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Cyanobacterial blooms in natural waters in southern Portugal: a water management perspective

2008; Inter-Research Science Center; Volume: 53; Linguagem: Inglês

10.3354/ame01228

1616-1564

Helena M. Galvão, M.P. Reis, Elisabete Valério, Rita B. Domingues, Carolina Ortiz Rocha da Costa, Delmar Muniz Lourenço, Sı́lvia Condinho, R Miguel, Ana B. Barbosa, Custódia Gago, Nuno Torres Faria, Sérgio Paulino, Paulo Pereira,

Marine Toxins and Detection Methods

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 53:129-140 (2008) - DOI: https://doi.org/10.3354/ame01228 AME Special: 'Progress and Perspectives in Aquatic Microbial Ecology: Highlights of the SAME 10, Faro, Portugal, September 2007' Cyanobacterial blooms in natural waters in southern Portugal: a water management perspective Helena M. Galvão1,*, Margarida P. Reis1, Elisabete Valério2, Rita B. Domingues1, Cristina Costa1, Dulce Lourenço3, Sílvia Condinho3, Rute Miguel1, Ana Barbosa1, Conceição Gago4, Natália Faria2, Sérgio Paulino2, Paulo Pereira2 1Faculdade de Ciências do Mar e do Ambiente (FCMA), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal 2National Health Institute Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016 Lisboa, Portugal 3Águas do Algarve, S.A., Rua do Repouso n° 10, 8000-302 Faro, Portugal 4CCDR Algarve (Ambiente e Ordenamento), R. Dr. José de Matos n° 13, 8000-503 Faro, Portugal *Email: hgalvao@ualg.pt ABSTRACT: This synthesis of 3 studies from 2 regions of southern Portugal (Alentejo and Algarve) was part of a workshop focusing on cyanobacteria held at the SAME 10. The first study monitored impacts of the large Alqueva dam on the Guadiana estuary since 1996, revealing changes in sediment load, nutrient regime and phytoplankton succession. Prior to dam construction, dense cyanobacterial blooms occurred in the upper estuary during summer and fall. After dam construction, chlorophyll concentration, phytoplankton diversity and abundances of cyanobacteria decreased, contrary to predictions. Mycrocystins remained at low levels in the seston and undetectable in water samples, except during summer 2003 when the particulate fraction contained 1 µg l–1, while chlorophyll concentrations and abundances of potentially toxic cyanobacteria remained low. Algarve reservoirs studied since 2001 revealed differences in phytoplankton dynamics. In the western mesotrophic reservoirs (Bravura and Funcho), 40 to 50% of surface samples contained cyanobacterial concentrations of ≥2000 cells ml–1, while over 80% of samples from the eastern oligotrophic reservoirs (Odeleite and Beliche) exceeded this value. Spring blooms were dominated by Oscillatoriales in Odeleite and Beliche and by Chroococcales in Bravura and Funcho. Bloom composition seemed to depend on water temperature and management strategies, while toxin concentrations reflected the increased biomass of toxic species. Finally, phytoplankton communities and microcystin production in 5 Alentejo freshwater reservoirs were studied from May to December 2005 and April to July 2006. Cyanobacterial blooms occurred, with varying intensities, not only during summer but also occasionally in winter. Microcystins were detected in 23% of the samples (n = 51), but without correlation with cyanobacterial biomass. Although Microcystis aeruginosa seemed to be the major producer of microcystins, other potentially toxic species were found. In summary, the varying pattern of cyanobacterial bloom occurrence and toxicity requires a systematic approach to monitoring programs for adequate risk assessment. KEY WORDS: Cyanobacteria · Microcystins · Phytoplankton · Estuary · Freshwater reservoirs Full text in pdf format PreviousNextCite this article as: Galvão HM, Reis MP, Valério E, Domingues RB and others (2008) Cyanobacterial blooms in natural waters in southern Portugal: a water management perspective. Aquat Microb Ecol 53:129-140. https://doi.org/10.3354/ame01228 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 53, No. 1. Online publication date: September 18, 2008 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2008 Inter-Research.