Multiscale physical background to an exceptional harmful algal bloom of Dinophysis acuta in a fjord system

Díaz, Patricio A.; Peréz-Santos, Iván; Álvarez, Gonzalo; Garreaud, René; Pinilla, Elías; Díaz, Manuel; Sandoval, Alondra; Araya, Michael; Álvarez, Francisco; Rengel, José; Montero, Paulina; Pizarro, Gemita; López, Loreto; Iriarte, Luis; Igor, Gabriela; Reguera, B.

doi:10.1016/j.scitotenv.2021.145621

Cited by 42 publications

(22 citation statements)

References 84 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Puyuhuapi Fjord has been identified as the epicentre of regional events (Figure 9). Quasi monoalgal blooms there allowed toxin analyses of field populations where D. acuta represented 99% of the total Dinophysis population [62]. The profile consisted of OA (10-100 pg•cell −1 ) and DTX1 (2-20 pg•cell −1 ) in addition to PTX2 (4-90 pg•cell −1 ).…”

Section: Dinophysis Acutamentioning

confidence: 99%

Lipophilic Toxins in Chile: History, Producers and Impacts

et al. 2022

Self Cite

View full text Add to dashboard Cite

A variety of microalgal species produce lipophilic toxins (LT) that are accumulated by filter-feeding bivalves. Their negative impacts on human health and shellfish exploitation are determined by toxic potential of the local strains and toxin biotransformations by exploited bivalve species. Chile has become, in a decade, the world’s major exporter of mussels (Mytilus chilensis) and scallops (Argopecten purpuratus) and has implemented toxin testing according to importing countries’ demands. Species of the Dinophysis acuminata complex and Protoceratium reticulatum are the most widespread and abundant LT producers in Chile. Dominant D. acuminata strains, notwithstanding, unlike most strains in Europe rich in okadaic acid (OA), produce only pectenotoxins, with no impact on human health. Dinophysis acuta, suspected to be the main cause of diarrhetic shellfish poisoning outbreaks, is found in the two southernmost regions of Chile, and has apparently shifted poleward. Mouse bioassay (MBA) is the official method to control shellfish safety for the national market. Positive results from mouse tests to mixtures of toxins and other compounds only toxic by intraperitoneal injection, including already deregulated toxins (PTXs), force unnecessary harvesting bans, and hinder progress in the identification of emerging toxins. Here, 50 years of LST events in Chile, and current knowledge of their sources, accumulation and effects, are reviewed. Improvements of monitoring practices are suggested, and strategies to face new challenges and answer the main questions are proposed.

show abstract

Section: Dinophysis Acutamentioning

confidence: 99%

Lipophilic Toxins in Chile: History, Producers and Impacts

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…A fixed station was sampled from 26 to 28 February 2019 in PF. This fjord, the only one in the region with two connections with the open sea, has the highest water residence time (Díaz et al, 2021). It was selected as a hot spot of Dinophysis blooms and DSP outbreaks in Southern Chile according to the official monitoring data (IFOP) over the last ten years (data not shown).…”

Section: Field Samplingmentioning

confidence: 99%

Niche differentiation of Dinophysis acuta and D. acuminata in a stratified fjord

et al. 2021

Self Cite

View full text Add to dashboard Cite

Dinophysis acuta and D. acuminata are associated with lipophilic toxins in Southern Chile. Blooms of the two species coincided during summer 2019 in a highly stratified fjord system (Puyuhuapi, Chilean Patagonia). High vertical resolution measurements of physical parameters were carried out during 48 h sampling to i) explore physiological status (e.g., division rates, toxin content) and ii) illustrate the fine scale distribution of D. acuta and D. acuminata populations with a focus on water column structure and cooccurring plastid-bearing ciliates. The species-specific resources and regulators defining the realized niches (sensu Hutchinson) of the two species were identified. Differences in vertical distribution, daily vertical migration and in situ division rates (with record values, 0.76 d−1, in D. acuta), in response to the environmental conditions and potential prey availability, revealed their niche differences. The Outlying Mean Index (OMI) analysis showed that the realized niche of D. acuta (cell maximum 7 × 103 cells L−1 within the pycnocline) was characterized by sub-surface estuarine waters (salinity 23 -25), lower values of turbulence and PAR, and a narrow niche breath. In contrast, the realized niche of D. acuminata (cell maximum 6.8 × 103 cells L−1 just above the pycnocline) was characterized by fresher (salinity 17 -20) outflowing surface waters, with higher turbulence and light intensity and a wider niche breadth. Results from OMI and PERMANOVA analyses of co-occurring microplanktonic ciliates were compatible with the hypothesis of species such as those from genera Pseudotontonia and Strombidium constituting an alternative ciliate prey to Mesodinium. The D. acuta cell maximum was associated with DSP (OA and Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site.DTX-1) toxins and pectenotoxins; that of D. acuminata only with pectenotoxins. Results presented here contribute to a better understanding of the environmental drivers of species-specific blooms of Dinophysis and management of their distinct effects in Southern Chile. Previous article Highlights► 48 h of high frequency physical data for co-occurring blooms of 2 Dinophysis species. ► D. acuta (exceptional µ) thin layer briefly disrupted by an increase in turbulence. ► Co-occurring D. acuminata and D. acuta blooms showed a clear niche differentiation. ► Niche analysis results compatible with putative ciliate prey other than Mesodinium. ► D. acuta maximum associated with DSP toxins (OA, DTX1), D. acuminata with PTX2 only.

