Mapping the Deep

"Yes, it takes you into the science, and how oceanography is done. It explains how the sea floor and the currents were mapped out, and brings us up-to-date with the story of plate tectonics. Briefly, plate tectonics began to be understood properly in the 1960s. People looked the structure of the ocean crust, and the way that it gets younger towards the centre of the ocean ridges, and deduced that ocean crust must be forming even now as we speak. And as the ocean crust forms, it gradually slides apart and carries the continents with it. That really was a revolution in geology. Mapping the Deep is perhaps not quite as poetic as Rachel Carson’s book, but it is still wonderful. As a popular book on oceanography, it’s very hard to beat. People tried in the nineteenth century, by taking samples of the ocean bed systematically. But it was an awfully long and arduous business to do that. Later, after the second world war, people developed a picture of the ocean floor by bouncing sound waves off it. Through this technique, people then discovered the mid-ocean ridges. In turn, these ridges formed one major plank of evidence for plate tectonics. Much of this technology had initially been developed in the military for submarine tracking, but it was later used in civilian science. Another type of technology involved measuring the magnetism of rocks at a large scale simply by towing a magnetometer behind a ship or a plane. The Earth’s magnetism has flipped, with the North Pole becoming South, South becoming North, every million years or so. When this happens, stripes of different magnetism are formed in the ocean floor crust. Mapping out those stripes made people realise that the ocean crust was being progressively formed at the ocean ridges. For a brief while, people thought that the Earth must be expanding. Yes, lots. The history preserved in the oceans is not very long, so if you want to go back a billion years, then you have to go on land. For example, I spend a lot of time on the Silurian Period, which is about 400 million years ago. For that work, I have to travel to places like Wales, Scotland and Poland. “The sediment that piles up in the oceans tells beautiful, complete stories of the earth, and of the climate in particular.” But for the record of the last couple of hundred million years, and particularly the last hundred million years, the sediment that piles up in the oceans tells beautiful, complete stories of the earth, and of the climate in particular. A lot of our understanding of climate and how it works is derived from ocean sediments. We have also learned a lot from the oceans about animal species and evolution. Oh, I remember it vividly as if I were still there. I remember as a teenager opening National Geographic, and a folded map tumbled out. We were always used to seeing the oceans as just a pastel blue. And suddenly, you saw these mountain ranges, and fractures and cracks. You could see an entire ocean in front of you. It was, I think, for me and for many other people, a key moment in understanding what the Earth really is. Of course, we now know that those maps, beautifully constructed by the oceanographers Bruce Heezen and Mary Tharp, were in large part inspired guesses. But they got all the essentials right. Like Jules Verne, they conveyed a sense of mystery: in their case, the mystery of the oceans on a two-dimensional piece of paper."

"Of the five books that I chose, this is definitely the most scientific one. It’s written by Robert Kunzig, a former National Geographic writer, and it’s beautifully done. It’s about twenty years old, but it stands the test of time. Kunzig chronicles major discoveries in various areas of ocean science. There’s an excellent chapter on early attempts to map the ocean floor by satellite. In the Eighties, William Haxby, a scientist at Lamont-Doherty Earth Observatory in upstate New York, came up with a method to read the surface and the gravity of the ocean. From that, he was able to determine the general shape of the seafloor. This was a huge step forward in ocean mapping. Since then, researchers have made a lot of progress. Back when William Haxby was doing this, the resolution of ocean maps was not very good resolution, maybe over 20 kilometers or higher,. Today, we’re able to make maps that are about 4 kilometers in resolution. It’s an evolving science. To date, the most complete maps we have of the ocean floor are made by satellites, not by ocean mappers out at sea on ships. Kunzig’s book also contains wonderful writing on fascinating deep sea organisms that we’re still figuring out today. It’s a great primer on the various areas that are being researched in ocean science and provides a solid grounding on what scientists are exploring and the questions they’re asking about the ocean. My book is about Seabed 2030 , which is a new initiative to map the ocean by the end of this decade. The project started in 2017 when about 15 percent of the seafloor was mapped. Over the last six years it has brought that coverage up to 25 percent. It has made considerable progress, mainly by asking countries to share the ocean maps that are in their secret vaults, but it is still nowhere close to mapping the entire seafloor. My book also follows Cassie Bongiovanni—an ocean mapper who’s contributing to the Seabed 2030 project—on a private expedition with Victor Vascovo, a private equity investor turned ocean explorer. Vascovo wanted to dive the deepest points of all five oceans but no one knew where those points were, so he brought Bongiovanni on board to make the first maps of the deepest points. The book follows Cassie’s adventures and her maps into Seabed 2030 and we find out what happens to them, and then the book branches out from there to examine various aspects of how we’re discovering the deep sea. Yes. I hinted at the fact that there are secret map vaults. The geopolitics involved are very complicated. Currently, Seabed 2030 is trying to concentrate a lot of its efforts on the international sea floor (which constitutes about 50 percent of the ocean) because much of this territory has not yet been mapped, and as you move closer to shore, everything becomes more complicated. Many countries consider mapping within their waters to be spying, essentially. In some cases, they might be right. There are many questions about why people are making those maps and what they’re going to do with them. There are a lot of conspiracy theories floating around in this world. However, Seabed 2030 is a scientific effort. It was undertaken so that we might better understand the ocean and form a more complete outline of our planet – one that we’ve never had before."