Harmful Algae最新文献

{"title":"Sub-lethal effects of natural cyanobacterial blooms on fish: Enzymatic activity and swimming performance in Gasterosteus aculeatus","authors":"Francesco Masnadi ,&nbsp;Xuewei Qi ,&nbsp;John M. Taylor ,&nbsp;Joachim Sturve ,&nbsp;Valentina Di Santo ,&nbsp;Agnes M.L. Karlson","doi":"10.1016/j.hal.2025.102965","DOIUrl":"10.1016/j.hal.2025.102965","url":null,"abstract":"<div><div>Cyanobacterial blooms are intensifying worldwide due to eutrophication and climate change, increasing cyanotoxin exposure to aquatic organisms. This study investigated the physiological, biochemical, and behavioural impacts of cyanobacterial blooms on the three-spined stickleback (<em>Gasterosteus aculeatus</em>), a widespread mesopredatory fish. Adult sticklebacks were exposed for two weeks to naturally collected bloom material dominated by toxic <em>Nodularia spumigena</em>, non-toxic <em>Aphanizomenon</em> sp., or a 50:50 mix. We measured toxin accumulation (NOD_eq), hepatic enzymatic activities (ethoxyresorufin-O-deethylase [EROD], glutathione S-transferases [GSTs], glutathione reductase [GR], and catalase [CAT]), and escape swimming performance (centre-of-mass velocity, angular velocity, distance, and duration) in a multiparametric endpoints approach. Sub-lethal toxin levels in muscle tissue ranged from 0.006 to 0.077 µg g⁻¹ d.w. Results showed that fish exposed to toxic-dominated treatments showed significantly elevated EROD activity (up to 200 % increase), moderate increases in GR and GSTs, and reduced CAT activity compared to controls. Notably, distance travelled during escape responses was reduced by ∼50 % in the high-toxicity treatment and showed an inverse correlation with EROD activity, suggesting a trade-off between detoxification effort and swimming performance. Overall, our results demonstrate that EROD is a sensitive biomarker for cyanotoxin exposure in fish under natural bloom conditions. This finding highlights the need to consider natural cyanotoxin effects when interpreting environmental assessments, particularly given the projected increase in bloom frequency and severity under future climate scenarios.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"150 ","pages":"Article 102965"},"PeriodicalIF":4.5,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"More sustained, more severe blooms and shifting monthly patterns of the toxigenic dinoflagellate Karenia brevis on the West Florida Shelf","authors":"Patricia M. Glibert ,&nbsp;Cynthia A. Heil ,&nbsp;Ming Li","doi":"10.1016/j.hal.2025.102967","DOIUrl":"10.1016/j.hal.2025.102967","url":null,"abstract":"<div><div>Various recent reports, based on different approaches, data sets and time periods, have yielded different conclusions with regard to whether blooms of the Florida red tide dinoflagellate, <em>Karenia brevis</em>, have increased over time. Without question, however, there have been a number of recent blooms that have been long lasting, continuing through the summer months normally taken to be outside the ideal temperature niche for <em>K. brevis</em>. Here, using a recently developed bloom severity index, the time series of blooms from 1970 to 2019 is examined, focusing on how monthly patterns have changed over time. More severe blooms have been found since the mid 1990s, now lasting 4- to 5-months longer than in previous decades, a trend related to the Oceanic Niño Index (El Niño -Southern Oscillation). Since the mid-1990s, water temperature anomalies have been related to bloom severity with lags of 3 to 6 months. The most significant temperature increases have occurred in the latter months of the year when <em>K. brevis</em> growth typically is highest. Increased flow from the Caloosahatchee River, and its total nitrogen load, are also predictors of recent bloom severity with lags of several months. Cells that survive the now-warmer winter dry season have adequate nutrients and may experience more favorable nitrogen forms as the summer wet season develops, and as nutrients are recycled, may “over summer”. The stresses of increased warming and increased nutrient pollution on <em>K. brevis</em> blooms will continue to make managing these blooms a challenge for management as climate change trajectories continue.