The Deepest Map: The High-Stakes Race to Chart the World’s Oceans

In this fascinating account, journalist Trethewey (Imperiled Ocean) details the quest to “finish a complete map of the world’s seafloor by the end of the next decade.” She profiles scientists, businessmen, and hobbyists working on the Seabed 2030 Project, an initiative spearheaded by a Japanese philanthropic organization that in 2017 set out to plot the bottom of the world’s oceans. The cast of characters includes Cassie Bongiovanni, a shy oceanographer recruited by private equity investor Victor Vescovo to locate some of the “deepest points on the entire planet” so that he might one day set the record for the deepest dive (he agreed to share the expedition’s findings with the 2030 Project), and Richard Jenkins, founder of the Saildrone company, which manufactures unmanned submersibles capable of scanning the ocean floor. The mapping process, Trethewey explains, is conducted with sonar that measures depth by recording how long it takes for a “ping” to travel from the device to the bottom of the ocean and back. Attempts to squish together the history of ocean mapping, the intricacies of oceanographic methods, and the possible consequences of the 2030 Project’s success (a boom in deep sea mining, for one) can make this feel overstuffed, but Trethewey’s sharp eye for character brings out the humanity in the marine moonshot. It’s worth exploring. (July)