If a friend approached you and said, “hey, let’s talk about mapping the ocean floor,” you might (politely) yawn. Sounds kind of boring. But in the interest of comity, you make a countersuggestion: space exploration. Now, that’s interesting: Mars, Jupiter, Voyager, exoplanets. This may be a natural response, given pop culture’s adulation for space travel, but science writer Laura Trethewey would like a word.
Trethewey’s sharply written and entertaining new book, The Deepest Map, dives into the world of ocean mapping, and it’s not what you think. Remember those beautifully rendered National Geographic maps from the ‘60s, showing underwater mountains, plains and deep, virtually inaccessible, canyons. They’re more wishful thinking than accurate maps.
In reality, only around 25% of the ocean floor has been mapped, and much of that has been done in the past few years. A nonprofit called Seabed2030 is trying to finish the job by the end of the decade, but there’s a lot holding them back, and that’s where things get really interesting.
The book is littered with aha moments – things that make perfect sense, once you actually start thinking about them. For example, in the interest of national defense, countries zealously guard their coastlines’ underwater contours, making it challenging to map them.
Trethewey reveals a menagerie of real-life characters, playing sometimes outsized roles in this ocean mapping odyssey: a modern mapper, trying to get the best results in sometimes challenging circumstances; an occasionally altruistic billionaire explorer; a high-tech entrepreneur; an academic who could not advance because, woman. There are ocean scientists, passionate environmentalists and their equally passionate industry foes. Turns out, ocean mapping is a pretty dynamic niche.
Which leads us to ocean exploration’s dark underbelly. There’s a long history of terrestrial mapping that makes many people queasy about the ocean variety. Maps have long been a tool of conquest – once you map something, it’s easier to exploit.
Ocean mining interests want to scour the floor for manganese nodules and other materials. They maintain that the rare minerals they bring up are necessary for green technologies. They’re not wrong, but environmentalists point out that there are other, less damaging, ways to get there.
Miles deep in the ocean, there could be novel creatures and medicinal compounds, which mining could destroy before they are even discovered. Trethewey’s sentiments are quite clear on these points, but she doesn’t beat us over the head.
Another potential mining destination is hydrothermal vents, which harbor their own unique ecosystems. In the deep, dark ocean, organisms gather chemical energy from the vents, which may be how life originated on Earth. Projecting outward, these sites might provide clues for how life might develop on other worlds, such as Saturn’s moon, Enceladus. So, maybe there’s no real difference between ocean floor exploration and space travel.
I have no idea how Trethewey made ocean mapping interesting; I suppose years of legwork and deep commitment to the subject had something to do with it. Ultimately, it exposes an entire world that’s much larger than the world we already know. It’s like finding an unexplored mansion, hiding for years on your own property.