| AVS 54th International Symposium | |
| Marine Biofouling Topical Conference | Monday Sessions |
| Session MB+BI-MoM |
| Session: | Biological Interactions at the Marine Interface |
| Presenter: | K.J. Wahl, U.S. Naval Research Laboratory |
| Authors: | G.H. Dickinson, Duke University Marine Laboratory D. Ramsay, U.S. Naval Research Laboratory J.N. Russell, Jr., U.S. Naval Research Laboratory D. Rittschof, Duke University Marine Laboratory K.J. Wahl, U.S. Naval Research Laboratory |
| Correspondent: | Click to Email |
Barnacles adhere to all kinds of surfaces in the ocean. These animals settle as larval cyprids, and attach by exuding a protenaceous adhesive. Only recently, with the study of soft and transparent release coatings, has the investigation of the adhesive mechanisms of the barnacle base plate become accessible. We are employing a combination of optical and mechanical spectroscopy to understand the near surface properties of barnacles. Here we report on studies of Amphibalanus amphitrite (little striped barnacle) using a combination of micro-Raman and Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopies, Atomic Force Microscopy (AFM), and micromechanical compression testing to investigate base plate chemistry and mechanics. For barnacles grown on release surfaces, two base plate phenotypes are found - those with a ‘hard,’ thin adhesive morphology, and those with ‘gummy’ or compliant adhesive morphology. Micro-Raman, ATR-FTIR, and AFM spectroscopies show significant differences in the protein structure and mineralization of hard and gummy. ATR-FTIR spectroscopy of hard and gummy barnacles, with and without seawater present, showed strong time-dependent responses during reattachment. Mechanical differences between hard and gummy base plates were examined using a custom instrumented flat-punch mechanical tester. The base plate mechanical properties of composite moduli are of order 2 to 5 GPa, with statistically lower modulus for gummy barnacles. The overall flexibility of the barnacle base plate was similar for both hard and gummy barnacles, due to compensating morphologies. Release properties will be discussed in relation to base plate morphology and flexibility.