A new map traces the shape of the ocean floor around Antarctica. Knowledge of the shape of the ocean floor is essential for safe navigation, marine conservation, and understanding the Earth’s climate and geological history.
Scientists have created the most accurate map ever made of the mountains, canyons and plains that make up the ocean floor around Antarctica.
Covering an area of 48 million square kilometers, this chart details for the first time a new deepest point – a 7,432-metre-deep depression called the Factorian Deep.
Knowledge of the shape of the ocean floor is essential for safe navigation, marine conservation, and understanding the Earth’s climate and geological history.
But there is still a lot to learn. Large tracts of land were never properly observed.
The International Bathymetric Table of the Southern Ocean (IBCSO) project took five years to create the first attempt at a comprehensive map, published in 2013.
IBCSO and other similar projects around the world are gradually filling in the gaps in our scarce knowledge of the world’s ocean floor.
Ships and boats are encouraged to routinely turn on their sonar devices to take depth measurements. Governments, companies and institutions are encouraged to share data and make as much of it public as possible. And this bears fruit.
The new map covers the area from the bottom of the Southern Ocean to 50 degrees south. If you divide 48 million square kilometers into squares of 500 m grids, 23% of these cells have passed at least one modern depth measurement. This is a huge improvement over nine years ago.
Previously, IBCSO started at 60 degrees south, where less than 17% of the grids had modern measurement.
“You have to understand exactly what the change from 60 degrees to 50 degrees means; we’ve more than doubled the area of the graph,” says Boris Dorschel of the Alfred Wegener Institute in Germany.
Image: IBCSO/AWI/NIPPON FOUNDATION/SEABED2030
“We’ve increased the coverage of the region, but also increased the data density as we continue to acquire new data,” he told BBC News.
Much of the information in the chart comes from icebreakers supporting scientific efforts in Antarctica, including Britain’s former polar ship RRS James Clark Ross. (In the future, this British contribution will come from his successor, RRS Sir David Attenborough, affectionately known as Boaty McBoatface.)
On voyages between the White Continent and countries such as Chile, South Africa, and Tasmania, echo sounders survey the underwater terrain below.
And this activity is increasingly coordinated with research organizations of different nationalities working together to slightly change the course of the icebreakers.
More detailed maps of the seafloor are needed for a variety of reasons.
They are essential for safe navigation but also for the management and protection of fisheries because it is in the vicinity of seamounts that marine fauna tend to congregate. Each seamount is a core of biodiversity.
In addition, the solid seafloor influences the behavior of ocean currents and vertical mixing of water. This is the information needed to develop models that predict future climate change – because it’s the oceans that play a key role in moving heat around the planet.
“We can also study how the Antarctic ice sheet has changed over thousands of years just by looking at the seafloor,” explains Rob Larter of the British Antarctic Survey.
“There is a record of where the ice flowed and where the grounding zones (places in contact with the seafloor) lie. This is beautifully preserved in the form of the seafloor.”
The new map was made possible with funding from the Nippon Foundation in Japan and the support of SeaBed2030, the international effort to map Earth’s ocean floor by the end of the decade.
Currently, our knowledge of four-fifths of the planet’s underwater terrain comes only from low-resolution satellite measurements that infer the presence of seamounts and deep valleys from the gravitational effect on the sea surface. The water accumulates on the mass of a large seamount and sinks slightly where there is a moat.
An important discovery between the first and second versions of the IBCSO is the recognition of the deepest point in the Southern Ocean. This is a depression called the Factorian Deep at the southern end of the South Sandwich Trench. It is located at a depth of 7,432 m. This was measured and visited in 2019 by Texas adventurer Victor Vescovo aboard the Limiting Factor submarine.
The remote and often inhospitable nature of the Southern Ocean makes it difficult to map key parts of the bed. There is great hope that an emerging robotic craft class will be able to fulfill this task in the coming years.
The Southern Ocean International Bathymetric Table has been published in Scientific Data.
source: Noticias
[author_name]
