Fouling-release and chemical activity effects of a siloxane-based material on tunicates

First Barnacle (Amphibalanus amphitrite) Adhesion Strength Data on the Self-Polishing Coatings Off the Aegean Sea

The aim of this work is to study the adhesion strength of Amphibalanus amphitrite in the İzmir Bay and compare the results with the pseudobarnacle adhesion test. Normally, adhesion tests are performed to evaluate the performance of the antifouling coatings, but the test results can also be used to predict biofouling cleaning process efficacy. The biofouling process is highly dependent on environmental conditions. For this reason, laboratory tests are required to perform the performance tests on self-polishing coatings in cases where living organisms cannot be reached. For this purpose, different self-polishing antifouling coatings have been formulated. Field tests for the coatings were carried out in the Aegean Sea for 10 weeks. After 10 weeks, barnacle and pseudobarnacle adhesion tests were conducted on coatings. When the results were compared, similarity was observed between the adhesion strength of barnacles and pseudobarnacles with 10 mm diameter on coating with the rosin/xylene/BaSO4 (40:40:20 w/w %). The adhesion strength of barnacles and pseudobarnacles on the coating 12 was found to be 0.46 and 0.45 MPa, respectively. In conclusion, the present study exhibits the first data related to the adhesion strength of A. amphitrite on rosin-based self-polishing coatings in the Aegean Sea. Moreover, based on field tests, a pseudobarnacle adhesion test methodology was developed to mimic barnacles and the correlation between barnacle and pseudobarnacle tests was examined.

Periodic ultraviolet-C illumination for marine sensor antifouling

Ultraviolet light has intriguing potential as a marine antifoulant, targeting almost any species and applicable to almost any surface, while not accumulating in the environment. This study field-tested the effects of periodic ultraviolet-C illumination on marine macrofouling. Across four experiments, several UV illumination duty cycles were tested against controls with no illumination. Duty cycles between 1:2 (time with UV:total time per cycle) and 1:20 were all similarly effective, inhibiting almost all macrofouling at three different temperate Northeast Pacific and Northwest Atlantic sites. Susceptible taxa included barnacles, bryozoans, tunicates (colonial and solitary), and, to a slightly lesser extent, mussels. Duty cycles of 1:30 and 1:60 reduced but did not eliminate biofouling. Measurements of ultraviolet illumination on oceanographic sensors showed similar results. The results suggest further investigation of ultraviolet light as an antifoulant for marine sensors, including susceptibility of other taxa, optimizing illumination patterns, and exploring the potential for evolved resistance.