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"150 ","pages":"Article 102967"},"PeriodicalIF":4.5,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145047216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mesozooplankton grazing patterns and preferences during a cyanobacterial harmful algal bloom (cHAB) in a large eutrophic lake","authors":"Daniel I. Peters ,&nbsp;Lyndsie M. Collis ,&nbsp;Morgan D. Shaw ,&nbsp;Zak J. Slagle ,&nbsp;Henry A. Vanderploeg ,&nbsp;James M. Hood","doi":"10.1016/j.hal.2025.102963","DOIUrl":"10.1016/j.hal.2025.102963","url":null,"abstract":"<div><div>Mesozooplankton (200–2,000 µm) are an important link between primary producers and higher-level consumers and can influence phytoplankton biomass and community structure via grazing. Yet, during cyanobacteria harmful algal blooms (cHABs) we have a poor understanding of which food resources mesozooplankton use and their grazing pressure on phytoplankton. To investigate this, we conducted two gradient-grazer assays to measure mesozooplankton community grazing rates in western Lake Erie during the 2021 cHAB season. We measured mesozooplankton grazing on various food sources, including: total phytoplankton, phytoplankton major taxa (Cyanobacteria, Cryptophyta/Bacillariophyta, Chlorophyta), and autotrophic and heterotrophic picoplankton and nanoplankton. We used these data to estimate mesozooplankton feeding selectivity, the importance of each food source toward mesozooplankton carbon intake, as well as the percent standing stock and growth consumed by mesozooplankton. Mesozooplankton selected for autotrophic and heterotrophic nanoplankton, were neutrally selective for Cryptophyta/Bacillariophyta, and avoided Cyanobacteria and the total phytoplankton community. Mesozooplankton carbon intake was dominated by autotrophic nanoplankton and Cyanobacteria, indicating these food sources may be important in supporting zooplankton production during these cHAB events, although our understanding of the incorporation of Cyanobacteria carbon into mesozooplankton production is limited. While mesozooplankton grazed a small portion of total phytoplankton (1–12 % d^-1) and Cyanobacteria (5–13 % d^-1) standing stock biomass (&lt;200 µm), they exerted a relatively stronger control on the growth of total phytoplankton (4–38 % d^-1) and Cyanobacteria (64–106 % d^-1), primarily due to the low measured growth rates of these food items during the study. Our results demonstrate that mesozooplankton graze on Cyanobacteria during cHAB events, and under the right conditions influence cHAB dynamics through direct consumption of Cyanobacteria and indirect effects on Cyanobacteria grazers and competitors.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"150 ","pages":"Article 102963"},"PeriodicalIF":4.5,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Critical flow velocity thresholds for preventing persistent thermal stratification and cyanobacterial blooms in rivers","authors":"D.C. Davis ,&nbsp;J.A. Facey ,&nbsp;A.J. Brooks ,&nbsp;D.P. Westhorpe ,&nbsp;M. Balzer ,&nbsp;N. Williamson ,&nbsp;S.M. Mitrovic","doi":"10.1016/j.hal.2025.102962","DOIUrl":"10.1016/j.hal.2025.102962","url":null,"abstract":"<div><div>Toxic cyanobacterial harmful algal blooms (cHABs) are a major worldwide issue in freshwater environments, exacerbated by climate change with rising water temperatures and prolonged and intensified periods of thermal stratification. The Barwon-Darling River in Australia, a dryland river with a highly variable flow regime, often experiences persistent thermal stratification (PTS), i.e., continuous stratification for days or weeks, during periods of low discharge, commonly resulting in cHABs. This study evaluated whether a critical flow velocity threshold can prevent or disrupt the formation of PTS and subsequent cHABs. The relationships between gauged discharge and flow velocity were determined within six weir pools along the river using acoustic Doppler current profiling. These relationships were used to interpret 20 years of historic daily river discharge data as mean cross-sectional flow velocities which were then compared to cyanobacterial biovolumes over the same period, focusing predominantly on the potentially toxic genera <em>Dolichospermum</em>. An upper limiting relationship between flow velocity and <em>Dolichospermum</em> biovolume was found and almost all blooms &gt; 4 mm³/L (exceeding the Australian recreational safety guidelines for toxic cyanobacteria) occurred when maximum antecedent 7-day flow velocities were less than 0.05 m/s. Quantile regression estimates suggested maintaining flow velocities of 0.05 m/s can limit blooms to 3.96 mm³/L while increasing flow velocities will reduce this limit. These findings support the premise of using river flow velocity thresholds for cHAB management when blooms are related to PTS. These flow velocities should be applicable to other rivers in similar climates while the approach could be utilised more widely.