Vieira C. auteur aut IRD Thomas O. P. auteur aut IRD Culioli G. auteur aut IRD Genta-Jouve G. auteur aut IRD Houlbrèque Fanny auteur aut IRD Gaubert J. auteur aut IRD De Clerck O. auteur aut IRD Payri Claude auteur aut IRD text journalArticle eng text/pdf reformatted digital access 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 suggested the potential role of chemical mediators in this interaction. We performed in situ bioassays testing the allelopathy of crude extracts and isolated compounds of several Lobophora species, naturally associated or not with corals, against four corals in New Caledonia. Our results showed that, regardless of their natural association with corals, organic extracts from species of the genus Lobophora are intrinsically capable of bleaching some coral species upon direct contact. Additionally, three new C-21 polyunsaturated alcohols named lobophorenols A-C (1-3) were isolated and identified. Significant all elopathic effects against Acropora muricata were identified for these compounds. In situ observations in New Caledonia, however, indicated that while allelopathic interactions are likely to occur at the macroalgal-coral interface, Lobophora spp. rarely bleached their coral hosts. These findings are important toward our understanding of the importance of allelopathy versus other processes such as herbivory in the interaction between macroalgae and corals in reef ecosystems. specialized NOUVELLE CALEDONIE PACIFIQUE 036 6 18637 2016 2045-2322 https://www.documentation.ird.fr/hor/fdi:010066090 10.1038/srep18637 2045-2322 [F B010066090] https://www.documentation.ird.fr/hor/fdi:010066090 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers16-02/010066090.pdf IRD - Base Horizon / Pleins textes 2016-02-26 2017-08-23 fdi:010066090 fre