Christophe Vieira

Jeju National University | jejunu · Department of Biology

Allelopathy has been recently suggested as a mechanism by which macroalgae may outcompete corals in damaged reefs. Members of the brown algal genus Lobophora are commonly observed in close contact with scleractinian corals and have been considered responsible for negative effects of macroalgae to scleractinian corals. Recent field assays have sugge...

The tropical to warm-temperate marine brown macroalgal genus Lobophora (Dictyotales, Phaeophyceae) recently drew attention because of its striking regional diversity. In this study we reassess Lobophora global species diversity, and species distributions, and explore how historical factors have shaped current diversity patterns. We applied a series...

In studies on coral–algal interactions, particular attention has been devoted to corals. Focusing on the macroalgal genus Lobophora (Dictyotales, Phaeophyceae), common on coral reefs and extensively studied in coral–algal interactions, this review aims to summarize what is known and highlight the conditions necessary for Lobophora blooms, the contr...

Aim: Historical processes that shaped current diversity patterns of seaweeds remain poorly understood. Using Dictyotales, a globally distributed order of brown seaweeds as a model, we test if historical biogeographical and diversification patterns are comparable across clades. Dictyotales contain some 22 genera, three of which, Dictyota, Lobophora...

Corals and seaweeds fulfill important ecological functions in tropical reef ecosystems. In an environment where space is a limiting factor, competition between both players is critical in defining the structure of coral reef communities. Dramatic shifts from coral- to macroalgal-dominated reefs have highlighted competitive interactions between macr...

Cyanobacteria, known for their remarkable adaptability, are a diverse group of oxygenic photoautotrophic organisms found in various habitats worldwide. While their presence in aquatic ecosystems has been extensively studied, research on terrestrial and aerophytic cyanobacteria remains relatively limited, particularly concerning their taxonomic dive...

The systematics and biogeography of the brown seaweed genus Lobophora (Dictyotales) are increasingly being investigated globally using DNA data coupled with morphology. In Thailand, DNA-assisted Lobophora diversity assessment has been limited to the east coast. The present study employed molecular ( cox 3, psb A, and rbc L gene sequences) and morph...

Editorial on the Research Topic Seaweed phylogenetics, evolution, and biogeography

The Hildenbrandiales, a typically saxicolous red algal order, is an early diverging florideophycean group with global significance in marine and freshwater ecosystems across diverse temperature zones. To comprehensively elucidate the diversity, phylogeny, biogeography, and evolution of this order, we conducted a thorough re- examination employing m...

Caulerpa J.V. Lamouroux is a genus of green macroalgae belonging to the family Caulerpaceae in the order Bryopsidales. The genus comprises 104 currently accepted species, of which 51 have been recorded from Pacific Islands. Among these islands, French Polynesia is found in the middle of the South Pacific Ocean and includes five archipelagos (i.e.,...

Brown seaweeds are keystone species of coastal ecosystems, often forming extensive underwater forests, that are under considerable threat from climate change. Despite their ecological and evolutionary importance, this phylogenetic group, which is very distantly related to animals and land plants, is still poorly characterised at the genome level. H...

This study revisited the taxonomy and diversity of brown macroalgae within the Scytosiphonaceae family in French Polynesia, which had previously been recognized as encompassing only six species. Using the chloroplast and mitochondrial genes rbc L, psb A, and cox 3 as molecular markers in conjunction with morpho‐anatomical observations, we unveiled...

We reevaluated species diversity of the brown alga Lobophora in Vietnam’s Con Co Marine Protected Area (MPA), where only one species had previously been reported. Integrating morphological, ecological, and molecular analyses, we redefined the genus diversity, identifying nine species including two new ones: L. asiatica , L. boussoleae , L. lamourou...

Located in the heart of the South Pacific Ocean, the French Polynesian islands represent a remarkable setting for biological colonization and diversification, because of their isolation. Our knowledge of this region’s biodiversity is nevertheless still incomplete for many groups of organisms. In the late 1990s and 2000s, a series of publications pr...

The analysis of biological and ecological traits has a long history in evolutionary and ecological research. However, trait data are often scattered and standardised terminology that transcends taxonomic and biogeographical context are generally missing. As part of the development of a global trait database of marine species, we collated trait info...

Simple Summary: The present review provides (1) an updated checklist of the Vietnamese marine flora, (2) a review of molecular-assisted alpha taxonomic efforts, (3) an analysis of marine floral biodiversity spatial distribution nationally and regionally (South China Sea), (4) a discussion on the impact of anthropogenic and environmental stressors o...

