Journal Of Phycology[JOURNAL]
Sun
200 papers
Organelle genome evolution in the early-diverging brown algal lineage, Ishigeales.
Hwang H, Kim H, Choi SW … +2 more , Kawai H, Yoon HS
J Phycol · 2026 Jun · PMID 42187298 · Full text
The order Ishigeales is an early-diverging lineage of brown algae that exhibits remarkable morphological diversity ranging from simple filamentous forms to robust terete and foliose thalli, which may reflect complex evol...
The order Ishigeales is an early-diverging lineage of brown algae that exhibits remarkable morphological diversity ranging from simple filamentous forms to robust terete and foliose thalli, which may reflect complex evolutionary histories in their organelle genomes. However, limited organellar genomic data for the Ishigeales, presently confined to Ishige okamurae, have hindered a comprehensive understanding of organelle genome dynamics in that order. To address this, we de novo assembled the complete plastomes and mitogenomes of the four Ishigeales species: Pilinia rimosa, Petroderma maculiforme, I. okamurae, and I. foliacea. Phylogenetic analyses based on plastome and mitogenome datasets using both concatenation and coalescent-based approaches supported the divergence order from the less complex filamentous morphology of Pi. rimosa to the more morphologically complex terete and foliose Ishige species, yet it also revealed a phylogenetic conflict at the branching point of Pe. maculiforme, suggesting an intricate evolutionary history in filamentous species. Both plastomes and mitogenomes exhibited extensive genomic rearrangement. Notably, mitochondrial genome expansion was observed in Pi. rimosa and Pe. maculiforme, and massive cox2 gene duplication was found in Pi. rimosa. These expansions were likely driven by the proliferation of tandem repeats, and most copies are likely under relaxed purifying selection. Analysis of synonymous substitution rate to the nonsynonymous substitution rate revealed the rapid divergence in several plastid genes between I. okamurae and I. foliacea. In particular, the DPOR gene family exhibited a signal of relaxed purifying selection, potentially linked to their distinct morphological changes in Ishige species. Overall, our findings reveal that Ishigeales underwent lineage-specific differentiation and dynamic evolutionary patterns in the organelle genomes along with morphological variation.
Conspecific alarm cues induce chemical but not morphological defenses in Pseudo-nitzschia.
Zhang S, Zheng T, Zhou M … +6 more , Guo X, Bates SS, Liu G, Zeng H, Lei J, Li Y
J Phycol · 2026 Jun · PMID 42187266 · Publisher ↗
This study investigates the chemical and morphological responses of two domoic acid (DA)-producing diatoms, Pseudo-nitzschia multiseries and P. fukuyoi, to conspecific chemical cues released from mechanically damaged cel...
This study investigates the chemical and morphological responses of two domoic acid (DA)-producing diatoms, Pseudo-nitzschia multiseries and P. fukuyoi, to conspecific chemical cues released from mechanically damaged cells. Cell homogenate filtrate (CHF) was added to batch cultures via single or repeated doses to simulate acute and sustained cell disruption associated with grazing. Results showed that CHF exposure did not affect growth rate, cell abundance, and morphological traits, including chain density, average chain length, and frustule silicification, in either species. In contrast, cellular DA content increased significantly in response to CHF addition, reaching up to 2.16-fold higher in P. multiseries and 1.44-fold in P. fukuyoi, particularly during the decline phase. The magnitude of these toxicogenic responses depended on species identity, growth stage, and cue delivery regime, with repeated or persistent cue exposure eliciting stronger responses. Algal physiological parameters and environmental conditions (pH, nutrients, bacterial abundance) remained largely unchanged, indicating that toxin induction was primarily driven by direct sensing of algal-derived infochemicals rather than indirect environmental effects. Notably, enhanced DA production occurred without detectable reductions in growth or cell abundance. These findings demonstrate that Pseudo-nitzschia can deploy efficient, chemically mediated defenses in response to conspecific alarm cues, with important implications for toxin regulation, grazer-prey interactions, and the ecological dynamics of harmful algal blooms.
Correction to "Population and herbarium genomics provide a comprehensive framework for a revision of Microcoleus (Cyanobacteria)".
J Phycol · 2026 Jun · PMID 42183776 · Publisher ↗
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Optimization of ultrasound-assisted extraction of phenolic compounds from Sargassum carpophyllum using response surface methodology.
Liu X, Yin Q, Chen X … +3 more , Xie E, Jiang F, Liu Y
J Phycol · 2026 Jun · PMID 42149128 · Publisher ↗
Sargassum spp. has been used in traditional Chinese medicine for nearly 2000 years to treat a variety of diseases due to its pharmacologically active components such as phenolics. In this work, response surface methodolo...
