“…Essential oils (EOs), as a special chemical group of algal metabolites, play an important role in communication in marine ecosystems, both interspecies and intraspecies, as well as in interactions with the surrounding environment. These compounds are involved in various algal ecological functions: they are defenses against predators and herbivores; they act as pheromones (allelochemicals; take part in the adaptation to abiotic stresses; and are important for the inhibition of bacterial and/or fungal fouling [1,[10][11][12]. The essential oil metabolites present in marine algae species contain a mixture of different chemical classes such as hydrocarbons, fatty acids, esters, alcohols, carboxylic acids, aldehydes, ketones, terpenes, polyphenols, furans, pyrazines, pyridines, halogenated amines, and sulphur compounds [1,2].…”