A bloom of<i>Dinophysis acuta</i>in a thin layer off North-West Portugal

Moita, MT; Sobrinho-Gonçalves, L.; Oliveira, Paulo B.; Palma, S.; Falcão, Manuela

doi:10.2989/18142320609504160

Cited by 42 publications

(44 citation statements)

References 10 publications

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“…D. acuta is very seasonal and replaces D. acuminata in August-September during very hot summers with marked thermal stratification in Galicia (Escalera et al, 2006), where two mechanisms have been suggested for the numerical increase of D. acuta (i) in situ growth in late summer, when there is a combination of moderate upwelling and marked thermal stratification, and (ii) advection of shelf populations during relaxation and downwelling, especially in the autumn (Reguera et al, 1995). Further studies have confirmed the association of D. acuta blooms with marked thermal stratification and moderate upwelling pulses in Galicia (Escalera et al, 2006) and especially in Northern Portugal (Moita et al, 2006), where stratification in summer is more intense due to a wider and flatter shelf, and latitudinal changes in upwelling winds (Moita and da Silva, 2001).…”

Section: Introductionmentioning

confidence: 74%

Bloom dynamics of Dinophysis acuta in an upwelling system: In situ growth versus transport

et al. 2010

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Section: Introductionmentioning

confidence: 74%

Bloom dynamics of Dinophysis acuta in an upwelling system: In situ growth versus transport

et al. 2010

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“…Results here show that strong thermal stratification and deepened thermoclines, combined with average upwelling conditions observed during July-August 1989/90 promoted Dinophysis acuta growth on the adjacent shelf, the region where this neritic species reaches maximal densities (Palma et al, 1998;Moita et al, 2006). The ''pelagic seed banks'' (sensu Smayda, 2002b) of D. acuta then inoculated near shore habitats, leading to formation of intense summer blooms detected in all the Galician Rías Baixas (Reguera et al, 1995).…”

Section: Interannual Climate Variability and Trends In Dinophysis Popmentioning

confidence: 83%

“…1B). Conditions in that region, with a wider continental shelf and more stability, are optimal for summer growth of D. acuta populations later transported to the Galician region (Moita et al, 2006(Moita et al, , 2016.…”

Section: Local Conditions Preceding D Acuta Bloom Developmentmentioning

confidence: 97%

Climate variability and Dinophysis acuta blooms in an upwelling system

et al. 2016

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Dinophysis acuta is a frequent seasonal lipophilic toxin producer in European Atlantic coastal waters associated with thermal stratification. In the Galician Rías, populations of D. acuta with their epicentre located off Aveiro (northern Portugal), typically co-occur with and follow those of Dinophysis acuminata during the upwelling transition (early autumn) as a result of longshore transport. During hotter than average summers, D. acuta blooms also occur in August in the Rías, when they replace D. acuminata. Here we examined a 30-year (1985-2014) time series of D. acuta from samples collected by the same method in the Galician Rías. Our main objective was to identify patterns of distribution and their relation with climate variability, and to explain the exceptional summer blooms of D. acuta in 1989-1990. A dome-shaped relationship was found between summer upwelling intensity and D. acuta blooms; cell maxima were associated with conditions where the balance between upwelling intensity and heating, leading to deepened thermoclines, combined with tidal phase (3 days after neap tides) created windows of opportunity for this species. The application of a generalized additive model based on biological (D. acuta inoculum) and environmental predictors (Cumulative June-August upwelling CUI, average June-August SST and tidal range) explained more than 70% of the deviance for the exceptional summer blooms of D. acuta, through a combination of moderate (35,000-50,000mskm) summer upwelling (CUI), thermal stratification (SST>17°C) and moderate tidal range (∼2.5m), provided D. acuta cells (inoculum) were present in July. There was no evidence of increasing trends in D. acuta bloom frequency/intensity nor a clear relationship with NAO or other long-term climatic cycles. Instead, the exceptional summer blooms of 1989-1990 appeared linked to extreme hydroclimatic anomalies (high positive anomalies in SST and NAO index), which affected most of the European Atlantic coast.

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“…Successive occurrences of these 2 species have led to prolonged closures of shellfish harvesting on European Atlantic coasts, in New Zealand and in Chile (Reguera & Pizarro 2007). D. acuta is a common member of the late summer-autumn (August to November) phytoplankton assemblage in northwest Iberian coastal waters , Moita et al 2006. In years when very hot summers and moderate upwelling allow the establishment of deeper thermoclines, this species replaces D. acuminata as the main DSP agent and leads to more prolonged shellfish closures (Escalera et al 2006b).…”

Section: Introductionmentioning

confidence: 99%

Growth, behaviour and cell toxin quota of Dinophysis acuta during a daily cycle

Pizarro

Escalera²,

González-Gil³

et al. 2008

Mar. Ecol. Prog. Ser.

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), a high frequency of dead cells (up to 15%) and cells with starch granules (up to 93%), and no evidence of recent mixotrophic behaviour. Still, the cells, which did not perform vertical migration, aggregated around salinity-driven density discontinuities in the top 5 m and had a high cell toxin quota (determined by liquid chromatography-mass spectrometry) for this species. A 3.5-fold difference was found between maximum (during the night) and minimum values of cell toxin quota. Okadaic acid (OA) was the predominant toxin and changes in cell quota of different toxins showed different daily patterns in the content of okadaiates and pectenotoxins; thus, the toxin profile is influenced by the time of sampling. Dissolved toxins (adsorbed by resins in passive samplers from 8 to 14 November) also reached annual maxima and reflected the vertical distribution of D. acuta cells. These results emphasize the need to parameterize physiological conditions and behaviour of Dinophysis populations during different phases of the population growth and hydrodynamic scenarios.

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A bloom ofDinophysis acutain a thin layer off North-West Portugal

Cited by 42 publications

References 10 publications

Bloom dynamics of Dinophysis acuta in an upwelling system: In situ growth versus transport

Bloom dynamics of Dinophysis acuta in an upwelling system: In situ growth versus transport

Climate variability and Dinophysis acuta blooms in an upwelling system

Growth, behaviour and cell toxin quota of Dinophysis acuta during a daily cycle

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