Biofouling is a major problem shared among all maritime sectors employing submerged structures where it leads to substantially increased costs and lowered operational lifespans if poorly addressed. Insight into the ongoing processes at the relevant marine locations is key to effective management of biofouling. Of specific concern for the marine renewable energy (MRE) sector is the fact that information on biofouling composition and magnitude across geographies is dispersed throughout published papers and consulting reports. To enable rapid access to relevant key biofouling events the present work describes a European biofouling database to support the MRE sector and other maritime industries. The database compiles in one document qualitative and quantitative data for challenging biofouling groups, including non-native species associated with MRE and related marine equipment, in different European Ecoregions. It provides information on the occurrence of fouling species and data on key biofouling parameters, such as biofouling thickness and weight. The database aims to aid the MRE sector and offshore industries in understanding which biofouling communities their devices are more susceptible to at a given site, to facilitate informed decisions. In addition, the biofouling mapping is useful for the development of biosecurity risk management plans as well as academic research.

By combining quartz crystal microbalance with dissipation monitoring (QCM-D) and surface plasmon resonance (SPR), the organic mass, water content, and corresponding protein film structure of fibrinogen adsorbed to acrylic polymeric substrates with varying polymer chain flexibility was investigated. Albumin and immunoglobulin G were included as reference proteins. For fibrinogen, the QCM-D model resulted in decreased adsorbed mass with increased polymer chain flexibility. This stands in contrast to the SPR model, in which the adsorbed mass increased with increased polymer chain flexibility. As the QCM-D model includes the hydrodynamically coupled water, we propose that on the nonflexible polymer significant protein conformational change with water incorporation in the protein film takes place. Fibrinogen maintained a more native conformation on the flexible polymer, probably due to polymer chain rearrangement rather than protein conformational change. In comparison with immunoglobulin G and albumin, polymer chain flexibility had only minor impact on adsorbed mass and protein structure. Understanding the adsorption and corresponding conformational change of a protein together with the mutual rearrangement of the polymer chain upon adsorption not only has implications in biomaterial science but could also increase the efficacy of molecular imprinted polymers (MIPs).

Rosin-based coatings loaded with 0.1% (w/v) ivermectin were found to be effective in preventing colonization by barnacles (Balanus improvisus) both on test panels as well as on yachts for at least two fouling seasons. The leaching rate of ivermectin was determined by mass-spectroscopy (LC/MS-MS) to be 0.7 ng cm 72 day 71. This low leaching rate, as deduced from the Higuchi model, is a result of the low loading, low water solubility, high affinity to the matrix and high molar volume of the model biocide. Comparison of ivermectin and control areas of panels immersed in the field showed undisturbed colonisation of barnacles after immersion for 35 days. After 73 days the mean barnacle base plate area on the controls was 13 mm 2 , while on the ivermectin coating it was 3 mm 2 . After 388 days, no barnacles were observed on the ivermectin coating while the barnacles on the control coating had reached a mean of 60 mm 2 . In another series of coated panels, ivermectin was dissolved in a cosolvent mixture of propylene glycol and glycerol formal prior to the addition to the paint base. This method further improved the anti-barnacle performance of the coatings. An increased release rate (3 ng cm 72 day 71 ) and dispersion of ivermectin, determined by fluorescence microscopy, and decreased hardness of the coatings were the consequences of the cosolvent mixture in the paint. The antifouling mechanism of macrocyclic lactones, such as avermectins, needs to be clarified in further studies. Beside chronic intoxication as ivermectin is slowly released from the paint film even contact intoxication occurring inside the coatings, triggered by penetration of the coating by barnacles, is a possible explanation for the mode of action and this is under investigation.

The efficacy of antifouling coatings designed to minimise the release of biocide, either by embedded (non-covalent) or tethered (covalently bonded) biocides, relies on sufficient bioavailability of the active compound upon contact between the organism and the coating. This investigation is focused on whether coating hardness affects the efficacy of embedded coating systems. Two experimental, non-eroding and waterborne latex paint formulations composed mainly of polystyrene (PS) or polyvinyl versatate (PV) were chosen for their difference in mechanical properties measured in terms of Buchholz indentation resistance. Ivermectin was added to both formulations to a final concentration of 0.1% (w/v) and the steady state release rate was measured according to ISO 15181 at between 34 and 70 ng cm(-2) day(-1) for both formulations. Field trials conducted over 3 months showed significant differences in anti-barnacle efficacy between the formulations despite their similar release profiles. The softer PV coating showed complete anti-barnacle efficacy, ie no barnacles were detected, while the harder PS coating showed no efficacy against barnacle colonisation during the same time period. The results indicate a new antifouling strategy whereby a route of intoxication is triggered by the organism itself upon interaction with the coating and its embedded biocide. This finding opens new possibilities in controlling macrofouling by low emission antifouling coatings.