Apparatus and method for harvesting plankton and/or other biomass from a dead zone in a body of water comprising at least one support float provided to float on a surface of a body of water. At least one support structure is coupled to the at least one support float, and is configured to support a substantially rigid frame within a dead zone below the surface in the body of water. A main funnel is coupled to the support structure within the dead zone to collect descending biomass and funnel it toward a lower funnel that is coupled to the bottom of the main funnel. A collection canister is preferably disposed within the lower funnel to store the descending biomass. A guide floats on the water surface. A hauling structure is preferably coupled to the guide float, and is configured to haul the collection canister from the lower funnel to the surface.
