Harmful Algae最新文献

{"title":"Population dynamics of dominant dinoflagellate species in the North Sea: in situ growth rates, photosynthetic potential, and losses due to parasitism","authors":"Eva Pérez Blanco ,&nbsp;Paulo Sérgio Salomon ,&nbsp;Per Carlsson ,&nbsp;Cathérine Legrand ,&nbsp;Edna Granéli","doi":"10.1016/j.hal.2024.102604","DOIUrl":"10.1016/j.hal.2024.102604","url":null,"abstract":"<div><p>In the North Sea, <em>Tripos</em> and <em>Dinophysis</em> are commonly occurring mixotrophic planktonic dinoflagellate genera. In order to understand their bloom dynamics, an occurring bloom dominated by <em>T. furca</em> and <em>D. norvegica</em> was followed for several days. High cell abundances of these species were located to estimate: <em>in situ</em> growth rates from cell cycle analyses, depth distributions, growth rates sustained by photosynthesis, and parasite infection prevalence in all <em>T. furca, T. fusus, D. norvegica</em> and <em>D. acuminata</em>. Cell abundances were over 10000 cells L⁻¹ for <em>T. furca</em> and up to 18000 cells L⁻¹ for <em>D. norvegica</em>. Cells accumulated between 15-25 m depth and presented low specific <em>in situ</em> growth rates of 0.04-0.15 d⁻¹ for <em>T. furca</em> and 0.02-0.16 d⁻¹ for <em>D. norvegica.</em> Photosynthesis could sustain growth rates of 0.01-0.18 d⁻¹ for <em>T. furca</em> and 0.02 to 0.14 d⁻¹ for <em>D. norvegica</em>, suggesting that these species were relying mainly on photosynthesis. Parasite infections where generally low, with occasional high prevalence in <em>D. norvegica</em> (by <em>Parvilucifera</em> sp.) and <em>T. fusus</em> (by <em>Amoebophrya</em> sp.), while both parasites showed comparable prevalence in <em>D. acuminata</em>, which could offset <em>in situ</em> growth rates by parasite-induced host mortality. The restructuring effect of parasites on dinoflagellate blooms is often overlooked and this study elucidates their effect to cell abundances and their growth at the final stages of a bloom.</p></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":null,"pages":null},"PeriodicalIF":6.6,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139924497","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":"Transcriptome analysis of the harmful alga Heterosigma akashiwo under a 24-hour light-dark cycle","authors":"Nanjing Ji ,&nbsp;Junyue Wang ,&nbsp;Wencong Huang ,&nbsp;Jinwang Huang ,&nbsp;Yuefeng Cai ,&nbsp;Song Sun ,&nbsp;Xin Shen ,&nbsp;Yue Liang","doi":"10.1016/j.hal.2024.102601","DOIUrl":"10.1016/j.hal.2024.102601","url":null,"abstract":"<div><p>The photoperiod, which is defined as the period of time within a 24-hour time frame that light is available, is an important environmental regulator of several physiological processes in phytoplankton, including harmful bloom-forming phytoplankton. The ichthyotoxic raphidophyte <em>Heterosigma akashiwo</em> is a globally distributed bloom-forming phytoplankton. Despite extensive studies on the ecological impact of <em>H. akashiwo</em>, the influence of the photoperiod on crucial biological processes of this species remains unclear. In this study, gene expression in <em>H. akashiwo</em> was analyzed over a 24-hour light-dark (14:10) treatment period. Approximately 36 % of unigenes in <em>H. akashiwo</em> were differentially expressed during this 24-hour treatment period, which is indicative of their involvement in the response to light-dark variation. Notably, the number of differentially expressed genes exhibited an initial increase followed by a subsequent decrease as the sampling time progressed (T0 vs. other time points). Unigenes associated with photosynthesis and photoprotection reached their peak expression levels after 2–4 h of illumination (T12-T14). In contrast, the expression of unigenes associated with DNA replication peaked at the starting point of the dark period (T0). Furthermore, although several unigenes annotated to photoreceptors displayed potential diel periodicity, genes from various photoreceptor families (such as phytochrome and cryptochrome) showed unique expression patterns. Collectively, our findings offer novel perspectives on the response of <em>H. akashiwo</em> to the light-dark cycle, serving as a valuable resource for investigating the physiology and ecology of this species.