Next Generation Sequencing and mass spectrometry reveal high taxonomic diversity and complex phytoplankton-phycotoxins patterns in Southeastern Pacific fjords

Abstract

In fjord systems, Harmful Algal Blooms (HABs) not only constitute a serious problem when affecting the wildlife and ecosystems, but also human health and economic activities related to the marine environment. This is mostly due to a broad spectrum of toxic compounds produced by several members of the phytoplankton. Nevertheless, a deep coverage of the taxonomic diversity and composition of phytoplankton species and phycotoxin profiles in HAB prone areas are still lacking and little is known about the relationship between these fundamental elements for fjord ecosystems. In this study, a detailed molecular and microscopic characterization of plankton communities was performed, together with an analysis of the occurrence and spatial patterns of lipophilic toxins in a HAB prone area, located in the Southeastern Pacific fjord region. Microscopy and molecular analyses based on the 18S rRNA gene fragment indicated high diversity and taxonomic homogeneity among stations. Four toxigenic genera were identified: Pseudo-nitzschia, Dinophysis, Prorocentrum, and Alexandrium. In agreement with the detected species, liquid chromatography coupled with mass spectrometry revealed the presence of domoic acid (DA), pectenotoxin-2 (PTX-2), dinophysistoxin-2 (DTX-2), and 13-desmethyl spirolide C (SPX-1). Furthermore, a patchy distribution among DA in different net haul size fractions was found. Our results displayed a complex phytoplankton-phycotoxin pattern and for the first time contribute to the characterization of high-resolution phytoplankton community composition and phycotoxin distribution in fjords of the Southeastern Pacific region.

Do inferences about freshwater phytoplankton communities change when based on microscopy or high‐throughput sequencing data?

“…While Abad et al (2016) report a good agreement of spatial and temporal patterns of marine zooplankton communities assessed with microscopy and HTS in multivariate ordination, this was not the case for phytoplankton. Furthermore, few freshwater studies that investigate the whole phytoplankton community (Xiao et al, 2014; Gran‐Stadniczeñko et al, 2019) compare traditional approaches with HTS for more than 1 year; most studies are snapshots of biodiversity (Charvet, Vincent, & Lovejoy, 2012; Stoeck et al, 2014; Groendahl et al, 2017) or cover few months (Abad et al, 2016; Eiler et al, 2013; Boopathi & Ki, 2016; Moreno‐Pino et al, 2018). Thus, studies are needed that compare inferences about the whole phytoplankton community made with microscopy‐ and HTS‐based data over a multi‐year period.…”

Influence of Estuarine Water on the Microbial Community Structure of Patagonian Fjords

“…Climate forcing by the El Niño-Southern Oscillation and the Southern Annular Mode has been linked to interannual variations in environmental conditions, such as higher sea surface temperature, changes in wind direction and intensity, and decreased freshwater discharge to the marine system due to drought (Garreaud, 2018;León-Muñoz et al, 2018). These regional variations can affect the marine microbial community, modifying primary production, and they have even been proposed as possible triggers of harmful algal blooms in the area (Iriarte, 2018;Moreno-Pino et al, 2018). For example, a harmful algal bloom of Pseudochattonella cf.…”

Interannual Variability of Dinophysis acuminata and Protoceratium reticulatum in a Chilean Fjord: Insights from the Realized Niche Analysis

“…D. acuta and D. acuminata are the most frequent and abundant Dinophysis species in southern Chile’s fjords (53–41° S) [8,9,10,11,12,13]. DSP have been of special concern in this geographical area since the 1970s, when intoxications by diarrhetic toxins were first reported following the consumption of contaminated shellfish extracted from the Reloncaví Sound [14].…”

“…DTX-1 has been detected in plankton samples from this region [20,21], although the causative organism remains to be identified. More recently, DTX-2 has been detected in the plankton associated with the presence of D. acuta [13]. PTXs presence in southern Chile have been detected in filter feeders [22], plankton assemblages [13,20], and Diaion ® resin passive samplers [23], with the production of PTX-2 by D. acuminata confirmed in isolates from this area [24].…”

“…More recently, DTX-2 has been detected in the plankton associated with the presence of D. acuta [13]. PTXs presence in southern Chile have been detected in filter feeders [22], plankton assemblages [13,20], and Diaion ® resin passive samplers [23], with the production of PTX-2 by D. acuminata confirmed in isolates from this area [24]. Finally, YTXs have been recorded in southern Chile both in bivalves and plankton samples containing P. reticulatum [12,21,25,26], whereas AZAs have been detected only in bivalves [27].…”