Plant Nursery in Space

A more economical, smaller space requirement and better oxygen production would be an aqua culture of plankton and Sargasso seaweed. I have read reports in Discover, Nature and other magazines that Sargasso seaweed produces 20% more oxygen than trees do per pound of biomass. I believe the original reports from the research groups are online. sorry I don't remember the authors or the month of the mags although it was early this year.

One could run a closed tank with plastic pipes running through the tank to extract oxygen and use the tank for biological sewage treatment thus supplying fertilizer.
DuPont makes a plastic that separates free oxygen by osmosis.

Ronald G. Butler Jr.