Sargassum spp. has been used in traditional Chinese medicine for nearly 2000 years to treat a variety of diseases due to its pharmacologically active components such as phenolics. In this work, response surface methodology (RSM) was employed to optimize the ultrasound-assisted extraction (UAE) procedures to obtain phenolic compounds from Sargassum carpophyllum, a brown alga widely growing on the coastline of Asian countries. The effects of four extraction variables including ethanol concentration (EtOH%) in the solvent, liquid-solid ratio, ultrasonic power, and duty cycle ratio (DCR) were evaluated using a central composite design (CCD), with the total phenol content (TPC) and antioxidant activity as the two responses. Two quadratic regression models were generated, and the optimum extraction conditions for the highest TPC and antioxidant activity were 50% ethanol, a 40 mL · g of liquid-solid ratio, 260 W, and a 5/6 DCR. The corresponding predicted TPC and antioxidant activity were 2.884 mg phloroglucinol (PHG) · g algae and 3.188 mg Trolox · g algae, respectively, which were in close agreement with the experimental validation values of 2.907 mg PHG · g algae and 3.267 mg Trolox · g algae, respectively. The results suggested that the two regression models could sufficiently describe the UAE procedure and optimize the TPC and antioxidant activity. Results of the Fourier Transform Infrared Spectrometer (FTIR) spectra revealed that phenolic compounds were the major composition of the optimized extract. This work provides essential knowledge in phenolic compounds extraction from S. carpophyllum through mathematical modeling and could be a useful reference for developing upscale UAE procedures.
Unveiling coralline diversity of mesophotic rhodoliths in subtropical Japan, including new species of Sporolithon, emended genera Orientalilithon and Roseolithon (Corallinophycidae, Rhodophyta).
Min-Khant-Kyaw, Baba M, Terada R … +1 more , Kato A
J Phycol · 2026 Jun · PMID 42126258 · Full text
The mesophotic zone off Tanegashima Island (approximately 30-40 m deep) is a marine macroalgal hotspot in subtropical Japan; however, the taxonomic diversity of calcifying red algal community remains poorly understood. O...
The mesophotic zone off Tanegashima Island (approximately 30-40 m deep) is a marine macroalgal hotspot in subtropical Japan; however, the taxonomic diversity of calcifying red algal community remains poorly understood. Our phylogenetic analyses based on psbA, rbcL, and COI-5P gene markers disclosed the presence of at least 12 rhodolith-forming non-geniculate coralline algae from five genera across three orders. The confirmation of previously described Lithophyllum neo-okamurae, L. okamurae (Corallinales), and Orientalilithon confluens (Hapalidiales) herein extended their vertical distributional range. The remaining nine species represent novelty, with four newly described and five unnamed taxa: Crustaphytum sp., Roseolithon aggregatum sp. nov., R. sparsituberculatum sp. nov., Orientalilithon compactum sp. nov., Orientalilithon sp. 2, Hapalidiales sp. (Hapalidiales), Sporolithon variotuberculatum sp. nov., Sporolithon sp. 1, and Sporolithon sp. 2 (Sporolithales). Roseolithon aggregatum barely differs from R. sparsituberculatum by external growth form and length of protuberances. These two mesophotic species can be separated from the shallow-water R. littorale and R. sabulosum (1-6 m depth) in Japan based on depth-stratified distribution. Orientalilithon compactum and O. confluens can, at present, be identified by DNA sequences and to some degree by spatial distribution. Sporolithon variotuberculatum is a genetically verified Japanese species of Sporolithon and appears to be related to S. molle from Egypt. They morpho-anatomically differed by the number of cells in paraphyses, the diameter of sporangial pore openings, and the size of stalk cells subtending tetra-/bisporangia. This study underscores the remarkable species diversity of Japanese rhodoliths in subtropical mesophotic ecosystems that deserve further investigation.
Genomic and secondary metabolites of the marine cyanobacterium Capilliphycus salinus ALCB114379.
Passos GS, Dextro RB, Machado MJ … +6 more , Feitosa AMT, Silva NP, Cruz RB, Andreote APD, Pinto E, Fiore MF
J Phycol · 2026 Jun · PMID 42104842 · Full text
Assembling high-quality genomes from underexplored environments can be helpful for understanding microbial diversity and identifying novel species. The Cyanobacterium type strain Capilliphycus salinus ALCB114379 is a rep...
