For eons, humans have looked at the surface of the ocean and wondered what is below. Not just within the water itself, but also at the deepest reaches of the seabed floor.
Until the 1950s, scientists assumed it was both dreary and featureless. But then sonar technology, perfected during the Second World War, changed everything.
Ships began dragging sonars on their journeys across the Atlantic Ocean, as well as dredgers and drills to take rock cores. All that data ended up at what is now known as the Lamont-Doherty Earth Observatory at Columbia University in New York, recorded into a ledger in India ink with crow-feather quill pens on blue linen pages.
Painstakingly, the mathematician Marie Tharp and a colleague began translating those data points into maps, eventually unearthing a controversial picture.
The ocean floor, they discovered, is not barren. It has breathtakingly complex topography. There are underwater volcanoes, deep rifts, trenches, mountain ranges. Nor is it made of the same stuff as the continents. It is thinner and younger.
These findings eventually proved a theory that changed our understanding of our planet: Continents move across the face of Earth on tectonic plates as ocean floor is dying and being born. Continents themselves are born and die. Today, using complex math, geophysicists can recreate land masses that have been absorbed into Earth’s mantle, ghosts of those that lived many millions of years ago.
The advances gave a far more accurate picture of the ocean floor, making navigation safer. But since then, efforts to map the topography of the sea have crawled ahead at a glacial pace. Today, less than a fifth is mapped and much of that has happened in the past few years. But, in honour of the United Nation’s Decade of Ocean Science, scientists have pledged to map the entire ocean floor for the first time by 2030 in the Nippon Foundation-GEBCO Seabed 2030 Project.