Live Science: Fertilizing the oceans with iron — a tactic that “geoengineers” have proposed to fight global warming — could inadvertently spur the growth of toxic microbes, warn scientists who analyzed water samples from past iron-fertilization experiments. Toxin-producing algae that thrive on iron and can contaminate marine life are more widespread than suspected, the researchers said. The finding could impact proposed iron-fertilization projects. “This work definitely reveals a wrinkle in those plans,”…