Source: Oceans Deeply
Author: Paul Tullis
To date, only 5 percent of the sea floor has been mapped in detail, but an international consortium plans to map the rest over the next 13 years. The results could revolutionize our understanding of deep-sea biodiversity.
When a 9.1 – magnitude earthquake struck off the coast of Sumatra on December 26, 2004, a tsunami quickly formed, sending a wave as high as 80ft (24m) across the Indian Ocean that, along with the earthquake, killed more than 230,000 people.
But it wasn’t just the earthquake that propelled the finger of the highest wave: It was also the topography of the sea floor. For instance, along the Southwest Indian Ridge, a skinny contour of shallow water south and east of Madagascar, the 2004 tsunami was as high in some places as it was off the coast of India.
A better map of the seabed could lead to the ability to warn people where a tsunami will be biggest, potentially saving lives, and better tsunami prediction models are just one reason for an exceedingly ambitious new effort, launched in June, to map the entire sea floor by 2030. The resolution will vary by depth, but will generally be 328ft (100m). Just 5 percent of the ocean, which covers 71 percent of the Earth’s surface, is currently mapped in such detail. We know more about the topography of other planets’ moons than we do of our own ocean floor.
“There are so many uses for this data,” said Martin Jakobsson, professor of marine geology and geophysics at Stockholm University and head of its department of geological sciences. He is lead author of the roadmap for the Seabed 2030 project, initiated by the General Bathymetric Chart of the Oceans, an international organization under the International Hydrological Organization and the International Oceanographic Commission of UNESCO, funded in large part by the Nippon Foundation, a Japan-based nonprofit dedicated to social innovation.
Jakobsson’s work deals mainly with the marine cryosphere – ice sheets that extend into the ocean. Identifying sills along the coasts, which affect the flow of warmer water into coastal glaciers, will be one benefit of the new database. Other benefits include understanding circulation patterns that affect climate and tides, fisheries management, locating underwater hazards and a potential wealth of new information about the biodiversity of the largely unexplored deep sea.
“Mapping the seafloor is a great thing for science and can help conservation,” said Kristina M. Gjerde, senior high seas adviser for the Global Marine and Polar Programme at the International Union for the Conservation of Nature, source of the well-known “red list” of endangered species. “Often the places with the highest level of biological diversity are in places with a seamount or trench, where there are more currents and more nutrients. This will give us an idea of where to look for areas, including corridors for connectivity, where we can add protections.”