Before too much longer, according to the participants in one of the AAAS press conferences this morning, we could be topping off our fuel tanks with processed pond scum, also known as algae. An algae-based biofuels industry would make the trade-off with food go away: algae will happily grow in ponds built out in the desert, or in other sites not useful for farming. It will thrive in waste water from sewage treatment plants and the like. It will eat up carbon dioxide from power plants, assuming that you bubble the exhaust through the algae pond on the way out. And every one of the intensely green algae cells is bulging with rich, oily lipids that are virtually gas-tank ready. Oh, and the residual solids are useful as fertilizer, or even as food additives.