Runoff from farms dumps fertilizer nutrients into the world’s oceans. This causes dead zones which are oxygen-starved where few or no fish can live. The Baltic Sea currently has a project to oxygenate dead areas using windmill and air pump technology (See http://www.cnn.com/2012/07/17/world/europe/dead-zone-baltic-oxygen). However, transporting air underwater requires expensive piping, much energy to overcome water buoyancy and ballasted piping to keep the bubble manifold from floating upward. Moreover, underwater manifold discharge nozzles may tend to plug with algae. One solution is to use electrolysis to separate the water oxygen from the water. This mature technology has many advantages over pumping air.
1. Electrolysis produces more oxygen than air;
2. Wires determine where the oxygen goes without fighting piping buoyancy;
3. Electrodes have no nozzles to foul;
4. Electrodes are easier to replace than manifolds;
5. Oxygen volume and timing control is simple whereas air control valve require complex electro mechanical systems.
Application: Underwater turbines, oscillating cylinders (http://www.asme.org/kb/news---articles/articles/arctic-engineering---offshore-technology/out-of-the-vortex), wave generator or windmills generate alternating current (A/C). This alternating current is transported by wires to a dead zone field. A/C to direct current (D/C) converters converts A/C to D/C. This D/C is distributed to an anode and cathode array strategically located under the dead zone. Salty sea water provides electrode electrolytes. The two illustrations show how this may be set up. The first illustration show an underwater turbine located in water current. A/C energy is transported by wires the A/C to D/C converter. D/C connects to anchored electrodes and produce oxygen that oxygenate the surrounding salty water and the hydrogen is collected or vents to the surface. Collected hydrogen could serve as an energy source. The second illustration shows how river discharge could be oxygenated right at the mouth of the river which is a source of nutrients. In this case, the river may provide the water flow current to generate power needed for electrolysis. Deployment: In the US, there are dead zone all along the East and Gulf coasts (http://upload.wikimedia.org/wikipedia/commons/c/c7/Aquatic_Dead_Zones.jpg). This system, if deployed offshore, could be powered by the East shore tides.
Environmental Impact: Alaskan whales use bubbles to corral fish. Fish don't like to cross walls of bubbles. Therefore, the oxygen should be pulsed in different areas to prevent creating walls of bubbles that fish won't cross.