An appraisal of Ulva (Ulvophyceae, Chlorophyta) taxonomy

Tran, Lan-Anh T.; Vieira, Christophe; Steinhagen, Sophie; Maggs, Christine A.; Hiraoka, Masanori; Shimada, Shoichi; Nguyen, Tu Van; Clerck, Olivier De; Leliaert, Frédérik

doi:10.1007/s10811-022-02815-x

Cited by 18 publications

(20 citation statements)

References 87 publications

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“…It became obvious that several species, species-complexes, and singletons could not be identified to species level, due to the absence of reference material, whereas other clades contained sequences with name applications of different species concepts and therefor reflected polyphyletic species groups (Steinhagen et al 2019a(Steinhagen et al , 2022c. Such difficulties of name applications have been recently discussed for several of the most commonly applied molecular markers that are used in Ulva identification and delimitation (Tran et al 2022). One large problem during molecular identification is the inconsistency of species name applications to sequences uploaded to genetic repositories such as GenBank and the reality that often sequence names are not updated in said databases once the taxonomy or systematics of respective species have changed.…”

Section: Discussionmentioning

confidence: 99%

“…The species rich genus Ulva encompasses > 550 species names, including several described subspecies, varieties, and forms (Guiry and Guiry 2022). During the last decade, several new species have been described (Chen et al 2015;Phillips et al 2016;Krupnik et al 2018;Lagourgue et al 2022) and allegedly well-defined species concepts have been taxonomically revised (Hughey et al 2019(Hughey et al , 2022Steinhagen et al 2019a, b;Fort et al 2022;Tran et al 2022). Today, 85 species are currently regarded taxonomically valid and > 70 species are declared with an uncertain taxonomic status (Guiry and Guiry 2022).…”

Section: Introductionmentioning

confidence: 99%

“…Hayden et al 2003;Steinhagen et al 2019a, b, c). Genetic markers most suitable for species identification and delimitation within the genus Ulva are tufA, rbcL, and ITS (Kraft et al 2010;Tran et al 2022). However, a re-occurring problem of DNA barcoding studies (which widely rely on well annotated and curated genetic databases) is the absence of suitable reference sequences of vouchers of lecto-and holotypes (Tran et al 2022).…”

Section: Introductionmentioning

confidence: 99%

“…Genetic markers most suitable for species identification and delimitation within the genus Ulva are tufA, rbcL, and ITS (Kraft et al 2010;Tran et al 2022). However, a re-occurring problem of DNA barcoding studies (which widely rely on well annotated and curated genetic databases) is the absence of suitable reference sequences of vouchers of lecto-and holotypes (Tran et al 2022). Assigning species names to genetic sequences and reliably identifying organisms that have a highly cryptic diversity (such as the genus Ulva) requires access to, and genetic information of, the respective type vouchers of the species.…”

Section: Introductionmentioning

confidence: 99%

“…Under the genus Ulva, foliose forms (widely known as sea lettuces) and tubular forms (formerly allocated to the genus Enteromorpha but placed in synonymy with the genus Ulva based on genetic data) (Hayden et al 2003) are grouped together. Whereas recent efforts have been made to molecularly identify foliose type specimens (Steinhagen et al 2019a;Fort et al 2021Fort et al , 2022Hughey et al 2022;Tran et al 2022), information for tubular Ulva species is limited to recently described species (e.g. Chen et al 2015;Lagourgue et al 2022).…”

Section: Introductionmentioning

confidence: 99%

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The unheeded existence of the tubular greens: molecular analyses reveal the distribution of a new Ulva species (Ulvophyceae, Chlorophyta), Ulva capillata sp. nov. in the Atlantic-Baltic Sea transect

2022

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The ubiquitous and species rich genus Ulva comprises entities of green macroalgae with variable morphologies. Ulva species are important from ecological and economic perspectives, but their identification is often problematic. Current knowledge on Ulva diversity has focused mainly on foliose individuals of temperate regions, but genetic and morphological data on tubular species are often insufficient and the species richness is ambiguous due to the lack of molecularly identified type vouchers. Together with a previous study, our study demonstrates that due to the crypticity of tubular entities of the genus Ulva present in the Atlantic-Baltic Sea transect, certain species remained undetected until recently whereas molecular evidence of other historically identified species is missing. An entity which appears to be a relatively frequent species in the Atlantic-Baltic Sea transect and which was probably mis-identified with other species in the past is here described as Ulva capillata sp. nov.. The description is based on molecular identification using tufA and rbcL sequences, and by comparing the species´ phylogenetic relationships, distribution and range margins in the Atlantic-Baltic Sea transect, as well as on morpho-anatomical characters, and early ontogenetic development. By comparisons with closely related and potentially morphologically overlapping species concepts we were able to identify the uniqueness of U. capillata. Therefore, the description of U. capillata as a new species within the genus Ulva is supported by a combination of molecular, morphological, and ontogentic evidence which confirm their uniqueness in comparison to other species concepts.Furthermore, our results strongly emphasize the importance and necessity to molecularly investigate especially tubular historic type vouchers within the genus Ulva to facilitate a clear species identification to omit continuing with taxonomic confusion and ongoing misapplication of names of e.g. cryptic species concepts within this important green algal genus.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The unheeded existence of the tubular greens: molecular analyses reveal the distribution of a new Ulva species (Ulvophyceae, Chlorophyta), Ulva capillata sp. nov. in the Atlantic-Baltic Sea transect

