Ocean deoxygenation impacts on the vision and vision-mediated behaviours of a highly visual marine predator

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Gymnodinium catenatum paralytic Shellfish toxin production and photobiological responses under marine heat waves

Publication . Lopes, Vanessa M.; Court, Mélanie; Seco, Martim Costa; Borges, Francisco O.; Vicente, Bernardo; Lage, Sandra; Braga, Ana Catarina; Duarte, Bernardo; Santos, Catarina Frazão; Amorim, Ana; Reis Costa, Pedro; Rosa, Rui

Marine heatwaves (MHWs) have doubled in frequency since the 1980s and are projected to be exacerbated during this century. MHWs have been shown to trigger harmful algal blooms (HABs), with severe consequences to marine life and human populations. Within this context, this study aims to understand, for the first time, how MHWs impact key biological and toxicological parameters of the paralytic shellfish toxin (PST) producer Gymnodinium catenatum, a dinoflagellate inhabiting temperate and tropical coastal waters. Two MHW were simulated—category I (i.e., peak: 19.9 ◦C) and category IV (i.e., peak: 24.1 ◦C)—relative to the estimated baseline in the western coast of Portugal (18.5 ◦C). No significant changes in abundance, size, and photosynthetic efficiency were observed among treatments. On the other hand, chain-formation was significantly reduced under category IV MHW, as was PSP toxicity and production of some PST compounds. Overall, this suggests that G. catenatum may have a high tolerance to MHWs. Nevertheless, some sublethal effects may have occurred since chain-formation was affected, suggesting that these growth conditions may be sub-optimal for this population. Our study suggests that the increase in frequency, intensity, and duration of MHWs may lead to reduced severity of G. catenatum blooms.

2023-02-14Journal article

Open Access

Projecting future climate change-mediated impacts in Three Paralytic Shellfish Toxins-Producing dinoflagellate species

Publication . Borges, Francisco O.; Lopes, Vanessa M.; Amorim, Ana; Santos, Catarina F.; Reis Costa, Pedro; Rosa, Rui

Simple Summary Harmful algal blooms present a particular risk for marine ecosystems and human health alike. In this sense, it is important to accurately predict how toxin-producing microalgae could be affected by future climate change. The present study applied species distribution models (SDMs) to project the potential changes in the habitat suitability and distribution of three key paralytic shellfish toxin (PST)-producing dinoflagellate species (i.e., Alexandrium catenella, A. minutum, and Gymnodinium catenatum), up to 2040/50 and 2090/2100, across four different greenhouse gas emission scenarios, and using four abiotic predictors (i.e., sea surface temperature, salinity, current velocity, and bathymetry). In general, considerable contractions were observed for all three species in the lower latitudes of their distribution, together with projected expansions into higher latitudes, particularly in the Northern Hemisphere. This study aims to entice further research on the future biogeographical impacts of climate change in toxin-producing microalgae species while, at the same time, helping to advise the correct environmental management of coastal habitats and ecosystems. Toxin-producing microalgae present a significant environmental risk for ecosystems and human societies when they reach concentrations that affect other aquatic organisms or human health. Harmful algal blooms (HAB) have been linked to mass wildlife die-offs and human food poisoning episodes, and climate change has the potential to alter the frequency, magnitude, and geographical extent of such events. Thus, a framework of species distribution models (SDMs), employing MaxEnt modeling, was used to project changes in habitat suitability and distribution of three key paralytic shellfish toxin (PST)-producing dinoflagellate species (i.e., Alexandrium catenella, A. minutum, and Gymnodinium catenatum), up to 2050 and 2100, across four representative concentration pathway scenarios (RCP-2.6, 4.5, 6.0, and 8.5; CMIP5). Despite slightly different responses at the regional level, the global habitat suitability has decreased for all the species, leading to an overall contraction in their tropical and sub-tropical ranges, while considerable expansions are projected in higher latitudes, particularly in the Northern Hemisphere, suggesting poleward distributional shifts. Such trends were exacerbated with increasing RCP severity. Yet, further research is required, with a greater assemblage of environmental predictors and improved occurrence datasets, to gain a more holistic understanding of the potential impacts of climate change on PST-producing species.

2022Journal article

Open Access

Impacts of climate change on the biogeography of three amnesic shellfish toxin producing diatom species

Publication . Borges, Francisco O.; Lopes, Vanessa M.; Santos, Catarina Frazão; Reis Costa, Pedro; Rosa, Rui

Harmful algal blooms (HABs) are considered one of the main risks for marine ecosystems and human health worldwide. Climate change is projected to induce significant changes in species geographic distribution, and, in this sense, it is paramount to accurately predict how it will affect toxin-producing microalgae. In this context, the present study was intended to project the potential biogeographical changes in habitat suitability and occurrence distribution of three key amnesic shellfish toxin (AST)-producing diatom species (i.e., Pseudo-nitzschia australis, P. seriata, and P. fraudulenta) under four different climate change scenarios (i.e., RCP-2.6, 4.5, 6.0, and 8.5) up to 2050 and 2100. For this purpose, we applied species distribution models (SDMs) using four abiotic predictors (i.e., sea surface temperature, salinity, current velocity, and bathymetry) in a MaxEnt framework. Overall, considerable contraction and potential extirpation were projected for all species at lower latitudes together with projected poleward expansions into higher latitudes, mainly in the northern hemisphere. The present study aims to contribute to the knowledge on the impacts of climate change on the biogeography of toxin-producing mi

2022-01Journal article

Open Access