A low-turbulent aspirating type aerator, introduced into a body of liquid, comprising of: a gas conveyance tube having a gas inlet end and a gas outlet end; a gas-liquid mixture chamber incorporating; an impeller affixed to a rotatable shaft, at the least one gas intake opening and at the least one gas-liquid discharge opening at or near bottom end of gas-liquid mixture chamber.Rotation of the impeller creates a low-pressure zone (vacuum) allowing gas conveyed via gas conveyance tube to come into contact with rotating impeller forming a gas-liquid mixture at the impeller interface wherein bubbles are formed. Gas-liquid mixture chamber confines gas bubbles thereby allowing the action of impeller and liquid shearing force to produce and discharge micro-sized gas bubbles of predominantly less than 0.85 millimeters. The micro-sized gas bubbles generated have an long residence or gas hold up time within the body of liquid, wherein gas within bubble can, based on a concentration gradient, diffuse into liquid thereby providing the capacity to provide a high gas (oxygen) transfer rate.