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102962"},"PeriodicalIF":4.5,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144932171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Faunal associations of holopelagic Sargassum spp. in the subtropical and tropical northern Atlantic: A review","authors":"L.Verónica Monroy-Velázquez ,&nbsp;Hazel M. Canizales-Flores ,&nbsp;Karla A. Camacho-Cruz ,&nbsp;Makeda Corbin ,&nbsp;Patricia Briones-Fourzán ,&nbsp;Brigitta I. van Tussenbroek","doi":"10.1016/j.hal.2025.102961","DOIUrl":"10.1016/j.hal.2025.102961","url":null,"abstract":"<div><div>Holopelagic <em>Sargassum</em> spp. (<em>Sargassum</em> from hereon) are the founding seaweeds of biodiverse high-sea rafts. The floating rafts provide substrate, shelter, feeding-, and breeding grounds for numerous marine species, making them unique communities in the high seas. Similar to other pelagic systems, the community associated with the rafts is dynamic, inherently variable, and defined by the dynamics of the rafts and interactions between the seaweed and associated fauna. The high biodiversity, including organisms from different trophic levels, results in multiple interactions and complex food webs, which are covered in this review. Additionally, we highlight how floating <em>Sargassum</em> acts as a vector of ecological connectivity, influencing distant ecosystems such as coastal and deep-sea habitats. These cross-ecosystem interactions occur through organism transport, organic matter export and trophic linkages. Understanding these connections is key to recognizing the broader ecological role of <em>Sargassum</em> rafts and the multiple ecosystem services they provide.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102961"},"PeriodicalIF":4.5,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144920281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Salinity adaption and toxicity of harmful algal blooms in three bays of Great Salt Lake (USA)","authors":"W.A. Wurtsbaugh ,&nbsp;Malin Olofsson ,&nbsp;Gregory L. Boyer ,&nbsp;Amy M. Marcarelli","doi":"10.1016/j.hal.2025.102959","DOIUrl":"10.1016/j.hal.2025.102959","url":null,"abstract":"<div><div>Cyanobacterial blooms can be harmful to animals and humans exposed to their toxins; however, their environmental drivers and boundaries still need to be elucidated. Salinity has been demonstrated to be an important driver of community composition that sets boundaries of species migration and survival. The filamentous cyanobacteria <em>Nodularia spumigena</em> forms dense blooms in estuaries around the world, produces the hepatotoxin nodularin, and has been thought to not survive or fix nitrogen (N) in high salinities. From 2005–2009 we studied three bays of Great Salt Lake (USA), two of which are estuaries with salinities ranging from 0 to &gt;90 g <span>l</span>^-1 while the third, Gilbert Bay, had a salinity near 160 g <span>l</span>^-1. Bear River Bay and the larger Gilbert Bay were meso‑eutrophic, while Farmington Bay, which receives direct inputs of secondary-treated sewage, was hypereutrophic with mean chlorophyll concentrations of 149 µg <span>l</span>^-1 and dense blooms of <em>N. spumigena.</em> Cell densities were &gt;500 times those of <em>Nodularia</em> studied in the Baltic Sea. In Farmington Bay blooms occur at salinities ranging from 8–50 g <span>l</span>^-1, which are much higher than usually reported for this taxon. Concentrations of the cyanotoxin nodularin reached 660 µg <span>l</span>^-1 (mean = 41 µg <span>l</span>^-1), far above critical thresholds for contact recreation and above those causing bird mortalities elsewhere. The mean N₂ fixation rate of <em>Nodularia</em> measured over a salinity range of 14 to 52 g <span>l</span>^-1 was 47 mg N m^-2 <span>d</span>^-1, which is among the highest reported values for freshwater and marine ecosystems. The local adaptation of <em>Nodularia</em> to the extreme salinity conditions in Great Salt Lake furthers our understanding of salinity adaptation and the potential spread of this species to new regions.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"150 ","pages":"Article 102959"},"PeriodicalIF":4.5,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145047226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Responses of a harmful algal bloom-causing dinoflagellate Prorocentrum obtusidens to elevated temperature and urea","authors":"Wei-Ping Zhang ,&nbsp;Yang Zhou ,&nbsp;Wen-Jing Sun ,&nbsp;Shuo-Yu Zhang ,&nbsp;Shu-Feng Zhang ,&nbsp;Jae-Seong Lee ,&nbsp;Minghua Wang ,&nbsp;Da-Zhi Wang","doi":"10.1016/j.hal.2025.102958","DOIUrl":"10.1016/j.hal.2025.102958","url":null,"abstract":"<div><div>Elevated temperature and nitrogen (N) availability affect dinoflagellates differently; however, their interactive effects remain largely unexplored. This study investigated the physiological and transcriptomic responses of a harmful algal bloom-causing dinoflagellate, <em>Prorocentrum obtusidens</em>, to