Abstract

Through the analysis of information gathered from various sources (expeditions) from the western Patagonia (50-54ºS), southern Chile, we report the current status of harmful microalgae and marine toxins, in a sub Antarctic area with few anthropogenic influences like aquaculture but highly mediated by global change (e.g. glaciers melting and freshening). We conducted weekly sampling during a 3 month period in one station in the Strait of Magellan (53º47’S, 73º54’W) during 2013, and other expeditions with several sampling sites at the Magellan strait (72º17’-70º4’W) during 2014 and 2015 (50°- 53° S). Field observations included mainly CTD, vertical net tows and niskin bottle sampling (plankton), and scuba diving for both benthic sediment and bivalve mollusc samples. The toxin profiles were determined by MALDI-TOF, LC-MS/MS and LC-Fl. Our results shows presence of numerous HAB taxa (Alexandrium catenella, A. ostenfeldii, Protoceratium reticulatum, Gonyaulax spinifera, Dinophysis acuminata, D. acuta, Prorocentrum lima and Pseudo-nitzschia spp.), and associated toxins, primarily gonyauxtoxin 3-2, yessotoxins, pectenotoxin-2, traces of dinophysistoxin-1 and okadaic acid, and domoic acid. This new configuration about marine toxins and toxic microalgae for fjords and channels in western Patagonia confirm it as a vulnerable place for the occurrence of red tides events produced by emerging toxins besides those already historically known. This condition provides the basis for future scenarios distribution of HAB in sub-Antarctic waters that likely will be affected by stress factors such as climate change and ocean acidification.