Hi, Your set-ups look great! As far as a wind turbine is concerned, I would go about it in one of two ways:
1) Mechanical-Get some wind turbine blades (very cheap) see link (1) and attach them to a hub connected to a rotary pump (link (3)) and pump water up and maybe onto a water fall like structure to increase gas-liquid exchange time.
2) Electrical-Again acquire some wind turbine blades from link 1 and attach them to a hub, which in turn can get connected to a DC motor to create electricity to run a low voltage air pump (link (2)).
A hub is easily made out of wood or plastic by drawing a circle and cutting it out, blades easily mount on with two screws and you are ready to go.
If you have further questions feel free to ask.
-Best of Luck, and keep the photos coming!
1)
http://www.windstuffnow.com/main/turbine_blade.htm
2)
http://www.aquamasters.com/airpumps.htm
3)
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_327149_327149