Browsing by Author "Vieira, Christophe"
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- Diversity and origin of the genus Lobophora in the Mediterranean Sea including the description of two new speciesPublication . Vieira, Christophe; Aharonov, Andre; Paz, Guy; Engelen, Aschwin; Tsiamis, Konstantinos; Einav, Rachel; De Clerck, OlivierThe 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 specimens across the Mediterranean Sea (Spanish coast, Balearic Islands, Greece and Israel), with an exhaustive effort in the Balearic Islands. Molecular analyses disclosed the presence of three species, none of them conspecific with the name L. variegata, as they were recorded up to now in the Mediterranean Sea. The most common species in the Mediterranean Sea is L. delicata. We here describe L. schneideri sp. nov., so far found only in Haifa Bay (Israel), where it forms large and dense populations. Similar to L. delicata, L. schneideri occurs across the North Atlantic Ocean. Though a recent range expansion or introduction cannot be ruled out, we regard the North Atlantic Ocean, including the Greater Caribbean and the Mediterranean Sea, as the natural range of both L. schneideri and L. delicata. A third species, described here as L. lessepsiana sp. nov., is found along the Israeli coast as well as in the Red Sea and is most probably a recent introduction through the Suez Canal. Further exploration along the North African coast, the Levantine Sea and the Aegean Sea, would probably increase the currently known species diversity for this group in the Mediterranean Sea.
- Lobophora (Dictyotales, Phaeophyceae) from the western Indian Ocean: diversity and biogeographyPublication . Vieira, Christophe; Rasoamanendrika, Faravavy A.; Zubia, Mayalen; Bolton, John J.; Anderson, Robert J.; Engelen, Aschwin; D'hondt, Sofie; Leliaert, Frederik; Payri, Claude; Kawai, Hiroshi; De Clerck, OlivierThe 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, Mozambique, and the Red Sea, considerably improving our knowledge of Lobophora diversity and biogeography in this region. Eight additional species are identified from the western Indian Ocean, raising the total number of Lobophora species to 43. Fifteen species are new to science and described herein. With ca. 40% of the global diversity, the western Indian Ocean is second only to the Central IndoPacific. Of the species identified to date, 29 appear to be restricted to the western Indian Ocean, three are shared with the Atlantic (four including L. lessepsiana introduced to the western Mediterranean Sea) and 12 have a wider distribution in the Indo-Pacific. The western Indian Ocean supports a high diversity with ca. 67% of its Lobophora restricted to this region, which is comparable to the Central Indo-Pacific (62%) and the Caribbean (61%). The presence of several putative endemic species in the western Indian Ocean islands and the Red Sea illustrates that these provinces played an important role in Lobophora species diversification within the western Indian Ocean by producing locally new species. The small number of species shared between the western Indo-Pacific and Atlantic indicates that this oceanic boundary - associated with the temperate Agulhas marine province, and the Benguela current and upwelling - acts as an effective dispersal barrier.
- Species specificity of bacteria associated to the brown seaweeds Lobophora (Dictyotales, Phaeophyceae) and their potential for Induction of rapid coral bleaching in Acropora muricataPublication . Vieira, Christophe; Engelen, Aschwin H.; Guentas, Linda; Aires, Tânia; Houlbreque, Fanny; Gaubert, Julie; Serrao, Ester A.; De Clerck, Olivier; Payri, Claude E.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 suggest that macroalgae may act as vectors and/or foster proliferation of microorganisms pathogenic for corals. Using a combination of high throughput sequencing, bacterial culturing, and in situ bioassays we question if the adversity of macroalgal associated bacteria to corals is mediated by specific bacterial taxa. Using Illumina sequencing, we characterized and compared the bacterial community from two Lobophora (Dictyotales, Phaeophyceae) species. The two species presented distinctive bacterial communities. Both species shared approximately half of their OTUs, mainly the most abundant bacteria. Species-specific OTUs belong to Planctomycetes, Proteobacteria, and Bacteroidetes. In total, 16 culturable bacterial strain were isolated and identified from the Lobophora surface, consisting of 10 genera (from nine families, four classes, and three phyla), some of which are not known as, but are related to pathogens involved in coral diseases, and others are naturally associated to corals. When patches of marine agar with 24 h cultures of each of these bacteria were placed in direct contact with the branches of the scleractinian coral Acropora muricata, they caused severe bleaching after 24 h exposure. Results suggest that regardless of taxonomic affinities, increase in density of these bacteria can be adverse to corals. Nevertheless, the microbial community associated to macroalgal surface may not represent a threat to corals, because the specific bacterial screening and control exerted by the alga preventing specific bacterial proliferation.
- Species specificity of bacteria associated to the brown seaweeds lobophora (dictyotales, phaeophyceae) and their potential for induction of rapid coral bleaching in acropora muricataPublication . Vieira, Christophe; Engelen, Aschwin H.; Guentas, Linda; Aires, Tânia; Houlbreque, Fanny; Gaubert, Julie; Serrão, Ester; De Clerck, Olivier; Payri, Claude E.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 suggest that macroalgae may act as vectors and/or foster proliferation of microorganisms pathogenic for corals. Using a combination of high throughput sequencing, bacterial culturing, and in situ bioassays we question if the adversity of macroalgal associated bacteria to corals is mediated by specific bacterial taxa. Using Illumina sequencing, we characterized and compared the bacterial community from two Lobophora (Dictyotales, Phaeophyceae) species. The two species presented distinctive bacterial communities. Both species shared approximately half of their OTUs, mainly the most abundant bacteria. Species-specific OTUs belong to Planctomycetes, Proteobacteria, and Bacteroidetes. In total, 16 culturable bacterial strain were isolated and identified from the Lobophora surface, consisting of 10 genera (from nine families, four classes, and three phyla), some of which are not known as, but are related to pathogens involved in coral diseases, and others are naturally associated to corals. When patches of marine agar with 24 h cultures of each of these bacteria were placed in direct contact with the branches of the scleractinian coral Acropora muricata, they caused severe bleaching after 24 h exposure. Results suggest that regardless of taxonomic affinities, increase in density of these bacteria can be adverse to corals. Nevertheless, the microbial community associated to macroalgal surface may not represent a threat to corals, because the specific bacterial screening and control exerted by the alga preventing specific bacterial proliferation.