Assembling high-quality genomes from underexplored environments can be helpful for understanding microbial diversity and identifying novel species. The Cyanobacterium type strain Capilliphycus salinus ALCB114379 is a representative of Oscillatoriales order isolated from a supralittoral zone of the south Atlantic Ocean in Brazil, an ecotone characterized by significant environmental fluctuations due to its transitional nature between the tidal and terrestrial environments. Here, we present its genome assembled into a single contig and circularized, with a total size of 7.7 Mb and 99.67% completeness. The genome has 6204 protein-coding genes, including several involved in the biosynthesis of secondary metabolites. Despite being a homocytous genus, C. salinus ALCB114379 possesses a gene cluster for the biosynthesis of molybdenum-type nitrogenase, indicating a potential for N fixation. Additionally, the genome contains other gene clusters related to the biosynthesis of biotechnologically relevant compounds, such as microcyclamide (mca), a cytotoxic cyanopeptide, and mycosporine-like amino acids (MAAs), with photoprotective and antioxidant functions. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis showed the detectable production of three MAAs, with shinorine being the most abundantly produced compared with porphyra-334 and palythine. This work provides insights into the Cyanobacteria phylogenomics and metabolism, highlighting the potential of C. salinus ALCB114379 as a source of specific metabolites for biotechnological applications.
How do I publish the name of a new species of algae? A basic guide.
Guiry MD
J Phycol · 2026 Jun · PMID 42101059 · Full text
A basic guide to the requirements of the International Code of Nomenclature for algae, fungi, and plants for the publication of a valid name of new species (and infraspecific taxa) of living algae is provided. It is inte...
A basic guide to the requirements of the International Code of Nomenclature for algae, fungi, and plants for the publication of a valid name of new species (and infraspecific taxa) of living algae is provided. It is intended to aid phycologists so that an accurate inventory of the world's algal diversity is achieved. A checklist of actions necessary when preparing for publication of algae names is included.
Protein acetylation regulates the wound-induced asexual spore formation in Pyropia yezoensis.
Zhang Z, You W, Guan X … +3 more , Tang F, Poetsch A, Wang D
J Phycol · 2026 Jun · PMID 42080667 · Publisher ↗
Lysine acetylation (LysAc) of proteins plays critical regulatory roles in a wide range of biological processes in both prokaryotes and eukaryotes. However, characteristics of LysAc and related proteins in red algae have...
Lysine acetylation (LysAc) of proteins plays critical regulatory roles in a wide range of biological processes in both prokaryotes and eukaryotes. However, characteristics of LysAc and related proteins in red algae have not been investigated. In a marine aquaculture species Pyropia yezoensis, thallus cells form and release asexual spores under wound stress, and this process provides an essential source of seedlings in aquaculture. In order to elucidate the underlying regulatory mechanisms during spore formation, we performed a global acetylproteome analysis in both intact and wounded thalli. A total of 4647 LysAc sites were identified on 1398 proteins. Among them, 361 proteins exhibited differential acetylations (DAPs) at the time of sporangia formation and 382 at the time of spore maturation. Functional classification of all the DAPs revealed that they were primarily associated with central metabolic pathways, highlighting the importance of lysine acetylation in asexual spore formation. Particularly, >30 proteins related to photosynthesis and carbon fixation showed coordinated decline, consistent with the repressed photosynthetic efficiency after wounding. Starch was accumulated and the LysAc on the catalytic domain of starch synthase significantly increased during spore formation. Proteins related to cytoskeleton remodeling also had variations in LysAc, aligning with the observed depolymerization of microfilaments in spores. Our study provides not only fundamental information in protein acetylation in Pyropia as a prominent example for red seaweeds but also valuable insights on the post-translational regulation in wound-induced spore formation.
Dominance and toxicity without lethality: Exploring biomass, cyanometabolites, and Daphnia responses across Cyanobacterial strains.
Wejnerowski Ł, Dulić T, Akter S … +12 more , Rybak M, Piasecka A, Szymkowiak J, Kamiński O, Czerepska A, Pniewski F, Svirčev Z, Poniecka E, Zawierucha K, Taylor K, Dziuba MK, Meriluoto J
J Phycol · 2026 Jun · PMID 42080663 · Full text
Cyanobacteria are cosmopolitan, important components of biomass with a remarkable ability to synthesize a diverse array of bioactive compounds, some of which may have toxic effects on other organisms and ecosystems. In t...