elevated temperature (22 °C vs. 26 °C) under three N conditions (16 μM nitrate, 8 and 16 μM urea) after 32 days of exposure. Elevated temperature enhanced cell growth across all N conditions, with a more pronounced increase in urea-grown cells, regardless of the insignificant interaction between temperature and N. Physiological responses to elevated temperature varied under N conditions. The nitrate-grown cells had higher particulate organic carbon (POC) content, C:N ratio, and activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), phosphoenolpyruvate carboxykinase, and urease, but lower particulate organic N (PON) content. The low urea-grown cells showed higher C:N ratio, total carbohydrate content, and activities of carbonic anhydrase (CA), glutamine synthetase (GS), and urease, but lower phosphoenolpyruvate carboxylase activity, total protein, and total antioxidant capacity. The high urea-grown cells exhibited higher maximum photosynthetic efficiency, POC content, C:N ratio, and activities of CA, RubisCO, GS, and urease. Transcriptomic analysis revealed that elevated temperature increased the expression of genes associated with photosynthesis under all N conditions. The nitrate-grown cells produced more energy to mitigate thermal stress, whereas the urea-grown cells decreased energy production. These findings suggest that <em>P. obtusidens</em> is more resilient to future ocean warming when grown with urea, and predictions of dinoflagellate responses to warming oceans should consider N conditions in the environment.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102958"},"PeriodicalIF":4.5,"publicationDate":"2025-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144912873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sargassum transport to the Amazon Coast: Explaining the stranding through meteorological and oceanographic conditions","authors":"João Pedro Mancio de Amorim ,&nbsp;Alexandre Melo Casseb do Carmo ,&nbsp;José Eduardo Martinelli Filho","doi":"10.1016/j.hal.2025.102955","DOIUrl":"10.1016/j.hal.2025.102955","url":null,"abstract":"<div><div>Over the recent years, different areas around the tropical Atlantic Ocean experienced an increase in pelagic <em>Sargassum</em> stranding events. Such incidents pose ecological and socioeconomic challenges, since they are difficult to predict and can impact coastal communities. In this study, we investigate the physical mechanisms behind <em>Sargassum</em> stranding events on the Brazilian Amazon Coast, focusing on the northeastern Pará region (northern Brazil), especially during the sporadic massive events registered in May 2014, April 2015, March 2019 and March 2025. We used a combination of observational data, reanalysis, forecast products, and Lagrangian experiments to explore the role of meteorological and oceanographic conditions during the occurrence of the strandings. Our results suggest that the events are related to the rainy season, when the Intertropical Convergence Zone (ITCZ) is positioned at its southernmost extent, bringing intense rainfall and northeasterly winds to the region. These winds can increase the landward transport of floating particles into the Amazon Continental Shelf (ACS). The results from the Lagrangian simulations highlighted the importance of wind drag and local processes (<em>i.e.</em>, tidal currents and Stokes drift) in promoting the intrusion of floating particles into the inner shelf, particularly in the northeastern sector of the ACS, which emerges as a preferential pathway for the entrance of offshore <em>Sargassum</em> patches. This pathway was also highlighted by the sighting of <em>Sargassum</em> close to this area prior to the massive event of 2025, reinforcing the role of winds and tidal currents in connecting the northeastern offshore sector of ACS to the coast. While global reanalysis products and forecast systems provided valuable insights, future research should focus on the implementation of regional models to provide more accurate predictions near the coast, improving predictive capabilities to mitigate the impacts of these phenomena.