The brown macroalgal genus Lobophora plays important ecological roles in many marine ecosystems. This group has received much attention over the past decade, and a considerable number of new species have been identified globally. However, our knowledge of the genus diversity and ecology along south-east Asian coasts are still limited. Given the gro...

Species diversity of Ulva in Vietnam was investigated using three commonly used genetic markers, the nuclear encoded rDNA ITS region and the plastid encoded rbcL and tufA genes. Single locus species delimitation methods, complemented with morphological and ecological information resulted in the delimitation of 19 species. This diversity is largely...

The analysis of biological and ecological traits has a long history in evolutionary and ecological research. However, trait data are often scattered and standardised terminology that transcends taxonomic and biogeographical context are generally missing. As part of the development of a global trait database of marine species, we collated trait info...

Coastal refugia during the Last Glacial Maximum (~21 ka) have been hypothesized at high latitudes in the North Atlantic, suggesting marine populations persisted through cycles of glaciation and are potentially adapted to local environments. Here, whole‐genome sequencing was used to test whether North Atlantic marine coastal populations of the kelp...

The green seaweed Ulva is important from ecological and economic perspectives, but the identification of species is often problematic. Here we assessed and discussed different perspectives to establish a stable taxonomic framework for Ulva, which will benefit both ecological and applied research. We evaluated (1) the performance of commonly used DN...

We re-evaluated the diversity of Lobophora using an integrative taxonomic approach based on a broad sampling across French Polynesian archipelagos. Our results show that French Polynesia supports at least 37 Lobophora species of which ~57% (21) are endemic. This level of endemicity is comparable to that presently known in the Caribbean and the west...

The calcified encrusting brown algal genus Newhousia is reported from three new archipelagos in the Pacific: (1) Society Islands, French Polynesia; (2) Guam, Mariana Islands; and (3) Vanuatu. Newhousia presents a simple morphology consisting of small, rounded, two-layered calcified blades with limited interspecific variability in morphological feat...

In the study of the evolution of biological complexity, a reliable phylogenetic framework is needed. Many attempts have been made to resolve phylogenetic relationships between higher groups (i.e., interordinal) of brown algae (Phaeophyceae) based on molecular evidence, but most of these relationships remain unclear. Analyses based on small multi-ge...

The brown algal genus Lobophora (Dictyotales, Phaeophyceae) is an important ecological component of tropical marine systems. Although still scantily sampled, 35 species of Lobophora were discovered previously from the western Indian Ocean. This study updates previous diversity estimates by incorporating recent collections from Madagascar, Mozambiqu...

Considered as holobiont systems, marine macroalgae and their microbiota constitute functional units displaying a large diversity of interactions. Main factors driving the assembly of epiphytic microbiota, and subsequent interactions with the host, are often associated to environmental differences but also to host taxonomy displaying specific chemic...

The genomic era continues to revolutionize our understanding about the evolution of biodiversity. In phycology, emphasis remains on assembling nuclear and organellar genomes, leaving the full potential of genomic datasets to answer long standing questions about the evolution of biodiversity largely unexplored. Here, we used Whole Genome Sequencing...

Freshwater specimens of an encrusting red alga were collected from rivers in Tahiti, French Polynesia. Observed morphological features corresponded to those of the genus Hildenbrandia (Hildenbrandiales, Florideophyceae), confirmed by genetic data. rbcL and 18S rDNA sequences of the Tahitian specimens were 4.95-5.15 % and 0.94 %, respectively, ident...

A floristic survey of the marine algal biodiversity of Antsiranana Bay, northern Madagascar, was conducted during November 2018. This represents the first inventory encompassing the three major macroalgal classes (Phaeophyceae, Florideophyceae and Ulvophyceae) for the little-known Malagasy marine flora. Combining morphological and DNA-based approac...

The genetic diversity of freshwater Hildenbrandia species (Florideophyceae, Hildenbrandiales) from Japan was reassessed based on specimens collected from Kagoshima (Kyushu), Hyogo and Kanagawa Prefectures (Honshu), using rbcL and 18S rDNA sequences. Phylogenetic results suggested the occurrence of only one species of freshwater Hildenbrandia in Jap...

Stress-induced reductions in the world's coral populations are, in many locations, giving way to an increase in macroalgae, for example the common brown macroalgal genus Lobophora. While many ecological studies report a single species (Lobo-phora variegata), DNA-based identification methods have recently shown that Lobophora is a highly diverse gen...

