Base plate mechanics of the barnacleBalanus amphitrite(=Amphibalanus amphitrite)

Abstract

The mechanical properties of barnacle base plates were measured using a punch test apparatus, with the purpose of examining the effect that the base plate flexural rigidity may have on adhesion mechanics. Base plate compliance was measured for 43 Balanus amphitrite (=Amphibalanus amphitrite) barnacles. Compliance measurements were used to determine flexural rigidity (assuming a fixed-edge circular plate approximation) and composite modulus of the base plates. The barnacles were categorized by age and cement type (hard or gummy) for statistical analyses. Barnacles that were 'hard' (> or =70% of the base plate thin, rigid cement) and 'gummy' (>30% of the base plate covered in compliant, tacky cement) showed statistically different composite moduli but did not show a difference in base plate flexural rigidity. The average flexural rigidity for all barnacles was 0.0020 Nm (SEM +/- 0.0003). Flexural rigidity and composite modulus did not differ significantly between 3-month and 14-month-old barnacles. The relatively low flexural rigidity measured for barnacles suggests that a rigid punch approximation is not sufficient to account for the contributions to adhesion mechanics due to flexing of real barnacles during release.

In situATR–FTIR characterization of primary cement interfaces of the barnacleBalanus amphitrite

“…These coatings offer the advantages of being environmentally benign and the potential of having much longer life times. While fouling-release coatings composed of poly(dimethylsiloxane) have shown promise, progress in improving their effectiveness remains hindered by the complexity and limited understanding of the chemistry of marine bioadhesives and the process of bioadhesion (Berglin and Gatenholm 2003;Wiegemann and Watermann 2003;Holm et al 2005;Wendt et al 2006;Ramsay et al 2008). A better fundamental understanding of the various forms of marine bioadhesives would significantly benefit the development of fouling-release coatings by introducing new ways to interfere with bioadhesion of fouling organisms.…”

Barnacles resist removal by crack trapping

“…Above the proteinaceous cement layer in many barnacles is a calcified base plate, imparting further mechanical rigidity to the adhesive interface. The compliance of base plates for the barnacle B. amphitrite was recently measured by Ramsay et al [18]. Finally, the exterior shell structure of many species of barnacles has been demonstrated to be mechanically robust owing to a combination of shell mineralization and architectural geometry of the interlocking plates [19,20].…”

“…The size of the barnacle, a, may range from 1.5 to 5 mm. Base plate stiffness D has been measured for laboratory-grown B. amphitrite barnacles [18] and was found to range between 0.0002 and 0.008 Nm, with most measurements having D , 0.003 Nm (37 of 43 measurements). An estimate of the effective modulus of the base plate was made from these values and the measured thickness of each base plate; the estimate was 3 -6 GPa without considering the hollow structure and assuming n b ¼ 0.3.…”

“…Recent experiments by Ramsay et al [18] reported on direct measurements of base plate compliance of the barnacle B. amphitrite. As the soft tissue has very low modulus and does not fully occupy the shell's interior, its effect on the deformation of the shell and the base plate can be neglected.…”

Temperature Affects Adhesion of the Acorn Barnacle (Balanus amphitrite)

“…Barnacle adhesion has been well documented (Bourget 1980;Crisp and Bourget 1985;Holm 1990;Konya and Miki 1994;Holm et al 2000;Swain et al 2000;Callow and Callow 2002;Dahlstrom et al 2004;Holm et al 2004b;Holm et al 2005; Kavanagh et al 2005;Wendt et al 2006;Wiegemann et al 2006;Conlan et al 2008;Ramsay et al 2008) making them an excellent model organism for our current study.…”