Cyanobacteria are cosmopolitan, important components of biomass with a remarkable ability to synthesize a diverse array of bioactive compounds, some of which may have toxic effects on other organisms and ecosystems. In this study, filamentous cyanobacterial strains isolated predominantly from temperate European freshwaters (Aphanizomenon, Chrysosporum, Cuspidothrix, Dolichospermum, Planktothrix, Raphidiopsis), with a subset from Arctic waters (Microcoleus, Phormidesmis), were qualitatively screened for commonly studied cyanometabolites, using immunoassays and chromatographic techniques. We also assessed the effects of culture extracts and filtrates on the survival of Daphnia magna and Daphnia pulicaria. The results indicated a broad capacity among tested strains to produce toxic and bioactive compounds. Specifically, we detected anabaenopeptins, anatoxin-a, cylindrospermopsin, microcystins, and saxitoxins. Although numerous strains showed the potential to produce a variety of toxic and bioactive compounds and reached high biomass after 40 days of incubation, their extracts and filtrates frequently had negligible negative effects on the survival of Daphnia. In contrast, significant lethality was observed in response to planktic Limnothrix sp. and glacial Microcoelus autumnalis that tested negative for the studied compounds, as well as for an Aphanizomenon klebahnii strain in which only anabaenopeptins were detected. We also observed a positive relationship between the biomass used to prepare cyanobacterial extracts and Daphnia survival, and this result raises the question of whether there is a trade-off between the growth rates of strains and their toxicities. Our study extends the current knowledge of the geographical distribution of toxic cyanobacteria and suggests that some of them may also produce other, yet unidentified toxic compounds.
Phytoplankton growth and potential cyanotoxin production differ in response to nitrogen and phosphorus amendments in late summer communities from Kabetogama Lake (Minnesota, United States).
Larson JH, Maki RP, Bailey SW … +5 more , Christensen VG, Loftin KA, Stelzer EA, Smith JC, McWhorter SA
J Phycol · 2026 Jun · PMID 42068159 · Full text
Cyanotoxins such as microcystin (MC), cylindrospermopsin, and saxitoxin are secondary metabolites that are rich in nitrogen (N). Most cyanobacteria grow best on reduced inorganic N (ammonium, NH), but when NH is absent,...
Cyanotoxins such as microcystin (MC), cylindrospermopsin, and saxitoxin are secondary metabolites that are rich in nitrogen (N). Most cyanobacteria grow best on reduced inorganic N (ammonium, NH), but when NH is absent, cyanobacteria can activate physiological pathways to process other N forms (e.g., nitrate; NO). Studies on some cyanobacterial cultures have indicated that expression of N stress response genes is associated with MC gene expression. If accurate, NH additions could reduce N stress and therefore cyanotoxin production. Lakes experiencing changes in N form and supply could thus experience changes in cyanobacterial toxicity independent of shifts in abundance. We performed nutrient amendments on phytoplankton communities from Kabetogama Lake (Minnesota, United States) over 2 years (four experiments total), to assess the role of N and phosphorus amendments on growth and toxicity of phytoplankton. Natural communities were collected during cyanobacterial blooms and exposed to short laboratory experiments with amendments of NH, NO, orthophosphate, or a combination of all three. In three of four experiments, biomass responses were consistent with N-limitation based on chlorophyll a or biovolume estimates. In experiments with evidence for N-limited growth, MC gene expression was lower in NH treatments than in the control in 2021 but higher than in the control in 2022. The proportion of heterocytes (specialized cells for N fixation) was positively correlated with MC gene expression. These experiments reinforce the strong connection between N physiology and MC gene expression, but variation in taxonomic composition within genera or even species remains a possible cause of inconsistency in whole-community responses.
Molecular mechanisms, metabolic remodeling, and energy reallocation underlying calcification in the coccolithophore Gephyrocapsa huxleyi.
Wang C, Liu Y, Lin G … +3 more , Deng X, Lin S, Jiao N
J Phycol · 2026 Jun · PMID 42059404 · Publisher ↗
Coccolithophores play a dual role in the marine carbon cycle, serving as CO sinks through photosynthesis while simultaneously emitting CO via calcification, resulting in uncertainty regarding their net carbon sequestrati...
