Staticvsdynamic settlement and adhesion of diatoms to ship hull coatings

Abstract

Many experiments utilize static immersion tests to evaluate the performance of ship hull coatings. These provide valuable data; however, they do not accurately represent the conditions both the hull and fouling organisms encounter while a ship is underway. This study investigated the effect of static and dynamic immersion on the adhesion and settlement of diatoms to one antifouling coating (BRA 640), four fouling-release coatings (Intersleek(®) 700, Intersleek(®) 900, Hempasil X3, and Dow Corning 3140) and one standard surface (Intergard(®) 240 Epoxy). Differences in community composition were observed between the static and dynamic treatments. Achnanthes longipes was present on all coatings under static immersion, but was not present under dynamic immersion. This was also found for diatoms in the genera Bacillaria and Gyrosigma. Melosira moniformis was the only diatom present under dynamic conditions, but not static conditions. Several common fouling diatom genera were present on panels regardless of treatment: Amphora, Cocconeis, Entomoneis Cylindrotheca, Licmophora, Navicula, Nitzschia, Plagiotropis, and Synedra. Biofilm adhesion, diatom abundance and diatom diversity were found to be significantly different between static and dynamic treatments; however, the difference was dependent on coating and sampling date. Several coatings (Epoxy, DC 3140 and IS 700) had significantly higher biofilm adhesion on dynamically treated panels on at least one of the four sampling dates, while all coatings had significantly higher diatom abundance on at least one sampling date. Diversity was significantly greater on static panels than dynamic panels for Epoxy, IS 700 and HX3 at least once during the sampling period. The results demonstrate how hydrodynamic stress will significantly influence the microfouling community. Dynamic immersion testing is required to fully understand how antifouling surfaces will respond to biofilm formation when subjected to the stresses experienced by a ship underway.

Conditioning of self-assembled monolayers at two static immersion test sites along the east coast of Florida and its effect on early fouling development

“…The two test sites were chosen since the population density and the seasonal variation of organisms have been studied extensively at both sites (Swain et al 2006;Zargiel et al 2011;Sweat and Johnson 2013;Zargiel and Swain 2013;Ralston and Swain 2014). The water was used to precondition self-assembled monolayers (SAMs) with different end group chemistries.…”

Antifouling properties of oligo(lactose)-based self-assembled monolayers

“…Resistance to non-specific protein adsorption may be considered to be a general indication of surface inertness, but its use here is also related to potential biomedical applications, as well as a means to explore the relevance of protein adsorption tests as predictors of marine antifouling properties. U. linza is a major macrofouling alga which colonizes surfaces through the production of vast quantities of microscopic motile spores (Callow and Callow 2006), while diatoms are interesting microfoulers in that they frequently succeed in fouling submerged artificial surfaces, and produce thick slime even on biocidal antifouling paints, and also adhere tenaciously to fouling-release coatings based on silicone elastomers (Zargiel et al 2011, Zargiel andSwain 2014). Three oligo(lactose) thiols, forming di-, tetra-and hexasaccharides (containing 1, 2, and 3 lactoside groups, respectively, see Figure 1), were investigated.…”

Seasonal variations in fouling diatom communities on the Yantai coast

“…Based on the development of marine antifouling technology, people initially focused on the diatom community structure of the antifouling coating surface. Zargiel et al (2011) andSwain (2014) reported that the hull coatings of cargo ships affected the community structure of fouling diatoms, and the main fouling diatom species varied signifi cantly with different coatings and the geographical area. The effects of static and dynamic immersion on the adhesion and settlement of diatoms were different, and the diversity of diatoms on static panels was signifi cantly greater than that on dynamic panels.…”