The impact of local and climate change drivers on the formation, dynamics, and potential recurrence of a massive fish-killing microalgal bloom in Patagonian fjord

Díaz, Patricio A.; Peréz-Santos, Iván; Basti, Leila; Garreaud, René; Pinilla, Elías; Barrera, Facundo; Tello, Alfredo; Schwerter, Camila; Arenas-Uribe, Sara; Soto-Riquelme, Camila; Navarro, Pilar; Díaz, Manuel; Álvarez, Gonzalo; Linford, Pamela; Altamirano, Robinson; Mancilla-Gutiérrez, Guido; Rodríguez-Villegas, Camilo; Figueroa, Rosa Isabel

doi:10.1016/j.scitotenv.2022.161288

Cited by 19 publications

(13 citation statements)

References 87 publications

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“…Suspended particulate matter (SPM, µg L -1 ), was determined by gravimetry using the weight difference 200 between the dried filter and the same filter before filtration (Grasshoff et al, 2009). Particulate organic carbon (POC, µmol L -1 ), total nitrogen (TN, µmol L -1 ), stables carbon (δ 13 C, ‰) and nitrogen (δ 15 N, ‰) isotopes were obtained following the method described by Verardo et al, (1990), with modifications by Barrera et al, (2017) and Díaz et al, (2023), and measured at the Stable Isotope Facility at the Pontifical Catholic University of Chile by using an elemental analyzer (EA Flash 2000 Thermo Finnigan), interfaced to a continuous flow isotope ratio mass spectrometer (IRMS 205 Delta V Advantage). We calculated the relative importance of allochthonous and autochthonous organic matter with two-source endmember mixing models (Bianchi, 2007).…”

Section: Biogeochemical Parameters and Analysismentioning

confidence: 99%

“…ESSW is one of the main causes of hypoxia and LDOW inside Patagonian fjords (e.g., Puyuhuapi Fjord and Jacaf Channel). Nevertheless, these conditions are also found in other areas far from the influence of ESSW, e.g., the Reloncaví system (Reloncaví Fjord and Reloncaví Sound), Aysén, Comau, and Quitralco 90 fjords (Figure 1) (Silva and Vargas, 2014;Linford et al, 2023;Díaz et al, 2023).…”

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confidence: 90%

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Oceanographic Processes Favoring Deoxygenation Inside Patagonian Fjords

Linford

Peréz-Santos

Montero

et al. 2023

Preprint

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Abstract. The dissolved oxygen (DO) levels of oceanic-coastal waters has decreased over the last decade owing to the increase in surface water temperature caused by climate change. In addition, biological and human activity in coastal zones, bays, and estuaries has contributed to the acceleration of current deoxygenation. The Patagonian fjord and channel system is one world region where low DO water (LDOW, 30 %–60 % oxygen saturation) and hypoxia conditions (< 30 % oxygen saturation, 2 ml L−1 or 89.2 µmol L−1) is observed. An in-situ data set of hydrographic and biogeochemical parameters (2017 stations), collected from sporadic oceanographic cruises between 1970 and 2021, was used to quantify the mechanism involved in the presence of LDOW and hypoxic conditions in northern Patagonian fjords. Results denoted two main areas with LDOW (e.g., Puyuhuapi Fjord-Jacaf channel, Comau Fjord, and the Reloncaví estuarine system) extending from 25–400 m depth. Simultaneously, hypoxia was recorded in the Puyuhuapi Fjord, Jacaf Channel, and Quitralco Fjord. Quitralco registered the lowest values of DO (9.36 µmol L−1 and 1.6 % oxygen saturation) of the entire Patagonian fjord system. Areas of LDOW and hypoxia coincided with the accumulation of inorganic nutrients. Water mass analysis confirmed the contribution of equatorial subsurface water in the advection of the LDOW to only the Puyuhuapi Fjord and Jacaf Channel. In addition, in Puyuhuapi Fjord, hypoxic conditions occurred when the community respiration rate (6.6 g C m−2d−1) exceeded the gross primary production estimate (1.9 g C m−2d−1) possibly due to the increased consumption of DO during the use of both autochthonous and allochthonous organic matter. Biogeochemical processes and circulation regimens also contribute to deoxygenation and will be part of the discussion of the present research.