Coccolithophores play a dual role in the marine carbon cycle, serving as CO sinks through photosynthesis while simultaneously emitting CO via calcification, resulting in uncertainty regarding their net carbon sequestration potential. In addition, their calcite coccoliths (CaCO) can increase the carbon export efficiency by functioning as ballasts for organic matter. Although biogeochemically significant, the molecular mechanisms governing calcification and associated metabolic adaptations in coccolithophores remain poorly characterized, impeding accurate predictions of their responses to climate change. Through comparative multiomics analyses of calcified (RCC1266) and noncalcified (PML B92/11) Gephyrocapsa huxleyi strains, as well as chemically induced decalcified and recalcified states, we screened several ion transport genes, which potentially facilitate Ca and HCO uptake/transport coupled with H extrusion during calcification in the calcified strain, along with their associated proteins, including signal molecules and chaperones. Furthermore, an energy-intensive process was observed in calcifying cells, and this process was principally sustained by enhanced photosynthetic efficiency, supplemented by glucose accumulation as an energy reserve and COX6B translational upregulation, providing nocturnal energy. Notably, calcifying cells employed an energy conservation strategy characterized by transcriptional downregulation yet translational maintenance of photosynthesis and carbon metabolism genes while simultaneously upregulating protein biosynthesis and trafficking pathways to probably meet calcification demands, a process potentially facilitated by increased glutamine biosynthesis. Through multiomic technology, our findings provide insights into the molecular adaptations in the calcified coccolithophorid cells, revealing critical physiological trade-offs, carbon metabolism, and energy allocation that can inform predictions of their acclimation capacity under changing oceanic conditions.
Epitypification of Merismopedia tranquilla (Cyanobacteria) prompts phylogenetic reassessment of the genus and the description of two morphologically similar genera.
Pokorný J, Kaštovský J, Štenclová LM
J Phycol · 2026 Jun · PMID 42053466 · Full text
The genus Merismopedia is morphologically characterized by its distinctive colony arrangement yet exhibits considerable variability among species. Recent studies suggested that Merismopedia is polyphyletic, and its most...
The genus Merismopedia is morphologically characterized by its distinctive colony arrangement yet exhibits considerable variability among species. Recent studies suggested that Merismopedia is polyphyletic, and its most likely true lineage was provisionally placed within the Microcystaceae. However, the available molecular data for most of the extant species were scarce, and notably, its type species, Me. tranquilla, lacked contemporary distributional and molecular data. In the present study, we sampled multiple localities to capture the potential morphological and genetic variability within Merismopedia. Using culture-dependent and -independent methods, we collected an extensive dataset of 16S rRNA gene and 16S-23S ITS rRNA region sequences. This dataset included the type locality of Me. tranquilla, from which we successfully recovered morphologically authentic isolates and established an epitype. Subsequent phylogenetic analyses of Merismopedia- and Microcrocis-like taxa revealed the placement of Merismopedia sensu stricto within the Geminocystaceae, herein reinstated to Merismopediaceae and further confirmed extensive polyphyly. Based on these findings, we propose two new genera (Neomerismopedia and Planktopedia), and a new species, Me. sepulta. Additionally, we transfer Microcrocis gigas to Merismopedia. We proposed the provisional transfer of Me. hyalina to Synechocystis; however, further revision is needed. These taxonomic revisions provide a foundation for a comprehensive reevaluation of this widespread and morphologically diverse group of Cyanobacteria.
Novel Hydrurus species (Chrysophyceae) and their adaptations to high-altitude European and Arctic snowfields.
Procházková L, Andersen RA, Leya T … +4 more , Řezanka T, Lukeš M, Nedbalová L, Remias D
J Phycol · 2026 Jun · PMID 42053443 · Full text
Colored snow caused by green algae (Chlorophyceae) is well known, but melting snowpacks can also harbor golden-brown blooms consisting of Chrysophyceae. We collected 14 samples of cryoflora in the Austrian and Swiss Alps...
Colored snow caused by green algae (Chlorophyceae) is well known, but melting snowpacks can also harbor golden-brown blooms consisting of Chrysophyceae. We collected 14 samples of cryoflora in the Austrian and Swiss Alps, the High Tatras in Slovakia, and in Arctic Svalbard. Eight laboratory unicellular flagellated strains were established from eight sites and phylogenetic analyses (18S rRNA and rbcL gene sequences) revealed new taxa belonging to the order Hydrurales (Chrysophyceae). Some formed tetrahedral swarmers; others were capsoid or amoeboid forms. Characteristics of vegetative cells and molecular markers, including the ITS2 rRNA region, supported the description of eight species: Hydrurus novisii sp. nov., H. klavenessii sp. nov., H. tatrae sp. nov., H. pulcher sp. nov., H. pascheri sp. nov., H. svalbardensis sp. nov., H. nivalis sp. nov. and H. nemcovae sp. nov. Pulse-amplitude-modulate (PAM) fluorometry indicated that the photosystem II of Arctic populations was adapted to high light conditions. Abundant polyunsaturated fatty acids supported cell survival at temperatures around 0°C, and the composition of these acids differed among species. The cells contained compatible solutes that could act as antifreeze agents. The main carotenoid fucoxanthin caused the overall golden-brown pigmentation. The closest relatives of the new species were reported from snow and cold mountain streams and lakes, indicating that these Hydruralian microalgae prefer low temperatures and elevated irradiation. The large number of new species discovered during this limited sampling campaign suggests the underestimated diversity of phototrophic microbes in melting snow. Consequently, the genus Hydrurus shows a similar high relevance for snow algae blooms as Chloromonas does within the green algae.
