Continental shelf off northern Chilean Patagonia: A potential risk zone for the onset of Alexandrium catenella toxic bloom?

Harmful Algal Blooms (HAB) pose a severe socio-economic problem worldwide. The dinoflagellate species Alexandrium catenella produces potent neurotoxins called saxitoxins (STXs) and its blooms are associated with the human intoxication named Paralytic Shellfish Poisoning (PSP). Knowing where and how...

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Published in:Marine pollution bulletin 2022-11, Vol.184, p.114103-114103, Article 114103
Main Authors: Rodríguez-Villegas, Camilo, Figueroa, Rosa I., Pérez-Santos, Iván, Molinet, Carlos, Saldías, Gonzalo S., Rosales, Sergio A., Álvarez, Gonzalo, Linford, Pamela, Díaz, Patricio A.
Format: Article
Language:English
Subjects:
Alexandrium catenella
Chilean Patagonia
Cyst beds
Paralytic shellfish toxins (PST)
Submarine canyons
Upwelling
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Summary:Harmful Algal Blooms (HAB) pose a severe socio-economic problem worldwide. The dinoflagellate species Alexandrium catenella produces potent neurotoxins called saxitoxins (STXs) and its blooms are associated with the human intoxication named Paralytic Shellfish Poisoning (PSP). Knowing where and how these blooms originate is crucial to predict blooms. Most studies in the Chilean Patagonia, were focused on coastal areas, considering that blooms from the adjacent oceanic region are almost non-existent. Using a combination of field studies and modelling approaches, we first evaluated the role of the continental shelf off northern Chilean Patagonia as a source of A. catenella resting cysts, which may act as inoculum for their toxic coastal blooms. This area is characterized by a seasonal upwelling system with positive Ekman pumping during spring-summer, and by the presence of six major submarine canyons. We found out that these submarine canyons increase the vertical advection of bottom waters, and thus, significantly enhance the process of coastal upwelling. This is a previously unreported factor, among those involved in bloom initiation. This finding put this offshore area at high risk of resuspension of resting cysts of A. catenella. Here, we discuss in detail the physical processes promoting this resuspension. •Alexandrium catenella resting cysts were found in continental shelf sediments off northern Patagonia.•Seasonal upwelling and submarine canyons can resuspend A. catenella resting cysts.•The continental shelf off northern Patagonia is a risk zone for PST outbreaks.
ISSN:0025-326X
1879-3363
DOI:10.1016/j.marpolbul.2022.114103