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Eugomontia sacculata. A. Branched filaments with thick crosswalls within shell of Mya arenaria Linnaeus, 1758. Slide preparation of decalcified material in KARO ® , strain IS06004-1. B. Vegetative cell with 2 pyrenoids (arrows), strain IS07004. C. Sporophyte with balloon-like middle cells, strain IS07004. D. Branched filaments within a transparent mollusc shell, strain IS06004-1. Gomontia polyrhiza cf. E. Single cell. Note the layered walls of rhizoidal branches. Slide preparation of decalcified mollusc shell. Scale bars = 10 µm (A, B), 25 µm (C, E), 50 µm (D).
Source publication
Knowledge relating to the distribution of microfilamentous green algae in marine environments in the northern North Atlantic is extended with collections from waters around Iceland in the years 1999 and 2005 to 2007. These algae were looked for and some of them identified in the field samples,while the identification of most species depended on mor...
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... nature it grew in calcified material (e.g. dead shells of molluscs and barnacles) as irregularly branched filaments of cylindrical cells, 3-7 µm in diameter and 3-6 times as long. The transverse walls were occasionally thickened ( Fig. 2A). Rounded to sacshaped sporangia were observed and measured 25-60 µm across. Table 1. eschweizerbart_xxx Table 1. Samplings stations for Ulvellaceae and other microfilamentous green seaweeds at the coast of Iceland with coordinates and sampling ...
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... culture, plants formed similar irregularly branched filaments. The cylindrical cells were 10-17 µm in width and 4-25 µm long. Each cell contained a parietal chloroplast with 1 (-2) pyrenoids (Fig. 2B). Thickenings of transverse walls were occasionally observed. Balloon-like swollen cells, considered to be sporangia occurred in the middle part of plants and measured up to 70 µm across (Fig. 2C). The cultured plants also grew into transparent mollusc shells (Fig. 2D). The studied plants were similar to plants from Helgoland cultured ...
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... branched filaments. The cylindrical cells were 10-17 µm in width and 4-25 µm long. Each cell contained a parietal chloroplast with 1 (-2) pyrenoids (Fig. 2B). Thickenings of transverse walls were occasionally observed. Balloon-like swollen cells, considered to be sporangia occurred in the middle part of plants and measured up to 70 µm across (Fig. 2C). The cultured plants also grew into transparent mollusc shells (Fig. 2D). The studied plants were similar to plants from Helgoland cultured by Kornmann ...
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... 4-25 µm long. Each cell contained a parietal chloroplast with 1 (-2) pyrenoids (Fig. 2B). Thickenings of transverse walls were occasionally observed. Balloon-like swollen cells, considered to be sporangia occurred in the middle part of plants and measured up to 70 µm across (Fig. 2C). The cultured plants also grew into transparent mollusc shells (Fig. 2D). The studied plants were similar to plants from Helgoland cultured by Kornmann ...
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... with multiple rhizoids were commonly found in calcareous substrata (Fig. 2E). In a few localities these Gomontia-phases were found in association with plants resembling the gametophyte of Gomontia polyrhiza as illustrated by Kornmann (1959). We therefore refer our finds to this species although similar Gomontia-phases are known from other species, such as Collinsiella cava (Yendo) Printz and Monostroma spp. ...
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... at the following sites (cf. Fig. 1 Plants in culture formed tufts of isodiametric filaments with cylindrical cells, 7-10 µm in width and 1-3 times as long (Fig. 20A). Alternate branches were often at 70 to 90° angle to the main axes. When attached to a solid substratum, a pseudoparenchymatous basal layer was formed with cells 1-1.5 times as long as wide (Fig. 20D). Multicellular hairs occurred both on upright branches and from the basal layer ( Figs 20B, 20C). The hairs tapered gradually from the ...
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... following sites (cf. Fig. 1 Plants in culture formed tufts of isodiametric filaments with cylindrical cells, 7-10 µm in width and 1-3 times as long (Fig. 20A). Alternate branches were often at 70 to 90° angle to the main axes. When attached to a solid substratum, a pseudoparenchymatous basal layer was formed with cells 1-1.5 times as long as wide (Fig. 20D). Multicellular hairs occurred both on upright branches and from the basal layer ( Figs 20B, 20C). The hairs tapered gradually from the slightly swollen base to the apex measuring 4-5 µm in diameter just above the base and 2.5 µm at the apex with cells 10-15 times as long as wide. Each vegetative cell contained a parietal chloroplast ...
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... attached to a solid substratum, a pseudoparenchymatous basal layer was formed with cells 1-1.5 times as long as wide (Fig. 20D). Multicellular hairs occurred both on upright branches and from the basal layer ( Figs 20B, 20C). The hairs tapered gradually from the slightly swollen base to the apex measuring 4-5 µm in diameter just above the base and 2.5 µm at the apex with cells 10-15 times as long as wide. ...
