An apparatus for harvesting algae from an open body of water includes a boat having a pair of spaced apart parallel flotation members and a deck disposed on and connected to the members. The spaced apart members define an area therebetween forming a process channel. A separating mechanism disposed on the boat separates the process channel into a plurality of process channel sections arranged in series. The process channel sections are disposed intermediate the flotation members. Each of the process channel sections include a deflector plate, a scum beach, a scum trough, and diffused air piping. The diffused air piping is in fluid communication with a dissolved air flotation system.