And finally, some plants only "breathe," at night in order to save water - I also remember this (many if not most plants control water loss through transpiration by shutting down their stomata during , but I'm pretty much sure that no plants are able to photosynthesise at night! That would be an interesting species...
Overall, seems like some relatively serious misunderstandings of the basic science if even I (not a great GCSE mark in biology...) find myself wringing my hands...
There are three types of plants, and instead of explaining them, let me just provide links.
The type of plant that breathes at night are the CAM ones.
* http://en.wikipedia.org/wiki/C3_carbon_fixation - most common, almost all plants are like this
* http://en.wikipedia.org/wiki/C4_carbon_fixation - very efficient, corn is the most common example
* http://en.wikipedia.org/wiki/CAM_photosynthesis - night breathing, pineapple is the example
Not necessarily. Consider photorespiration -- under certain conditions, some plants will use oxygen instead of carbon dioxide.
> I'm pretty much sure that no plants are able to photosynthesise at night
Some reactions in photosynthesis are light independent, and many plants (especially ones in hot and arid environments) will perform these reactions at night in order to conserve water.
Not having scrolled down far enough to see the end, this is the moment where i hoped this article would burst into a wild jungle of different scenarios and scientific data analysis. But it ended... :(
Still nice thing to ponder about though...
There are many studies being done, and done previously, on the viability of algae oxygenating artificial atmospheres.
[15 minutes later - this is the best link I've been able to find - from a Navy research paper in 1963, no less:
-- snip --
The results obtained with a small pilot plant containing 6200 ml of algal suspension have been evalu- ated; the effects of light intensity, rate of stirring, rate of carbon dioxide supply, and other variables were part of this study. Light energy was supplied by six 1500-watt incandescent lamps which extended through the suspension and were encased in 50-mm O.D. cooling jackets. When the light intensity at the surface of these jackets was 34,000 foot-candles (the limit with the equipment at hand), the oxygen production was 4500 cc per hour.
Oxygen production increases with light intensity, but the oxygen produced per watt of electrical en- ergy expended is constant over a wide range of light intensities. The amount of electrical energy re- quired to provide enough oxygen for one man is between 30 and 50 kw, depending on the design of the gas exchanger. This high requirement makes the process prohibitive at present; but the development of more efficient high-intensity light sources could change the outlook.
The dependability of the algal system in providing a constant supply of oxygen has been assured by this study; also, the volume requirements of the algal system are competitive with existing systems for carbon dioxide removal and oxygen production.
-- snip --