Meeting Abstract
Marine fouling is the settlement of microorganisms on wet surfaces. Many studies have designed structures that mimic the microscopic patterns of dermal denticles on shark skin to prevent marine fouling. For example, industrial surfaces inspired by shark denticles reduced marine fouling and decrease bacterial growth by up to 87%. However, we found no quantitative evidence to justify the claim that shark skin is antifouling. This study quantifies marine fouling on shark skin from the blacktip shark (Carcharhinus limbatus) along dorsal and ventral surfaces, which provided a range of denticle densities and varying morphology. We hypothesized that significant growth would occur on control and shark skin surfaces during the 120 hour experimental period. We also expected to find increased percent cover where denticle density was lowest. Shark skin and control samples, sterile petri dishes, were exposed to agitated flow-through seawater and daylight cycles for 120 hours (five days). We quantified fouling every 24 hours by removing the surface from water flow, photographing, and then using NIH ImageJ to quantify percent cover. When control surfaces were exposed to seawater conditions, significant growth (more than 30% cover) was present after a 24 hour time period. At 24 hours of exposure, shark skin showed less than 0.01% growth and on average there was only 1.7% cover at the end of the 120 hour experimental period. We showed that percent cover over time increased as denticle density increased. These data suggests that denticle density plays a key role in preventing fouling, as denticle presence led to significantly less microorganism settlement over time when compared to a control. Future research will be conducted to determine if shark skin prevents bacterial growth and if denticle morphology impacts fouling.
