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

Abstract

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.

• Authors: Camilo Rodríguez-Villegas, Rosa I Figueroa, Iván Pérez-Santos, Carlos Molinet, Gonzalo S Saldías, Sergio A Rosales, Gonzalo Álvarez, Pamela Linford, Patricio A Díaz
• Journal: Marine pollution bulletin (Mar Pollut Bull) Vol. 184 Pg. 114103 (Nov 2022) ISSN: 1879-3363 [Electronic] England
• PMID: 36115195 (Publication Type: Journal Article)
• Copyright: Copyright © 2022 Elsevier Ltd. All rights reserved.

Topics

• Humans
• Chile
• Dinoflagellida
• Shellfish Poisoning
• Harmful Algal Bloom
• Oceans and Seas
• Cysts