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... hairs occurred both on upright branches and from the basal layer ( Figs 20B, 20C). The hairs tapered gradually from the slightly swollen base to the apex measuring 4-5 µm in diameter just above the base and 2.5 µm at the apex with cells 10-15 times as long as wide. Each vegetative cell contained a parietal chloroplast with a single pyrenoid (Fig. 20D). Ovoid sporangia, developed from the vegetative cells, they were intercalary or lateral (Figs 20E, ...
Citations
... (Verbruggen et al. 2009;Leliaert et al. 2011;Gunnarsson & Nielsen 2016;Bartolo et al. 2022). Despite being common and widespread in marine benthic environments, they are poorly studied and are often overlooked in biodiversity surveys. ...
... Morphologically, Ulvella includes microscopic filaments forming disc-shaped thallus, generally with a clearly defined border, or filaments remaining discrete, not aggregating into a central pseudoparenchyma. Species can be distinguished by cells dimensions, number of pyrenoids, presence and position of hyaline Acrochaete-type hairs, shape and size of sporangia, and spore germination pattern (Nielsen et al. 2013(Nielsen et al. , 2014Gunnarsson and Nielsen 2016). Ulvella currently includes species that have been previously assigned to the genera Acrochaete N. Pringsheim, E n d o p h y t o n N . ...
... It is likely that U. endozoica is a common tropical species, but its microscopic size and unusual habitat make it an easily overlooked species. Gunnarsson and Nielsen (2016) studied the microfilamentous green algae from Iceland and reported that some species, including Ulvella spp., were detected only after culture studies. In our study, combined incubation of field-collected substrata with DNA barcoding provided an accurate identification of U. endozoica and insights about its ecology and distribution. ...
... Since this gorgonian genus does not occur in Brazil (Cordeiro et al. 2020), the new record of U. endozoica is somewhat surprising and evidences that U. endozoica is not host specific, but it can also grow on red algae. Most Ulvella species usually does not exhibit host specificity (Gunnarsson and Nielsen 2016 (Nielsen et al. 2013), whereas U. leptochaete can grow as endophyte in Champia Desvaux and as epiphyte in Chaetomorpha Kützing (O'Kelly et al. 2004). Other common microfilamentous green alga, Phaeophila dendroides (P. ...
The small size (< 5 mm) of marine microfilamentous green algae makes it difficult to identify based on field collections, remaining largely unnoticed. To catalogue the diversity of these diminutive marine algae, a combination of culture-based taxonomic studies and DNA barcoding has proven to be a successful approach. During subtidal surveys in the northeastern Brazil, microfilamentous green algae were isolated as epiphytes on red algae cultured in laboratory. In this work, we used thallus ontogeny and plastid tufA gene sequences to elucidate the taxonomic identity of these isolates. Molecular and morphological evidence revealed that Brazilian specimens correspond to Ulvella endozoica, a poorly known species thought to be endemic to Florida, its type locality. Since U. endozoica was not found in gorgonian corals, as in the original description, this species does not follow a host specificity pattern, growing in more diverse substrata than previously thought. The origin of U. endozoica in Brazil remains undetermined, and we concluded that it is a cryptogenic species. Limited sampling, troublesome taxonomy, and difficulty in finding Ulvella species make them overlooked in Western Atlantic, resulting in taxonomic and biogeographic gaps. Our results expand southward the known distribution range of U. endozoica, demonstrating that an integrative barcode and laboratory culture-based approach is critical to uncover these inconspicuous algae.
... Benthic macroalgae can grow attached to rocks (epilithic), in sand or mud (epipelic) on the surfaces of animals (epizoic), inside animals and plants (endophytic), on the surfaces of other algae or plants (epiphytic) such as seagrass leaves, and mangrove roots and pneumatophores (Borowitzka et al., 2006;Hurd et al., 2014;Hogarth, 2015;Gunnarsson and Nielsen, 2016;Neto and Sousa, 2018). Epiphytic species are characterized by being generally facultative (Diez et al., 2013) and their life style has been interpreted as a direct consequence of substrate limitation of benthic organisms (Harder, 2008). ...
The taxonomic composition and diversity of host and epiphytic macroalgal species are important elements in the structure and diversity of marine ecosystems. In this paper, the current state of knowledge and diversity of epiphytic macroalgae and their hosts in Cuba are determined. A systematic review of the scientific literature published from 1900 to 2018 was carried out. The current status of knowledge, main trends, composition, species richness and diversity in the different habitats and areas of the shelf were determined according to the records. We identified 37 publications dealing with the composition and diversity of epiphytism in macroalgae. The studies are grouped into two periods: the first one begins in 1955 addressing only the taxonomy; and the second one begins after 1989 focused on ecology. The flora of Cuban epiphytic macroalgae and hosts is 131 and 130 species, respectively. Habitats with greater structural complexity possess a greater richness of epiphytes, taxonomic structure and alpha diversity. The distribution patterns of epiphytic richness are influenced by both the sampling bias and the limited approach to epiphytism in phycological studies. The average taxonomic distinction (Δ+) expected for the habitats and zones of the Cuban shelf is 82, with 95% confidence limits between 77.21 and 100. Differences in species richness are the component that contributes most significantly to increasing the beta diversity of the epiphytic macroalgae due to the high environmental heterogeneity.
