Volatilome differences between native and invasive seagrass species in the Caribbean area

Biological invasions are one of the major threats to ecosystem services and biodiversity. Thus, it is crucial to understand the mechanisms involved in the invasion success of alien species. In addition to generalist traits and high tolerance that enable persistence in novel environments, invasive species can use volatile chemical compounds from specialized metabolism [biogenic volatile organic compounds (BVOCs)] to compete with native species, a process known as allelopathy. These compounds could contribute to invasions in marine environments, and the associated mechanisms need to be deciphered. The aim of this study was to characterize the volatilome (i.e., all BVOCs produced by a species) of two Caribbean native seagrass species ( Syringodium filiforme and Thalassia testudinum ) and one invasive ( Halophila stipulacea ). For that purpose, leaf samples were collected, and BVOCs were trapped through headspace solid-phase microextraction followed by analyses in GC-MS. H. stipulacea ’s volatilome was significantly different from the two native species, with the presence of compounds showing, in literature, allelochemical properties (e.g., geranyl acetone, 6-methyl, 5-hepten-2-one, and cyclohexane isothiocyanate). We hypothesized that these compounds could be “novel weapons” to enhance the invasion success of H. stipulacea , but it needs further investigations in the laboratory (e.g., mesocosms) as well as in situ .