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102955"},"PeriodicalIF":4.5,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144908900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Walruses are potentially exposed to paralytic shellfish toxin concentrations that impact their health during Alexandrium blooms in the Alaskan Arctic","authors":"Patrick Charapata ,&nbsp;Evangeline Fachon ,&nbsp;Donald M. Anderson ,&nbsp;Gay Sheffield ,&nbsp;Emily K. Bowers ,&nbsp;Robert S. Pickart ,&nbsp;Peigen Lin ,&nbsp;Kathi A. Lefebvre","doi":"10.1016/j.hal.2025.102960","DOIUrl":"10.1016/j.hal.2025.102960","url":null,"abstract":"<div><div>Harmful algal bloom (HAB) activity of <em>Alexandrium catenella</em>, a dinoflagellate that produces paralytic shellfish toxins (PSTs), has increased in the Alaskan Arctic due to warming ocean conditions. Arctic wildlife exposure to PSTs due to these blooms remains unknown. The Pacific walrus (<em>Odobenus rosmarus divergens</em>) is a marine mammal that preys primarily on efficient vectors of PSTs (benthic invertebrates), making walruses an important model for assessing PST exposure risks. Here, we used paired <em>Alexandrium</em> data (<em>Alexandrium</em> cell and cyst densities and PST content), and PSTs measured in benthic invertebrates (clams, worms, and gastropods) to construct and validate trophic transfer models of PSTs in a critical Arctic food chain. Further, we used observed PSTs in walrus prey to estimate daily walrus oral PST doses (µg STX eq. kg^-1) during summers (2019 and 2022) with well-characterized and widespread <em>Alexandrium</em> blooms. Models were validated using various model metrics, however, predictions underestimated toxicity (STX eq.) of invertebrates. Observed PSTs in walrus prey resulted in 89 % (<em>n</em> <em>=</em> 47 of 53 total; 2019) and 67 % (<em>n</em> <em>=</em> 41 of 61; 2022) of PST doses exceeding thresholds posing a moderate health risk to walruses (&gt; 11.6 μg STX eq. kg^-1). Ledyard Bay in the northeastern Chukchi Sea was identified as a PST exposure risk hotspot because it contained the highest estimated doses, while walruses simultaneously occupied the neighboring Point Lay haulout. Additional studies are required to assess how HAB activity will impact walrus health as well as food-security and food-safety for Indigenous communities that rely on walruses for subsistence.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102960"},"PeriodicalIF":4.5,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144912872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Climate change will boost the invasion of the harmful cyanobacterium Raphidiopsis raciborskii in South America","authors":"Felipe Morais Zanon ,&nbsp;Bruno Henrique Mioto Stabile ,&nbsp;Beatriz Melissa Campos ,&nbsp;Érica Oliveira de Lima ,&nbsp;Matheus Juan Alarcon Sampaio ,&nbsp;Yasmin Rodrigues de Souza ,&nbsp;Leonardo Rodrigues Tolardo ,&nbsp;Mayra Koma Gomes ,&nbsp;Luddy Searom Carias de Moraes ,&nbsp;Gabriela Sponchiado Hein ,&nbsp;Jaqueline Dantas da Silva ,&nbsp;Larissa da Silva Pinha ,&nbsp;Loiani Oliveira Santana ,&nbsp;Mariana Albuquerque ,&nbsp;Vinicius da Silva ,&nbsp;João Vitor Bredariol ,&nbsp;Gabriel Arthur Lopes da Silva ,&nbsp;Gabriel Delabio da Silva ,&nbsp;Aline Aparecida Aguiar Ferreira ,&nbsp;Luíz Fernando Esser ,&nbsp;Luzia Cleide Rodrigues","doi":"10.1016/j.hal.2025.102957","DOIUrl":"10.1016/j.hal.2025.102957","url":null,"abstract":"<div><div>The invasive cyanobacterium species <em>Raphidiopsis raciborskii</em> was first recorded in the Indo-Malaysian region in 1899, and studies currently report its presence in tropical, subtropical, and temperate environments around the world. In addition to its plasticity in colonizing new environments, <em>R. raciborskii</em> deserves attention for its ability to produce saxitoxin and cylindrospermopsin, which can cause the death of aquatic organisms and harm human health. In this work, we assessed the effect of global climate change towards the end of this century on the potential expansion of <em>R. raciborskii</em> using ecological niche models (ENMs). We applied a set of machine learning algorithms within the ensemble prediction approach to estimate the potential distribution of the species in South America under projected climate change, considering different carbon emission scenarios. In the moderate scenario, the northern Amazon basin, the southern Orinoco basin, and part of the North Atlantic basin showed increased environmental suitability for the species. In the pessimistic scenario, the basin with the greatest increase in suitability was the Paraná-Paraguay basin. Several basins remained highly suitable in both current and future scenarios, especially in Brazil. This study highlights the importance of understanding and addressing the impacts of climate change on the distribution of the invasive species <em>R. raciborskii</em>. South American countries must implement monitoring measures to assess the expansion of blooms of this species, as well as government actions to control water quality, given the strong impact of these organisms on biodiversity and ecosystem services.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"149 ","pages":"Article 102957"},"PeriodicalIF":4.5,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144895575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}