We're forgetting that Jora turned Nami's Climatact into art, thereby rendering it useless. At least that is how Brook makes it sound when speaking about his Soul Solid. The idea sea water would negate Jora's DF effects is intriguing, and possible when considering a similar weakness occurs for Kalifa's DF. Hopefully Oda gets down to it without making Nami, Chopper, and Brook incompetent or weak.