2022

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The first record of a non-native seaweed from South Georgia and confirmation of its establishment in the Falkland Islands: Ulva fenestrata Postels & Ruprecht

Mrowicki

Brodie

2023

Polar Biol

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Detecting non-native species can be challenging, particularly in the case of taxa such as seaweeds, which can be difficult to distinguish based on morphology and often require molecular-assisted taxonomy for reliable identification. The sub-Antarctic island of South Georgia supports unique and important marine biodiversity, including a rich seaweed flora, but despite its isolation, its inshore ecosystems are susceptible to the introduction of potentially invasive non-native species. Here, we provide the first report of a non-native seaweed in South Georgia, Ulva fenestrata Postels & Ruprecht (Ulvophyceae, Chlorophyta), and confirm its widespread presence in the Falkland Islands via molecular-assisted taxonomy. Phylogenetic analyses of tufA and rbcL-3P genetic markers enabled the identification of a specimen collected from Grytviken, South Georgia in November 2021 as U. fenestrata. In terms of tufA sequence, this sample was identical to specimens collected from four sites spanning West and East Falkland in 2013 and 2018. This study represents the second Southern Hemisphere record of U. fenestrata, which is generally regarded as a Northern Hemisphere species. Our findings provide a foundation for monitoring this potentially invasive species in South Georgia, and for determining its likely source and mode of arrival, while emphasising the importance of robust biosecurity measures.

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Salinity as a tool for strain selection in recirculating land-based production of Ulva spp. from germlings to adults

Cardoso,

Meiβner,

Sawicki

et al. 2023

J Appl Phycol

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The genus Ulva is globally distributed and has been thoroughly studied because of its functional biochemical composition, rapid growth rates and opportunistic features, and interest in Ulva cultivation is growing worldwide. In Europe, mostly near- and on-shore flow-through cultivation systems are used and land-based recirculating aquaculture systems (RAS) using fresh water or artificial seawater have not been developed for Ulva. While RAS provides quality control and can be located inland, maintenance costs are high. Using selected strains adapted to low-salinity could reduce seawater production costs and improve the economic feasibility. Therefore, our study assessed how salinity can be used as a tool for strain selection and optimization of functional traits. Growth rates and antioxidant activity of three species (four strains) of tubular and foliose Ulva from the NE-Atlantic and Mediterranean (foliose: Ulva lacinulata – two geographical strains, tubular: Ulva linza and Ulva flexuosa) were followed for three weeks at salinities ranging from 10 to 30 PSU. The tubular strains achieved optimal growth at a lower salinity than U. lacinulata. However, growth rates of both foliose strains were higher than of tubular strains, even at sub-optimal salinity. Therefore, U. lacinulata is a good candidate for RAS with artificial seawater, and the cost of salt can be reduced by up to 33.3% (20 PSU) without significantly reducing the growth rate of U. lacinulata. Higher antioxidant activity was achieved by reducing the salinity to 10 PSU for 10 days, suggesting that the functional traits of cultivated Ulva lacinulata can be optimized prior to harvest.

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An appraisal of Ulva (Ulvophyceae, Chlorophyta) taxonomy

Cited by 18 publications

References 87 publications

The unheeded existence of the tubular greens: molecular analyses reveal the distribution of a new Ulva species (Ulvophyceae, Chlorophyta), Ulva capillata sp. nov. in the Atlantic-Baltic Sea transect

The unheeded existence of the tubular greens: molecular analyses reveal the distribution of a new Ulva species (Ulvophyceae, Chlorophyta), Ulva capillata sp. nov. in the Atlantic-Baltic Sea transect

The first record of a non-native seaweed from South Georgia and confirmation of its establishment in the Falkland Islands: Ulva fenestrata Postels & Ruprecht

Salinity as a tool for strain selection in recirculating land-based production of Ulva spp. from germlings to adults

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