Are integrative systematic tools efficient toward unraveling species diversity with the genus Jania (Corallinaceae, Rhodophyta)?
Maridakis C, Freire VP, Marani G … +3 more , Sancho MT, Le Gall L, Rousseau F
J Phycol · 2026 Jun · PMID 42053442 · Full text
The articulated genus Jania currently comprises 54 accepted species, making it the fourth most speciose genus among corallines, following Lithophyllum, Amphiroa, and Lithothamnion. Unlike these other genera, Jania is rel...
The articulated genus Jania currently comprises 54 accepted species, making it the fourth most speciose genus among corallines, following Lithophyllum, Amphiroa, and Lithothamnion. Unlike these other genera, Jania is relatively easy to identify at a generic rank. However, morpho-anatomical characters are insufficiently discriminant for species identification, making DNA sequences essential for reliable species delimitation. We evaluated species diversity within Jania using the most comprehensive sampling to date, spanning a broad geographic range with a focus on the Mediterranean and Caribbean regions. Our data set comprised 186 specimens from the National Herbarium of the Muséum national d'Histoire naturelle (PC), including four type specimens with the basionyms Jania micrarthrodia, Corallina polydactyla, Corallina mauritiana, and Jania digitata. We also incorporated publicly available sequences from GenBank and Barcode of Life Data System (BOLD) to delimit species and infer their phylogenetic relationships using the psbA and COI genes. Through an integrative taxonomic approach, combining morpho-anatomical traits, molecular systematics, and biogeography, we delineated 39 putative species-28% fewer than the currently accepted number. Most of the putative species had a restricted distribution, whereas five were widely distributed. We determined seven species from the European Atlantic and Mediterranean seas and six from the Caribbean. Furthermore, we demonstrated that intergenicular morphometry is an unreliable trait for species identification, highlighting the morphological plasticity of Jania. Many putative species remained unidentified (67%), while some of those putative species included specimens with different identifications. Additional sequences of type specimens would be crucial for further resolving taxonomy and bridging the gap between type-bearing name and putative species delineated based on molecular data.
Seasonal succession and niche differentiation in Skeletonema species driven by temperature and salinity in inner Tokyo Bay.
Katano T, Suematsu T, Tanaka A … +2 more , Yasui-Tamura S, Hashihama F
J Phycol · 2026 Jun · PMID 42029180 · Full text
The genus Skeletonema is a dominant diatom in coastal waters worldwide, frequently causing blooms, and it includes several cryptic species. To elucidate the occurrence patterns and niche differentiation among Skeletonema...
The genus Skeletonema is a dominant diatom in coastal waters worldwide, frequently causing blooms, and it includes several cryptic species. To elucidate the occurrence patterns and niche differentiation among Skeletonema species in Tokyo Bay, Japan, sampling was conducted between June 2021 and February 2023. Species composition and abundance were determined using species-specific quantitative polymerase chain reaction (qPCR) and were analyzed using an environmental framework in temperature, salinity, and nutrient concentrations. Niche characteristics were determined using outlying mean index (OMI) analysis, focusing on five frequently detected species: S. ardens, S. marinoi-dohrnii complex, S. menzelii, S. potamos, and S. japonicum. Seasonal succession was evident, wherein S. japonicum predominated in winter, followed by the S. marinoi-dohrnii complex in spring and S. menzelii, S. ardens, and S. potamos in summer. Principal component analysis indicated that S. japonicum was associated with low temperature and high salinity, whereas other frequently detected species were positively correlated with temperature. The OMI analysis revealed that niche breadth differed among species, with S. potamos, S. marinoi-dohrnii complex, and S. menzelii showing a wide niche breadth and S. ardens and S. japonicum being specialists. Marginality was highest for S. potamos, indicating an association with low salinity, but it was lowest for S. japonicum due to a high frequency of high-salinity conditions. This study demonstrated that (1) seasonal succession in the bay is primarily structured by associations with temperature and salinity but (2) niche partitioning is not always clear. When the environment was highly disturbed in the summer rainy season, more than two Skeletonema species frequently co-occurred, suggesting potential competition for nutrients.
A comprehensive review of Gracilaria vermiculophylla invasion along the east coast of the United States-Current knowledge and future directions.