</p></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":null,"pages":null},"PeriodicalIF":6.6,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139817802","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":"A Pseudo-nitzschia metabarcoding approach with a calibrated ITS1 reference sequence database applied in the Taiwan Strait","authors":"Biaobiao Niu ,&nbsp;Jinxiu Pang ,&nbsp;Nina Lundholm ,&nbsp;Cuiwen Liang ,&nbsp;Sing Tung Teng ,&nbsp;Qixiang Zheng ,&nbsp;Xin Guo ,&nbsp;Yang Li","doi":"10.1016/j.hal.2024.102602","DOIUrl":"10.1016/j.hal.2024.102602","url":null,"abstract":"<div><p><em>Pseudo-nitzschia</em> is a cosmopolitan phytoplankton genus of which some species can form blooms and produce the neurotoxin domoic acid (DA). Identification of <em>Pseudo-nitzschia</em> is generally based on field material or strains followed by morphological and/or molecular characterization. However, this process is time-consuming and laborious, and can not obtain a relatively complete and reliable profile of the <em>Pseudo-nitzschia</em> community, because species with low abundance in the field or potentially unavailable for culturing may easily be overlooked. In the present study, specific ITS primer sets were designed and evaluated using <em>in silico</em> matching. The primer set ITS-84F/456R involving the complete ITS1 region was found optimal. Based on matching with a <em>Pseudo-nitzschia</em> ITS1 reference sequence database carefully-calibrated in this study, a metabarcoding approach using annotated amplicon sequence variants (ASV) was applied in the Taiwan Strait of the East China Sea during two cruises in the spring and summer of 2019. In total, 48 <em>Pseudo-nitzschia</em> species/phylotypes including 36 known and 12 novel were uncovered, and verified by haplotype networks, ITS2 secondary structure comparisons and divergence analyses. Correlation analyses revealed that temperature was a key factor affecting the seasonal variation of the <em>Pseudo-nitzschia</em> community. This study provides an overview of the <em>Pseudo-nitzschia</em> community in the Taiwan Strait, with new insights into the diversity. The developed metabarcoding approach may be used elsewhere as a standard reference for accurate annotation of <em>Pseudo-nitzschia</em>.</p></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":null,"pages":null},"PeriodicalIF":6.6,"publicationDate":"2024-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139820849","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":"Toxins and Biliary Atresia: Is Karenia Brevis (Red Tide) The Culprit?","authors":"Rita Wyrebek ,&nbsp;Jamie L. Fierstein ,&nbsp;Rebecca G. Wells ,&nbsp;Joana Machry ,&nbsp;Sara Karjoo","doi":"10.1016/j.hal.2024.102596","DOIUrl":"https://doi.org/10.1016/j.hal.2024.102596","url":null,"abstract":"<div><h3>Objective</h3><p>The study objective was to evaluate the association between <em>Karenia brevis (K. brevis)</em> exposure during pregnancy and the prevalence of biliary atresia (BA) in offspring.</p></div><div><h3>Study Design</h3><p>This was a hospital-based, case-control study in which cases were infants diagnosed with BA at Johns Hopkins All Children's Hospital from October 2001 to December 2019. Cases were matched 1:4 by age to controls who were randomly selected from a pool of healthy infants hospitalized during the study period for common pediatric diagnoses. Infants were excluded if they had congenital anomalies and/or were non-Florida residents. Gestational <em>K. brevis</em> exposure levels (cells/liter) were determined from Florida Fish and Wildlife Conservation Commission exposure data at 10- and 50 mile radii from the mother's zip code of residence. Multivariable conditional logistic regression determined odds of BA in offspring in relation to maternal gestational <em>K. brevis</em> exposure adjusted for infant sex, race/ethnicity, coastal residence, and seasonality.</p></div><div><h3>Results</h3><p>Of 38 cases and 152 controls, no significant inter-group differences were observed for infant race/ethnicity, season of birth, or coastal residence. Median gestational exposure at the 10 mile radius was 0 cells/liter in both groups. A greater proportion of cases had no gestational <em>K. brevis</em> exposure (63.2 %, <em>n</em> = 24) in comparison to controls (37.5 %, <em>n</em> = 57; <em>p</em> = .04) at a 10 mile radius. At a 50 mile radius, cases had a peak median exposure at 6 months of gestation compared to controls’ peak at 9 months. After adjustment for sex, seasonality, race/ethnicity, and coastal residence, there was no significant association between BA and maximum <em>K. brevis</em> exposure per trimester of pregnancy observed at a 10- or 50 mile radius.</p></div><div><h3>Conclusion</h3><p>In this matched case-control study, we observed no association between gestational <em>K. brevis</em> (cells/liter) exposure at a 10- or 50 mile radius from maternal zip code of residence and BA in offspring.