Penny Chisholm: The tiny creature that secretly powers the planet

Oceanographer Penny Chisholm introduces us to an amazing little being: Prochlorococcus, the most abundant photosynthetic species on the planet. A marine microbe that has existed for millions of years, Prochlorococcus wasn't discovered until the mid-1980s — but its ancient genetic code may hold clues to how we can reduce our dependence on fossil fuels.