Apparatus for extracting a material from a body of liquid and methods therefore are disclosed. A transport member comprises at least one continuous loop configured to pass through a continuous orbit. The material sufficiently adheres to at least a portion of the at least one continuous loop. A scraping member urges against at least a portion of the continuous loop for removing at least some of any of the material adhered to the continuous loop. Such an apparatus can be a harvester that includes a frame having a first end and a second end. A first conveyor drum can be supported by the frame adjacent the first end and can have an outer surface for engaging the transport member. A second conveyor drum can be supported adjacent the second end and can have an outer surface for engaging the transport member. The at least one continuous loop can extend between the first conveyor drum and the second conveyor drum and frictionally engage at least a portion of each respective outer surface of the first conveyor drum and the second conveyor drum.