</p></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":null,"pages":null},"PeriodicalIF":6.6,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139738374","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":"Long-term stability of the genome structure of the cyanobacterium, Dolichospermum in a deep German lake","authors":"J.N. Woodhouse ,&nbsp;M.A. Burford ,&nbsp;B.A. Neilan ,&nbsp;A. Jex ,&nbsp;S. Tichkule ,&nbsp;K. Sivonen ,&nbsp;D.P. Fewer ,&nbsp;H-P Grossart ,&nbsp;A. Willis","doi":"10.1016/j.hal.2024.102600","DOIUrl":"https://doi.org/10.1016/j.hal.2024.102600","url":null,"abstract":"<div><p><em>Dolichospermum</em> is a cyanobacterial genus commonly associated with toxic blooms in lakes and brackish water bodies worldwide, and is a long-term resident of Lake Stechlin, northeastern Germany. In recent decades, shifts in the phosphorus loading and phytoplankton species composition have seen increased biomass of <em>Dolichospermum</em> during summer blooms from 1998, peaking around 2005, and declining after 2020. Cyanobacteria are known to rapidly adapt to new environments, facilitated by genome adaptation. To investigate the changes in genomic features that may have occurred in Lake Stechlin <em>Dolichospermum</em> during this time of increased phosphorus loading and higher biomass, whole genome sequence analysis was performed on samples of ten akinetes isolated from ten, 1 cm segments of a sediment core, representing a ∼45-year period from 1970 to 2017. Comparison of these genomes with genomes of extant isolates revealed a clade of <em>Dolichospermum</em> that clustered with the ADA-6 genus complex, with remarkable genome stability, without gene gain or loss events in response to recent environmental changes. The genome characteristics indicate that this species is suited to a deep-chlorophyll maximum, including additional light-harvesting and phosphorus scavenging genes. Population SNP analysis revealed two sub-populations that shifted in dominance as the lake transitioned between oligotrophic and eutrophic conditions. Overall, the results show little change within the population, despite diversity between extant populations from different geographic locations and the in-lake changes in phosphorus concentrations.</p></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":null,"pages":null},"PeriodicalIF":6.6,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1568988324000349/pdfft?md5=884638038dcc3938bea4a49330d019de&pid=1-s2.0-S1568988324000349-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139738373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bacterial community shifts induced by high concentration hydrogen peroxide treatment of Microcystis bloom in a mesocosm study","authors":"Taylor L. Hancock ,&nbsp;Elizabeth K. Dahedl ,&nbsp;Michael A. Kratz ,&nbsp;Hidetoshi Urakawa","doi":"10.1016/j.hal.2024.102587","DOIUrl":"https://doi.org/10.1016/j.hal.2024.102587","url":null,"abstract":"<div><p>Hydrogen peroxide has gained popularity as an environmentally friendly treatment for cyanobacterial harmful algal blooms (cHABs) that takes advantage of oxidative stress sensitivity in cyanobacteria at controlled concentrations. Higher concentrations of hydrogen peroxide treatments may seem appealing for more severe cHABs but there is currently little understanding of the environmental impacts of this approach. Of specific concern is the associated microbial community, which may play key roles in the succession/recovery process post-treatment. To better understand impacts of a high concentration treatment on non-target microbial communities, we applied a hydrogen peroxide spray equating to a total volume concentration of 14 mM (473 mg/L, 0.04%) to 250 L mesocosms containing <em>Microcystis</em> bloom biomass, monitoring treatment and control mesocosms for 4 days. Cyanobacteria dominated control mesocosms throughout the experiment while treatment mesocosms experienced a 99% reduction, as determined by bacterial amplicon sequencing, and a 92% reduction in bacterial cell density within 1 day post-treatment. Only the bacterial community exhibited signs of regrowth, with a fold change of 9.2 bacterial cell density from day 1 to day 2. Recovery consisted of succession by Planctomycetota (47%) and Gammaproteobacteria (17%), which were likely resilient due to passive cell component compartmentalization and rapid upregulation of <em>dnaK</em> and <em>groEL</em> oxidative stress genes, respectively. The altered microbiome retained beneficial functionality of microcystin degradation through a currently recognized but unidentified pathway in Gammaproteobacteria, resulting in a 70% reduction coinciding with bacterial regrowth. There was also an 81% reduction of both total nitrogen and phosphorus, as compared to 91 and 93% in the control, respectively, due to high expressions of genes related to nitrogen (<em>argH, carB, glts, glnA</em>) and phosphorus (<em>pntAB, phoB, pstSCB</em>) cycling. Overall, we found a portion of the bacterial community was resilient to the high-concentration hydrogen peroxide treatment, resulting in Planctomycetota and Gammaproteobacteria dominance. This high-concentration treatment may be suitable to rapidly end cHABs which have already negatively impacted the aquatic environment rather than allow them to persist.