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Aquaculture is a billion dollar industry and biofouling of aquaculture installations has heavy economic penalties. The natural antifouling (AF) defence mechanism of some seaweed that inhibits biofouling by production of reactive oxygen species (ROS) inspired us to mimic this process by fabricating ZnO photocatalytic nanocoating. AF activity of fishing nets modified with ZnO nanocoating was compared with uncoated nets (control) and nets painted with copper-based AF paint. One month experiment in tropical waters showed that nanocoatings reduce abundances of microfouling organisms by 3-fold compared to the control and had higher antifouling performance over AF paint. Metagenomic analysis of prokaryotic and eukaryotic fouling organisms using next generation sequencing platform proved that nanocoatings compared to AF paint were not selectively enriching communities with the resistant and pathogenic species. The proposed bio-inspired nanocoating is an important contribution towards environmentally friendly AF technologies for aquaculture.

For the first time, densities and diversity of microorganisms developed on the ocean glider were investigated using flow cytometry and Illumina MiSeq sequencing of 16S and 18S rRNA genes. Ocean gliders are autonomous buoyancy-driven underwater vehicles, equipped wi th sensors continuously recording physical, chemical, and biological parameters. Biofilms on the glider were exposed to periodical oscillations of salinity, oxygen, temperature, pressure, depth and light, due to periodic ascending and descending of the vehicle. Among the unpainted surfaces, the highest microbial abundance was observed on the bottom of the glider's body, while the lowest density was recorded on the glider's nose. Antifouling pai nts had the lowest densities of microorganisms. Multidimentional analysis showed that microbial communities formed on unpainted parts of the glider shared some similarity wi th non-toxic paint but they were significantly different from ones on toxic antifouling paint and seawater.

The antifouling (AF) properties of zinc oxide (ZnO) nanorod coated glass substrata were investigated in an out-door mesocosm experiment under natural sunlight (14:10 light: dark photoperiod) over a period of five days. The total bacterial density (a six-fold reduction) and viability (a three-fold reduction) was significantly reduced by nanocoatings in the presence of sunlight. In the absence of sunlight, coated and control substrata were colonized equally by bacteria. MiSeq Illumina sequencing of 16S rRNA genes revealed distinct bacterial communities on the nanocoated and control substrata in the presence and absence of light. Diatom communities also varied on nanocoated substrata in the presence and the absence of light. The observed AF activity of the ZnO nanocoatings is attributed to the formation of reactive oxygen species (ROS) through photocatalysis in the presence of sunlight. These nanocoatings are a significant step towards the production of an environmentally friendly AF coating that utilizes a sustainable supply of sunlight.