation: Department of Applied Biology, Faculty of Experimental Sciences, Elche Campus, Miguel Hernández University, Elche, E-03202, Alicante, Spain. aasencio@umh.es.
authors.forename: Antonia D
authors.identifier: http://orcid.org/0000-0002-4021-9184
authors.initials: AD
authors.lastname: Asencio
authors.affiliation: Laboratory of Algology, Faculty of Biology, Espinardo Campus, Murcia University, Murcia, E-30100, Spain.
authors.forename: Marina
authors.initials: M
authors.lastname: Aboal
mesh_terms: D000458:Cyanobacteria / Q000502:physiology; D005068:Eutrophication; D058086:Microalgae / Q000187:drug effects* / Q000502:physiology; D052998:Microcystins / Q000633:toxicity*; D010788:Photosynthesis / Q000187:drug effects*
chemical_list: D052998:Microcystins
keywords: Cyanobacteria; Diatoms; Interspecific competence; Microcystins; Red algae; ToxY-PAM analyzer