Brown algae (Phaeophyceae) are habitat‐forming species in coastal ecosystems and include kelp forests and seaweed beds that support a wide diversity of marine life. Host‐associated microbial communities are an integral part of phaeophyte biology, and whereas the bacterial microbial partners have received considerable attention, the microbial eukaryotes associated with brown algae have hardly been studied. Here, we used broadly targeted “pan‐eukaryotic” primers (metabarcoding) to investigate brown algal‐associated eukaryotes (the eukaryome). Using this approach, we aimed to investigate the eukaryome of seven large brown algae that are important and common species in coastal ecosystems. We also aimed to assess whether these macroalgae harbor novel eukaryotic diversity and to ascribe putative functional roles to the host‐associated eukaryome based on taxonomic affiliation and phylogenetic placement. We detected a significant diversity of microeukaryotic and algal lineages associated with the brown algal species investigated. The operational taxonomic units (OTUs) were taxonomically assigned to 10 of the eukaryotic major supergroups, including taxonomic groups known to be associated with seaweeds as epibionts, endobionts, parasites, and commensals. Additionally, we revealed previously unrecorded sequence types, including novel phaeophyte OTUs, particularly in the Fucus spp. samples, that may represent fucoid genomic variants, sequencing artifacts, or undescribed epi‐/endophytes. Our results provide baseline data and technical insights that will be useful for more comprehensive seaweed eukaryome studies investigating the evidently lineage‐rich and functionally diverse symbionts of brown algae.
In the last decades, there has been an increase of macroalgal species appearing in new geographic regions. These new records are being linked to non-intentional global human-mediated transport. In Iceland three macroalgae species have been reported as non-indigenous. We updated the number of non-indigenous macroalgae to 8 species, 4 of which are potentially invasive. Pathways and vectors of each macroalga introduction are identified. The red algae group does not stand out in Iceland as in the nearest territories. The number of non-indigenous macroalgae will probably increase in the near future due to (1) secondary spread of species via shipping vector; (2) the growing trend of aquaculture in Norway, where surface currents will probably allow the spread of algae to Iceland; and (3) the increase of studies focusing on this matter. To address the problem, we suggest that local monitoring and mitigation programs should be implemented across Iceland, and that regulatory and preventive measures for the maritime traffic vector should be developed.
Background
Brown algae (Phaeophyceae) are essential species in coastal ecosystems where they form kelp forests and seaweed beds that support a wide diversity of marine life. Host- associated microbial communities are an integral part of phaeophyte biology. The bacterial microbial partners of phaeophytes have received far more attention than microbial eukaryotes. The pre-requisite to understand the ecology of phaeophytes and their host-associated microbes is to know their diversity, distribution and community dynamics. To our knowledge, this is the first study to investigate phaeophyte-associated eukaryotes (the eukaryome) using broadly targeting ‘pan-eukaryotic’ primers and high throughput sequencing (HTS). Using this approach, we aimed to unveil the eukaryome of seven large common phaeophyte species. We also aimed to assess whether these macroalgae harbour novel eukaryotic diversity and to ascribe putative functional roles to the host-associated eukaryome, based on taxonomic affiliation and phylogenetic placement.
Results
Our sequence dataset was dominated by phaeophyte reads, from the host species and potential symbionts. We also detected a broad taxonomic diversity of eukaryotes in the phaeophyte holobiomes, with OTUs taxonomically assigned to ten of the eukaryotic major Kingdoms or supergroups. A total of 265 microeukaryotic and epi-endophytic operational taxonomic units (OTUs) were defined, using 97% similarity cut off during clustering, and were dominated by OTUs assigned to Stramenopiles, Alveolata and Fungi. C Almost one third of the OTUs we detected have not been found in previous molecular environmental surveys, and represented potential novel eukaryotic diversity.
This potential novel diversity was particularly diverse in phylogenetic groups comprising heterotrophic and parasitic organisms, such as labyrinthulids and Oomycetes, Cercozoa, and Amoebozoa.
Conclusions
Our findings provide important baseline data for future studies of seaweed-associated microorganisms, and demonstrate that microeukaryotes and epi-endophytic eukaryotes should be considered as an integral part of phaeophyte holobionts. The potential novel eukaryotic diversity we found and the fact that the vast majority of macroalgae in marine habitats remain unexplored, demonstrates that brown algae and other seaweeds are potentially rich sources for a large and hidden diversity of novel microeukaryotes and epi-endophytes.
