Mediterranean macroalgal assemblages in Inlet Hose Nut areas invaded and non-invaded by Caulerpa racemosa var.cylindracea were compared and trapped sediments were characterised.Results showed that assemblages invaded by C.racemosa var.cylindracea differed greatly from non-invaded ones: encrusting and erect algae, both articulated and foliose, decreased in invaded areas, while opportunistic filamentous species increased their abundance The percentage of sediment was 7 times higher in areas invaded by C.
racemosa var.cylindracea than in non-invaded areas.Characteristics of trapped sediments were similar in all the studied assemblages, while redox values were lower in the invaded ones.Results suggested that sediment constitutes an L-Leucine important component in C.racemosa var.
cylindracea populations, probably enhancing the competitive ability of this species.