When I’m thirsty, I often fancy a cool drink of green algae, filled with Spirulina, a vitamin-and protein-packed beverage resembling pond scum that’s promoted as an immune-boosting elixir. I think of algae as benign or beneficial: clinging to a damp tree trunk, like the primitive one-celled Protococcus; as a source of biodiesel, aka oilgae; or […]