Among dinoflagellates responsible for benthic harmful algal blooms, the genus Ostreopsis primarily described from tropical areas has been increasingly reported from subtropical and temperate areas worldwide. Several species of this toxigenic genus produce analogs of palytoxin, thus representing a major threat to human and environmental health. The...

The brown algae (Phaeophyceae) are a group of multicellular heterokonts that are ubiquitous in today’s oceans. Large brown algae from multiple orders are the foundation to temperate coastal ecosystems globally, a role that extends into arctic and tropical regions, providing services indirectly through increased coastal productivity and habitat prov...

The subclass Corallinophycidae is the only group of red algae characterized by the presence of calcite crystals in their cell walls. Except for the Rhodogorgonales, the remaining orders - collectively called corallines - are diverse and widely distributed, having calcified cell walls and highly variable morphology. Corallines constitute the group w...

The coral reefs of French Polynesia (FP) have experienced repeated macroalgal blooms over the last decades. These events have prompted intense efforts in fundamental and applied research on macroalgae in this ecoregion, especially regarding species of the order Fucales (Turbinaria ornata and Sargassum pacificum). Recently, however, these proliferat...

Distributed in tropical and warm‐temperate waters worldwide, Lobophora species are found across the Greater Caribbean (i.e., Caribbean sensu stricto, Gulf of Mexico, Florida, the Bahamas, and Bermuda). We presently discuss the diversity, ecology, biogeography and evolution of the Greater Caribbean Lobophora species based on previous studies and an...

The brown alga Lobophora (Dictyotales, Phaeophyceae) is an important macroalga in the North-eastern Atlantic archipelagos (i.e., Macaronesia). Notably in the Canaries it can dominate benthic assemblages. While the genus has been the subject of several ecological studies in the Canaries, no study has yet been conducted to assess species-level divers...

The marine benthic cyanobacteria on coral reefs of Moorea Island (French Polynesia) show significant changes in species diversity in response to environmental impacts. To study these changes in cyanobacterial diversity, we examined pristine and degraded coral reefs by combining microscopy of morphological properties of the taxa with characterizatio...

Surveys of the seaweed flora of the Falkland Islands and of Tierra del Fuego revealed the presence of a new species of brown alga. Dictyota falklandica sp. nov. inhabits the shallow rocky infralittoral in sheltered localities and the lower intertidal in more exposed sites. Dictyota falklandica has a regular to irregular habit of dichotomously branc...

A 6-h toxicity test of cosmetic ingredients (methylparaben, 2-phenoxyethanol, sodium dodecyl sulfate, triethanolamine) was developed, based on the photosynthetic maximum quantum yield (Fv/Fm) of immobilized gametophytes of the brown macroalga Undaria pinnatifida. From calculated EC50 values, the toxicity ranking of the tested ingredients is: SDS (0...

Both mating system variation and the propensity of many seaweeds to reproduce both sexually and asexually, leave a strong imprint in the genetic structure of species. In this respect, we study the population genetic structure of Dictyota dichotoma , a common haplodiplont brown subtidal seaweed. This benthic species is widespread in the NE-Atlantic,...

Sampling in the framework of the research program called ‘La Planète Revisitée’ in Kavieng and Madang (Papua New Guinea) brought thus far unknown diversity of the brown algal genus Lobophora to the surface. DNA‐assisted alpha taxonomy allowed identifying the presence of 16 species Lobophora from these two localities, which only share four species i...

Lobophora is a common tropical to temperate genus of brown algae found in a plethora of habitats including shallow and deep‐water coral reefs, rocky shores, mangroves, seagrass beds and rhodoliths beds. Recent molecular studies have revealed that Lobophora species diversity has been severely underestimated. Current estimates of the species numbers...

The brown algal genus Lobophora is widely reported from the Mediterranean Sea. Contrary to studies in the Indo-Pacific and Caribbean regions, little attention has been given to Lobophora in the Mediterranean Sea, at least using molecular tools. To address this knowledge gap, we sampled speci- mens across the Mediterranean Sea (Spanish coast, Balear...

Supplementary material - High metabolomic variation for seaweeds in response to environmental changes: a case study of the brown algae Lobophora in coral reefs

In the marine environment, macroalgae face changing environmental conditions and some species are known for their high capacity to adapt to the new factors of their ecological niche. Some macroalgal metabolites play diverse ecological functions and belong to the adaptive traits of such species. Because algal metabolites are involved in many process...

