THE DEEPEST MAP

An engrossing look at deep-sea exploration.

Mapping the ocean floor requires complex technology, politics, and patience, but it attracts brilliant scientists, entrepreneurs, and as many adventurous billionaires as space travel. Fortunately, it has also attracted journalist Trethewey, author of Imperiled Ocean. As she writes, the sentence, “We know more about the surface of the moon than we do about the bottom of the ocean…appears in almost every article you read about the deep sea nowadays.” Yet life exists at the deepest points throughout the world: “blown-out, flattened volcanoes known as guyots, mud volcanos spewing methane, underwater lakes known as brine pools that are so salty they are lethal to almost every life-form except a few microorganisms that might be analogues to the aliens we seek on distant planets.” One of the author’s main characters is Texas financier Victor Vescovo. Already featured in Susan Casey’s fine recent book, The Underworld, Vescovo has outfitted a research ship, commissioned a cutting-edge submersible, and proceeded to dive to the deepest points in all five oceans. Since no one knew precisely where those points were, a good deal of mapping occurred along with pioneering scientific experiments and hair-raising adventures, all of which Trethewey vividly recounts. Researchers yearn for an alternative to survey ships, which cost upward of $50,000 per day. Unmanned drones work fairly well, but they have not caught on. Crowdsourcing accounts recruit fishing vessels, luxury yachts, cruise ships, and commercial shippers that routinely use sonar depth finders to contribute to the effort, and experts are digging through industrial archives for soundings filed and forgotten. Mapping the seafloor will bring benefits, but Trethewey reminds readers that intrepid explorers who mapped the continents were followed by colonists who proceeded to “consume, exhaust, and extinguish” the resources and human cultures they found. The deep sea is a treasure of pure metals. Commercial deep-sea mining is about to begin, and the process is horrendously destructive.

Essential reading for environmentalists, armchair adventure divers, and those who care about the world’s oceans.