Slime you can believe in. Now who can argue with that?

Exxon is investing millions in developing algae strains that serve two functions:

1. suck up CO₂
2. excrete oil

On Tuesday, Exxon plans to announce an investment of $600 million in producing liquid transportation fuels from algae — organisms in water that range from pond scum to seaweed. The biofuel effort involves a partnership with Synthetic Genomics, a biotechnology company founded by the genomics pioneer J. Craig Venter.

The agreement could plug a major gap in the strategy of Exxon, the world’s largest and richest publicly traded oil company, which has been criticized by environmental groups for dismissing concerns about global warming in the past and its reluctance to develop renewable fuels.