Carbon black is a pigment made from the likes of coal, tar and oil, and 8.1 million tons of the stuff is produced every year, emitting millions of tons of CO2. Apparel start-up Vollebak went in search of a new way to dye things black, and found it in algae. Its Black Algae T-Shirt was both a commercial experiment and an educational campaign, and there was no guarantee it would pay off, but with more algae products in the works, it looks like the brand is onto something.