</p></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":null,"pages":null},"PeriodicalIF":6.6,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139738365","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":"Physical drivers of Noctiluca scintillans (Dinophyceae) blooms outbreak in the northern Taiwan Strait: A numerical study","authors":"Zhonghao Lin ,&nbsp;Peng Zhan ,&nbsp;Jianping Li ,&nbsp;Jun Sasaki ,&nbsp;Zhongfeng Qiu ,&nbsp;Chun Chen ,&nbsp;Shuangyan Zou ,&nbsp;Xiaotong Yang ,&nbsp;Haifeng Gu","doi":"10.1016/j.hal.2024.102586","DOIUrl":"10.1016/j.hal.2024.102586","url":null,"abstract":"<div><p>The red <em>Noctiluca scintillans</em> (<em>RNS</em>) blooms often break out near Pingtan Island, in the northern Taiwan Strait from April to June. It is essential to gain insights into their formation mechanism to predict and provide early warnings for these blooms. Previous studies and observations showed that <em>RNS</em> blooms are the most likely to occur when winds are weak and shifting in direction. To explore this phenomenon further, we employed a high-resolution coastal model to investigate the hydrodynamics influencing <em>RNS</em> blooms around Pingtan Island from April to June 2022. The model results revealed that seawater exhibited weak circulation but strong stratification during <em>RNS</em> blooms. Residence time were examined through numerical experiments by releasing passive neutrally buoyant particles in three bays of Pingtan Island. The results showed a significantly longer residence time during <em>RNS</em> blooms, indicating reduced flushing capabilities within the bays, which could give <em>RNS</em> a stable environment to multiply and aggregate. This hydrodynamic condition provided a favorable basis for <em>RNS</em> blooms breakout near Pingtan Island. The shifts and weakening of the prevailing northeast wind contributed substantially to weakening the flow field around Pingtan Island and played a crucial role in creating the hydrodynamics conducive to <em>RNS</em> blooms. Our study offers fresh insights into the mechanisms underpinning <em>RNS</em> blooms formation near Pingtan Island, providing a vital framework for forecasting <em>RNS</em> blooms in this region.</p></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":null,"pages":null},"PeriodicalIF":6.6,"publicationDate":"2024-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139684209","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":"Mechanisms of harmful effects of Microcystis aeruginosa on a brackish water organism Moina mongolica based on physiological and transcriptomic responses","authors":"Hongtao Liu ,&nbsp;Hao Xing ,&nbsp;Zhangyi Xia ,&nbsp;Tingting Wu ,&nbsp;Jinlin Liu ,&nbsp;Aiqin Li ,&nbsp;Fangling Bi ,&nbsp;Yuqing Sun ,&nbsp;Jianheng Zhang ,&nbsp;Peimin He","doi":"10.1016/j.hal.2024.102588","DOIUrl":"https://doi.org/10.1016/j.hal.2024.102588","url":null,"abstract":"<div><p>To investigate the detrimental impacts of cyanobacterial bloom, specifically <em>Microcystis aeruginosa</em>, on brackish water ecosystems, the study used <em>Moina mongolica</em>, a cladoceran species, as the test organism. In a chronic toxicology experiment, the survival and reproductive rates of <em>M. mongolica</em> were assessed under <em>M. aeruginosa</em> stress. It was observed that the survival rate of <em>M. mongolica</em> fed with <em>M. aeruginosa</em> significantly decreased with time and their reproduction rate dropped to zero, while the control group remained maintained stable and normal reproduction. To further explore the underlying molecular mechanisms of the effects of <em>M. aeruginosa</em> on <em>M. mongolica</em>, we conducted a transcriptomic analysis on newly hatched <em>M. mongolica</em> cultured under different food conditions for 24 h. The results revealed significant expression differences in 572 genes, with 233 genes significantly up-regulated and 339 genes significantly down-regulated. Functional analysis of these differentially expressed genes identified six categories of physiological functional changes, including nutrition and metabolism, oxidative phosphorylation, neuroimmunology, cuticle and molting, reproduction, and programmed cell death. Based on these findings, we outlined the basic mechanisms of microcystin toxicity. The discovery provides critical insights into the mechanisms of Microcystis toxicity on organisms and explores the response mechanisms of cladocerans under the stress of Microcystis.