show abstract

“…In Chile the hydrological impacts of LCCs have been evaluated mainly in south-central Chile (< 41 • S; Stehr et al, 2010;Aguayo et al, 2016;Martínez-Retureta et al, 2020;Barría et al, 2021;Galleguillos et al, 2021) and not in tributary basins to the coastal system of northwestern Patagonia. Nevertheless, using rivers like Puelo River as sentinels, several studies have reported anomalous events in fjords of northwestern Patagonia (e.g., surface hypoxia events, harmful algal blooms), mainly during severe droughts (Valle-Levinson et al, 2007;León-Muñoz et al, 2013Iriarte et al, 2017;Díaz et al, 2021). Although northern Patagonian basins have not yet been modified by irrigation channels or reservoirs and still maintain extensive little-degraded native forest cover (CONAF and UACH, 2014;Astorga et al, 2018), recent threats such as increased wildfires and their joint effect with climate change have not been evaluated hydrologically to date.…”

Section: Introductionmentioning

confidence: 99%

Climate and Land Cover Trends Affecting Freshwater Inputs to a Fjord in Northwestern Patagonia

et al. 2021

View full text Add to dashboard Cite

Freshwater inputs strongly influence oceanographic conditions in coastal systems of northwestern Patagonia (41–45°S). Nevertheless, the influence of freshwater on these systems has weakened in recent decades due to a marked decrease in precipitation. Here we evaluate potential influences of climate and land cover trends on the Puelo River (640 m3s–1), the main source of freshwater input of the Reloncaví Fjord (41.5°S). Water quality was analyzed along the Puelo River basin (six sampling points) and at the discharge site in the Reloncaví Fjord (1, 8, and 25 m depth), through six field campaigns carried out under contrasting streamflow scenarios. We also used several indicators of hydrological alteration, and cross-wavelet transform and coherence analyses to evaluate the association between the Puelo River streamflow and precipitation (1950–2019). Lastly, using the WEAP hydrological model, land cover maps (2001–2016) and burned area reconstructions (1985–2019), we simulated future land cover impacts (2030) on the hydrological processes of the Puelo River. Total Nitrogen and total phosphorus, dissolved carbon, and dissolved iron concentrations measured in the river were 3–15 times lower than those in the fjord. Multivariate analyses showed that streamflow drives the carbon composition in the river. High streamflow conditions contribute with humic and colored materials, while low streamflow conditions corresponded to higher arrival of protein-like materials from the basin. The Puelo River streamflow showed significant trends in magnitude (lower streamflow in summer and autumn), duration (minimum annual streamflow), timing (more floods in spring), and frequency (fewer prolonged floods). The land cover change (LCC) analysis indicated that more than 90% of the basin area maintained its land cover, and that the main changes were attributed to recent large wildfires. Considering these land cover trends, the hydrological simulations project a slight increase in the Puelo River streamflow mainly due to a decrease in evapotranspiration. According to previous simulations, these projections present a direction opposite to the trends forced by climate change. The combined effect of reduction in freshwater input to fiords and potential decline in water quality highlights the need for more robust data and robust analysis of the influence of climate and LCC on this river-fjord complex of northwestern Patagonia.

show abstract

Multiscale physical background to an exceptional harmful algal bloom of Dinophysis acuta in a fjord system

Cited by 42 publications

References 84 publications

Lipophilic Toxins in Chile: History, Producers and Impacts

Lipophilic Toxins in Chile: History, Producers and Impacts

Niche differentiation of Dinophysis acuta and D. acuminata in a stratified fjord

Climate and Land Cover Trends Affecting Freshwater Inputs to a Fjord in Northwestern Patagonia

Contact Info

Product

Resources

About