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Section: Biogeochemical Parameters and Analysismentioning

confidence: 99%

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confidence: 90%

Oceanographic Processes Favoring Deoxygenation Inside Patagonian Fjords

Linford

Peréz-Santos

Montero

et al. 2023

Preprint

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“…To study these interactions, physical–chemical properties and the target organisms should be sampled with the same spatio-temporal resolution [ 2 , 3 ]. Semi-enclosed systems, such as fjords and coastal embayments, possess a variety of micro-environments and marked vertical and horizontal gradients that promote growth and retention of phytoplankton populations, including those of harmful microalgal species [ 2 , 4 ]. Vertical distributions of motile dinoflagellates (including Dinophysis ) are largely controlled by interactions between microalgal morphology (size, shape, and colony formation) and behaviour (swimming, diurnal vertical migration, and aggregation) [ 5 ], and by physical and chemical processes on micro- and fine scales [ 6 , 7 ].…”

Section: Introductionmentioning

confidence: 99%

Dinophysis acuminata or Dinophysis acuta: What Makes the Difference in Highly Stratified Fjords?

et al. 2023

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Dinophysis acuminata and D. acuta, which follows it seasonally, are the main producers of lipophilic toxins in temperate coastal waters, including Southern Chile. Strains of the two species differ in their toxin profiles and impacts on shellfish resources. D. acuta is considered the major cause of diarrhetic shellfish poisoning (DSP) outbreaks in Southern Chile, but there is uncertainty about the toxicity of D. acuminata, and little information on microscale oceanographic conditions promoting their blooms. During the austral summer of 2020, intensive sampling was carried out in two northern Patagonian fjords, Puyuhuapi (PUY) and Pitipalena (PIT), sharing D. acuminata dominance and D. acuta near detection levels. Dinophysistoxin 1 (DTX 1) and pectenotoxin 2 (PTX 2) were present in all net tow samples but OA was not detected. Although differing in hydrodynamics and sampling dates, D. acuminata shared behavioural traits in the two fjords: cell maxima (>103 cells L−1) in the interface (S ~ 21) between the estuarine freshwater (EFW)) and saline water (ESW) layers; and phased-cell division (µ = 0.3–0.4 d−1) peaking after dawn, and abundance of ciliate prey. Niche analysis (Outlying Mean Index, OMI) of D. acuta with a high marginality and much lower tolerance than D. acuminata indicated an unfavourable physical environment for D. acuta (bloom failure). Comparison of toxin profiles and Dinophysis niches in three contrasting years in PUY—2020 (D. acuminata bloom), 2018 (exceptional bloom of D. acuta), and 2019 (bloom co-occurrence of the two species)—shed light on the vertical gradients which promote each species. The presence of FW (S < 11) and thermal inversion may be used to provide short-term forecasts of no risk of D. acuta blooms and OA occurrence, but D. acuminata associated with DTX 1 pose a risk of DSP events in North Patagonian fjords.

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“…Moreover, this expansion is being consolidated in the sediments of these new areas, where resting stages of this species have been found, guaranteeing a “seed bank” for potential new blooms [ 3 , 4 , 5 , 6 ]. Changing climatic conditions and increasing water temperatures are expected to promote the expansion of A. catenella [ 7 , 8 ] and of other ichthyotoxic species, such as Heterosigma akashiwo and Pseudochattonella verruculosa , outbreaks of which have also occurred under conditions associated with climate change [ 9 , 10 , 11 ]. A bloom of P. verruculosa in 2016 affected 45 salmon farms, causing losses of around USD 800 million [ 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

Toxic Algal Bloom Recurrence in the Era of Global Change: Lessons from the Chilean Patagonian Fjords

Díaz

Figueroa

2023

Microorganisms

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Toxic and harmful algal blooms (HABs) are a global problem affecting human health, marine ecosystems, and coastal economies, the latter through their impact on aquaculture, fisheries, and tourism. As our knowledge and the techniques to study HABs advance, so do international monitoring efforts, which have led to a large increase in the total number of reported cases. However, in addition to increased detections, environmental factors associated with global change, mainly high nutrient levels and warming temperatures, are responsible for the increased occurrence, persistence, and geographical expansion of HABs. The Chilean Patagonian fjords provide an “open-air laboratory” for the study of climate change, including its impact on the blooms of several toxic microalgal species, which, in recent years, have undergone increases in their geographical range as well as their virulence and recurrence (the species Alexandrium catenella, Pseudochattonella verruculosa, and Heterosigma akashiwo, and others of the genera Dinophysis and Pseudo-nitzschia). Here, we review the evolution of HABs in the Chilean Patagonian fjords, with a focus on the established connections between key features of HABs (expansion, recurrence, and persistence) and their interaction with current and predicted global climate-change-related factors. We conclude that large-scale climatic anomalies such as the lack of rain and heat waves, events intensified by climate change, promote the massive proliferation of these species by creating ideal conditions for their growth and persistence, as they affect water-column stratification, nutrient inputs, and reproductive rates.

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The impact of local and climate change drivers on the formation, dynamics, and potential recurrence of a massive fish-killing microalgal bloom in Patagonian fjord

Cited by 19 publications

References 87 publications

Oceanographic Processes Favoring Deoxygenation Inside Patagonian Fjords

Oceanographic Processes Favoring Deoxygenation Inside Patagonian Fjords

Dinophysis acuminata or Dinophysis acuta: What Makes the Difference in Highly Stratified Fjords?

Toxic Algal Bloom Recurrence in the Era of Global Change: Lessons from the Chilean Patagonian Fjords

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