Aim Biogeographical processes underlying Indo‐Pacific biodiversity patterns have been relatively well studied in marine shallow water invertebrates and fishes, but have been explored much less extensively in seaweeds, despite these organisms often displaying markedly different patterns. Using the marine red alga Portieria as a model, we aim to gain...

Les algues des récifs coralliens regroupent un ensemble hétérogène d’organismes tous capables de faire la photosynthèse, mais que l’histoire évolutive a fait diverger en plusieurs grandes lignées indépendantes. Bien qu’il n’ait aucune signification taxonomique, le terme « algue » est utilisé par commodité pour évoquer des végétaux marins aux formes...

Les algues des récifs coralliens regroupent un ensemble hétérogène d’organismes tous capables de faire la photosynthèse mais que l’histoire évolutive a fait diverger en plusieurs grandes lignées indépendantes. Bien qu’il n’ait aucune signification taxonomique, le terme ‘algue’ est utilisé par commodité pour évoquer des végétaux marins aux formes et...

Recent volcanic lava flows extending into the ocean represent an ideal opportunity to study the long-term successional development of marine floral assemblages on the bare new substratum. We describe the floral assemblages of nine lava flows of different ages (prehistoric to 2007) at Piton de la Fournaise (Reunion Island, Indian Ocean) based on a s...

Although Lobophora belongs to a marine algal family (Dictyotaceae) that produces a large array of secondary metabolites, it has received little attention compared to other genera, such as Dictyota, in terms of natural compounds isolation and characterization. However, metabolites produced by Lobophora species have been found to exhibit a wide array...

The existence of massive cryptic diversity in algae makes linking DNA-based lineages to existing taxa exceedingly difficult. A better integration of historical collections into modern taxonomic research is therefore highly desirable. Using the brown algal genus Lobophora as a test case, we explore the feasibility of linking taxonomic names to clade...

While reef degradation is occurring worldwide, it is not uncommon to see phase shifts from coral to macroalgal dominated reefs. Numerous studies have addressed the mechanisms by which macroalgae may outcompete corals and a few recent studies highlighted the putative role of bacteria at the interface between macroalgae and corals. Some studies sugge...

While reef degradation is occurring worldwide, it is not uncommon to see phase shifts from coral to macroalgal dominated reefs. Numerous studies have addressed the mechanisms by which macroalgae may outcompete corals and a few recent studies highlighted the putative role of bacteria at the interface between macroalgae and corals. Some studies sugge...

The calcified encrusting brown-algal genus Newhousia was collected in 2012 from two sites in Madang Lagoon, northern Papua New Guinea. This is the first report of that enigmatic genus since its original description in 2004 from Oahu in the Hawaiian Islands. Morphologies of thalli from both Papuan localities agree with the original diagnosis and the...

L'algue brune Lobophora représente une composante benthique importante au sein des récifs coralliens tropicaux, et a à attirer dès le début des années 80 l'attention des écologistes marins en proliférant de façon remarquable au détriment des coraux. Les écologistes marins ne s’accordent toujours pas pour conclure si le changement de communauté au p...

During the Atimo Vatae research cruise of 2010, the seaweed flora of the southern coast of Madagascar was extensively sampled. Here we report on the species diversity and biogeographic affinities of the brown algal order Dictyotales, which was assessed using DNA-barcoding makers. Molecular identification resulted in 23 MOTU's belonging to 9 genera....

Coral reef degradation is often associated with regime shifts from coral- to macroalgal-dominated reefs. These shifts demonstrate that under certain conditions (e.g. coral mortality, decrease in herbivory, increased nutrients supply) some macroalgae may overgrow corals. The outcome of the competition is dependent on algal aggressiveness and the cor...

The combination of global sampling with the use of molecular techniques is giving a good idea of global patterns of diversity and offers a proper background for speciation studies. Recent molecular studies substantially fueled species identification of the cosmopolitan brown algal genus Lobophora (Dictyotales, Phaeophyceae). Here we use a global sc...

The impact of petroleum contamination and of burrowing macrofauna on abundances of Marinobacter and denitrifiers was tested in marine sediment mesocoms after 3 months incubation. Quantification of this genus by qPCR with a new primer set showed that the main factor favoring Marinobacter abundance was hydrocarbon amendment followed by macrofauna pre...

Although coral reefs are facing severe challenges from a variety of natural and anthropogenic stresses, there is anecdotal evidence that the high-latitude coral species Alveopora japonica Eguchi, 1968, has increased its population over the past two decades around Jeju Island, off the southern coast of Korea. The present study provides the first eco...