Pseudo-nitzschia Blooms in a Coastal Upwelling System: Remote Sensing Detection, Toxicity and Environmental Variables

The NW coast of the Iberian Peninsula is dominated by extensive shellfish farming, which places this region as a world leader in mussel production. Harmful algal blooms in the area frequent lead to lengthy harvesting closures threatening food security. This study developed a framework for the detect...

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Bibliographic Details
Published inWater (Basel) Vol. 11; no. 9; p. 1954
Main Authors Torres Palenzuela, Jesus M., González Vilas, Luis, Bellas, Francisco M., Garet, Elina, González-Fernández, África, Spyrakos, Evangelos
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.09.2019
Subjects
Abundance
Algal blooms
Autumn
Biomass
Chlorophyll
Domoic acid
Eutrophication
Food security
Galician rias
Harvesting
MERIS algorithms
Microorganisms
Plankton
Poisoning
Pseudo-nitzschia
Remote sensing
Salinity
Satellite imagery
Satellites
Shellfish
Shellfish farming
Toxicity
Toxins
Upwelling
United States > US
California
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Summary:The NW coast of the Iberian Peninsula is dominated by extensive shellfish farming, which places this region as a world leader in mussel production. Harmful algal blooms in the area frequent lead to lengthy harvesting closures threatening food security. This study developed a framework for the detection of Pseudo-nitzschia blooms in the Galician rias from satellite data (MERIS full-resolution images) and identified key variables that affect their abundance and toxicity. Two events of toxin-containing Pseudo-nitzschia were detected (up to 2.5 μg L−1 pDA) in the area. This study suggests that even moderate densities of Pseudo-nitzschia in this area might indicate high toxin content. Empirical models for particulate domoic acid (pDA) were developed based on MERIS FR data. The resulting remote-sensing model, including MERIS bands centered around 510, 560, and 620 nm explain 73% of the pDA variance (R2 = 0.73, p < 0.001). The results show that higher salinity values and lower Si(OH)4/N ratios favour higher Pseudo-nitzschia spp. abundances. High pDA values seem to be associated with relatively high PO43, low NO3− concentrations, and low Si(OH)4/N. While MERIS FR data and regionally specific algorithms can be useful for detecting Pseudo-nitzschia blooms, nutrient relationships are crucial for predicting the toxicity of these blooms.
ISSN:2073-4441
2073-4441
DOI:10.3390/w11091954