Mythbusters: 1st Plague, Water into Blood
Working from scientifically well-understood modern analogies from Cameroon, Jacobovici suggests that an earthquake beneath Egypt could have released gasses that turned the waters of the Nile “blood-red,” to use Jacobovici’s term.
In The Exodus Decoded, geophysicist George Kling explains the Cameroon phenomenon as high concentrations of iron in the deep waters at the bottom of the Lake Nyos bubbling up to the surface and reacting with oxygen in the air to form iron hydroxide. To put it crudely, the waters of Lake Nyos “rusted.” Jacobovici posits that “If the Nile turned blood-red as the result of a gas leak, then the chain of events described in the Bible could have been set into motion.”
It’s worth noting that Kling describes the color of Lake Nyos as “reddish-brownish,” while Jacobovici continually uses the term “blood-red.” I’m not really convinced that these are the same color, but that’s perhaps a useless aesthetic nitpick (“rust-red” and “blood-red” are both red because of iron).