Posidonia oceanica samples were exposed to argon and oxygen plasma at varying plasma energies. The untreated and treated samples were characterized to study the weight loss, wettability, surface roughness, and surface chemical functionalities. It was observed that oxygen plasma treatment showed greater weight loss than the argon plasma treatment. Superhydrophilic surfaces (theta < 5 degrees) were achieved at 180 kJ argon-plasma treatment and 6 kJ and 18 kJ oxygen-plasma treatments. The surface roughness increases as the plasma energies were increased for the argon-plasma treatment; however, opposite trend was seen for the oxygen-plasma treatment. The -CH2 groups and the aliphatic C-H groups were absent from the FT-IR spectra of the superhydrophilic samples. (C) 2013 Elsevier B.V. All rights reserved.