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Microplankton composition off NW Iberia at the end of the upwelling season: source areas of harmful dinoflagellate blooms

2008; Inter-Research; Volume: 355; Linguagem: Inglês

10.3354/meps07261

1616-1599

Bibiana G. Crespo, I. G. Teixeira, F. G. Figueiras, Carmen G. Castro,

Marine Biology and Ecology Research

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 355:31-43 (2008) - DOI: https://doi.org/10.3354/meps07261 Microplankton composition off NW Iberia at the end of the upwelling season: source areas of harmful dinoflagellate blooms B. G. Crespo*, I. G. Teixeira, F. G. Figueiras, C. G. Castro Instituto de Investigacións Mariñas, CSIC, Eduardo Cabello 6, Vigo 36208, Spain *Email: bibiana@iim.csic.es ABSTRACT: The Rías Baixas of Galicia are 4 bays on the NW Iberia Peninsula that experience harmful dinoflagellate blooms toward the end of the upwelling season, in late summer to early autumn. In order to identify the source areas of initial bloom populations, we studied the hydrographic regime and the microplankton composition in the NW Iberian margin at the end of summer 1991. Three distinctive oceanographic features were recognised as possible sources of initial populations: (1) the onset of a northward stream, the Iberian Poleward Current (IPC), which can transport seed populations to the region; (2) a subsurface chlorophyll maximum (SCM); and (3) weak upwelling at the coast, which can promote the growth of dinoflagellates. While the SCM held populations of the small dinoflagellates Heterocapsa niei and Prorocentrum minimum, larger dinoflagellates Prorocentrum micans, Dinophysis acuminata, Gymnodinium catenatum and the raphidophycean Heterosigma akashiwo, which habitually form blooms in the Rías Baixas, were only found in upwelled coastal waters, mostly off the Rías. These species occurred with a microplankton assemblage composed of other large dinoflagellates and diatoms, which is characteristic of the final summer upwelling events in the Rías. It is hypothesised that the Rías Baixas can be both the source and the target of harmful dinoflagellate blooms. Summer upwelling, through cyst resuspension and subsequent germination in the nearby stratified waters, would provide the initial populations. Downwelling, which promotes the accumulation of dinoflagellates in the interior of the Rías, would ensure blooms and hence replenish the sediments with new cysts. KEY WORDS: Harmful dinoflagellates · Coastal upwelling · Iberian Poleward Current · Subsurface chlorophyll maximum · NW Iberia · Rías Baixas Full text in pdf format PreviousNextCite this article as: Crespo BG, Teixeira IG, Figueiras FG, Castro CG (2008) Microplankton composition off NW Iberia at the end of the upwelling season: source areas of harmful dinoflagellate blooms. Mar Ecol Prog Ser 355:31-43. https://doi.org/10.3354/meps07261 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 355. Online publication date: February 26, 2008 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2008 Inter-Research.