In 2017, an international team of experts from around the world, united under the non-profit General Bathymetric Chart of the Oceans (Gebco), launched the first effort to create a comprehensive map of the world’s oceans.
While the earliest oceanographers trawled waters one painstaking knot at a time, recent advances in sonar technology mean that a single ship can now provide thousands of square kilometers’ worth of high-resolution maps during an expedition.But the underwater discoveries that await aren’t only of interest to mapmakers or marine researchers. Far below the ocean’s surface lies buried treasure: precious metals, rare earth elements, oil and diamonds – riches that have, until now, remained inaccessible to even the most intrepid of prospectors.Some ecologists fear that a map of our sea floor will allow extractive industries the chance to profit from these resources, potentially endangering marine habitats and coastal communities in the process. A global bathymetric map – that is, a map of the ocean’s floor – would certainly offer a better understanding of our blue planet, but it also might plunge us into a realm once reserved for science fiction: robot submarines, underwater volcanoes, sea jewels, coral with pharmaceutical properties, Wild West maritime law, toxic sediment plumes, and an ocean-based enterprise curiously devoid of humans or ships. Once the map is made, will it be used as a tool for responsible management and conservation, or wielded like pirate’s bounty, a guidebook to extraction and exploitation?Only 15% of the Earth’s ocean is mapped. Zoom in on the middle of the Pacific in Google Earth, for example, and you’ll find a representation of the ocean floor based on satellite and gravity-derived bathymetry: low resolution, indirect, often inaccurate....More than 100 years later, Gebco and the Nippon Foundation formally announced Seabed 2030, a project that aims to map the entire sea floor by the year 2030 using data gathered from vessels around the world – including soundings from those early expeditions.Modern ships like the kind used in Seabed 2030 are now outfitted with multibeam bathymetry, sonar systems that emit sound waves in a fan shape beneath a ship’s hull. Each sonar ping measures the time it takes for a signal to reach the seafloor and return to the surface, a calculation of the water’s depth that can be marked as a coordinate on a grid.
http://www.bbc.com/f...the-ocean-floor