</p></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":null,"pages":null},"PeriodicalIF":6.6,"publicationDate":"2024-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139733186","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":"Transcriptome analysis of the harmful alga Heterosigma akashiwo under a 24-hour light-dark cycle","authors":"Nanjing Ji, Junyue Wang, Wencong Huang, Jinwang Huang, Yuefeng Cai, Song Sun, Xin Shen, Yue Liang","doi":"10.1016/j.hal.2024.102601","DOIUrl":"https://doi.org/10.1016/j.hal.2024.102601","url":null,"abstract":"","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":null,"pages":null},"PeriodicalIF":6.6,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139877824","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":"Current status and prognosis of Raphidiopsis raciborskii distribution in Bulgaria as part of the southeastern region of Europe","authors":"Detelina Belkinova ,&nbsp;Desislava Stoianova ,&nbsp;Mihaela Beshkova ,&nbsp;Stefan Kazakov ,&nbsp;Plamen Stoyanov ,&nbsp;Rumen Mladenov","doi":"10.1016/j.hal.2024.102578","DOIUrl":"10.1016/j.hal.2024.102578","url":null,"abstract":"<div><p>The cyanobacterial species <em>Raphidiopsis raciborskii</em> (Wołoszyńska) Aguilera et al. has a high invasiveness potential, which in less than a century leads to its cosmopolitan spread. In the temperate climate of Europe<em>, R. raciborskii</em> has been reported in many countries, but there is still a lack of detailed information about the current status of its distribution in lakes of Bulgaria, as a part of the southeastern range of its spread in Europe. We investigated the distribution of the species using data on the phytoplankton of 122 lakes surveyed during 13-years period (2009–2022). The species was found in 33 lakes (up to 324 m asl), and 14 new localities were registered during the studied period. The results reveal that the number of lakes with the presence of <em>R. raciborskii</em> (27 % of all research lakes) and its contribution to the total phytoplankton biomass, has increased significantly over the last decade. The species has successfully adapted and dominated the phytoplankton in 9 lakes, forming a bloom in 8 of them. The dominant position of <em>R. raciborskii</em> causes loss of species and functional diversity of phytoplankton and displaces the native bloom-forming cyanobacteria.</p><p>Lakes with and without the species were compared based on the available data on bioclimatic and local environmental variables. Statistically significant differences were established with respect to water transparency, conductivity, maximum depth and maximum air temperature in the warmest month. Species distribution models (SDMs) were used to identify lakes in high risk of future invasion by <em>R. raciborskii</em>. The results of the SDMs implementation confirmed the high maximum air temperature and low water transparency to be important predictors of the occurrence of <em>R. raciborskii</em> in freshwater lakes in Bulgaria. In the areas with high summer temperatures the most suitable for <em>R. raciborskii</em> development were found to be shallow polymictic or medium deep lakes with small surface area and low water transparency. In areas with a suitable climate, the large, deep reservoirs with high transparency as well as macrophyte dominated lakes have a low probability of occurrence of <em>R. raciborskii</em>. Future colonization of lakes above 500 m asl (but most likely below 700 m asl) is also possible, especially in the conditions of global warming. SDMs account for climatic and biogeographic differences of lakes and could help in elucidating the underlying factors that control the occurrence and adaptation of <em>R. raciborskii</em> in a given area.</p></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":null,"pages":null},"PeriodicalIF":6.6,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S156898832400012X/pdfft?md5=801879b1a3057c719ada340583737abe&pid=1-s2.0-S156898832400012X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139518216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}