Nelson LM, McCoy SJ
J Phycol · 2026 Jun · PMID 42029174 · Publisher ↗
Gracilaria vermiculophylla, a red macroalga native to the Northwest Pacific, is now widespread in coastal estuarine ecosystems along the East Coast of the United States. Its broad environmental tolerance, high capacity f...
Gracilaria vermiculophylla, a red macroalga native to the Northwest Pacific, is now widespread in coastal estuarine ecosystems along the East Coast of the United States. Its broad environmental tolerance, high capacity for asexual reproduction via fragmentation, and ability to alter habitat structure have allowed it to persist and thrive, often outcompeting native macrophytes. This review synthesizes 48 studies on G. vermiculophylla from the East Coast of the United States, categorizing them into nine research areas: (1) Habitat Formation and Alteration; (2) Trophic Dynamics and Grazer Interactions; (3) Impacts on Nutrient Cycling and Biogeochemical Processes; (4) Microbial and Microalgal Interactions; (5) Responses to Climate Change; (6) Population Genetics; (7) Chemical Ecology; (8) Economic Impacts; and (9) Restoration and Management Implications. Although ecological and physiological studies dominate the literature, applied research on management, climate change impacts, and socio-economic outcomes remains limited. Addressing these knowledge gaps will require interdisciplinary approaches that link ecological, social, and economic dimensions to better develop effective management strategies. Effective management of G. vermiculophylla on the U.S. East Coast will require adaptive, context-dependent strategies that account for local habitat conditions, reproductive mode, and trade-offs between localized functions and the loss of native ecosystem services.
Revealing novelty from the southwestern Atlantic, Yemanjia gen. nov. and Olokunococcus gen. nov. from the coral cyanobiome of the Abrolhos Bank.
Aiube YRA, Moreira APB, Caires TA … +3 more , Tenório MMB, de Moura RL, Salomon PS
J Phycol · 2026 Apr · PMID 42021627 · Full text
Cyanobacteria comprise over 6000 species and inhabit diverse environments, including marine invertebrates such as sponges and corals. High-throughput sequencing has indicated an abundance of Cyanobacteria communities in...
Cyanobacteria comprise over 6000 species and inhabit diverse environments, including marine invertebrates such as sponges and corals. High-throughput sequencing has indicated an abundance of Cyanobacteria communities in these hosts, yet taxonomic resolution has remained low below the phylum level. Most cultured Cyanobacteria from corals have been isolated from black band disease lesions. However, many other associated taxa remain unidentified, such as the Cyanobacteria detected with microscopy and isotopic studies near coral symbiosomes. Recently, a polyphasic approach revealed six new genera from sponges. Following a similar strategy-integrating molecular phylogeny, morphology, ecology, and chemotaxonomy-we describe two novel genera and three new species of Cyanobacteria from reef-building corals of the Abrolhos Banks (southwestern Atlantic). Two filamentous strains were assigned to the new genus Yemanjia (Cymatolegaceae), closely related to the genus Rhodoploca. A third coccoid strain was assigned to the new genus Olokunococcus (Aegeococcaceae), phylogenetically related to Aegeococcus. All isolates presented phycoerythrins. The closest formally described relatives of these new taxa are all sponge-associated, suggesting an evolutionary and ecological link between host and Cyanobacterial lineage. By providing formal taxonomic anchors for coral-associated Cyanobacteria, our results expand the current knowledge of the coral cyanobiome and facilitate the interpretation of existing and future coral microbiome datasets.
The interaction between PII and NAGK regulates arginine biosynthesis in the green microalga Haematococcus pluvialis.
Ma R, Chen Z, Liu J … +10 more , Meng X, Tao X, Chen Y, Zhang C, Wang L, Lu K, Li X, Song K, Chen J, Xie Y
J Phycol · 2026 Jun · PMID 41999177 · Publisher ↗
PII protein is widely acknowledged to regulate intracellular nitrogen and carbon metabolism by interacting with several crucial proteins. N-acetyl-L-glutamate kinase (NAGK), a rate-limiting enzyme for arginine biosynthes...
