Hydrodynamic and chemical conditions during onset of a red-tide assemblage in an estuarine upwelling ecosystem

Álvarez‐Salgado, Xosé Antón; Figueiras, F. G.; Villarino, M. L.; Pazos, Yolanda

doi:10.1007/s002270050271

Cited by 13 publications

(11 citation statements)

References 74 publications

(82 reference statements)

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“…However, conversion of our fluxes into velocities produce values consistent with those recorded from current meter arrays under comparable hydrographic conditions (Figueiras et al, 1994;ÁlvarezSalgado et al, 1998). Anyway, results from direct current measurements indicate water displacements at a given position and depth within the embayment, whilst box model fluxes are representative for crosssections and volumes of the order of 10 4 m 2 and 10 6 m 3 respectively.…”

Section: D Box Model Approach To the Water Circulation Of A Coastal supporting

confidence: 66%

Surface Waters of the NW Iberian Margin: Upwelling on the Shelf versus Outwelling of Upwelled Waters from the Rı́as Baixas

Álvarez‐Salgado

Gago

Míguez

et al. 2000

Estuarine, Coastal and Shelf Science

153

110

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Section: D Box Model Approach To the Water Circulation Of A Coastal supporting

confidence: 66%

Surface Waters of the NW Iberian Margin: Upwelling on the Shelf versus Outwelling of Upwelled Waters from the Rı́as Baixas

Álvarez‐Salgado

Gago

Míguez

et al. 2000

Estuarine, Coastal and Shelf Science

153

110

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“…However, in all areas shown in Table 1, average Si : NO 3 molar ratios were 6 (in areas where P. australis was the dominant toxin producer) to 8 (in areas where P. multiseries was the dominant toxic species). This indicates that silicate was sufficient for diatom growth and that silicate enrichment was probably occurring in these upwelling areas by mineralization processes (Alvarez-Salgado et al 1998). These observations indicate that nutrient requirements for toxin production in situ may not always be effectively predicted by laboratory experiments using cultured isolates of Pseudonitzschia.…”

Section: Discussionmentioning

confidence: 95%

Domoic acid production near California coastal upwelling zones, June 1998

Trainer

Adams

Bill

et al. 2000

Limnology & Oceanography

179

149

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Sea lion mortalities in central California during May and June 1998 were traced to their ingestion of sardines and anchovies that had accumulated the neurotoxin domoic acid. The detection of toxin in urine, feces, and stomach contents of several sea lions represents the first proven occurrence of domoic acid transfer through the food chain to a marine mammal. The pennate diatoms, Pseudo-nitzschia multiseries and P. australis, were the dominant, toxinproducing phytoplankton constituting algal blooms near Monterey Bay, Half Moon Bay, and Oceano Dunes, areas where sea lions with neurological symptoms stranded. Toxic Pseudo-nitzschia were also found near Morro Bay, Point Conception, Point Arguello, and Santa Barbara, demonstrating that these species were widespread along the central California coast in June 1998. Measurements of domoic acid during three cruises in early June showed the highest cellular toxin levels in P. multiseries near Point Año Nuevo at 6 pg cell Ϫ1 and in P. australis from Morro Bay at 78 pg cell Ϫ1 . Maximum cellular domoic acid levels were observed within 20 km of the coast between 0 and 5 m depth, although toxin was also measured to depths of 40 m. Hydrographic data indicated that the highest toxin levels and greatest numbers of toxic cells were positioned in water masses associated with upwelling zones near coastal headlands. Nutrient levels at these sites were less than those typically measured during periods of active upwelling, due to the 1998 El Niño event. The flow of cells and/or nutrients from coastal headlands into embayments where cells can multiply in a stratified environment is a possible mechanism of bloom development along the central California coast. This coupling of toxic Pseudo-nitzschia growth near upwelling zones with physical processes involved in cell transport will be understood only when long-term measurements are made at several key coastal locations, aiding in our capability to predict domoic-acid producing algal blooms.In May and June 1998, at least 70 California sea lions (Zalophus californianus) and one northern fur seal (Callorhinus ursinus) were found stranded along the central California coast. This stranding event occurred between 15 May 1 Corresponding author (Vera.L.Trainer@noaa.gov). AcknowledgmentsWe thank the captain and the crew of the RV Ballena, RV Shana Rae, and PB Bluefin for their help during these cruises, at times under strenuous conditions. We acknowledge the following people for their help in providing useful information that directed the locations of the cruises:

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“…Its situation in a productive upwelling region enables the port of Vigo, and its ria, to host one of the most economically important mariculture industries in Europe [ Blanton et al ., ; Figueiras et al ., ], an activity that coexists with roles as a major ship‐building center, Europe's principal landing point for fish, an area of ecological interest, and a major focus of tourism [ Huntington et al ., ; Fernández et al ., ]. At the end of summer, blooms of toxic alga (Harmful Algal Blooms or HAB) have frequently been observed to have a negative impact on this mariculture of mussels [ Álvarez‐Salgado et al ., ; González Vilas et al ., ]. Many HAB events in the ria have been associated with dinoflagellate species like Gymnodinium catenatum , Dinophysis acuta , and D. acuminata , whose outbreaks often coincide with the onset of downwelling conditions [ Estrada , ; Reguera et al ., ; Figueiras et al ., ; Sordo et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Surface water subduction during a downwelling event in a semienclosed bay

et al. 2016

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The Ría de Vigo is a bay strongly influenced by upwelling‐downwelling cycles along the adjacent coast of NW Iberia. Moored and ship‐board observations during September 2006 showed that subduction, initially associated with an estuarine circulation, strengthened when a strong downwelling circulation, resulting from northward wind over the coastal ocean, was generated in the outer Ría causing ambient waters to be advected outward in the lower layer. Incoming surface waters confined the estuarine circulation to the shallow interior and displaced isopleths downward through the water column at ∼10 m d−1. As the estuarine circulation retreated inward, strong flow convergence developed between middle and inner ria in the layer above 15 m, while divergence developed beneath. The convergence increased through the period of downwelling‐favorable wind at a rate consistent with the observed isopleth displacement velocities. The coefficient of turbulent diffusion Kt, from a microstructure profiler, indicated that mixing was strong in the estuarine circulation and subsequently in the downwelling zone, where localized instabilities and temperature‐salinity inversions were observed. During the downwelling, concentrations of phytoplankton, including potentially harmful species, increased, especially in the middle and inner ria, as a result of inward advection, subduction, and the ability of the dinoflagellates to maintain their position in the water column by swimming. In the course of the 5 day event, the water mass of all but the innermost Ría was flushed completely and replaced by waters originating in the coastally trapped poleward flow along the Atlantic coastline.

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Hydrodynamic and chemical conditions during onset of a red-tide assemblage in an estuarine upwelling ecosystem

Cited by 13 publications

References 74 publications

Surface Waters of the NW Iberian Margin: Upwelling on the Shelf versus Outwelling of Upwelled Waters from the Rı́as Baixas

Surface Waters of the NW Iberian Margin: Upwelling on the Shelf versus Outwelling of Upwelled Waters from the Rı́as Baixas

Domoic acid production near California coastal upwelling zones, June 1998

Surface water subduction during a downwelling event in a semienclosed bay

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