Marine biofouling field tests, settlement assay and footprint micromorphology of cyprid larvae ofBalanus amphitriteon model surfaces

Abstract

Atomic force microscopy (AFM), laboratory settlement assays and field tests were used to correlate cyprid footprint (FP) morphology with the behaviour of cyprids on different substrata. AFM imaging under laboratory conditions revealed more porous and larger FPs on glass exposing a CH3-surface than on aminosilane functionalised (NH2-) surfaces. The secreted FP volume was found to be similar on both substrata (2.1-2.6 microm(3)). Laboratory settlement assays and marine field tests were performed on three substrata, viz. untreated clean glass, NH2-glass, and CH3-glass. The results distinguished settlement preferences for NH2-glass and untreated glass over CH3-terminated surfaces, suggesting that cyprids favour settling on hydrophilic over hydrophobic surfaces. On combining observations from different length scales, it is speculated that the confined FP size on NH2-glass may induce a higher concentration of the settlement inducing protein complex. Settlement may be further facilitated by a stronger adherence of FP adhesives to the NH2-surface via Coulombic interactions.

Quantifying the exploratory behaviour ofAmphibalanus amphitritecyprids

“…Cyprids took longer steps on the hydrophilic bare glass and NH 2 -treated glass, compared to hydrophobic CH 3 -treated glass. This distinction between hydrophilic and hydrophobic glass surfaces correlates with the settlement preferences of A. amphitrite, as reported by Phang et al (2009). This latter study also describes marine fouling field tests, where barnacle and macrofouler recruitment was found to be higher on hydrophilic vs hydrophobic glass surfaces.…”

“…Microscope slides (Sail Brand, China) were cleaned, coated, and verified using the materials and procedures described in Phang et al (2009). All surfaces, viz bare glass, NH 2 -coated glass, and CH 3 -coated glass, were used in experiments without further rinsing.…”

“…This adhesion is mediated by a secreted footprint protein (Walker and Yule 1984). Atomic force microscopy (AFM) measurements reveal differences in footprint size and the morphology of deposited footprint protein on hydrophilic vs hydrophobic surfaces (Phang et al 2008(Phang et al , 2009). The latter study draws a correlation between nanoscale interactions between cyprids and surfaces and marine fouling, in the form of cyprid settlement preferences and the comprehensive bioresponse provided by a marine fouling field test.…”

“…Chaw and W.R. Birch observed on hydrophilic surfaces may allow the cyprids to cover larger distances as they explore the solid surface. Taking into account the settling preferences reported by Phang et al (2009), it may be inferred that cyprids explore a less favourable surface by more meticulous local probing and that they explore a more favoured surface by taking steps that cover a larger distance in a shorter time.…”

Imaging SPR combined with stereoscopic 3D tracking to study barnacle cyprid–surface interactions

“…E.g. Phang et al reported a mean footprint thickness of 6-8 nm on surfaces with different chemical termination (Phang, Chaw et al 2009) while Guo et al observed even higher values (10-20 nm) on surfaces with different wettability (Guo, Puniredd et al 2014). …”