PII protein is widely acknowledged to regulate intracellular nitrogen and carbon metabolism by interacting with several crucial proteins. N-acetyl-L-glutamate kinase (NAGK), a rate-limiting enzyme for arginine biosynthesis, is regarded as a potential target of PII protein. Nevertheless, the regulatory function remains ambiguous in green algae and has not been investigated in Haematococcus pluvialis. In this study, the NAGK enzyme and PII protein of H. pluvialis (designated as HpNAGK and HpPII, respectively) and their interaction relationships were characterized. The results indicated that HpNAGK showed high similarity with the same enzyme in the green algae. A subcellular localization assay indicated that both HpPII and HpNAGK were located in the chloroplasts. Yeast two-hybrid, pull-down, and bimolecular fluorescence complementation assays distinctly verified the interaction between HpPII and HpNAGK, which occurs in the chloroplasts. The structure of the HpPII-HpNAGK complex was predicted through docking analysis. Moreover, the HpNAGK activity was significantly enhanced by HpPII in the presence of glutamine in vitro. Under nitrogen starvation, HpNAGK activity declined in vivo, concomitant with a reduction in arginine accumulation. The regulatory function of HpPII on HpNAGK activity aligned with that in Chlamydomonas reinhardtii but differed from that in Dunaliella salina, suggesting species specificity among green algae. These findings provide insights into the regulatory function of PII protein in green algae and help to unveil the response mechanisms of H. pluvialis to different nitrogen statuses.
A unique sessile loricate euglenid, Lepocinclis loricata sp. nov. (Euglenophyta, Phacaceae), from South Africa: Evolutionary implications.
Zakryś B, Janse van Vuuren S, Kluczek A … +1 more , Łukomska-Kowalczyk M
J Phycol · 2026 Jun · PMID 41983647 · Full text
In this paper, we describe Lepocinclis loricata sp. nov. (Phacaceae), a sessile loricate euglenid that differs from all known loricate taxa by its unique combination of the presence of a lorica, monad morphology, sessile...
In this paper, we describe Lepocinclis loricata sp. nov. (Phacaceae), a sessile loricate euglenid that differs from all known loricate taxa by its unique combination of the presence of a lorica, monad morphology, sessile habit, and phylogenetic position within the Phacaceae. Populations of this species inhabit two turbid, silt-rich waterbodies, namely an artificial impoundment in the Western Cape Province and a natural, small river in the Free State Province, South Africa. The cylindrical, transparent loricae of L. loricata sp. nov. are attached to fine clay and silt particles suspended in the water column. Each lorica encloses a rigid, spindle-shaped monad containing numerous chloroplasts without pyrenoids and two large, rod-like paramylon grains. Phylogenetic analyses place L. loricata sp. nov. within the Lepocinclis clade, representing a loricate euglenid identified in the family Phacaceae. This discovery provides new insight into the diversification and adaptive evolution of photosynthetic euglenids and the independent emergence of sessility within the group.
Photoacclimation of cryptophytes and diatoms to light variability in the Western Antarctic Peninsula.
Ferreira A, Costa RR, Jesus B … +6 more , Brito AC, Silveira SB, Brotas V, Guerreiro CV, Secchi ER, Mendes CRB
J Phycol · 2026 Apr · PMID 41954079 · Full text
Meltwater stratification during austral summer along the rapidly warming Western Antarctic Peninsula (WAP) exposes coastal phytoplankton to sudden light shifts. Such variability is thought to modulate phytoplankton dynam...
Meltwater stratification during austral summer along the rapidly warming Western Antarctic Peninsula (WAP) exposes coastal phytoplankton to sudden light shifts. Such variability is thought to modulate phytoplankton dynamics, yet the photoacclimation capacity of Antarctic phytoplankton, especially cryptophytes, remains unclear. We grew a pennate diatom (Fragilariopsis cylindrus), a centric diatom (Porosira glacialis), and a cryptophyte (Geminigera cryophila) in microcosms subjected to low (30 μmol photons · m · s), high (450 μmol photons · m · s), and very low (6 μmol photons · m · s) light over 24 days at 3°C, while monitoring cell growth, pigments, photo system II (PSII) quantum yield, and non-photochemical quenching (NPQ). All taxa maintained positive growth (0.12-0.25 · d) and rapidly adjusted pigment ratios after light shifts, demonstrating efficient photoacclimation. The small pennate diatom reached 10-fold higher cell densities than the centric diatom, although the latter accumulated more chlorophyll per cell and consumed twice as much inorganic nitrogen. Geminigera cryophila exhibited the most flexible short-term NPQ response, dissipating over 60% of excess energy during high light pulses, yet this flexibility did not translate into any apparent advantage in growth over both diatoms during the period of the experiment. Field data showed cryptophyte dominance in shallower, more stratified waters, whereas diatoms prevailed in more mixed waters. Our results show that all three species can acclimate to Antarctica's complex light regime over days to weeks, yet cryptophytes may have a competitive advantage under sustained high light at shorter timescales. As warming and glacial melting continue, potentially favoring smaller cells over large bloom-forming diatoms, it is crucial to understand how it will impact carbon export and trophic transfer.
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