In Situ Imaging of Barnacle (Balanus amphitrite) Cyprid Cement Using Confocal Raman Microscopy
Barnacles are a model for research on permanent underwater adhesion and the wider process of marine biofouling. A detailed understanding of the permanent adhesive secreted by the cypris larva for permanent settlement, the so-called cyprid cement, has potential to lead to novel antifouling solutions. There is a need for micro-analytical chemical in situ methods to gain more insight into the process of adhesion and the chemical composition of the cement. In this study, the applicability of confocal Raman microscopy for imaging the cyprid cement beneath permanently attached juvenile barnacles (Balanus amphitrite) was explored. Based on acquired area scans Raman images for characteristic chemical functional groups were obtained. In addition to showing the morphology of the attachment apparatus, the images provided information on chemical composition, in particular the hydration state of the cement, and demonstrated the potential of this method for in situ studies of adhesion at the micro-scale.