“What’s special is that it’s creating a phenomenon commonly known as the red tide that is reproducing and spreading on a frightening scale.”

“The charmed water burned away, a still and awful red,” Pitt quoted.

Sandecker flicked a glance at Gunn and then focused on Pitt. “You got the message.”

“But not the connection,” Pitt admitted.

“You men are all divers,” said Chapman, “so you probably know that red tide is caused by microscopic creatures called dinoflagellates, tiny organisms that contain a red pigment that gives the water a reddish-brown color when they proliferate and float in mass.”

Chapman pressed a button on the remote control box and continued lecturing as an image of a strange-looking microorganism flashed on the viewing screen. “Red tides have been recorded since ancient times. Moses supposedly turned the Nile to blood. Homer and Cicero also mentioned a red bloom in the sea, as did Darwin during the voyage in the Beagle. Outbreaks in modern times have occurred around the world. The most recent came off the west coast of Mexico after the water turned slimy and noxious. The resulting red tide caused the deaths of literally billions of fish, shellfish, and turtles. Even barnacles were wiped out. Beaches were closed for 200 miles and hundreds of natives and tourists died from eating fish that was contaminated by a species of deadly, toxin-containing dinoflagellates.”

“I’ve scuba dived in red tides,” said Pitt, “and suffered no ill effects.”

“Fortunately you swam through one of the many common, harmless varieties,” Chapman explained. “There is, however, a newly discovered mutant species that produces the most lethal biological toxins we’ve ever known. No sea life lives that comes in the slightest contact with it. A few grams of it if evenly dished out could put every human on the face of the earth in a cemetery.”

“That potent.”

Chapman nodded. “That potent…”

“And if the toxin isn’t bad enough,” added Sandecker, “the little critters consume themselves in an orgy of marine cannibalism that drastically decreases the oxygen in the water and causes any surviving fish and algae to suffocate.”

“It gets even worse,” Chapman carried on. “Seventy percent of all new oxygen is provided by diatoms, the tiny plant forms such as algae that live in the sea. The rest comes from vegetation on land. I see no need to enter into a lengthy discourse on how diatoms in the water or trees in the jungle manufacture oxygen through photosynthesis. You’ve all had that in elementary school. The smothering toxicity of the dinoflagellates as they cluster and bloom into a red tide kills the diatoms. No diatoms, no oxygen. The tragedy is we take oxygen for granted, never thinking that a slight imbalance of the amount created by plants and what we burn off in carbon dioxide could mean our last gasp.

“Any possibility they’ll eat themselves out of existence?” asked Giordino.