to create oilgae:
1. You need the bottom of the pool sealed (like a swimming pool)
2. You need the top covered to prevent foreign plants from sprouting.
3. You need 350 gallons of water to create one gallon of oilgae.
Problems 1 and 2 are solved by the plastic bag, and since this uses waste and/or sea water, 3 is covered as well. I think his general idea has merit. Algae has its own natural sea-worthy bag it lives in. We could tweak algae cell DNA to grow to monster size, say 3 inch diameter balls, inject their food and CO2 inside and let them sun bathe in free open ocean "farm fields" until harvest.