Floraciones de cianobacterias y valores de microcistina-LR sestónica y disuelta en embalses de la cuenca hidrográfica del Miño-Sil (NW-España)
- Lorena Lago 1
- Sandra Barca 1
- Rufino Vieira-Lanero 1
- Fernando Cobo 2
- 1 Universidade de Santiago de Compostela. Estación de Hidrobioloxía “ Encoro do Con ”
- 2 Universidade de Santiago de Compostela. Departamento de Zooloxía e Antropoloxía Física
ISSN: 1133-3669
Year of publication: 2016
Issue Title: AÑO INTERNACIONAL DE LAS LEGUMBRES
Issue: 16
Pages: 113-125
Type: Article
More publications in: Mol: boletín de la Sociedad de Ciencias de Galicia
Abstract
Between October 2012 and February 2015, 181 water samples from nine reservoirs (As Conchas, Cachamuíña, Castadón, Faramontaos, Os Peares, Prada, Salas and Vilasouto), all belong- ing to the catchment area of Miño-Sil, were analyzed. 64 samples, from Vilasouto reservoir, were considered for a more detailed study. The cyanobacteria species were identified and quantified, and the concentration of the microcystin-LR (MC-LR) was determined, both the sestonic and the dis- solved fraction. The cyanobacteria were identified and quantified according to the UNE-EN15204 standard, using a settling chamber combined under an inverted microscope Nikon Eclipse TE 2000-S. The detection and determination of both fractions of MC-LR were conducted by means of an enzyme immunoassay, with the EnviroGard Microcystins QuantiTube kit. In all the reservoirs, except in Salas reservoir in which any cyanobacteria or MC-LR were detected, ten species of potentially toxic cyanobacteria were identified: Anabaena circinalis, Anabaena crassa, Anabaena flos-aquae, Anabaena planctonica, Aphanizomenon flos-aquae, Gomphosphaeria sp., Microcystis aeruginosa, Planktothrix agardhii, Planktothrix rubescens and Woronichinia naegeliana. However, MC-LR found out only in five of these reservoirs (Vilasouto, Castadón, Cachamuíña, Os Peares and Faramontaos). The species that emerged were: A. planctonica, Gomphosphaeria sp. and P. rubescens in Vilasouto; M. aeruginosa in As Conchas, Cachamuíña and Castadón; A. circinalis in Prada and Faramontaos; W. naegeliana in Os Peares, A. flos-aquae in Faramontaos and Aph. flos-aquae in Lindoso. As Conchas and Lindoso reservoirs, in spite of being one after the other in the Lima river, had different non-toxic blooms of M. aeruginosa and Aph. flos-aquae respectively; while Cachamuíña and Castadón reservoirs, which are located in the same way that the previous, these in the Lonia river, showed toxic outcrops of M. aeruginosa. The cyanobacte- rial species identified in Vilasouto reservoir were Anabaena planctonica, Gomphosphaeria sp., Planktothrix agardhii and Planktothrix rubescens; all potentially toxic. P. rubescens was the dom- inant specie in the early months of 2013 and 2014. The bloom of 2013 was the most intense (with a maximum abundance of 257550 cel./ml in February and of 1448000 cel./ml in April), extending even until July. The concentration of sestonic and dissolved MC-LR in Vilasouto exceeded the limit value proposed by WHO (1 μg/l) in different periods: October of 2012, from January to July of 2013 and in March and May of 2014; all showing a significant Spearman correlation (α = 0,05) with the abundance of A. planctonica and P. rubescens.